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data sheet rev. 1.00 / september 201 1 zssc312 3 clite ? capacitive sensor signal conditioner
zssc31 23 cl ite? c apacitiv e sensor signal conditione r ? 201 1 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c o ntained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publication is subject to changes without notice. brief description the ZSSC3123 clite? is a cmos integrated circuit for accurate capacitance - to - digital conversion and sensor - specific correction of capacit ive sensor sig - nals. digital compensation of sensor offset, sensiti - vity and temperature drift is accomplished via an internal digital signal processor running a correction algorithm with calibration coefficients stored in a non - volatile eeprom. the zssc31 23 is configurable for capacitive sen - sors with capacitances up to 260pf and a sensitivity of 125af/lsb to 1pf/lsb depending on resolu tion, speed, and range settings . it is compatible with both single capacitive sensors (both terminals must be accessible) and differential capacitive sensors. measured and corrected sensor values can be output as i 2 c ? * , spi, pdm, or alarms. the i 2 c? interface can be used for a simple pc - controlled calibration procedure to program a set of calibration coefficients into an on - chip eeprom. the calibrated ZSSC3123 and a specific sensor are mated digitally: fast, precise, and without the cost overhead of trimming by external devices or la ser. features ? maximum t arget input capacitance : 260pf ? sampling rates as fast as 0.7 ms @ 8 - bit; 1.6ms @ 10 - bit ; 5.0ms @ 12 - bit; 18.5ms @ 14 - bit ? digital compensation of sensor: piece - wise 1 st and 2 nd order sensor compensation or up to 3 rd order single - region sensor compensation ? digital compensation of 1 st and 2 nd order temperature gain and offset dr ift ? internal temperature compensation reference (no external components) ? programmable capacitance span and offset ? layout customized for die - die bonding with sensor for low - cost , high - density chip - on - board assembly ? accuracy ? 0.25 % fso@ - 40 to 125c, 3v, 5v, vsupply 10% * i 2 c? is a registered trademark of nxp. ? see data sheet section 1.3 for restrictions. benefits ? minimized calibration costs: no laser trimming, one - pass calibration using a digital interface ? wide capacitance range to support a broad portfolio of different sensor elements ? excellent for low - power battery applicati ons interfaces ? i2c ? or spi interface easy connection to a c ? pdm outputs (filtered analog ratiometric) for both capacitance and temperature ? up to two alarms that can act as full push - pull or open - drain switches physical characteristics ? supply voltage: 2.3v to 5.5v ? typical current consumption 650 a down to 60 a depending on configuration ? typical sleep mode current: 1 a at 8 5c ? operation temperature: C 40c to +125c ? die or tssop14 package available support ? ZSSC3123 ssc evaluation kit available: ssc evaluati on board, samples, software, documentation. ? support for industr ial mass calibration available. ? quick circuit customization option for large production volumes. application : digital output , alarms v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e r e a d y v s s s d a / m i s o s c l / s c l k c 0 s s a l a r m _ h i g h c c a l a r m _ l o w c l i t e ? z s s c 3 1 2 3 0 . 1 f
zssc31 23 cl ite? c apacitiv e sensor signal conditione r ? 201 1 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c o ntained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. clite? ZSSC3123 block diagram application : analog ou tput application : differential capacitance input part ordering codes sales code description package ZSSC3123aa1b ZSSC3123 clite? die temperature range: - 40c to +125c tested dice on un - sawn wafer ZSSC3123aa1c ZSSC3123 clite? die temperature range : - 40c to +125c tested dice on frame ZSSC3123aa2 ZSSC3123 clite? tssop14 temperature range: - 40c to +125c C lead - free package tube: add Dt to sales code reel: add Dr ZSSC3123kit ZSSC3123 ssc evaluation kit: communication board, ssc evaluation boa rd, sensor replacement board, evaluation software, usb cable, 5 ic samples kit sales and further information www.zmdi.com ssc@zmdi.com zentrum mikroelektronik dresden ag grenzstras se 28 01109 dresden germany zmd america, inc. 8413 excelsior drive suite 200 madison, wi 53717 usa zentrum mikroelektronik dresden ag, japan office 2nd floor, shinbashi tokyu bldg. 4 - 21 - 3, shinbashi, minato - ku tokyo, 105 - 0004 japan zmd far east, ltd. 3f, n o. 51, sec. 2, keelung road 11052 taipei taiwan zentrum mikroelektronik dresden ag, korean office posco centre building west tower, 11th floor 892 daechi, 4 - dong, kangnam - gu seoul, 135 - 777 korea phone +49.351.8822.7.772 fax +49.351.8822.8.7772 phone +1 .608.829.1987 fax +1.608.829.2984 phone +81.3.6895.7410 fax +81.3.6895.7301 phone +886.2.2377.8189 fax +886.2.2377.8199 phone +82.2.559.0660 fax +82.2.559.0700 disclaimer : this information applies to a product under development. its characteristics and s pecifications are subject to change without notice. zentrum mikroelektronik dresden ag (zmd ag) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. the information furnished hereby is believed to be true and accurate. however, under no circumstances shall zmd ag be liable to any customer, licensee, or any other third party for any special, indirect, incide ntal, or consequential damages of any kind or nature whatsoever arising out of or in any way related to the furnishi ng, performance, or use of this technical data. zmd ag hereby expressly disclaims any liability of zmd ag to any customer, li censee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of zmd ag fo r any damages in connection with or arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability , or otherwise. z s s c 3 1 2 3 c l i t e ? c a p a c i t i v e s e n s o r s i g n a l c o n d i t i o n e r d i g i t a l c o r e a n a l o g c o r e s e n s o r c 0 c 1 ( o p t i o n a l ) o u t p u t c o m m u n i c a t i o n m u x c 0 c c c 1 v s s v d d ( 2 . 3 t o 5 . 5 v ) t e m p s e n s o r c l k / r e s e t c / a d c d c r e f c a p o f f s e t c a p s c l / s c l k s d a / m i s o r e a d y / p d m _ c a l a r m _ l o w / p d m _ t s s a l a r m _ h i g h r e a d y p d m i 2 c / s p i l o w a l a r m h i g h a l a r m e e p r o m r o m d s p 0 . 1 f 0 . 1 f v c o r e v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e r e a d y v s s s d a / m i s o s c l / s c l k c 0 s s a l a r m _ h i g h c 1 a l a r m _ l o w c l i t e ? z s s c 3 1 2 3 0 . 1 f c c v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e v s s c 0 c c c l i t e ? z s s c 3 1 2 3 0 . 1 f c a p . a n a l o g o u t p u t l e d p d m _ c p d m _ t a l a r m _ h i g h t e m p a n a l o g o u t p u t
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 4 of 67 contents 1 ic characteristics ................................ ................................ ................................ ................. 8 1.1 absolute maximum ratings ................................ ................................ ............................ 8 1.2 operating conditions ................................ ................................ ................................ ...... 8 1.3 electrical parameters ................................ ................................ ................................ ...... 9 1.4 current consumption graphs ................................ ................................ ....................... 12 1.4.1 update mode current consumption ................................ ................................ ........ 12 1.4.2 sleep mode current consumption ................................ ................................ ........... 12 1.5 output pad dr ive strength ................................ ................................ ............................ 13 1.6 temperature sensor nonlinearity ................................ ................................ ................. 14 2 circuit description ................................ ................................ ................................ .............. 15 2.1 signal flow and block diagram ................................ ................................ .................... 15 2.2 analog front en d ................................ ................................ ................................ .......... 15 2.2.1 capacitance - to - digital converter ................................ ................................ ............. 15 2.2.2 temperature measurement ................................ ................................ ..................... 21 2.3 digital core ................................ ................................ ................................ ................... 22 3 normal operation mode ................................ ................................ ................................ ..... 22 3.1 power - on sequence ................................ ................................ ................................ ..... 24 3.2 measurement cycle ................................ ................................ ................................ ...... 24 3.3 measurement modes ................................ ................................ ................................ .... 25 3.3.1 update mode ................................ ................................ ................................ ........... 25 3.3.2 sleep mode ................................ ................................ ................................ ............. 29 3.4 status and diagnostics ................................ ................................ ................................ . 31 3.4.1 eeprom error detection and correction ................................ ................................ 32 3.4.2 alarm diagnostics ................................ ................................ ................................ .... 33 3.5 output modes ................................ ................................ ................................ ............... 33 3.6 i 2 c a nd spi ................................ ................................ ................................ ................... 33 3.6.1 i 2 c features and timing ................................ ................................ .......................... 34 3.6.2 spi features and timing ................................ ................................ ......................... 35 3.6.3 i 2 c and spi commands ................................ ................................ ........................... 36 3.6.4 data fetch (df) ................................ ................................ ................................ ....... 36
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 5 of 67 3.6.5 measurement request (mr) ................................ ................................ ................... 38 3.6.6 ready pin ................................ ................................ ................................ ................ 39 3.7 pdm (pulse density modulation) ................................ ................................ .................. 39 3.8 alarm output ................................ ................................ ................................ ................. 41 3.8.1 alarm registers ................................ ................................ ................................ ....... 41 3.8.2 alarm operation ................................ ................................ ................................ ....... 41 3.8.3 alarm output configuration ................................ ................................ ..................... 43 3.8.4 alarm polarity ................................ ................................ ................................ .......... 43 4 command mode ................................ ................................ ................................ ................. 44 4.1 command format ................................ ................................ ................................ ......... 44 4.2 command encodings ................................ ................................ ................................ .... 44 4.3 command response and data fetch ................................ ................................ ........... 46 5 eeprom ................................ ................................ ................................ ............................ 49 5.1.1 zmdi configuration register (zmdi_confi g, eeprom word 02 hex ) ...................... 51 5.1.2 capacitance analog front end configuration (c_config, eeprom word 06 hex ) ... 52 5.1.3 temperature analog front end configuration (t_config, eeprom word 11 hex ) .. 53 5.1.4 customer configuration register (cust_config, eeprom word 1c hex ) ................ 54 6 calibration and signal conditioning math ................................ ................................ ........... 55 6.1 capacitance signal conditioning ................................ ................................ .................. 55 6.2 temperature signal compensation ................................ ................................ .............. 57 6.3 limits on coefficient ranges ................................ ................................ ........................ 58 7 application circuit examples ................................ ................................ .............................. 59 7.1 digital output with optional alarms ................................ ................................ .............. 59 7.2 analog output with optional alarms ................................ ................................ ............. 60 7.3 bang - bang control system ................................ ................................ ............................ 61 7.4 differential input capacitance ................................ ................................ ....................... 62 7.5 external refere nce capacitor ................................ ................................ ....................... 63 8 esd/latch - up - protection ................................ ................................ ................................ ... 63 9 pin configuration and package ................................ ................................ .......................... 64 10 test ................................ ................................ ................................ ................................ ..... 65
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 6 of 67 11 reliability ................................ ................................ ................................ ............................ 66 12 customiz ation ................................ ................................ ................................ ..................... 66 13 part ordering codes ................................ ................................ ................................ ........... 66 14 related documents ................................ ................................ ................................ ............ 66 15 glossary ................................ ................................ ................................ ............................. 66 16 document revision history ................................ ................................ ................................ 67 list of figures figure 1.1 best case settings (typical part) ................................ ................................ ................................ ........ 12 figure 1.2 worst case settings (typical part) ................................ ................................ ................................ ..... 12 figure 1.3 typical current consumption during sleep mode (no measurements) ................................ .............. 12 figure 1.4 output high drive strength graph ................................ ................................ ................................ ...... 13 figure 1.5 output low drive strength graph ................................ ................................ ................................ ....... 13 figure 1.6 first order fit (typical part) ................................ ................................ ................................ ................ 14 figure 1.7 second order fit (typical part) ................................ ................................ ................................ ........... 14 figure 2 .1 ZSSC3123 block diagram ................................ ................................ ................................ ................... 15 figure 3.1 general operation ................................ ................................ ................................ ............................... 23 figure 3.2 power - on sequence with fast startup bit set in eeprom ................................ ............................... 24 figure 3.3 measurement cycle timing ................................ ................................ ................................ ................ 25 figure 3.4 measurement sequence in update mode ................................ ................................ ........................... 26 figure 3.5 i 2 c and spi data fetching in update mode ................................ ................................ ........................ 29 figure 3.6 measurement sequence in sleep mode (only i 2 c, spi, or alarms) ................................ ................... 30 figure 3.7 i 2 c and spi data fetching in sleep mode ................................ ................................ ........................... 31 figure 3.8 i 2 c timing diagram ................................ ................................ ................................ ............................. 34 figure 3.9 spi timing diagram ................................ ................................ ................................ ............................. 35 figure 3.10 i 2 c measurement packet reads ................................ ................................ ................................ ......... 37 figure 3.11 spi output packet with positive edge sampling ................................ ................................ ................. 38 figure 3.12 i 2 c mr ................................ ................................ ................................ ................................ .................. 38 figure 3.13 spi mr ................................ ................................ ................................ ................................ ................. 39 figure 3.14 example of alarm function ................................ ................................ ................................ .................. 42 figure 3.15 alarm output flow chart ................................ ................................ ................................ ..................... 42 figure 4.1 i 2 c command format ................................ ................................ ................................ .......................... 44 figure 4.2 command mode data fetch ................................ ................................ ................................ ................ 47 figure 7.1 digital output with optional alarms example ................................ ................................ ...................... 59 figure 7.2 analog output with optional alarms example ................................ ................................ ..................... 60 figure 7.3 bang - bang control system example ................................ ................................ ................................ .. 61 figure 7.4 differential input capacitance example ................................ ................................ .............................. 62 fi gure 7.5 ext. reference input capacitance example ................................ ................................ ........................ 63
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 7 of 67 figure 9.1 ZSSC3123 pin - out diagram ................................ ................................ ................................ ............... 64 list of tables table 2.1 cdc multiplier ................................ ................................ ................................ ................................ ...... 18 table 2.2 selection settings for c ref , and c off , and mult (capacitance ranges are nominal values) ............... 19 table 3.1 cdc resolution and conversion times ................................ ................................ .............................. 25 table 3.2 update rate settings ................................ ................................ ................................ .......................... 26 table 3.3 time periods between capacitance measurements and temperature measurements for different mult, resolution and update ra tes ................................ ................................ ................................ ..... 27 table 3.4 status table ................................ ................................ ................................ ................................ ......... 32 table 3.5 diagnostic detection ................................ ................................ ................................ ............................ 32 table 3.6 normal operat ion diagnostic table ................................ ................................ ................................ .... 32 table 3.7 output modes ................................ ................................ ................................ ................................ ...... 33 table 3.8 pin assignment for output selections ................................ ................................ ................................ . 33 table 3.9 i 2 c parameters ................................ ................................ ................................ ................................ .... 34 table 3.10 spi parameters ................................ ................................ ................................ ................................ .... 35 table 3.11 i 2 c and spi command types ................................ ................................ ................................ .............. 36 table 3.12 low pass filter example for r = 10k ? ................................ ................................ ................................ 40 table 4.1 command list and encodings ................................ ................................ ................................ ............. 45 table 4.2 respons e bits ................................ ................................ ................................ ................................ ...... 48 table 4.3 command diagnostic bits ................................ ................................ ................................ .................. 48 table 5.1 eeprom word assignments ................................ ................................ ................................ .............. 49 table 5.2 zmdi_config bit assignments ................................ ................................ ................................ ............. 51 table 5.3 c_config bit assignments ................................ ................................ ................................ ................... 52 table 5.4 t_config bit assignments ................................ ................................ ................................ ................... 53 table 5.5 cust_config bit assignments ................................ ................................ ................................ .............. 54 table 7.1 example 1: configuration settings ................................ ................................ ................................ ...... 59 table 7.2 example 2: configuration settings ................................ ................................ ................................ ...... 60 table 7.3 example 3: configuration settings ................................ ................................ ................................ ...... 61 table 7.4 example 4: configuration settings ................................ ................................ ................................ ...... 62 table 7.5 example 5: configuration settings ................................ ................................ ................................ ...... 63 table 9.1 storage and soldering condition ................................ ................................ ................................ ......... 64 table 9.2 ZSSC3123 pin assignments for tssop - 14 ................................ ................................ ........................ 64
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 8 of 67 1 ic characteristics 1.1 absolute maximu m ratings parameter symbol min typ max units analog supply voltage v dd - 0.3 6.0 v voltages at analog i/o C in pin v ina - 0.3 v dd +0.3 v voltages at analog i/o C out pin v outa - 0.3 v dd +0.3 v storage temperature range t stor - 5 5 150 c 1.2 operating condi tions see important footnotes at the end of the following table. parameter symbol min typ max units supply voltage to gnd v supply 2.3 5.5 v ambient temperature range 1 t amb - 40 125 ? c output pads/pins drive strength 2 i out 1.5 20 ma external capacit ance between v dd pin and gnd c vsupply 100 220 470 nf external capacitance between vcore and gnd sleep mode c vcore_sm 10 110 nf external capacitance between vcore and gnd update mode c vcore_um 90 330 nf input capacitance span (full scale values) c 0 2 260 pf external reference capacitance c 1 2 260 pf external isolating capacitance (mult1) ? (cc pin to sensor common node) 3 c cc 16 pf i 2 c pull - up resistor 2 r pu 1 2.2 k ? sda/miso load capacitance c sda 200 pf 1 caution: if buying die, select t he proper package to ensure that the maximum junction temperature is not exceeded. 2 see section 1.5 for full details on output pad drive strengths. 3 an external isolating capacitor allows a non - galvanic conn ection to special differential or external reference sensor types. ccc could also be used to lower the overall capacitance level to a value that is supported by the ZSSC3123 because it limits the maximum capacitance seen by the ZSSC3123 input to cc even if c0 and c1 have higher values. ? the series combination of sensor and cc must not exceed the maximum capacitance allowed for the chosen mult setting.
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 9 of 67 1.3 electrical parameters see important footnotes at the end of the following table. parameter symbol conditions min typ max units supply current update mode current (varies with part configuration ) 1 i dd best case settings : * mult 1, 8 - bit, 125ms power down 6 0 100 a worst case settings : mult 1, 14 - bit, 0ms power down 7 50 11 00 extra current with pdm enabled * i pdm 150 a sleep mode current 1 i sleep - 40 to 85c 0. 6 1 a - 40 to 125c 1 3 a voltage levels power - on - reset level v por 1. 6 1. 7 2.2 v acti ve regulated v oltage v reg note: regulated voltage can be measured on the vcore pin. 2. 4 2.5 5 2.7 v capacitance - to - digital converter (cdc) resolution r es cdc 8 14 bits excitation frequency of external capacitances c 0 and c 1 (for a s ystem f requency f sys ) f exc f sys /2 khz integral nonlinearity (inl) 2 inl cdc mult 1, 10% to 90% input , 14 - bit 0.2 % differential nonlinearity (dnl) * dnl cdc mult 1, 10% to 90% input , 14 - bit 0.9 lsb eeprom number of erase/write cycles n wri_eep @85 ? c 100k data retention t wri_eep @100 ? c 10 y ear temperature conversion resolution in c * r es temp - 40 to 125c, 8 - bit mode 0.64 0.96 1.6 c - 40 to 125c, 14 - bit mode 0.01 0.015 0.025 nonlinearity first order fit * , 3 inl cdc - 40 to 125c 0.5 1 c nonlinearity second order fit * , 4 inl cdc - 40 to 125c 0.2 0.4 c
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 10 of 67 parameter symbol conditions min typ max units voltage dependency * psr temp v supply > v reg +0.25v 0.03 0.1 c/v 2.3v v supply v reg + 0.25v 1.25 2.25 pdm output output range * v pdm_range 10 90 %v supply pdm f requen cy f pdm f sys /8 khz filter settling time * , 5 t sett 0% to 90% lpfilter 10k ? /400nf 9.2 ms ripple * , 5 v ripp 0% to 90% lpfilter 10k ? /400nf 1 .0 mv/v pdm additional error (including ratiometricity error) * e pdm - 40 to 125 ? c 0.1 0.5 % digital i/o vo ltage output level low v ol 0 0.2 v supply voltage output level high v oh 0.8 1 v supply voltage input level low v il 0 0.2 v supply voltage input level high v ih 0.8 1 v supply communication pin input capacitance * c in 10 pf total system capaciti ve tolerance between parts * c tol all capacitive values in the specification are subject to this variation 10 % trimmed system frequency f sys all timing in this specification is subject to this variation. 1.76 1.85 1.94 mhz frequency variation over vo ltage and temperature f var all timing in this specification is subject to this variation. 10 % start - up - time * , 6, 7 power - on (por) to data ready t sta fastest and slowest settings 4.25 55 ms update rate (update mode) * , 6, 7 t resp_up fastest and slow est settings 0.70 165 ms response time (sleep mode) * , 6, 7 t resp_sl fastest and slowest settings 1.25 45 ms parasitic to gnd tolerance including package parasitics (pins c0, cc, and c1) * mult 1 10 pf mult 2 20 mult 4 40 mult 8 80 peak - to - peak noise @ output (100 measurements in 14 bit) * n out mult 1, 2, 4, 8 5 20 lsb
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 11 of 67 parameter symbol conditions min typ max units accuracy err or mult 1, - 40 to 125c * , 8, 9,10 ae out 3v ? 10%, 3.3v ? 10%, 5v ? 10% 0.25 0.75 %fso 2.5v ? 10% 0.50 1.25 mult 2, 4, 8, - 40 to 125c * , 8, 9, 10 ae out 3v ? 10%, 3.3v ? 10%, 5v ? 10% 0.50 1.25 %fso 2.5v ? 10% 1.50 3.00 * parameter not tested during production but guaranteed by design. 1 see section 1.4 for full details for current consumption in each mode. 2 parameter measured using internal test capacitors (0pf to 7pf in mult 1). 3 assumes optimal calibration points of 0 c and 100 c; see section 1.6 for more details. 4 assumes optimal calibration points of - 20 c, 40 c and 100 c; see section 1.6 for more details. 5 see section 3.7 for more details . 6 see section 3 for more det ails. 7 timing values are for a nominal oscillator, for worst case, 10% total frequency variation, multiply by 0.9 (min time) or 1.1 (max time). 8 accuracy specification includes a 2 - point temperature calibration for correcting the internal tc. 9 accuracy specification assumes maximum parasitics of 10pf to ground. 10 accuracy specification does not include pdm errors, see the pdm output electrical parameters for additional errors when using pdm.
zssc31 23 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 12 of 67 1.4 current consumption graphs part current consumption depends on a number of different factors including voltage, temperature, capacitive input, mult, r e solution, and power down time. the best way to calculate the ZSSC3123 s power consumption is to measure the current consumption wi th the actual setup. if measuremen t is not possible, then the graphs in this section can provide a starting point for estimating the current consumption. 1.4.1 update mode current consumption figure 1 . 1 best case settings (typical part) figure 1 . 2 worst case settings (typical part) 1.4.2 sleep mode current consumption figure 1 . 3 typical current consumption during sleep mode ( no measurements )
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 13 of 67 1.5 output pad drive strength figure 1 . 4 output high drive strength graph figure 1 . 5 output low drive strength graph 20ma max. allowed 0 20 1.8 2.3 2.8 3.3 3.8 4.3 4.8 5.3 vsupply (v) output high drive strength (ma) , cold / best case hot / worst case typical 20ma max. allowed 0 20 1.8 2.3 2.8 3.3 3.8 4.3 4.8 5.3 vsupply (v) output low drive strength (ma) , cold / best case hot / worst case typical
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 14 of 67 1.6 temperature sensor nonlinearity temperature sens or nonlinearity can vary depending on the type of calibration and the selected calibration points . it is highly recommended that a temperature calibration is done with calibration points at least 20 c apart from each other. figure 1 . 6 and figure 1 . 7 show the resulting nonlinearity error for the full temperature range ( - 40c to 125c) using the optimal calibration points , 0c and 100c for a first - order fit and - 20c, 40c, a nd 100c for a second - order fit. figure 1 . 6 first order fit (typical part) figure 1 . 7 second order fit (typical part) temperature error -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 -50 0 50 100 150 temperature (c) error (c) 2.5v 3v 5v temperature error -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 -50 0 50 100 150 temperature (c) error (c) 2.5v 3v 5v
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 15 of 67 2 circuit description 2.1 signal flow an d block diagram as seen in figure 2 . 1 , the ZSSC3123 comprises three main blocks: the analog core, digital core, and output communication. the capacitive input is first sampled by the analog core using a charge - bala ncing cdc and is adjusted for the appropriate capaci tance range using the cdc_o ffset, and cdc_r eference, and cdc_ m ult settings. the digital core corrects the digital sample with an on - chip digital signal processor (dsp), which uses coefficients stored in e eprom for precise conditioning. an internal temperature sensor can be used to compensate for temperature effects of the capacitive input. a temperature value can also be calibrated and output as a 14 - bit reading. the corrected capacitance value can be read using four different output types, i 2 c, spi, pdm, and alarms. they can all be directly interfaced with a microcontroller, and optional filtering of the pdm output can provide a ratiometric analog output. the alarm pins can also be used to control a variet y of analog circuitry. figure 2 . 1 ZSSC3123 block diagram 2.2 analog front end 2.2.1 capacitance - to - digital converter a 1 st order charge - balancing capacitance - to - digital converter (cdc) is used to convert the in put capacitance to the digital domain. the cdc uses a chopper - stabilized design to decrease any drift over temperature. the cdc interfaces to the sensor capacitor through the input multiplexer that controls whether the measurement is a capacitance or a tem perature measurement. the input multiplexer also allows for two sensor capacitance configurations: a single sensor capacitance or a ratio based differential capacitive sensor , two - sensor, capacitor configuration , where the reference capacitor is part of th e sensor. as part of a switched - capacitor network the z s s c 3 1 2 3 c l i t e ? l o w v o l t a g e c a p a c i t i v e s e n s o r s i g n a l c o n d i t i o n e r d i g i t a l c o r e a n a l o g c o r e s e n s o r c 0 c 1 ( o p t i o n a l ) o u t p u t c o m m u n i c a t i o n m u x c 0 c c c 1 v s s v d d ( 2 . 3 v t o 5 . 5 v ) t e m p s e n s o r c l k / r e s e t c / a d c d c r e f c a p o f f s e t c a p s c l / s c l k s d a / m i s o r e a d y / p d m _ c a l a r m _ l o w / p d m _ t s s a l a r m _ h i g h r e a d y p d m i 2 c / s p i l o w a l a r m h i g h a l a r m e e p r o m r o m d s p 0 . 1 f 0 . 1 f v c o r e
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 16 of 67 reference capacitor c 1 is driven by a square wave voltage of the frequency f exc (refer to section 1.3 ). the sensor capacitance c 0 is not exposed to dc voltag es in order to prevent aging effects of some sen sor types. the c on - figuration of the cdc is controlled by programming settings in eeprom word c_config. (see table 5 . 3 for settings.) 2.2.1.1. single ended in the case of a si ngle - sensor capacitor, the cdc output is proportional to the ratio of the sensor capacitor to an internal reference capacitor ( c ref ). this internal reference capacitor value can be adjusted using the 3 - bit trim cdc_reference and a 2 - bit range selection cdc _mult ( bit setting s in table 5 . 3 ) . to optimize the measured end - resolution further, another internal capacitor ( c off ) allows the subtraction of a defined offset capacitance using the 3 - bit trim cdc_offset ( bit sett ing in table 5 . 3 ). equation s (1) to (2) describe the cdc output for a single sensor capacitance measurement. select the valu es of c mult, cdc_offset, and cdc_reference by using the tables in section 2.2.1.4 . (1) (2) with (3) a nd (4) w here : symbol description z sensor measured sensor ratio, must be in the range [0 to 1] c 0 input sensor capaci tance c off zero shift of cdc c ref reference capacitance z cdc digital raw converted capacitance value res programmable cdc resolution of 8, 10, 12, or 14 bits ( bit setting in table 5 . 3 ) c mult capacitance range multiplier (see table 2 . 1 ) cdc_offset cdc offset trim setting (selection see section 2.2.1.4 and bit setting see table 5 . 3 ) cdc_reference cdc reference setting (selection see section 2.2.1.4 and bit setting see table 5 . 3 ) sensor res c cd z 2 z ? ? ref off 0 sensor c ) c c ( z ? ? pf 1 offset _ cdc 44 . 1 c off ? ? ? pf 1 reference _ cdc 44 . 1 c ref ? ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 17 of 67 2.2.1.2. single ended with external reference some sensors include an external reference capacitor a s part of the sensor construction. if the external reference capacitance ( c 1 ) is constant or increases with increasing input sensor capacitance ( c 0 ) , the n use cdc output equation s (5) to (7 ) . in this case the cdc_reference should be set to zero (bit setting in table 5 . 3 ) . (5) (6) (7) w here symbol description z sensor measured sensor ratio, must be in the range [0 to 1] c 0 input sensor capacitance c off zero shift of cdc c 1 external reference capacitance z cdc digital raw converted capacitance value res programmable cdc resolution of 8, 10, 12, or 14 bits ( bit setting in table 5 . 3 ) c mult capacitance range mult iplier (see table 2 . 1 ) cdc_offset cdc offset trim setting (selection see section 2.2.1.4 and bit setting see table 5 . 3 ) 2.2.1.3. diff erential a differential capacitive sensor includes two capacitors c 0 and c 1 that are captured as a ratio. the differential sensor is built so that the sensor input capacitance c 0 increases while the external reference capacitance c 1 decreas es over the inpu t signal range , but the total sum always remains constant. equations describe the cdc output for a differential sensor capacitance measurement. t he cdc_reference and cdc_offset capacitor trim bits need to be set to zero, and t he differential bit needs to b e set to one. (see table 5 . 3 for bit numbers and settings). the mult bits should be set so that the total capacitance (c 0 + c 1 ) falls in the corresponding capacitance range (see table 2 . 1 ). the sum of c 0 and c 1 must not be bigg er than the selected m ults maximum input range , except when cc is used as a dec o upling capacitor. in differential mode special sensor types can allow a non - galvanic connection with a n external isolat ing capacitor c cc between the sensor and the cc pin to avoid wear caused by mechanical moving parts . 1 off 0 sensor c ) c c ( z ? ? sensor res c cd z 2 z ? ? pf 1 offset _ cdc 44 . 1 c off ? ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 18 of 67 (8) (9) symbol description z sensor measured sensor ratio, must be in the range [0 to 1] c 0 input sensor capacitance (moves in the opposite direction of c 1 ) c 1 external reference capacitance (moves in the opposite direction of c 0 ) z cdc digital raw converted capacitance value res programmable cdc resolution of 8, 10, 12, or 14 bits ( bit setting in table 5 . 3 ) 2.2.1.4. capaci tive range selection for either single - ended or differential sensor s, the correct capacitance range must be selected using the mult bits as seen in table 2 . 1 . (see table 5 . 3 for bit numbers). if using a single - ended sensor, then the minimum and maximum capacitance inputs should fall into the specified ranges. if using a differential sensor then the total capacitance ( c 0 + c 1 ) must fall into this range. the mult range affects the conversion time (see section 3.2 ) note: if the range is set to a lower input value and a higher input capacitance value is applied , the output can come back into range. the limit is about 500% of the selec ted maximum input value, e.g. for capacitance setting mult1, cdc_of fset at zero and cdc_reference at 7, an input value above 117pf will give a non - saturated input value. table 2 . 1 cdc multiplier eeprom encodi ng (cdc_mult) frequency multiplier (mult) reference multiplier total capacitance multiplier (c mult ) capacitance range (full scale values) 00 b 1 1.44 1.44 2pf to 8pf 01 b 2 2.88 5.76 8pf to 32pf 10 b 4 5.76 23.04 32pf to 130pf 11 b 8 11.52 92.16 130pf to 2 60pf ? ? 1 0 0 sensor c c c z ? ? sensor res cdc z 2 z ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 19 of 67 for singled ended sensors u se table 2 . 2 as guidance to select appropriate values for the cdc ( c off ) and ( c ref ) for a particular capacitance input range. the cdc_offset and cdc_reference bits are found in eepr om word c_config. (see table 5 . 3 for bit numbers ) . using table 2 . 2 , the cdc input range can be adjusted to optim ize the coverage of the sensor signal and offset values to give the maximum sensor span that can be pro cessed without losing resolution. choose a range by fitting the input sensor span within the narrowest range in the table , but note that these tables are only approximate, so the range should be experimentally c hosen with the actual setup. also n ote that since internal capacitance values can vary over process (see spec parameter c tol in section 1.3 ), the min imum and max imum sensor span should be at least 10% within th e min and max of the chosen range respectively. in addition, be awar e of the effects of parasitics; i f the parasitics for a particular m ult range exceed the parasitic to ground tolerance given in section 1.3 , th en the next mult range should be considered since the cdc frequency is reduced by the mult factor. note: a c ref setting of 0 (marked with * in the following tables) is only supported with an external reference capacitor (c1) for single - ended sensors. c1 ca pacitance values should be within the defined range f or each mult setting. table 2 . 2 selection settings for c ref , and c off , and m ult ( c apacitance ranges are nominal values ) (a) mult 1: sensor capacitors rangi ng from 2pf to 10 pf (full scale values) production caused tolerances can change the nominal capacitance values by ? 10% 0 0.0 c1 0.0 1.4 0.0 2.9 0.0 4.3 0.0 5.8 0.0 7.2 0.0 8.6 0.0 10.1 1 1.4 c1 1.4 2.9 1.4 4.3 1.4 5.8 1.4 7.2 1.4 8.6 1.4 10.1 1.4 11.5 2 2.9 c1 2.9 4.3 2.9 5.8 2.9 7.2 2.9 8.6 2.9 10.1 2.9 11.5 2.9 13.0 3 4.3 c1 4.3 5.8 4.3 7.2 4.3 8.6 4.3 10.1 4.3 11.5 4.3 13.0 4.3 14.4 4 5.8 c1 5.8 7.2 5.8 8.6 5.8 10.1 5.8 11.5 5.8 13.0 5.8 14.4 5.8 15.8 5 7.2 c1 7.2 8.6 7.2 10.1 7.2 11.5 6 8.6 c1 8.6 10.1 8.6 11.5 8.6 13.0 7 10.1 c1 10.1 11.5 10.1 13.0 10.1 14.4 3 4 5 6 7 cdc_offset not recommended prohibited cdc_reference 3-bit set 0* 1 2
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 20 of 67 (b) mult 2: sensor capacitors ranging from 8pf to 32pf (full scale values) (c) mult 4: sensor capacitors ranging from 32pf to 130pf (full scale values) (d) mult 8: sensor capacitors ranging from 130pf to 260pf (full scale values) 1 0 0.0 c1 0.0 5.8 0.0 11.5 0.0 17.3 0.0 23.0 0.0 28.8 0.0 34.6 0.0 40.3 1 5.8 c1 5.8 11.5 5.8 17.3 5.8 23.0 5.8 28.8 5.8 34.6 5.8 40.3 2 11.5 c1 11.5 17.3 11.5 23.0 11.5 28.8 11.5 34.6 11.5 40.3 3 17.3 c1 17.3 23.0 17.3 28.8 17.3 34.6 17.3 40.3 4 23.0 c1 23.0 28.8 23.0 34.6 23.0 40.3 5 28.8 c1 28.8 34.6 28.8 40.3 6 34.6 c1 34.6 40.3 7 cdc_offset cdc_reference 3-bit set 7 not recommended 2 3 4 5 6 prohibited 0* 1 0 0.0 c1 0.0 23.0 0.0 46.1 0.0 69.1 0.0 92.2 0.0 115.2 0.0 138.2 0.0 161.3 1 23.0 c1 23.0 46.1 23.0 69.1 23.0 92.2 23.0 115.2 23.0 138.2 23.0 161.3 2 46.1 c1 46.1 69.1 46.1 92.2 46.1 115.2 46.1 138.2 46.1 161.3 3 69.1 c1 69.1 92.2 69.1 115.2 69.1 138.2 69.1 161.3 4 92.2 c1 92.2 115.2 92.2 138.2 92.2 161.3 5 115.2 c1 115.2 138.2 115.2 161.3 6 138.2 c1 138.2 161.3 7 not recommended 2 3 4 5 prohibited 0* 3-bit set cdc_offset cdc_reference 6 7 1 0 0.0 c1 0.0 92.2 0.0 184.3 0.0 276.5 1 92.2 c1 92.2 184.3 92.2 276.5 2 184.3 c1 184.3 276.5 3 4 5 6 7 not recommended 3-bit set cdc_offset cdc_reference 7 0* 2 3 4 5 6 prohibited
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 21 of 67 2.2.2 temperature measurement the temperature signal comes from an internal ptat (proportional to absolute temperature) circuit that is a meas - ure of the die temperature. the ptat ( v ptat ) voltage is used in the cdc to charge an internal cap acitor ( c t ), while the bandgap voltage (v bg ) is used to charge the offset and the reference trimmable capacitors. the cdc temperature output (z temp ) is defined by equation s (1 0) to (13) : (10) with (11) with (12) a nd (13) symbol description z temp measured internal temperature res programmable cdc resolution of 8, 10, 12, or 14 bits ( bit setting in table 5 . 4 ) v ptat internal ptat voltage v bg internal bandgap voltage c t temperatu re measurement capacitor c toff temperature cdc zero shift c tref temperature reference capacitance temp_trim temperature trim setting ( bit setting in table 5 . 4 ) cdc_offset cdc offset trim setting ( bit setting in table 5 . 4 ) cdc_reference cdc reference setting ( bit setting in table 5 . 4 ) note: the factory settings for temp_trim, cdc_offset , and cdc_reference are optimized for the full temperature range of - 40 c to 125 c guaranteeing a minimum effective resolution of 13 bits when 14 bits of reso - lution is selected. unless a different temperature range is needed, it is strongly recommended that these settings not be changed. tref toff t bg ptat res temp c c c ) v / v ( 2 z ? ? ? ? pf 1 trim _ temp 44 . 1 c t ? ? ? pf 1 offset _ cdc 44 . 1 c toff ? ? ? pf 1 reference _ cdc 44 . 1 c tref ? ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 22 of 67 2.3 digital core the digital core provides control logic for the analog front - end, performs input signal conditioning, and handles external communication. a digital signal processor (dsp) is used for conditioning and correcting the converted sensor and temperature in puts. the d sp can correct for up to a two - region piece - wise non - linear sensor input, and up to a second order non - linear temperature input. alternatively a third - order correction of the sensor input fo r one region and up to a second - order non - linear temper ature input can be selected. refer to section 6 for details on the signal conditioning and correction math. the analog front - end configuration and correction coefficients for both the capacitive sensor and the t emperature sensor are stored in an on - chip eeprom (see section 5 ). four different types of outputs are available: i 2 c, spi, pdm, and the alarms. these output modes are used in combination with the two measuremen t modes: update mode and sleep mode. for a full description of normal operation in each mode, refer to section 3 . the ZSSC3123 has an internal 1.85 mhz temperature - compensated oscillator that provides the time b ase for all operations. when vdd exceeds the por level , the reset signal de - asserts and the clock generator starts. see section 3.1 for the subsequent power - up sequence. the exact clock frequency influences the measurement cycle time (see the frequency variation spec in section 1.3 ). to minimize the oscillator error as the vdd voltage changes, an on - chip regulator supplies the oscillator block. 3 normal operation mode fig ure 3 . 1 gives a general overview of ZSSC3123 operation. details of operation, including the power - up sequence, measurement modes, output modes, diagnostics, and commands, are given in the subsequent sections.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 23 of 67 fig ure 3 . 1 general operation update mode (i 2 c, spi, pdm, or alarms) sleep mode (i 2 c, spi, or alarms) command received command received (i 2 c/spi only) no command mode (no measurement cycle. full command set is available.) yes start_nom no , afte r command window expires ( 3 ms / 10 ms ) command = s tart_cm? mr measurement request df data fetch command received. command = start_nom? execute command update rate period over or command received? update p eriod over yes perform measurement no fetch data normal operation mode perform initial measurement . start_cm command received power down (wait for command) command = i 2 c df or spi df? fetch data command = i 2 c mr or spi mr? no yes power down (wait for command.) no yes perform measurement yes command = i 2 c df or spi df? update digital output register, pdms, & alarms power - on reset update digital output register & alarms power down
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 24 of 67 measurement cycle power applied to device. command window starts after a short power - on - reset window. 1 st corrected signal measurement written to output register (i 2 c, spi, pdm s, alarms ) por command window capacitance conversion (cap conv) 3ms por when the fast startup bit is not set in eeprom , the command window is 10ms. temperature conversion (temp conv) temp dsp calculation (temp calc) cap dsp calculation (cap calc) 3.1 power - on sequence figure 3 . 2 shows the power - on sequence of the ZSSC3123 . on system power - on reset (por), the ZSSC3123 wakes as an i 2 c dev ice regardless of the output protocol programmed in eeprom. after power - on reset, the ZSSC3123 enters the command window. it then waits for a start_cm command for 3ms if the fast_startup eeprom bit is set or 10ms otherwise (see table 5 . 5 ). if the ZSSC3123 receives the start_cm command during the command window, it enters and remains in com mand mode. command mode is primarily used in the calibration environment. see section 4 for details on com mand mode. if during the power - on sequence, the command window expires without receiving a start_cm or if the part receives a start_nom command in command mode, the device will immediately assume its programmed output mode and will perform one complete measurement cycle. timing for the initial measurement is described in section 3.2 . at the end of the c apacitance dsp calculation, the first data is written to the output register. beyond thi s point, conversions are performed according to the programmed measurement mode settings (see section 3.3 ). figure 3 . 2 power - on sequence with fast startup b it s et in eeprom note : see section 3.2 for timing of the measurement cycle. timing values shown are typical; for the wo r st case values, multiply by 1.1 (nominal frequency 1 0 %). 3.2 measurement cyc le figure 3 . 3 shows a typical measurement cycle. at the start of a measurement, there is a small wakeup period and then an internal temperature conversion /temperature dsp calculation is performed followed by a capa citance conversion /capacitance dsp calculation . the length of these conversions depends on the setting of the resolution bits (see table 3 . 1 ). for capacitance measure ments, con version time also depends on the mul t selected by the cdc_mult bits (see table 2 . 1 ). both t he r esolution and the cdc_mult bits can be found in eeprom words c_config and t_config (see table 5 . 3 and table 5 . 4 for bit numbers). each conversion cycle is followed by a dsp calculation, which uses the programmed calibration coefficients to calculate corrected temperature and capacitance measurements. in update mode, a tempera ture conversion is not performed every measurement cycle because it is considered a slower moving quantity. in this case, the measurement cycle timing is the same as figure 3 . 3 without the temper ature conversion / temperature dsp calculation (see section 3.3.1 for more information).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 25 of 67 corrected signal measurement written to output register (i 2 c , spi , pdm, or alarms ) temperature conversion (temp conv) 0.30ms 1.15ms 4.5ms 18.0m s legend: timing for 8 - bit resolution timing for 10 - bit resolut ion timing for 12 - bit resolution timing for 14 - bit resolution wakeup 0.10m s temperature dsp calculation (temp calc) capacitance conversion (cap conv) capacitance dsp calculation (cap calc) 0.30 m s 0.30ms x mult. 1.15ms x mult. 4.50ms x mult. 18.0m s x mult. 0.25 m s figure 3 . 3 measurement cycle timing ** table 3 . 1 cdc resolution and conversion times eeprom encoding cdc resolution (bits) temperature conversion time ** (ms) capacitance conversion time ** (ms) 00 b 8 0. 30 0 . 30 * m ult 01 b 10 1. 15 1. 15 * mult 10 b 12 4.50 4 . 50 * mult 11 b 14 18. 0 18. 0 * mult 3.3 measurement modes the ZSSC3123 can be programmed to operate in either sleep mode or update mode. the measurement mode is selected with the measurement_mode bit in the z md i _config eeprom word (see table 5 . 2 ). in update mode, measurements are taken at a fixed, selectable rate (see section 3.3.1 ). in sleep mode, the part waits for com - man ds from the master before taking measurements (see section 3.3.2 ). fig ure 3 . 1 shows the differences in operation between the two measurement modes. 3.3.1 update mode in update mode, the digital core will perform conversions at an update rate selected with the update_rate bits in the zmd i _config eeprom word (see table 5 . 2 ). table 3 . 2 shows the po wer - down periods between conversions for the four update_rate settings. the benefit of slower update rates is power savings. update mode is compat - ible with all the different output modes; i 2 c, spi, pdms, and the alarms. as shown in figure 3 . 4 , at the completion ** all time values show n are typical; for the worst case values, multiply by 1.1 (nominal frequency 10%).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 26 of 67 wakeup temp conv cap calc cap conv write new corrected signal measurement to output register (i 2 c, spi, pdm s , alar ms) wakeup clite ? core activity cap conv write new corrected signal measurement to output register (i 2 c, spi, pdm s , alarms) power down period depends on selected update rate power down cap calc c ap conv power down cap calc write new corrected signal measurement to output register (i 2 c, spi, pdm s , alarms) wakeup power down temperature is measured after every sixth capacitive measurements temp calc of a measurement cycle, the digital output register, pdms, and/or alarms will be updated before powering down. when the power - down period expires, the ZSSC3123 will wake up and perform another measurement cy cle. if the part is programmed for the fastest update rate, there is no power down period, and measurements happen continuously. table 3 . 2 update rate settings ?? update_rate power down period (ms) 00 b 0 01 b 5 10 b 25 11 b 125 figure 3 . 4 measurement sequence in update mode note : see section 3.2 for measurement cycle timing. to calculat e the total time between capacitive measurements in update mode, add the measurement cycle timing from section 3.2 and the power down timing from table 3 . 2 . t ypical sett ings might be a capacitance measure - ment with a resolution of 12 - bits . in this example, the time between measurements = ( 4.5 ms+ 0.1ms+ 0. 3 ms) + (power down period). table 3 . 3 shows the time between measurements fo r the different update rate settings and bit resolutions . temperature measurements are performed every six capacitive measurements. the actual frequency of temperature conversions varies with the update rate and afe configuration settings. as shown in figure 3 . 4 when a temperature measurement is performed, a capacitance measurement occurs immediately after, so the total measurement cycle time is increased by the length of the temperature conversion /temperature dsp calculation. ?? all time values shown are typical; for the worst case values, multiply by 1.1 (nominal frequency 10%).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 27 of 67 to calculate the total time between temperature measurements in update mode, take the time between capaci - tive measurements as calculated in the above text and multiply that number by six (there are six capacitive mea - surements to every temper ature measurement) and then add the temperature conversion time /temperature dsp calculation time from table 3 . 1 for example a temperature measurement with a resolution of 12 - bits has a conversion time / dsp calculati on time of 4.5 ms +0.25ms (from table 3 . 1 ) continuing with the above example (12 - bit capacitive measurement with a multiplier of 1) the time between temperature measurements is (capaci - tance update time * 6) + 4.75m s . table 3 . 3 t ime periods b etween capacitance m easurements and temperature m easurements for d ifferent mult, r esolution and update r ate s mult1 total t ime between c apacitance m easurements (ms) total t ime betwee n t emperature m easurements (ms) cdc resolution (bits) u pdate r ate 00 b u pdate r ate 01 b u pdate r ate 10 b u pdate r ate 11 b u pdate r ate 00 b u pdate r ate 01 b u pdate r ate 10 b u pdate r ate 11 b 8 0.70 5.70 25.70 125.70 4.75 34.75 154.75 754.75 10 1.55 6.55 26.55 1 26.55 10.70 40.70 160.70 760.70 12 4.90 9.90 29.90 129.90 34.15 64.15 184.15 784.15 14 18.40 23.40 43.40 143.40 128.65 158.65 278.65 878.65 mult2 total t ime between c apacitance m easurements (ms) t otal t ime between t emperature m easurements (ms) cdc re solution (bits) update rate 00 b update rate 01 b update rate 10 b update rate 11 b update rate 00 b update rate 01 b update rate 10 b update rate 11 b 8 1.00 6.00 26.00 126.00 6.55 36.55 156.55 756.55 10 2.70 7.70 27.70 127.70 17.60 47.60 167.60 767.60 12 9.4 0 14.40 34.40 134.40 61.15 91.15 211.15 811.15 14 36.40 41.40 61.40 161.40 236.65 266.65 386.65 986.65 mult4 total t ime between c apacitance m easurements (ms) total t ime between t emperature m easurements (ms) cdc resolution (bits) update rate 00 b updat e rate 01 b update rate 10 b update rate 11 b update rate 00 b update rate 01 b update rate 10 b update rate 11 b 8 1.60 6.60 26.60 126.60 10.15 40.15 160.15 760.15 10 5.00 10.00 30.00 130.00 31.40 61.40 181.40 781.40 12 18.40 23.40 43.40 143.40 115.15 145.15 265.15 865.15 14 72.40 77.40 97.40 197.40 452.65 482.65 602.65 1202.65
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 28 of 67 mult8 total t ime between c apacitance m easurements ( ms ) total time between temperature m easurements (ms) cdc resolution (bits) update rate 00 b update rate 01 b update rate 10 b upda te rate 11 b update rate 00 b update rate 01 b update rate 10 b update rate 11 b 8 2.80 7.80 27.80 127.80 17.35 47.35 167.35 767.35 10 9.60 14.60 34.60 134.60 59.00 89.00 209.00 809.00 12 36.40 41.40 61.40 161.40 223.15 253.15 373.15 973.15 14 144.40 149.4 0 169.40 269.40 884.65 914.65 1034.65 1634.65 3.3.1.1. data fetch in update mode in update mode, i 2 c and spi are used to fetch data from the digital output register using a data fetch (df) com - mand (see section 3.6.3 ). detecting when data is ready to be fetched can be handled either by polling or by monitoring the ready pin (see section 3.6.6 for details on the ready pin). the status bits of a df tell whether or not the data is valid or stale (see section 3.4 regarding the status bits). as shown in figure 3 . 5 after a measurement cycle is complete, valid data can be fetched. if the next data fetch is performed too early, the data will be the same as the previous fetch with stale status bits. as shown in figure 3 . 5 , a rise on the ready pin can also be used to tell when valid data is ready to be fetched.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 29 of 67 ready pin temp conv write new corrected signal measurement to output register (i 2 c or spi) stale values i 2 c/spi df i 2 c/spi df valid read occurs write new corrected signal measurement to output register (i 2 c or spi) power down period depends on selected update rate power down stale values i 2 c/spi df i 2 c/spi df clite ? core activity cap conv power down cap calc serial interface activity i 2 c/spi df valid read occurs valid read occurs cap conv cap calc cap conv cap calc power down wakeup wakeup wakeup temp calc figure 3 . 5 i 2 c and spi data fetching in update mode note : see section 3.2 for timing of measurements. 3.3.2 slee p mode in sleep mode, the digital core will only perform conversions when the ZSSC3123 receives a measurement request command (mr); otherwise, the ZSSC3123 is always powered down. measurement request commands can only be sent using i 2 c or spi, so pdm is no t available. the alarms can be used in sleep mode but only in combination with i 2 c or spi. more details about mr commands in sleep mode operation can be found in section 3.3.2.1 . note: sleep mode power consumpt ion is significantly lower than update mode power consumption (see section 1.3 for exact values). figure 3 . 6 shows the measurement and communication sequence for sleep m ode. the master sends an mr command to wa ke the ZSSC3123 from power down. after the ZSSC3123 wakes up, a measurement cycle is performed consisting of both a temperature and a capacitance conversion followed by the dsp correction calculations. write new corrected signal measurement to output register (i 2 c or spi)
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 30 of 67 at the end of a measurement cycle, the digital output register and alarms will be updated before powering down. an i 2 c or spi data fetch (df) is performed during the power - down period to fetch the data from the output r egis - ter. in i 2 c the user can send another mr to s tart a new measurement cycle without fetching the previous data, but in spi, a df must be done before another mr can be sent. after the data has been fetched, the ZSSC3123 remains powered down until the master sends an mr command. the timing for measuremen ts can be found in section 3.2 . figure 3 . 6 measurement sequence in sleep mode (only i 2 c, spi, or alarms) note : see section 3.2 for timing of measurements. 3.3.2.1. data fetch in sleep mode in sleep mode, i 2 c and spi are used to request a measurement with a mr command and to fetch data from the digital output register using a data fetch (df) command (see section 3.6.3 ). as shown in figure 3 . 7 , after a measurement cycle is complete, valid data can be fetched. the preferred method of detecting valid data is to wait for a rise on the ready pin (se e section 3.6.6 for details on the ready pin). if the ready pin is not available, the user should wait for the measurements to complete before performing the df (see section 3.2 for measurement timing). the status bits of the df can be used to tell whether the data is valid or stale (see section 3.4 regarding the status bits) , but polling for the result should not be done as the serial communication causes increased noise in the system and can result in reduced conversion accuracy . if the next data fetch is performed too early, the status bits will be stale and the data will be invalid. wakeup command wakes clite tm ZSSC3123 clite tm core activity serial interface activity cap calc wr ite new corrected signal measurement to output register (i 2 c, spi, alarms) mr df cap conv temp conv power down power down valid read occurs temp calc
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 31 of 67 power down command wakes clite? ZSSC3123 clite ? core activity serial interface activity write new corrected signal measurement to output register (i 2 c or spi) power down stale values valid read occurs mr df df cap conv temp conv ready pin cap calc wakeup temp calc figure 3 . 7 i 2 c and spi data fetching in sleep mode note : see section 3.2 for timing of measurements. 3.4 status and diagnostics status bits (the two msbs of the fetched high data byte, see table 3 . 4 ) are provided in i 2 c and spi but not in pdm. the status bits are used to indicate the current state of the fetched data. diagnostic detection is available in i 2 c, spi and pdm. in i 2 c and spi diagnostics are reported as a saturated high capacitance and temperature output (see table 3 . 5 ). in pdm, diagnostics are reported as a railed high output level for both pdm_c (capacitive pdm) and pdm_t (temperature pdm). if a diagnostic val ue is reported then one or more of the errors shown in table 3 . 6 occurred in normal operation. configuration eeprom diagnostics are detected at initial power - up of the ZSSC3123 or a wakeup in sleep mode and are per manent diagnostics. all other diagnostics are detected during a measurement cycle and reported in the subsequent data fetch for i 2 c or spi or output register update for pdm.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 32 of 67 table 3 . 4 status table status bits (i 2 c or spi) pdm output definition 00 b clipped normal output valid data: data that has not been fetched since the last measurement cycle. 01 b not applicable stale data: data that has already been fetched since the last measurement cycle. note : if a data fetch is performed before or during the first measurement after power - on reset, then stale will be returned, but this data is actually invalid since the first measurement has not been completed. 10 b not applicable command mode: the ZSSC3123 is in command mode. 11 b not used not used table 3 . 5 diagnostic detection i 2 c or spi output pdm output definition saturated output 3fff h high output (railed) level a diagnostic has occurred in normal operation (see table 3 . 6 ). table 3 . 6 normal operation diagnostic table diagnostic type definition configuration error permanent an eeprom or ram parity error occurred in the initial lo ading of the configuration registers. ram parity error transient a ram parity error occurred during a microcontroller instruction in the last measurement cycle. eeprom error transient a ded eeprom error occurred in the last measurement cycle (see section 3.4.1 ). math warning transient an internal math overflow has occurred in the last measurement cycle and the output might be invalid. 3.4.1 eeprom error detection and correction the contents of the eeprom are prote cted via error checking and correction ( ecc ) . each of the 32 16 - bit words contains 6 parity bits enabling single - bit error correction and double - bit error detection (sec and ded) per word. in command mode both sec and ded errors are reported in the respons e byte (see section 4.3 ). if the fetched eeprom data has a ded error then the fetched data will be incorrect; however, if a sec error was reported then the fetched data has been corrected, and it is the users c hoice to write the data back to attempt to correct the error. during normal operation mode, a diagnostic will be flagged on any ded error, but an sec error will be automatically corrected and not flagged as a diagnostic.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 33 of 67 3.4.2 alarm diagnostics the alarm outputs do not report diagnostics. if diagnostics are needed with alarm outputs, then either digital or pdm outputs must also be used. 3.5 output modes the ZSSC3123 has four different output modes as shown in table 3 . 7 . see the corresponding reference sections for specifics on each mode. table 3 . 7 output modes output mode reference sections i 2 c section 3.6 read only spi pdm section 3.7 alarms section 3.8 as illustrated in the pin configuration in section 9 , the output communication modes share pin s. the output_selection bits in eeprom word zmd i _config (see section 5.1.1 ) select which of these outputs will be enabled. table 3 . 8 shows the pin configuration for the different output selections. table 3 . 8 pin a ssignment for output selections output selection i 2 c (001 b ) spi (011 b ) pdm_c (100 b ) pdm_c+t (110 b ) pin 08 alarm_ low alarm_low alarm_low pdm_t pin 09 alarm_high alarm_high alarm_high alarm_high pin 10 ready ready pdm_c pdm_c pin 12 sda miso sda sda pin 13 scl sclk scl scl pin 14 no input ss no input no input 3.6 i 2 c and spi two wire i 2 c and three - wire read - only spi are available for fetching data from the zssc31 23 . i 2 c is used to send c alibration commands to ZSSC3123 . to choose i 2 c or spi, set the corresponding output_selection bits in eeprom word zmd i _config .
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 34 of 67 sda scl t hdsta t hddat t low t sudat t high t susta t hdsta t susto t bus 3.6.1 i 2 c features and timing the ZSSC3123 uses an i 2 c - compatible communication protocol ?? 2 c slave address (00 h to 7f h ) is selected by the device_id bits in the cust_config eeprom word (see table 5 . 5 for bit assignments). the device will respond only to this addre ss if the communication lock is set by programming 011 b in the comm_lock bits in the zmd i _config eeprom word (see table 5 . 2 for bit assignments); otherwise, the device will respond to all i 2 c addresses. the factory setting for the i 2 c slave address is 28 h with comm_lock set. see figure 3 . 8 for the i 2 c timing diagram and table 3 . 9 for definitions of the parameters shown in the diagram . figure 3 . 8 i 2 c timing diagram table 3 . 9 i 2 c parameters parameter symbol min typ max units scl clock frequency f scl 20 1 400 khz start condition hold tim e relative to scl edge t hdsta 0.1 ? s minimum scl clock low width 2 t low 0.6 ? s minimum scl clock high width 2 t high 0.6 ? s start condition setup time relative to scl edge t susta 0.1 ? s data hold time on sda relative to scl edge t hddat 0 0.5 ? s data setup time on sda relative to scl edge t sudat 0.1 ? s ?? for more details, refer to http://www.standardics.nxp.com/literature/books/i2c/pdf/i2c.bus.specification.pdf or other websites for this specification.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 35 of 67 t bus t low sclk miso ss hiz z t hdss t high t clkd t suss hiz t clkd lkd parameter symbol min typ max units stop condition setup time on scl t susto 0.1 ? s bus free time between stop condition and start condition t bus 1 ? s 1 the minimum frequency of 20khz applies to calibration/test only (requi red to meet c ommand w indow timing). there is no minimum for n ormal o peration mode . 2 combined low and high widths must equal or exceed minimum scl period. 3.6.2 spi features and timing spi is available only as half duplex (read - only from the ZSSC3123 ). spi sp eeds of up to 800khz can be supported. the spi interface can be programmed to allow the master to sample miso on the falling - edge or rising - edge of scl via the spi_phase bit in eeprom word cust_config (see table 5 . 5 for bit assignments). see figure 3 . 9 for the spi timing diagram and table 3 . 10 for definitions of the parameters shown in the timing diagram. figure 3 . 9 spi timing diagram table 3 . 10 spi parameters parameter symbol min typ max units sclk clock frequency f scl 50 800 khz ss drop to first clock edge t hdss 2.5 ? s minimum scl k clock low width 1 t low 0.6 ? s minimum sclk clock high width 1 t high 0.6 ? s clock edge to data transition t clkd 0 0. 5 ? s
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 36 of 67 parameter symbol min typ max units rise of ss relative to last clock edge t suss 0.1 ? s bus free time between rise and fall of ss t bus 2 ? s 1 combined low and high widths must equal or exceed minimum sclk period. 3.6.3 i 2 c and spi commands as detailed in table 3 . 11 , there are three types of commands which allow the user to interface with the ZSSC3123 in the i 2 c or spi mod es. table 3 . 11 i 2 c and spi command types type description communication supported reference sections data fetch (df) used to fetch data in any digital mode i 2 c and spi section 3.6.4 measurement request (mr) used to start measurements in sleep mode i 2 c and spi section 3.6.5 calibration commands used in command mode during the calibration process i 2 c only section 4.2 3.6.4 data fetch (df) the data fetch (df) command is used to fetch data in any digital output mode. with the start of communication (for i2c after reading the slave address; for spi at the falling edge of ss) the entire output packet will be loaded in a serial output register . the register will be updated after the communication is finished. the output is always scaled to 14 bits independent of the programmed resolution. the ordering of the bits is b ig - endian. 3.6.4.1. i 2 c data f etch an i 2 c data fetch command starts with the 7 - bit slave address and the 8 th bit = 1 (read). the ZSSC3123 as the slave sends an acknowledge (ack) indicating success. the number of data bytes returned by the ZSSC3123 is deter mined by when the master send s the nack and stop condition. figure 3 . 10 shows examples of fetching two and three bytes respectively. the full 14 bits of capacitive data are fetched in the first two bytes. the msbs of the first byte are the sta tus bits. if temperature data is needed, additional temperature bytes can be fetched. in figure 3 . 10 , the three - byte data fetch returns 1 byte of temperature data (8 - bit accuracy) after the capacitive data. a fourt h byte can be fetched where the six msbs of the fetched byte are the six lsbs of a 14 - bit temperature measurement. the last two bits of the fourth byte are undetermined and should be masked off in the application.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 37 of 67 i 2 c df C 3 bytes: slave returns 2 capacitance data bytes & temperature high byte (t[13:6]) to master (s device slave address [6:0] cap. data [13:8] cap. data [7:0] device slave addr ess [6:0] cap. data [13:8] cap. data [7:0] temp. data [13:6] 2 2 slave address bit (example: bit 2) command or data bit (example: bit 2) status bit start condition stop condition acknowledge (ack) not acknowledge read/write (nack) (read = 1) s a s r n i 2 c df C 2 bytes: slave returns only capacitance data to the master in 2 bytes (s wait for slave ack master ack master ack master nack 14 13 11 12 10 8 9 a 6 5 7 3 4 2 n 1 0 6 s 5 2 1 r 0 a 14 13 15 11 12 10 8 9 a 6 5 7 3 4 2 a 1 0 s 6 s 5 4 2 3 1 r 0 a 15 6 5 7 3 4 2 s n 1 0 3 4 figure 3 . 10 i 2 c measurement packet reads 3.6.4.2. spi data fetch by default the spi interface will have data change after the falling edge of sclk. the master should sample miso on the rising (opposite) edge of sclk. this is configurable via the spi_phase bit in eeprom word cust_config (see table 5 . 5 for bit assignments). the spi protocol can handle high and low polarity of the clock line without configuration change. as seen in figure 3 . 11 the entire output packet is 4 bytes (32 bits). the high capacitive data byte comes first, followed by the low byte. then 14 bits of corrected temperature (t[13:0]) are sent: first the t[13:6] byte and then the {t[5:0],xx} byte. the last 2 bits of the final byte are undetermined and sh ould be masked off in the appli cation. if the user only requires the corrected capacitance value, the read can be terminated after the 2 nd byte. if the cor - rected temperature is also required but only at an 8 - bit resolution, the read can be terminated after the 3 rd byte is read.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 38 of 67 hiz s1 s0 c 13 c 12 c 7 c 6 c 0 t1 3 t 12 t1 t0 hiz sclk miso ss x figure 3 . 11 spi output packet with positive edge sampling packet = [ {s(1:0), c (13:8)}, { c (7:0)}, {t(13:6)},{t(5:0),xx}] where s(1:0) = status bits of packet (normal, command, busy, diagnostic) c (13:8) = upper 6 bits of 14 - bit capacitance data. c (7:0) = lower 8 bits of 14 - bit capacitance data. t(13:6) = corrected temperature data (if application does not require corrected temperature, te rminate read early) t(5:0),xx =. remaining bits of corrected temperature data for full 14 - bit resolution hiz = high impedance 3.6.5 measurement request (mr) a measurement request (mr) is a sleep - mode - only command sent by the master to wake up the ZSSC3123 and st art a new measurement cycle in both i 2 c and spi modes. see section 3.3.2 for more information on sleep mode. 3.6.5.1. i 2 c measurement request the i 2 c mr is used to wake up the device in sleep mode and start a complete me asurement cycle starting with a temperature measurement, followed by a capacitance measurement, followed by the dsp calculations, and then the results are written to the digital output register. as shown in figure 3 . 12 , the communication contains only the slave address and the write bit (0) sent by the master. after the ZSSC3123 responds with the slave ack, the master creates a stop condition. note: the i 2 c mr function can also be accomplished by sending Ddont care data after the address instead of immediately sending a stop bit. figure 3 . 12 i 2 c mr device slave address [6:0] 6 s 5 4 2 3 1 w 0 a s wait for slave ack 2 start condition stop condition acknowledge (ack) slave address bit read/write bit (example: bit 2) (example: write = 0) s a s w i 2 c mr C measurement request: slave starts a measur ement cycle
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 39 of 67 sclk miso ss x x ignore data 3.6.5.2. spi measurement request the spi mr is used to wake up the device in sleep mode and start a complete measurement cycle s tarting with a temperature measurement /temperature dsp calculation , followed by a capacitance measurement / c apacitance dsp calculations, and then the results are written to the digital output register. as shown in figure 3 . 13 , executing an spi mr command is a read of 8 bits, ignor ing the data that is returned. note : the spi mr function can also be accomplished by performing a full spi data fetch (see section 3.6.4.2 ) and ignoring the invalid data that will be returned. figure 3 . 13 spi mr 3.6.6 ready pin a rise on the ready pin indicates that new data is ready to be fetched from either the i 2 c or spi interface. the ready pin sta ys high until a data fetch (df) command is sent (see section 3.6.3 ); it stays high even if additional measurements are performed before the df. the ready pins output driver type is selectable as either full pu sh - pull or open drain via the ready_open_drain bit in eeprom word cust_config (see table 5 . 5 for bit assignments and settings). point - to - point communication most likely uses the full push - pull driver. if an applica tion requires interfacing to multiple parts, then the open drain option can allow for just one wire and one pull - up resistor to connect all the parts in a bus format. 3.7 pdm (pulse density modulation) pdm outputs for both corrected capacitance and temp e rature are available. pdm_c (capacitance pdm) appears on the ready/pdm_c pin, and pdm_t (temperature pdm) appears on the alarm_low/pdm_t pin if enabled using the output_selection bits (see table 5 . 2 ). the pdm frequency i s 231.2 5khz ? 1 0 % (i.e., the oscillator frequency 1.85mhz ? 10 % divided by 8 ). both pdm signals are 14 - bit values. in pdm mode, the ZSSC3123 must be programmed to update mode (see section 3.3.1 ). every time a co nversion cycle has finished, the pdm will begin outputting the new value. an analog output value is created by low - pass filtering the output; a simple first - order rc filter will work in this application. select the time constant of the filter based on the requirements for settling time and/or peak - to - peak ripple. important: the resistor of the rc filter must be 10k ? .
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 40 of 67 table 3 . 12 shows some filter examples using a 10k ? resistor. table 3 . 12 low pass filter example for r = 10k ? filter capacitance (nf) pdm_c desired analog output resolution vpp ripple (mv/v) 0 to 90% settling time (ms) 100 4.3 2.3 8 4 00 1.0 9.2 10 16 00 0. 3 36.8 12 64 00 0. 1 147.2 14 for a differen t (higher) resistor, the normalized ripple vpp[mv/v] can be calculated as (14) or the settling time t sett for a 0% to 90% settling can be calculated as (15) ZSSC3123 provides high and low clipp ing limits for the pdm output. eeprom words pdm_clip_high and pdm_c lip_low (eeprom registers 16 hex and 17 hex ; see table 5 . 1 ) are the 14 - bit high and low clipping limit registers respectively. the 14 - bit values map directly to the output of the ic and can be calculated as (16) these registers apply to both pdm_c and pdm_t. since diagnostics are reported in the pdm pin ( see section 3.4 ), clipping limits allow diagnostics to be differentiated from the normal output. for detection of the diag nostic signal, a pdm_clip_high limit of 97.5% (3e66 hex ) or lower is recommended. important: the default values for the high and low clipping limits ( 00 hex ) are not compatible with pdm output, so the clipping limits must be changed if the pdm output is used . otherwise, the pdm output will not work as expected. if the pdm output is not used, it is important to retain the default values of 00 hex for the clipping limits. ? ? ? ? ? ? ) nf c k r ( 4324 v / mv vpp ? ? ? ? ? ? ? ? ? nf c k r 0023 . 0 ms t sett ? ? ? ? ) 100 % _ level _ clip * 2 ( round clip _ pdm 14 ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 41 of 67 3.8 alarm output the alarm output can be used to monitor whether a corrected capacitance readin g has exceeded or fallen below pre - programmed values. the alarm can be used to drive an open - drain load connected to vdd, as demonstrated in section 7.2 , or it can function as a full push - pull driver. if a high voltage application is required, external devices can be controlled with the alarm pins, as demonstrated in section 7.3 . the two alarm outputs can be used at the same time, and these alarms can be used in combin ation with any of the other three modes; i 2 c, spi, or pdm. note: when both pmd_c and pdm_t are selected only alarm_high is available (see section 3.5 ). the alarm outputs are updated when a conversion cycle is co mpleted. the alarm outputs can be used in both update mode and sleep mode, but if sleep mode is used, i 2 c or spi must also be used to control the measure - ments (see section 3.3 ). 3.8.1 alarm registers four registers a re associated with the alarm functions: alarm_high_on, alarm_high_off, alarm_low_on, and alarm_low_off (see table 5 . 1 for eeprom addresses). each of these four registers is a 14 - bit value that deter - mines where the alarms turn on or off. the two high alarm registers form the output with hysteresis for the alarm_high pin, and the two low alarm registers form the output with hysteresis for the alarm_low pin. each of the two alarm pins can be configured independently u sing alarm_low_cfg and alarm_high_cfg located in eeprom word cust_config (see table 5 . 5 for bit assignments). note: if two high alarms or two low alarms are needed, see section 3.8.4 . 3.8.2 alarm operation as shown in figure 3 . 14 , the alarm_high_on register determines where the high alarm trip point is and the alarm_high_off register determines where the high alarm turns off if the high alarm has been activated. the high alarm hysteresis value is equal to alarm_high_on C alarm_high_off. the same is true for the low alarm where alarm_low_on is the low alarm trip point with alarm_low_off determining the alarm shut off point. the low alarm hysteresis value is equal to alarm_low_off C alarm_low_on. figure 3 . 15 shows output operation flowcharts for both the alarm_high and alarm_low pins.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 42 of 67 time corrected capacitance alarm_high_on alarm_high_off alarm_low_off alarm_low_on high alarm pin on low alarm pin on low alarm pin off hysteresis hysteresis high alarm pin off high alarm pin no yes measurement > alarm_high_on? alarm = on measurement alarm_high_off? alarm = off yes no low alarm pin no y es measurement < alarm_low_on? alarm = on measurement alarm_low_off? alarm = off yes no figure 3 . 14 examp le of alarm function figure 3 . 15 alarm output flow chart
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 43 of 67 3.8.3 alarm output configuration the user can select the output driver configuration for each alarm using the output configuration bit in the alarm_hig h_cfg and alarm_low_cfg registers in eeprom word cust_config (see table 5 . 5 for bit assign - ments). for applications, such as interfacing with a micro controller or controlling an external device (as seen in section 7.3 ), select the full push - pull driver for the alarm output type. for an application that directly drives a load connected to vdd, as demonstrated in section 7.2 , t he typical selection is the open - drain output type. an advantage of making an alarm output open drain is that in a system with multiple devices, the alarm outputs of each ZSSC3123 can be connected together with a single pull - up resistance so that one can detect an alarm on any device with a single wire. 3.8.4 alarm polarity for both alarm pins, the polarity of the alarm output is selected using t h e alarm polarity bit in the alarm_high_cfg and alarm_low_cfg registers in eeprom word cust_config (see table 5 . 5 for bit assignments). as shown in the example in section 7.3 , the alarms can be used to drive a high voltage humidity control system. since the humidi - fier or dehumidifier relays must be on when the alarms are on, the alarm polarity bits are set to 0 (active high). in the example given in section 7.2 , an alarm is used to turn on an led in an open drain configuration. in order for the led to be on when the alarm is on, the output must be low, so the alarm polarity bit is set to 1 (active low). another feature of the polarity bits is the ability to create two high alarms or two low alarms. for example, with applications requiring tw o high alarms, flip the polarity bit of the alarm_low pin, and it will act as a high alarm. however, in this case, the effect of the alarm low registers is also changed: the alarm_low_on register would act like the alarm_high_off register and the alarm_low _off register would act like the alarm_high_on register. the same can be done to achieve two low alarms: the alarm_high pin would have the polarity bit flipped, and the two alarm_high registers would have opposite meanings.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 44 of 67 4 command mode command mode is pri marily used for calibrating the ZSSC3123 . command mode is entered by sending a start_cm during the command window (see section 3.1 for more details on how to enter command mode). in command mode, a set of comman ds are available to the user to calibrate the part (see table 4 . 1 ). 4.1 command format command mode commands are only supported for the i 2 c protocol. as shown in figure 4 . 1 , co mmands are 4 - byte packets with the first byte being a 7 - bit slave address followed by 0 for write. the second byte is the com - mand byte and the last two bytes form a 16 - bit data field. figure 4 . 1 i 2 c command format 4.2 command encodings table 4 . 1 describes all the commands that are offered in command mode. note : only the commands listed in table 4 . 1 are valid. other encodings mi ght cause unpredictable results. if data is not needed for the command, zeros must be supplied as data to complete the 4 - byte packet. i 2 c write , command byte, and 2 command data bytes sta rt condition stop condition acknowledge (ack) read/write bit (example: write = 0) s 2 2 slave address bit (example: bit 2) command or data bit (example: bit 2) a s w device slave address command byte command data [15:8] command data [7:0] wait for wait for wait for wait for slave ack slave ack slave ack slave ack 6 s 5 4 2 3 1 w 0 a 6 5 7 3 4 2 0 1 a 14 13 15 11 12 10 8 9 a 6 5 7 4 2 0 1 s a 3
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 45 of 67 table 4 . 1 command list and encodings command byte 8 command bits (hex) thir d and fourth bytes 16 data bits(hex) description response time 00 h to 1f h 0000 h eeprom read of addresses 00 h to 1f h after this command has been sent and executed, a data fetch must be performed (see section 3.6.4 ). 100 s 40 h to 5f h yyyy h (y = data) write to eeprom addresses 00 h to 1f h the 2 bytes of data sent will be written to the address specified in the 6 lsbs of the command byte. 12ms 80 h 0000 h start_nom ends command mode and transitions to normal operat ion mode . length of initial conver - sions depends on tem - perature and capacitance resolution settings and the capacitance Dmult setting (see section 3 ). a0 h 0000 h start_cm start command mode: used to enter the command interpreting mode. start_cm is only valid during the power - on command window (see section 3.1 ). 100 s b0 h 0000 h get revision get the revision of the part. after this command has been sent and executed, a data fetch must be performed (see section 3.6.4 ). 100 s all time values shown are typical; for the worst case values, mult iply by 1.1 (nominal frequency 10%).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 46 of 67 4.3 command response and data fetch after a command has been sent and the execution time defined in table 4 . 1 has expired, an i 2 c data fetch (df) can be performed to fetch the response. as shown in f igure 4 . 2 , after the sla ve address has been sent, the first byte fetched is the response byte. the upper two status bits will always be 10 b to represent command mode (see section 3.4 ). the lower two bits are the response bits. table 4 . 2 describes the different responses that can be fetched. to determine if a command has finished executing, poll the part until a busy response is no longer received. the middle four bits of the response byte are c ommand diagnostic bits where each bit represents a different diagnostic (see table 4 . 3 ). for more information on eeprom errors see section 3.4.1 . note : regardless of wha t the response bits are, one or more of the diagnostic bits may be set indicating an error occurred during the execution of the command. note : only one command can be executed at a ti me. after a command is sent another command must not be sent until the ex ecution time of the first command defined in table 4 . 1 has expired. for all commands except eeprom read and get revision, the data fetch should be terminated after the res - ponse byte is read. if the command was a g et revision, then the user will fetch a one byte revision as shown in f igure 4 . 2 , example 2. the revision is coded with the upper nibble being the letter corresponding to a full layer change and the lower nibble be ing the metal change number, for example a0. if the command was an eeprom read, then the user will fetch two more bytes as shown in f igure 4 . 2 , example 3. if a corrected eeprom error diagnostic was flagged after an eeprom read, the user has the option to write this data back to attempt to fix the error. instead of polling to determine if a command has finished executing, the user can use the ready pin. in this case, wait for the ready pin to rise, which indicates th at the command has executed. then a data fetch can be performed to get the response and data (see f igure 4 . 2 ). see section 3.6.6 for more information on the ready pin.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 47 of 67 f igure 4 . 2 command mode data fetch r di agnostics [5:2] status [ 7 : 6 ] response [1:0] diagnostics [5:2] status [ 7 : 6 ] response [1:0] slave address bit command or data bit status bits (example: bit 2) (example: bit 2) (in command mode always 10) (1 ) i 2 c df C command status response C 1 byte (s wait for slave ack master ack master nack 5 3 4 2 0 1 n s 6 5 4 2 3 1 r 0 a device slave address [6:0] 6 7 2 2 start condition stop condition acknowledge (ack) not acknowledge read/write bit (nack) (example: read = 1) s a s r n (3) i 2 c eeprom df C command status response and eeprom data fetch C 3 bytes (s 6 s 5 4 2 3 1 0 a device slave address [6:0] 6 5 7 3 4 2 0 1 a 14 13 15 11 12 eeprom data high byte [15:8] 10 a 9 8 6 5 7 3 4 2 s n 1 0 eeprom data low byte [7:0] (2) i 2 c get revision df C command status response and clite? revision C 2 bytes (s 6 s 5 4 2 3 1 r 0 a device slave address [6:0] 6 5 7 3 4 2 0 1 a 6 5 7 3 4 clite? revision data byte [7:0] 2 n 1 0 s wait for slave ack master ack master ack master nack diagnostics [5:2] status [ 7 : 6 ] response [1:0] s
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 48 of 67 table 4 . 2 response bits encoding name description 00 b busy the command is busy executing. 01 b positive acknowledge the com mand executed successfully. 10 b negative acknowledge the command was not recognized or an eeprom write was attempted while the eeprom was locked. table 4 . 3 command diagnostic bits bit position name descrip tion 2 corrected eeprom error a corrected eeprom error occurred in execution of the last command. 3 uncorrectable eeprom error an uncorrectable eeprom error occurred in execution of the last command. 4 ram parity error a ram parity error occurred during a microcontroller instruction in the execution of the last command. 5 configuration error an eeprom or ram parity error occurred in the initial loading of the configuration registers.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 49 of 67 5 eeprom the eeprom array contains the calibration coefficients for gai n and offset, etc., and the configuration bits for the analog front end, output modes, measurement modes, etc. the ZSSC3123 eeprom is arranged as 32 16 - bit words (see table 5 . 1 ). the eeprom is divided into two sect ions. words 0 h to 15 h can only be written to if the eeprom is unlocked. after the eeprom is locked these locations can no longer be written to. the eeprom lock bits are in the zmd i _config register (see table 5 . 2 f or the bit assignment). words 16 h to 1f h (highlighted blue in table 5 . 1 ) are always unlocked and available to write to at all times. see section 4 for instructions on r ead - ing and writing to the eeprom in command mode via the i 2 c interface. when programming the eeprom, an internal charge pump voltage is used; therefore a high voltage supply is not needed. note: if the eeprom was accidentally locked, it can be unlocked wi th the following instructions (see section 4 for how to send commands). 1. enter command mode with a start_cm command. 2. send a n a2 h for the command byte and 0000 h for the command data. 3. send a n f0 h for the command by te and 0021 h for the command data. 4. clear the eeprom_lock bits in the zmd i _config register with an eeprom write command. 5. reset the part. there are four customer_id words available for customer use, two in the locked region and two in the unlocked region. th ey can be used as a customer serial number for module traceability. (see table 5 . 1 for customer_id eeprom addresses.) the integrity of the contents of the eeprom array is ensured via ecc (see section 3.4.1 ). table 5 . 1 provides a summary of the eeprom contents. the configuration register bits are explained in detail in the following subsections. table 5 . 1 eeprom word assignments eeprom word bit range ic default name description and notes 00 h 15:0 xxxx h cust_id0 customer id byte 0: for use by customer (default value is the upper 16 bits of the lot number) 01 h 15:0 xxxx h (llllllll b 000 0ssss b ) cust_id1 customer id byte 1: for use by customer (default value is the lower 8 bits of the lot number and an 8 bit wafer number) 02 h 15:0 0b00 h zmd i _config zmd i configuration register (see section 5.1.1 ) 03 h 15:0 00 06 h not available do not change ; must leave at factory settings 04 h 15:0 00 f t h not available do not change ; must leave at factory settings *** 05 h 15:0 0000 h not available do not change ; must leave at factory settings 06 h 15:0 0 c 0 6 h c_config afe capacitance configuration register: see table 5 . 3 . *** the t in the default setting for eeprom word 04 h represents the custom trim value determined by final test. do not change this setting.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 50 of 67 eeprom word bit range ic default name description and notes 07 h 15:0 0000 h sot_tco 2 nd order temperature offset correction for capacitance 08 h 15:0 0000 h tco temperature offset correction for capacitance 09 h h 15:0 00 00 h sot_tcg 2 nd order temperature gain correction for capacitance 0a h 15:0 0000 h tcg temperature gain correction for capacitance 0b h 15:0 0000 h offset offset correction for capacitance 0c h 15:0 2000 h gain_1 gain correction for capacitance (region 1) 0d h 15:0 0000 h sot_1 2 nd order correction for capacitance (region 1) 0e h 15:0 2000 h gain_2 gain correction for capacitance (region 2) 0f h 15:0 0000 h sot_2 or tot_1 2 nd order correction for capacitance (region 2) alternatively 3 rd order correction (only one region) 10 h 15:0 7fff h raw_break break point dividing region 1 from region 2 11 h 15:0 8 d 92 h t_config afe temperature configuration register (see table 5 . 4 ) 12 h 15:0 0000 h offset_t offset correction for temperat ure 13 h 15:0 2000 h gain_t gain correction for temperature 14 h 15:0 0000 h sot_t 2 nd order correction for temperature 15 h 15:0 0000 h t ref raw temperature reading reference point 16 h 13:0 0000 h pdm_clip_high pdm high clipping limit (keep at zero unless pd m is enabled ; must change default if pdm is used ) 17 h 13:0 0000 h pdm_clip_low pdm low clipping limit (keep at zero unless pdm is enabled ; may be change d if pdm is used ) 18 h 13:0 3fff h alarm_high_on high alarm on trip point 19 h 13:0 3fff h alarm_high_off high alarm off trip point 1a h 13:0 0000 h alarm_low_on low alarm on trip point 1b h 13:0 0000 h alarm_low_off low alarm off trip point 1c h 15:0 0028 h cust_config customer configuration register (see section 5.1.4 .) 1d h 15:0 0000 h not available do not change ; must leave at factory settings 1e h 15:0 xxxx h cust_id2 customer id byte 2: for use by customer (default value is the 8 bit x and 8 bit y coordinates on the wafer) 1f h 15:0 0000 h cust_id3 customer id byte 3 : for use by customer
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 51 of 67 5.1.1 zmd i configuration register (zmd i _config , eeprom word 02 hex ) this register is loaded at power - on reset and upon exiting command mode using a start_nom command. table 5 . 2 zmd i _config bit assignments bit range ic default name description and notes 0 0 b measurement_mode 0 = update mode 1 = sleep mode 2:1 00 b power_down_period power down period: ??? 00 b = 0ms 01 b = 5ms 10 b = 25ms 11 b = 125ms 3 0 b scale_sot_tc scales the sot tc terms: 0 = sca le x 1 1 = scale x 2 4 0 b gain4x_c multiply gain_1 and gain_2 by 0 = multiply by 1 1 = multiply by 4 7:5 000 b eeprom_lock 011 b = locked all other = unlocked when eeprom is locked, the internal charge pump is disabled and the eeprom can no longer be progr ammed. note: if the eeprom was accidentally locked, see section 5 for instructions for unlocking it. 10:8 011 b comm_lock 011 b = locked all other = unlocked when communication is locked, i 2 c communication will o nly respond to its programmed address. otherwise if communication is unlocked, i 2 c will respond to any address. ??? all time values shown are typical; for the worst case values, multiply by 1.1 (nominal frequency 10%).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 52 of 67 bit range ic default name description and notes 13:11 001 b output_selection 001 b = i 2 c 011 b = spi 100 b = pdm capacitance (+ 2 alarms) 11 0 b = pdm capacitance + temperature (+ 1 alarm) all othe r configurations are not allowed see table 3 . 8 for more details. 14 0 b third_order 0 = p iece - wise linear calibr ation with breakpoint 1 = t hird - order calibration 15 0 b not available do not change C must leave at f actory settings 5.1.2 capacitance analog front end configuration (c_config , eeprom word 06 hex ) this register is loaded immediately before a capacitance measurement is taken, so a power cycle is not needed for changes to take effect. table 5 . 3 c_config bit assignments bit range ic default name description and notes 2:0 11 0 b cdc_reference cdc reference capacitor selection (see table 2 . 2 ) 5:3 000 b cdc_offset cdc offset capa citor selection (see table 2 . 2 ) 9:6 0000 b not available do not change C must leave at factory settings 11:10 11 b resolution cdc resolution and sample rate: ??? 00 b = 8 bits at 0.7 ms rate 01 b = 10 bits at 1.6 ms ra te 10 b = 12 bits at 5.0 ms rate 11 b = 14 bits at 18.5 ms rate 13:12 00 b cdc_ m ult cdc multiplier : 00 b = 1 (2pf to 8pf) 01 b = 2 (8pf to 32pf) 10 b = 4 (32pf to 130pf) 11 b = 8 (130pf to 260pf) ??? all time values shown are typical; for the worst case values, multiply by 1.1 (nominal frequency 10%). see section 3.2 for additional timing factors.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 53 of 67 bit range ic default name description and notes 14 0 b differential differential input capacitance selection: 0 = single - ended 1 = differential 15 0 b not available do not change C must leave at factory settings 5.1.3 temperature analog front end configuration (t_config , eeprom word 11 hex ) this register is loaded immediately before a capacitance measurement is taken, so a power cycle is not needed for changes to take effect. table 5 . 4 t_config bit assignments bit range ic default name description and notes 2:0 010 b cdc_reference cdc reference capacitor selection. the factory settings are set for a full span temperature range from - 40c to +125c. note: do not change this setting from the factory setting unless a different temperature range is needed. 5:3 010 b cdc_offset cdc offset capacitor selection. the factory settings ar e set for a full span temperature range from - 40c to +125c. note: do not change this setting from the factory setting unless a different temperature range is needed. 8:6 110 b temp_trim trim setting used for the temperature measurement. the factory setti ngs are set for a full span temperature range from - 40c to +125c. note: do not change this setting from the factory setting unless a different temperature range is needed.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 54 of 67 bit range ic default name description and notes 9 0 b not available do not change C must leave at factory settings 11:10 11 b reso lution temperature resolution and sample rate: 00 b = 8 bits at 0.7 ms rate 01 b = 10 bits at 1.6 ms rate 10 b = 12 bits at 5.0 ms rate 11 b = 14 bits at 18.5 ms rate 15:12 1000 b not available do not change C must leave at factory settings 5.1.4 customer config uration register (cust_config , eeprom word 1c hex ) this register is loaded at power - on reset and upon exiting command mode after receiving a start_nom command. table 5 . 5 cust_config bit assignments bit range ic default name description and notes 6:0 0101000 b device_id i 2 c slave address 8:7 00 b alarm_low_cfg configure the alarm_low output pin: bits description 7 alarm polarity: 0 = active high 1 = active low 8 output configuration: 0 = full push - pull 1 = open drain all time values shown are t ypical; for the worst case values, multiply by 1.1 (nominal frequency 10%).
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 55 of 67 bit range ic default name description and notes 10:9 00 b alarm_high_cfg configure the alarm_high output pin: bits description 9 alarm polarity: 0 = active high 1 = active low 10 output configuration: 0 = full push - pull 1 = open drain 11 0 b spi_phase the edge of sclk that the master sample s miso on: 0 = positive edge 1 = negative edge 12 0 b ready_open_drain ready pin is 0 = full push - pull 1 = open drain 13 0 b fast_startup sets the command window length: 0 = 10 ms command window 1 = 3 ms command window 15:14 00 b not available do not chang e C must leave at factory settings 6 calibration and signal conditioning math zmdi can provide software and hardware with samples to perform the calibration. for a complete description and detailed examples, s ee ZSSC3123 _clite_ ssc_evaluation _kit_revx.x.pdf . for more details on the following equations, refer to ZSSC3123 technical note detailed equations for ZSSC3123 clite rev c silicon math (available on request). note for best results the calibration should be done with all settings set to the final applicat ion including supply voltage, measurement mode, update rate, output mode , resolution and afe settings in the final packaging. 6.1 capacitance signal conditioning the ZSSC3123 supports up to a two - region piece - wise , non - linear sensor input or a third - order corr ection selectable . the general form of the capacitance signal conditioning equation is provided below. note: the following equations are only meant to show the general form and capabilities of the ZSSC3123 sensor signal conditioning.
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 56 of 67 two - region piece - wise , non - linear sensor input (17) (18) (19) (20) or alternatively non - linear sensor input up to third - order correction (21) (22) where symbol description raw_c raw sensor reading. rawtc temperature corrected raw value. raw 1 raw value to be used for region 1 correction. raw 2 raw value used for region 2 correction. raw_break raw value at which the transition from region 1 to region 2 occurs. offset offset correction for sensor applied at 50% full scale input. gain_1 gain correction for sensor applied to region 1. sot_1 se cond - order correction for sensor region 1. gain_2 gain correction for sensor applied to region 2 C not used if only 1 region is used. sot_2 alternatively tot_1 second - order correction for sensor region 2 C not used if only 1 region is used. used as third - order term tot_1 for third - order correction. 2 2 2 1 2 1 raw * 2 _ gain ) raw * 2 _ gain ( * 2 _ sot raw * 1 _ gain ) raw * 1 _ gain ( * 1 _ sot out ? ? ? ? ) tcg _ sot t tcg ( t 1 ) tco _ sot t tco ( t offset c _ raw rawtc ? ? ? ? ? ? ? ? ? ? ? ? ? ? ) tcg _ sot t tcg ( t 1 ) tco _ sot t tco ( t offset c _ raw raw 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 2 1 3 1 raw * 1 _ gain ) raw * 1 _ gain ( * 1 _ sot ) raw * 1 _ gain ( * 1 _ tot out ? ? ? ) break _ raw , rawtc ( min raw 1 ? ) break _ raw rawtc , 0 ( max raw 2 ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 57 of 67 symbol description tco correction for offset drift due to temperature. tcg correction for sensitivity (gain) change due to temperature. sot_tco second - order correction for offset drift due to temperature. sot_tcg second - order correction for sensitivity change due to temperature. t ref raw temperature reading used as a reference temperature for the removal of all tc components. ? t difference between current raw temperature and the reference temperature. out corrected capacita nce output value. 6.2 temperature signal compensation temperature is measured internally. temperature correction contains both linear gain and offset terms as well as a second - order term to correct for any nonlinearity. note: the following equation is only meant to show the general form and capabilities of the internal ZSSC3123 t emperature signal conditioning. (23) where symbol range description raw_t [0,16383] raw temperature reading gain_t [ - 32768,32767] gain correction for internal temperature offset_t [ - 32768,32767] offset correction for internal temperature sot_t [ - 32768,32767] second - order correction for internal temperature t [ - 32768,32767] corrected temperature output value t _ offset t _ raw * t _ gain ) t _ raw ( * t _ sot t 2 ? ? ?
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 58 of 67 6.3 limits on coefficient ranges there are range limits on some of the calibrat ion coefficients that will be enforced by the calibration routine provided by zmdi. these limits ensure the integrity of the internal calculations and would only limit the most extreme cases of sensor correction. note : for alarm - only applications, it is cr itical that the coefficient verification feature of the calibration routine is used since diagnostics are not reported for the alarms (see section 3.4 for more details) the table below shows the limits for corre ction for the grade of temperature dependency and 2 nd nonlinearity of this dependency : coefficient correction condition tco 6060 ppm/k sot_tco 74 ppm/k 2 tcg 1 2120 ppm/k b ased on raw temperature values sot_tcg 1 47 ppm/k 2 b ased on raw temperature val ues
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 59 of 67 7 application circuit examples the ZSSC3123 provides functionality for many different configurations. the following examples correspond to the example circuits shown at the beginning of the specification; however, there are many other possibilities. co m - binations of these examples and many other options can give the user maximum design flexibility. settings for the configuration registers are given with each example. see table 5 . 1 for register addresses. in the examples below bits 3 and 4 of the zmd i _config register are marked with an x because they are calculated during calibration and are coefficient dependent (see section 6 ). 7.1 digital output with optional alarms in this example, a single - ended input capacitance is con - verted to the digital domain, corrected, and output via i 2 c. the configuration settings are shown in table 7 . 1 below. the ZSSC3123 operates in sleep mode, in w hich meas - urement commands are used during normal operation. in this exam ple, the i 2 c address is 28 h and the comm_lock is set. in this application, both alarm_high and alarm_low are used for digital communication. as shown in table 7 . 1 below, both alarms are configured as active high and full push - pull drivers for digital communication. the afe configuration registers select 14 - bit resolution for capacitance with a capacitance range from 2.9pf to 7.2pf. the inter nal temperature is set to 14 - bit resolution. figure 7 . 1 digital output with optional alarm s example table 7 . 1 example 1: configuration settings configuration reg ister 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 zmd i _config ( table 5 . 2 ) 0 ? 0 0 0 1 0 1 1 0 0 0 x x 0 0 1 cust_config ( table 5 . 5 ) 0 ? 0 ? 0 0 0 0 0 0 0 0 1 0 1 0 0 0 c_config ( table 5 . 3 ) 0 ? 0 0 0 1 1 0 ? 0 ? 0 ? 0 ? 0 1 0 0 1 1 t_config ( table 5 . 4 ) 1 ? 0 ? 0 ? 0 ? 1 1 0 ? 1* 1* 0* 0* 1* 0* 0* 1* 0* * the factory settings are set for a full span temperat ure range from - 40c to +125c. do not change this setting unless a different temperature range is needed. ? reserved setting C do not change factory settings. v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e r e a d y v s s s d a / m i s o s c l / s c l k c 0 s s a l a r m _ h i g h c c a l a r m _ l o w c l i t e ? z s s c 3 1 2 3 0 . 1 f
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 60 of 67 7.2 analog output with optional alarms in this example, a single - ended input capacitance is conver ted, corrected and then both capacitance and temperature are output via pdm, which are then low - pass filtered for analog outputs. one of the optional alarms controls an led. the configuration settings are shown below in table 7 . 2 . in the zmd i _config register, the output selection bits are set to 10 to select pdm. example low - pass filter values are given in section 3.7 . for pdm, update mode must be selected. in this appli - cation example, a 25ms power - down period has been used. in this application, alarm_high is used to turn on an led in an open - drain configuration. the output must be low for the led to be on, so the alarm_high polarity bit is set to active low. the pdm cli pping limits are set for 10% (666 hex ) to 90% (3999 hex ) output. the afe configuration registers show a resolution of 14 bits for capacitance; however, the pdm low pass filter may be set for a lower resolution with a faster settling time (see section 3.7 ). a capacitance range of 1.4 pf to 8.6 pf has been chosen, which requires a m ult setting of 1 . the internal temperature is set to 12 - bit resolution. figure 7 . 2 analog o utput with optional alarms example table 7 . 2 example 2: configuration settings configuration register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 zmd i _config ( table 5 . 2 ) 0 ? 0 1 1 0 0 1 1 0 0 0 x x 1 0 0 cust_config ( table 5 . 5 ) 0 ? 0 ? 0 0 0 0 1 0 0 0 1 0 1 0 0 0 c_config ( table 5 . 3 ) 0 ? 0 0 0 1 1 0 ? 0 ? 0 ? 0 ? 0 0 1 1 0 1 t_config ( table 5 . 4 ) 1 ? 0 ? 0 ? 0 ? 1 0 0 ? 1* 1* 0* 0* 1* 0* 0* 1* 0* pdm_clip_high 0 0 1 1 1 0 0 1 1 0 0 1 1 0 0 1 pdm_clip_low 0 0 0 0 0 1 1 0 0 1 1 0 0 1 1 0 * the factory settings are set for a full span temperature range from - 40c to +125c. do not change this setting unless a different temperature range is needed. ? reserved setting C do not change factory settings. v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e v s s c 0 c c c l i t e ? z s s c 3 1 2 3 0 . 1 f c a p . a n a l o g o u t p u t l e d p d m _ c p d m _ t a l a r m _ h i g h t e m p a n a l o g o u t p u t
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 61 of 67 7.3 bang - bang control system in this example, the only outputs are the alarm pins. they are programmed to control a h igh voltage bang - bang hu - midity control system. external devices are not needed if not using high voltage. if the humidity gets too high, the ZSSC3123 activates the dehumidifier using the alarm_high pin. if the humidity gets too low, it activates the hum idifier with the alarm_low pin. the alarm registers must be set to appropriate trip and hysteresis points (see section 3.8 ). the configuration settings are shown in table 7 . 3 . the output selection bits should either be set to i 2 c or spi since depending on the pdm configuration, both alarms are not supported. additionally, i 2 c and spi are lower power than pdm. this application does not use i 2 c or spi, so update mode must b e used because sleep mode commands cannot be sent. the fastest update rate is used for this example. external devices are needed to control the outputs because a voltage source greater than vdd is used. figure 7 . 3 bang - bang control system example the alarm pins control nmos devices so the alarm pins must be full push - pull and output high when the alarm is on, so the polarity bits are set to 0 and the open drain bits are set to 0. in this example application, a faster response time may be needed, so the afe configuration settings show 10 - bit resolution for both capacitance and internal temperature. c_config settings have been selected for a capacitance range of 5.8pf to 7.2pf (see table 2 . 2 ) . table 7 . 3 example 3: configuration settings configuration register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 zmd i _config ( table 5 . 2 ) 0 ? 0 0 0 1 0 1 1 0 0 0 x x 0 0 0 cust_config ( table 5 . 5 ) 0 ? 0 ? 0 0 0 0 0 0 0 0 1 0 1 0 0 0 c_config ( table 5 . 3 ) 0 ? 0 0 0 0 1 0 ? 0 ? 0 ? 0 ? 1 0 0 0 0 1 t_config ( table 5 . 4 ) 1 ? 0 ? 0 ? 0 ? 0 1 0 ? 1* 1* 0* 0* 1* 0* 0* 1* 0* * the factory settings are set for a full span temperature range from - 40c to +125c. do not change this setting unless a different temperature range is needed. ? reserved setti ng C do not change factory settings. dehumidifier gnd gnd 0.1 f v supply +2.3v to 5.5v humidifier gnd 12v 12v vdd vcore v ss alarm_high c0 alar m_low cc clite ? zssc312 3 0. 1 f
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 62 of 67 7.4 differential input capacitance this example shows that the full functionality of the ZSSC3123 including the applications illustrated in examples 1, 2, and 3, can be implemented with a differential input capacitance. the capacitor c cc allows a non - galvanic con - nection (e.g., to the moving part of a motion sensor as part of the sensor construction), but it is not needed for sensor types with existing galvanic connections. the configuration settings are shown in table 7 . 4 . the differential bit is set to select differential input capacitance. in this example, spi has been selected in update mode at the fastest update rate. the spi phase is set to 1 so that the master samples miso o n the negative edge of sclk . t he eeprom has been locked. the afe configuration registers select 14 - bit reso - lution for capacitance and 10 - bit resolution for internal temperature. because this is the differential config - uration, both the internal reference and offset capaci - tors are set to zero. figure 7 . 4 differential input capacitance example table 7 . 4 example 4: configuration settings configuration register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 zmd i _config ( table 5 . 2 ) 0 ? 0 0 1 1 0 0 0 0 1 1 x x 0 0 0 cust_config ( table 5 . 5 ) 0 ? 0 ? 0 0 1 0 0 0 0 0 1 0 1 0 0 0 c_config ( table 5 . 3 ) 0 ? 1 0 0 1 1 0 ? 0 ? 0 ? 0 ? 0 0 0 0 0 0 t_config ( table 5 . 4 ) 1 ? 0 ? 0 ? 0 ? 0 1 0 ? 1* 1* 0* 0* 1* 0* 0* 1* 0* * the factory settings are set for a full span temperature range from - 40c to +125c. do not change this setting unless a different temperature range is needed. ? reserved setting C do not change factory settings. v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e r e a d y v s s s d a / m i s o s c l / s c l k c 0 s s a l a r m _ h i g h c 1 a l a r m _ l o w c l i t e ? z s s c 3 1 2 3 0 . 1 f c c
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 63 of 67 7.5 external reference capacitor t his example demonstrates that the full functionality of the ZSSC3123 , in cluding the applications illustrated in examples 1, 2, and 3, can be implemented with an exter - nal reference capacitor in conjunction with a single - ended input capaci tance. in this example, the digital output is used. the external reference is used . the c onfiguration settings are shown in table 7 . 5 . example configuration settings show i 2 c in sleep mode with the comm_lock off so that the ZSSC3123 can res - pond to any i 2 c slave address. also the ready pin is configure d for open drain so that multiple devices can have their ready lines connected together. the afe configuration registers select 12 - bit resolution for capacitance and 12 - bit resolution for internal temper - ature. this example also shows an offset setting of 4.3 pf. figure 7 . 5 ext. reference input capacitance example table 7 . 5 example 5: configuration settings configuration register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 zmd i _config ( table 5 . 2 ) 0 ? 0 0 0 1 0 0 0 0 0 0 x x 0 0 0 cust_config ( table 5 . 5 ) 0 ? 0 ? 0 1 0 0 0 0 0 0 1 0 1 0 0 0 c_config ( table 5 . 3 ) 0 ? 0 0 0 1 0 0 ? 0 ? 0 ? 0 ? 0 1 1 0 0 0 t_config ( table 5 . 4 ) 1 ? 0 ? 0 ? 0 ? 1 0 0 ? 1* 1* 0* 0* 1* 0* 0* 1* 0* * the factory settings are set for a full span temperature range from - 40c to +125c. do not c hange this setting unless a different temperature range is needed. ? reserved setting C do not change factory settings. 8 esd/latch - up - protection all external module pins have an esd protection of >4000v and a latch - up protection of ? 100ma or (up to +8v / down to C 4v) relative to vss/vssa. the internal module pin vcore has an esd protection of > 2000v. esd protection referenced to the human body model is tested with devices in tssop14 packages during product qualification. the esd test follows the human bo dy model with 1.5kohm/100pf based on mil 883, method 3015.7. v s u p p l y ( + 2 . 3 v t o 5 . 5 v ) g n d 0 . 1 f v d d v c o r e r e a d y v s s s d a / m i s o s c l / s c l k c 0 s s a l a r m _ h i g h c 1 a l a r m _ l o w c l i t e ? z s s c 3 1 2 3 0 . 1 f c c r e f . c a p
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 64 of 67 9 pin configuration and package the standard package for the ZSSC3123 is a tssop - 14 (4.4 0.1mm body wide) with lead - pitch 0.65mm. see the notes in table 9 . 2 regarding connection requirements. table 9 . 1 storage and soldering condition storage and soldering tssop14 ? maximum storage temperature t max _ storage less than 10hrs, before mounting 150 ? c minimum stora ge temperature: t min _ storage at original packing only - 55 ? c maximum drybake temperature t drybake less than100hrs in summary, before mounting 125 ? c soldering peak temperature t peak less than 30s (ipc/jedec - std - 020 standard) 260 ? c figure 9 . 1 ZSSC3123 pin - out diagram table 9 . 2 ZSSC3123 pin assignments for tssop - 14 pin name description notes 1 vcore core voltage always connect to an external capacit or to gnd that is within the specifications given in section 1.3 for c vcore_sm and c vcore_um . this is the only internal module pin. r efer to section 8 for esd details . 2 c0 capacitor input 0 3 vss ground supply connecting to gnd for shielding is strongly recommended. 4 cc common capacitor input 1 14 2 13 3 12 4 11 5 10 6 9 7 8
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 65 of 67 pin name description notes 5 vss ground supply connecting to gnd for shielding is strongly recommended. 6 c1 capacitor input 1 if not used, must b e unconnected. 7 vdd supply voltage ( 2.3v to 5.5v ) must connect to vsupply. 8 alarm_low/ pdm_t low alarm output temperature pdm (see table 3 . 8 ) if not used, must be unconnected. 9 alarm_high high alarm output i f not used, must be unconnected. 10 ready/ pdm_c ready signal (conversion complete output) capacitance pdm (see table 3 . 8 ) if not used, must be unconnected. 11 vss ground supply must connect to gnd. 12 sda/mis o i 2 c data if in i 2 c mode master - in - slave - out if in spi mode (see table 3 . 8 ) if not used, must connect to vdd. 13 scl/sclk i 2 c clock if in i 2 c mode serial clock if in spi mode (see table 3 . 8 ) if not used, must connect to vdd. 14 ss slave select (input) if in spi mode (see table 3 . 8 ) if not used, must be unconnected. 10 test the test program is based on this datasheet. the final par ameters, which will be tested during production, are listed in the tables and graphs of section 1 .
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 66 of 67 11 reliability a reliability investigation according to the in - house non - automotive standard will be performed. 12 cus tomization for high - volume applications that require an upgraded or downgraded functionality compared to the ZSSC3123 , zmdi can customize the circuit design by adding or removing certain functional blocks. for this customization, zmdi has a considerable l ibrary of sensor - dedicated circuitry blocks, which enable zmdi to provide a custom solution quickly. please contact zmdi for further information. 13 part ordering codes please contact zmdi sales for additional information . contact zmdi sales for suppo rt and sales of the ZSSC3123 mass calibration system. 14 related documents visit zmdis website www.zmdi.com or contact your nearest sales office for the latest version of these documents. 15 glossary sales code description package zssc 3123aa1b ZSSC3123 clite? die temperature range: - 40c to +125c tested dice on un - sawn wafer ZSSC3123aa1c ZSSC3123 clite? die temperature range: - 40c to +125c tested dice on frame ZSSC3123aa2 ZSSC3123 clite? tssop14 temperature range: - 40c to +1 25c C lead - free package tube: add Dt to sales code reel: add Dr ZSSC3123kit ZSSC3123 ssc evaluation kit: communication board, ssc evaluation board, sensor replacement board, evaluation software, usb cable, 5 ic samples kit document file name ZSSC3123 clite? ssc evaluation kit description ZSSC3123 _clite_ ssc_evaluation _kit_revx.x.pdf term descri ption adc analog - to - digital converter cdc capacitance - to - digital converter dac digital - to - analog converter ecc error checking and correction ssc sensor signal conditioner
zssc312 3 cl ite? c apacitiv e sensor signal conditione r data sheet september 29, 2011 ? 2011 zentrum mikroelektronik dresden ag rev. 1.00 all rights reserved. the material c ontained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. the information furnished in this publicatio n is subject to changes without notice. 67 of 67 16 document revision history revision date description 1.00 september 2 9, 2011 fi rst release of document sales and further information www.zmdi.com ssc@zmdi.com zentrum mikroelektronik dresden ag grenzstrasse 28 01109 dresden germany zmd america, inc. 8413 exc elsior drive suite 200 madison, wi 53717 usa zentrum mikroelektronik dresden ag, japan office 2nd floor, shinbashi tokyu bldg. 4 - 21 - 3, shinbashi, minato - ku tokyo, 105 - 0004 japan zmd far east, ltd. 3f, no. 51, sec. 2, keelung road 11052 taipei taiwan zentr um mikroelektronik dresden ag, korean office posco centre building west tower, 11th floor 892 daechi, 4 - dong, kangnam - gu seoul, 135 - 777 korea phone +49.351.8822.7.772 fax +49.351.8822.8.7772 phone +1.608.829.1987 fax +1.608.829.2984 phone +81.3.6895.741 0 fax +81.3.6895.7301 phone +886.2.2377.8189 fax +886.2.2377.8199 phone +82.2.559.0660 fax +82.2.559.0700 disclaimer : this information applies to a product under development. its characteristics and specifications are subject to change without notice. ze ntrum mikroelektronik dresden ag (zmd ag) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. the information furnished hereby is believed to be true and accurate. however, under no circumstances shall zmd ag be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of any ki nd or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. zmd ag hereby expressly disclaims any liability of zmd ag to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of zmd ag for any da mages in connection with or arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability , or otherwise.
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