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iq switch ? proxsense ? series iqs232 datasheet - con?gurable 2 channel sensor with compensation for sensitivity reducing objects unparallelled features: o sub 4 a current consumption o automatic tuning for optimal operation in various environments & compensation against sensi- tivity reducing objects the iqs232 proxsense ? ic is a fully integrated two channel capacitive contact and proximity sensor with market leading sensitivity and automatic tuning of the sense electrodes. the iqs232 provides a minimalist implementation requiring as few as 2 external components. the device is ready for use in a large range of applications while programming options allow customisation in specialised applications. main features: o 2 channel input device o differentiated touch and distributed proximity electrode o ati: automatic tuning to optimum sensitivity o supply voltage 1 . 8 v to 3 . 6 v o internal voltage regulator and reference capacitor o otp options available o direct (logic level) and serial data output o low power modes (sub 4 a min) o adjustable proximity & touch thresholds o automatic drift compensation o development and programming tools available o small and cost effective so-8 package applications: o white goods and appliances o remote controls o of?ce equipment, toys, sanitary ware o flame proof, hazardous environment hu- man interface devices o proximity detection that enables back light- ing activation (patented) o wake-up from standby applications o replacement for electro mechanical switches o gui trigger on proximity detection. copyright ? azoteq iqs232 prelimanary datasheet v1.00 1of 33
iq switch ? proxsense ? series contents list of figures 3 list of tables 3 revision history 3 list of symbols 4 1 functional overview 5 1.1 pin outs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 analogue functionality 6 3 digital functionality 6 4 reference design 7 4.1 power supply and pcb layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.2 design rules for harsh emc environments . . . . . . . . . . . . . . . . . . . . . . . 8 5 high sensitivity 9 6 user con?gurable options 9 6.1 con?guring of devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7 description of user options 15 7.1 ati method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7.2 touch base values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7.3 touch thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7.4 proximity threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 7.5 halt time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.6 proximity base value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.7 sensitivity multipliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.8 base multipliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.9 base select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.10 charge transfer frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.11 streaming mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.12 noise detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.13 low power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.14 guard channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.15 output logic select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.16 ati delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.17 ati target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8 charge transfers 20 9 auto tuning implementation 21 9.1 full ati . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 9.2 partial ati . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 10 speci?cations 23 copyright ? azoteq iqs232 prelimanary datasheet v1.00 2of 33
iq switch ? proxsense ? series 11 mechanical dimensions 25 12 device marking 28 13 ordering information 28 14 contact information 29 15 memory map 30 references 33 list of figures 1.1 iqs232 pin-out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1 iqs232 reference design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.2 emc design choices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1 lp modes: charge cycles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8.1 charge transfer for iqs232. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 11.1 so 8 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 11.2 so 8 footprint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 11.3 so 8 silk screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 list of tables 1.1 iqs232 pin-outs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1 user selectable con?guration options: bank 0 . . . . . . . . . . . . . . . . . . . . . 10 6.2 user selectable con?guration options: bank 1 (full ati) . . . . . . . . . . . . . . . . 11 6.3 user selectable con?guration options: bank 1 (partial ati) . . . . . . . . . . . . . . 12 6.4 user selectable con?guration options: bank 2 . . . . . . . . . . . . . . . . . . . . . 13 6.5 user selectable con?guration options: bank 3 . . . . . . . . . . . . . . . . . . . . . 14 7.1 distributed proximity channels base values. . . . . . . . . . . . . . . . . . . . . . . . 17 7.2 iqs232 low power mode timings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1 iqs232 general operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 23 10.2 start-up and shut-down slope characteristics . . . . . . . . . . . . . . . . . . . . . . 23 10.3 pout and tout characteristics for each i/o . . . . . . . . . . . . . . . . . . . . . . 23 10.4 initial touch times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 10.5 repetitive touch rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 11.1 so-8 package dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 11.2 so 8 footprint dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 11.3 so-8 silk screen dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 revision history rev description date 0.01 preliminary march 2012 1.00 first release june 2012 copyright ? azoteq iqs232 prelimanary datasheet v1.00 3of 33
iq switch ? proxsense ? series list of symbols ati auto tuning implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 bp boost power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ch channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 cs count(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 cx sensor electrode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 emi electromagnetic interference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 esd electro-static discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ftb / eft (electrical) fast transient bursts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 gnd ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 lp low power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 lta long term average . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 nd noise detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 np normal power mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 otp one-time programmable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 p proximity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 po proximity output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 prox proximity event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 rdy ready . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 rf radio frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 scl i 2 c clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 sda i 2 c data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 t time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 thr threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 to touch output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 vddhi supply (input) voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 vreg internal regulator output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 copyright ? azoteq iqs232 prelimanary datasheet v1.00 4of 33
iq switch ? proxsense ? series 1 functional overview the iqs232 is a two channel capacitive proximity and touch sensor featuring an internal voltage regular and reference capacitor (cs). the device has two dedicated input pins for the connection of the sense electrodes (cx). two output pins for touch (for each channel) detection and one output (po) for proximity detection. the output pins can be con?gured as logic outputs or in a serial data streaming option on to0 (data) and to1 (clock). the device automatically tracks slow varying environmental changes via various ?lters, detect noise and has an automatic auto tuning implementation (ati) to tune the device for optimal sensitivity. 1.1 pin outs figure 1.1: iqs232 pin-out. the iqs232 is pin compatible with the iqs132, but has different electrical characteristics. refer to section 10 . table 1.1: iqs232 pin-outs pin stand alone streaming function 1 gnd gnd ground 2 cx0 cx0 sense electrode 3 vddhi vddhi power input 4 vreg vreg regulator pin 5 po/rf rdy/rf proximity output 6 to0 sda touch output 7 to1 scl touch output 8 cx1 cx1 sense electrode copyright ? azoteq iqs232 prelimanary datasheet v1.00 5of 33 g n d c x 0 v d d h i v r e g c x 1 t o 1 / s c l t o 0 / s d a p o 0 / r f / r d y
iq switch ? proxsense ? series 1.2 applicability all speci?cations, except where speci?cally men- tioned otherwise, provided by this datasheet are applicable to the following ranges: o temperature 40 c to + 85 c o supply voltage (vddhi) 1 . 8 v to 3 . 6 v 2 analogue functionality the analogue circuitry measures the capacitance of the sense electrodes attached to the cx pins through a charge transfer process that is period- ically initiated by the digital circuitry. the mea- suring process is referred to as a conversion and consists of the discharging of cs and cx, the charging of cx and then a series of charge transfers from cx to cs until a trip voltage is reached. the number of charge transfers re- quired to reach the trip voltage is referred to as the counts (cs). the capacitance measurement circuitry makes use of an internal c s and volt- age reference (v ref ). the analogue circuitry further provides functionality for: o power on reset (por) detection. o brown out detection (bod). 3 digital functionality the digital processing functionality is responsi- ble for: o device con?guration from otp settings after por. o management of bod and wdt events. o initiation of conversions at the selected rate. o processing of cs and execution of algorithms. o monitoring and automatic execution of the ati algorithm. o signal processing and digital ?ltering. o detection of prox and touch events. o managing outputs of the device. o managing serial communications. o manage programming of otp options. copyright ? azoteq iqs232 prelimanary datasheet v1.00 6of 33
iq switch ? proxsense ? series 4 reference design figure 4.1: iqs232 reference design. 4.1 power supply and pcb layout azoteq ics provide a high level of on-chip hardware and software noise ?ltering and esd protection (refer to section 10 ). designing pcbs with better noise immunity against emi, ftb and esd in mind, it is always advisable to keep the critical noise suppression components like the de-coupling capacitors and series resistors in figure 4.1 as close as possible to the ic. always maintain a good ground connection and ground pour underneath the ic. for more guidelines please refer to the relevant application notes as mentioned in section 4.2 . copyright ? azoteq iqs232 prelimanary datasheet v1.00 7of 33 r3 2k0 r4 2k0 vddhi vddhi vddhi gnd c1 1uf c2 1uf r5 2k0 vddhi r2 470r po r1 470r to0 to1 gnd c4 100pf c3 100pf vreg 4 vddhi 3 cx0 2 gnd 1 cx1 8 to1/scl 7 to0/sda 6 po0/rf&rdy 5 so-8 iqs232 to0 to1 po po to0 to1 r8 2k0 r7 2k0 r6 2k0 vddhi sda to mcu scl to mcu rdy to mcu
iq switch ? proxsense ? series 4.2 design rules for harsh emc environments figure 4.2: emc design choices. applicable application notes: [ 1 ], [ 2 ], [ 3 ], [ 4 ] copyright ? azoteq iqs232 prelimanary datasheet v1.00 8of 33 1) determine prox, touch & data requirements 2) choose device radiated rf azd015 ? rx > 1k may be required ? long cx traces not ok ? use rf detection as last resort fast transient bursts azd051 ? rx > 1k may be required ? long cx traces ok ? careful with cx pad size ? grounding very nb electro - static discharge azd013 ? preferably use rx of 470 ? rather use tvs than higher rx to protect ? grounding of tvs nb conducted rf azd052 ? preferably use rx of 470 ? filtering and grounding of supply very nb ? traces < 200mm ok what is the biggest emc threat? start
iq switch ? proxsense ? series 5 high sensitivity through patented design and advanced signal processing, the device is able to provide extremely high sensitivity to detect proximity. this enables designs to detect proximity at distances that can- not be equalled by most other products. when the device is used in environments where high levels of noise exist, a reduced proximity thresh- old is proposed to ensure reliable functioning of the sensor. when the capacitance between the sense electrode and ground becomes too large the sensitivity of the device may be in?uenced. for more guidelines on layout, please refer to [ 5 ], available on the azoteq web page, visit: www.azoteq.com 6 user con?gurable options the iqs232 provides one time programmable (otp) user options (each option can be modi- ?ed only once). the iqs232 can enter stream- ing mode (i 2 c debuging) at start-up where the otp options can be set and evaluated through the memory map, refer to section 15 , before programming otp setting for stand alone use. the device is fully functional in the default (un- con?gured) state. otp options are intended for speci?c applications. the con?guration of the device can be done on packaged devices or in- circuit. in-circuit con?guration may be limited by values of external components chosen. 6.1 con?guring of devices azoteq offers a con?guration tool (ct220 or later) and accompanying software (usbprog.exe) that can be used to program the otp user op- tions for prototyping purposes. more details re- garding the con?guration of the device with the usbprog program is explained by [ 6 ]: "azd007 - usbprog overview" which can be found on the azoteq website. alternate programming so- lutions of the iqs232 also exist. for further enquiries regarding this matter please contact azoteq at: proxsensesupport@azoteq.com or the local dis- tributor. copyright ? azoteq iqs232 prelimanary datasheet v1.00 9of 33
iq switch ? proxsense ? series table 6.1: user selectable con?guration options: bank 0 ati sys use base tch t thr 2 t thr 1 t thr 0 p thr 1 p thr 0 bit 7 bank 0 bit 0 bank 0: bit 7 ati:ati method section 7.1 0 = full 1 = partial bank 0: bit 6 system use bank 0: bit 5 base tch : ati base value for touch channels section 7.2 0 = 250 (less sensitive) 1 = 100 (more sensitive) bank 0: bit 4:2 t thr 2:t thr 1: touch thresholds (ch2 independent) section 7.3 000 = 4/64 001 = 1/64 (most sensitive) 010 = 2/64 011 = 8/64 100 = 12/64 101 = 16/64 110 = 24/64 111 = 32/64 (least sensitive) bank 0: bit 4:2 p thr 1:p thr 1: proximity threshold section 7.4 00 = 4 01 = 2 (most sensitive) 10 = 8 11 = 16 (least sensitive) copyright ? azoteq iqs232 prelimanary datasheet v1.00 10of 33
iq switch ? proxsense ? series table 6.2: user selectable con?guration options: bank 1 (full ati) t h alt 1 t h alt 0 sys use t thr 2 t thr 1 t thr 0 base1 base0 bit 7 bank 1 - full ati bit 0 bank 1: bit 7:6 t h alt 1:t h alt 0: halt time of long term average section 7.5 00 = 20 seconds 01 = 40 seconds 10 = never 11 = always (prox on 40) bank 1: bit 5 system use bank 1: bit 4:2 ch2 t thr 2:t thr 0: touch thresholds on ch2 section 7.3 000 = 4/64 001 = 1/64 (most sensitive) 010 = 2/64 011 = 8/64 100 = 12/64 101 = 16/64 110 = 24/64 111 = 32/64 (least sensitive) bank 1: bit 1:0 base1:base0: proximity (ch0) base value section 7.6 00 = 200 (150 with basesel set to alternative) 01 = 50 (350 with basesel set to alternative) 10 = 100 (500 with basesel set to alternative) 11 = 250 (700 with basesel set to alternative) copyright ? azoteq iqs232 prelimanary datasheet v1.00 11of 33
iq switch ? proxsense ? series table 6.3: user selectable con?guration options: bank 1 (partial ati) t h alt 1 t h alt 0 mul5 mul4 mul3 mul2 mul1 mul0 bit 7 bank 1 - partial ati bit 0 bank 1: bit 7:6 t h alt 1:t h alt 0: halt time of long term average section 7.5 00 = 20 seconds 01 = 40 seconds 10 = never 11 = always (prox on 40) bank 1: bit 5:4 mul5:mul4: sensitivity multipliers section 7.7 00 = lowest 11 = highest bank 1: bit 3:0 mul3:mul0: base multipliers section 7.8 0000 = lowest 1111 = highest copyright ? azoteq iqs232 prelimanary datasheet v1.00 12of 33
iq switch ? proxsense ? series table 6.4: user selectable con?guration options: bank 2 base sel t frq streaming nd pmode1 pmode0 cx1 block logic bit 7 bank 2 bit 0 bank 2: bit 7 base sel : base select section 7.9 0 = default 1 = alternative bank 2: bit 6 t frq : charge transfer frequency section 7.10 0 = 250khz 1 = 1mhz bank 2: bit 5 streaming: 2-wire streaming mode section 7.11 0 = disabled 1 = enabled bank 2: bit 4 nd: noise detect section 7.12 0 = disabled 1 = enabled bank 2: bit 3:2 pmode1:pmode0: low power mode section 7.13 00 =9ms (boost power mode) 01 = 32ms (normal power mode) 10 = 128ms (low power 1) 11 = 1s (low power 2) bank 2: bit 1 cx1 block: guard channel enable section 7.14 0 = disabled 1 = enabled bank 2: bit 0 logic: output logic select section 7.15 0 = active low 1 = active high copyright ? azoteq iqs232 prelimanary datasheet v1.00 13of 33
iq switch ? proxsense ? series table 6.5: user selectable con?guration options: bank 3 sys use sys use sys use sys use sys use sys use delay target bit 7 bank 3 bit 0 bank 3: bit 7:2 sys use: system use bank 3: bit 1 delay: ati delay after prox cleared section 7.16 0 = 0 seconds 1 = 10 seconds bank 3: bit 0 target: ati target counts section 7.17 0 = proximity channel - 1024; touch channels - 512 1 = proximity channel - 512; touch channels - 256 copyright ? azoteq iqs232 prelimanary datasheet v1.00 14of 33
iq switch ? proxsense ? series 7 description of user options this section describes the individual user pro- grammable options of the iqs232 in more de- tail. azoteq can supply pre-con?gured devices for large quantities. thresholds and other settings can also be evaluated in test mode streaming without pro- gramming the otp options. for appropriate software, visit www.azoteq.com 7.1 ati method the iqs232 can be setup to start in two ways; full ati and partial ati. in full ati mode, the de- vice automatically select the multipliers through the ati algorithm to setup the iqs232 as close as possible to its default sensitivity for the envi- ronment where it was placed. the designer can, however, select partial ati, and set the multipli- ers to a pre con?gured value. this will cause the iqs232 to only calculate the compensation (not the compensation and multipliers as in full ati), which allows the freedom to make the iqs232 more or less sensitive for its intended environ- ment of use. 7.2 touch base values the iqs232 has the option to change the base values of the touch channels during the ati al- gorithm. depending on the application, this pro- vides the user with another option to select the sensitivity of the touch channels (along with the touch thresholds, charge transfer frequency and the target counts) without changes in the hard- ware (cx sizes and routing, etc) the default base value 250, and can be set to 100 to in- crease the sensitivity. the base value cannot be changed independently for each channel. 7.3 touch thresholds the iqs232 has 8 touch threshold settings. the touch threshold is selected by the designer to obtain the desired touch sensitivity. the touch threshold is expressed as a fraction of the lta as follows: t th = selectedvalue lta (7.1) where lta is the long term average the touch event is triggered based on t thr , cs and lta. a touch event is identi?ed when for at least 2 consecutive samples of the following equation holds: t thr = < lta cs (7.2) with lower average cs (therefore lower lta) values the touch threshold will be lower and vice versa. changing the target counts of the touch channels, will also change the value of the lta, which affect the counts required for a touch event. the touch threshold for ch0 & ch2 is set in bank 0, while the touch threshold for ch1 is set in bank 1 (when in full ati-mode). this enables the designer to set the blocking channels touch threshold independently from the other two channels, when not using the par- tial ati feature. 7.4 proximity threshold the iqs232 has 4 proximity threshold settings. the proximity threshold is selected by the de- signer to obtain the desired sensitivity and noise immunity. the proximity event is triggered based on the selected proximity threshold; the cs and lta (long term average). the thresh- old is expressed in terms of counts; the same as cs. for a proximity event, the cs (counts) of the prox channel should fall the p thr value be- low the lta for at least 6 consecutive samples. copyright ? azoteq iqs232 prelimanary datasheet v1.00 15of 33
iq switch ? proxsense ? series 7.5 halt time the halt timer is started when a proximity or touch event occurs and is restarted when an event is removed or reoccurs. when a prox- imity condition occurs on any of the channels, the lta for that channel will be "halted", thus its value will be kept ?xed, until the proximity event is cleared, or the halt timer reaches the halt time. the halt timer will count to the se- lected halt time (t h alt ). if the timer expires, all outputs will be cleared. it is possible that the cs could be outside the ati band (target +- 160 or +- 80) when the timer expires, which will cause a re-ati event. the designer needs to select a halt timer value to best accommodate the re- quired application. 20 seconds the halt timer will halt for 20 sec- onds after the last proximity or touch event. 40 seconds the halt timer will halt for 40 sec- onds after the last proximity or touch event. never with the never halt option, the ?lter will not halt when any proximity or touch con- dition occurs. this means the lta will fol- low the cs and an event will clear when lta reaches below the cs + threshold value. always with the always option, the detec- tion of a proximity event will halt the lta for only 40 seconds and with the detec- tion of a touch event will halt the lta for as long as the touch condition applies. 7.6 proximity base value the iqs232 has the option to change the base value of the distributed proximity channel dur- ing the ati algorithm. depending on the appli- cation, this provides the user with another op- tion to select the sensitivity of the proximity de- tection without changes in the hardware (cx sizes and routing, etc). there are 4 available options, with another 4 options becoming avail- able when the basesel bit is set to alternative. 7.7 sensitivity multipliers sensitivity multipliers are added after the base value is selected through the base multipliers. if the sensitivity multipliers are selected high, the ati algorithm could reach the target counts without adding any compensation, thus render- ing the device less sensitive. for the same rea- soning, setting the sensitivity multipliers low, will add more compensation, and increase the de- vice sensitivity. 7.8 base multipliers base multipliers selects the base value of the ati algorithm. thus, if lower values are se- lected, the algorithm needs to add more sen- sitivity multipliers and compensation to reach the target counts, rendering the device more sensitive. for the same reasoning, the device will be less sensitive when using higher base multipliers. care should be taken when setting the base multipliers low, as setting them to low, could cause the algorithm not to reach the tar- get. not reaching the target impact the touch thresholds, as the are derived from the lta. 7.9 base select the base select bit, changes the values of the proximity channels base value options. this al- lows for a different range of available options, as illustrated in table 7.9 . copyright ? azoteq iqs232 prelimanary datasheet v1.00 16of 33
iq switch ? proxsense ? series table 7.1: distributed proximity channels base values. base select 0 1 200 150 base1:base0 50 350 100 500 250 700 7.10 charge transfer frequency the iqs232 has two available for the charge transfer frequency. the default (512khz) is more sensitive, while the 1mhz option allows for better immunity against false detection in appli- cations where moisture could be present near the sense electrodes. the faster frequency is recommended for better stability and response rate in applications with very thin overlays. 7.11 streaming mode there is a streaming bit available that allows for serial data communication on the iqs232. streaming is done via an i 2 c tm compatible 3- wire interface, which consist of a data (sda), clock (scl) and ready (rdy) line. the iqs232 can only function as a slave on the bus, and will only acknowledge on address 0x44h. the rdy line is to be used by the host controller as an indication of when to start communication to the device. the rdy line will be low when it is ready for communication, and it will high when it is do- ing conversions. the iqs232 will not ack on its address while the rdy line is high (thus while the iqs232 is doing conversions). 7.12 noise detect the iqs232 has advanced immunity to rf noise sources such as gsm cellular tele- phones, dect, bluetooth and wifi devices. design guidelines should however be followed to ensure the best noise immunity. notes for layout: o a ground plane should be placed under the ic, except under the cx lines o place the sensor ic as close as possible to the sense electrodes. o all the tracks on the pcb must be kept as short as possible. o the capacitor between vddhi and gnd as well as between vreg and gnd must be placed as close as possible to the ic. o a 100 pf capacitor can be placed in paral- lel with the 1uf capacitor between vddhi and gnd. another 100 pf capacitor can be placed in parallel with the 1uf capaci- tor between vreg and gnd. o when the device is too sensitive for a spe- ci?c application a parasitic capacitor (max 5pf) can be added between the cx line and ground. o proper sense electrode and button design principles must be followed. o unintentional coupling of sense electrode to ground and other circuitry must be lim- ited by increasing the distance to these sources. o in some instances a ground plane some distance from the device and sense elec- trode may provide signi?cant shielding from undesirable interference. however, if interference from rf noise sources persist after proper layout, see [ 2 ], the iqs232 has a noise detect function which will detect rf noise and block outputs from the device. dif- ferent antenna layouts can be used on the rf detect pin (pin 6) and more details can be found in [ 2 ]. copyright ? azoteq iqs232 prelimanary datasheet v1.00 17of 33
iq switch ? proxsense ? series 7.13 low power mode the iqs232 ic has four power modes specif- ically designed to reduce current consumption for battery applications. the power modes are implemented around the occurrence of charge cycle every t sample seconds (refer to table 7.2 ). lower sampling frequencies yield lower power consumption (but decreased response time). during normal operation charge cycles are initiated approximately every 50ms. this is referred to as normal power mode (np). the iqs232 by default charges in boost power mode. the timings for all the power modes are provided in the table below. while in any power mode the device will zoom to bp whenever a sampled count indicates a possible proximity or touch event. this improves the response time. the device will remain in bp for t zoom seconds and then return to the selected power mode. the zoom function allows reliable detection of events with counts being produced at the bp rate. table 7.2: iqs232 low power mode timings power mode t sample (ms) t bp (default) 9 t np 32 t lp 1 128 t lp 2 1000 copyright ? azoteq iqs232 prelimanary datasheet v1.00 18of 33
iq switch ? proxsense ? series figure 7.1: lp modes: charge cycles. 7.14 guard channel when the guard channel (or blocking channel) is enabled, the other touch outputs from the de- vice are blocked when a touch condition is de- tected on ch1 (ch1s touch output is still ac- tive). this can prevent accidental activation when picking up a product, or give a blocking function against water or other environmental factors. 7.15 output logic select the iqs232 can be set to sink or source current in stand-alone mode, by setting the logic output active high or active low. for characterisation data, please refer to table 10.3 . 7.16 ati delay the iqs232 allows an ati delay option of 0 seconds (immediately) or 10 seconds after the proximity output is cleared (and the countss are not within the allowed ati band). 7.17 ati target the default target counts of the iqs232 are 1000 for the proximity channel, and 500 for the touch channels. however, for some applica- tion, a less sensitive and lower target is accept- able, which will also increase the response rate. therefore, the ati target bit can be set, chang- ing the targets to 500 for the proximity channel, and 250 for the touch channels. copyright ? azoteq iqs232 prelimanary datasheet v1.00 19of 33
iq switch ? proxsense ? series 8 charge transfers the iqs232 samples in 3 time slots, with one internal c s capacitor. the charge sequence is shown in 8.1 , where ch0 is the proximity chan- nel, and charges before each of the 2 touch channels. the proximity channel is realised by connecting both sense electrodes with internal switches. therefore: ch0 is a distributed elec- trode formed by the 2 touch electrodes. figure 8.1: charge transfer for iqs232. copyright ? azoteq iqs232 prelimanary datasheet v1.00 20of 33 c h 1 0 c h 2 0 c h 1 c h 1 + c h 2 c x 0 c x 1 c x 0 c h 0 p r o x
iq switch ? proxsense ? series 9 auto tuning implementation ati is a sophisticated technology implemented in all but the ?rst generation proxsense ? de- vices that optimises the performance of the sen- sor in a wide range of applications and envi- ronmental conditions refer to application note [ 7 ], azd027 - auto tuning implementation. ati makes adjustments through internal reference capacitors to obtain optimum performance. ati adjusts internal circuitry according to two pa- rameters, the ati multipliers and the ati com- pensation. the ati multiplier can be viewed as a course adjustment and the ati compen- sation as a ?ne adjustment. the adjustment of the ati parameters will result in variations in the counts and sensitivity. sensitivity can be ob- served as the change in counts as the result of a ?xed change in sensed capacitance. the ati parameters have been chosen to provide signi?- cant overlap. it may therefore be possible to se- lect various combinations of ati multiplier and ati compensation settings to obtain the same counts. the sensitivity of the various options may however be different for the same counts. 9.1 full ati the iqs232 implements an automatic ati al- gorithm. this algorithm automatically adjusts the ati parameters to optimise the sense elec- trodes connection to the device. the device will execute the ati algorithm whenever the device starts-up and when the counts are not within a predetermined range. while the automatic ati algorithm is in progress this condition will be in- dicated in the streaming data and proximity and touch events cannot be detected. the device will only brie?y remain in this condition and it will be entered only when relatively large shifts in the counts has been detected. the automatic ati function aims to keep the counts constant, regardless of the capacitance of the sense elec- trode (within the maximum range of the device). the effects of auto-ati on the application are the following: o automatic adjustment of the device con?g- uration and processing parameters for a wide range of pcb and application de- signs to maintain an optimal con?guration for proximity and touch detection. o automatic tuning of the sense electrodes at start-up to optimise the sensitivity of the application. o automatic re-tuning when the device detects changes in the sensing electrodes capac- itance to accommodate a large range of changes in the environment of the appli- cation that in?uences the sense electrodes. o re-tuning only occurs during device opera- tion when a relatively large sensitivity re- duction is detected. this is to ensure smooth operation of the device during operation. o re-tuning may temporarily in?uences the nor- mal functioning of the device, but in most instances the effect will be hardly notice- able. o shortly after the completion of the re-tuning process the sensitivity of proximity detec- tion may be reduced slightly for a few sec- onds as internal ?lters stabilises. auto- matic ati can be implemented so effec- tively due to: o excellent system signal to noise ratio (snr). o effective digital signal processing to remove ac and other noise. o the very stable core of the devices. o the built in capability to accommodate a large range of sense electrodes capacitance. copyright ? azoteq iqs232 prelimanary datasheet v1.00 21of 33
iq switch ? proxsense ? series 9.2 partial ati if the ati select bit is set to partial ati, the touch threshold for ch2 is the same as for ch1 (see section 7.1 , ch2s touch threshold is now also set in bank 0). if the ati bit is not set (default), ch2 has its own touch threshold. the same applies to the proximity channels base value, which is not set in the ?rst two bits of bank 1 anymore. instead, the ?rst 5 bits of bank 1, changes to multiplier bits (both sensitivity and compensation). setting the partial ati bit is useful for production devices (after prototyping has revealed the correct setup) as it decreases the start-up time of the ic, since the full ati al- gorithm is not implemented at from a cold-start. copyright ? azoteq iqs232 prelimanary datasheet v1.00 22of 33
iq switch ? proxsense ? series 10 speci?cations absolute maximum speci?cations the following absolute maximum parameters are speci?ed for the device: exceeding these maxi- mum speci?cations may cause damage to the device. o operating temperature 40 c to + 85 c o supply voltage (vddhi - gnd) 3 . 6 v o maximum pin voltage vddhi + 0 . 5 v o maximum continuous current (for speci?c pins) 2 ma o minimum pin voltage gnd - 0 . 5 v o minimum power-on slope 100 v / s o esd protection 4 kv o moisture sensitivity level msl 3 table 10.1: iqs232 general operating conditions description condition parameter min typ max unit supply voltage vddhi 1.8 3.6 v internal regulator output 1.8 vddhi 3.3 vreg 1.62 1.7 1.79 v boost operating current 1.8 vddhi 3.3 i iqs 232 bp 148 a normal operating current 1.8 vddhi 3.3 i iqs 232 np 80 a low power operating current 1.8 vddhi 3.3 i iqs 232 lp 1 18 a low power operating current 1.8 vddhi 3.3 i iqs 232 lp 2 3.5 a table 10.2: start-up and shut-down slope characteristics description condition parameter min max unit por vddhi slope 100 v / s por 1.2 1.6 v bod bod 1.15 1.55 v table 10.3: pout and tout characteristics for each i/o symbol description conditions i source unit voh output high voltage vddhi = 3.3v 5 ma symbol description conditions i si nk unit vol output low voltage vddhi = 3.3v 10 ma copyright ? azoteq iqs232 prelimanary datasheet v1.00 23of 33
iq switch ? proxsense ? series table 10.4: initial touch times description parameter min max unit bp report rate 20 61 ms np report rate 63 120 ms lp1 report rate 63 216 ms lp2 report rate 63 1088 ms table 10.5: repetitive touch rates description sample rate response rate unit all power modes 5ms > 15 touches/second all power modes 9ms > 8 touches/second copyright ? azoteq iqs232 prelimanary datasheet v1.00 24of 33
iq switch ? proxsense ? series 11 mechanical dimensions figure 11.1: so 8 package. table 11.1: so-8 package dimensions. dimension [mm] a min 3.75 a max 4.15 b min 4.73 b max 5.13 h max 1.80 l min 5.70 l max 6.30 t min 0.30 t max 0.70 pitch 1.27 w min 0.31 w max 0.51 copyright ? azoteq iqs232 prelimanary datasheet v1.00 25of 33
iq switch ? proxsense ? series figure 11.2: so 8 footprint. table 11.2: so 8 footprint dimensions dimension mm pitch 1.27 c 5.40 y 1.55 x 0.60 figure 11.3: so 8 silk screen. copyright ? azoteq iqs232 prelimanary datasheet v1.00 26of 33

iq switch ? proxsense ? series table 11.3: so-8 silk screen dimensions dimension mm r1 3.20 r2 4.90 copyright ? azoteq iqs232 prelimanary datasheet v1.00 27of 33
iq switch ? proxsense ? series 12 device marking revision x = ic revision number temperature range t = i 40 c to 85 c (industrial) = c 0 c to 70 c (commercial) ic configuration zzzzzz = con?guration (hexadecimal) date code p = package house ww = week yy = year 13 ordering information orders will be subject to a moq (minimum order quantity) of a full reel. contact the of?cial distrib- utor for sample quantities. a list of the distributors can be found under the "distributors" section of www.azoteq.com. for large orders, azoteq can provide pre-con?gured devices. the part-number can be generated by using usbprog.exe or the interactive part number generator on the website. ic name iqs232 = iqs232 configuration zzzzzz = ic con?guration (hexadecimal) package type so = so-8 bulk packaging r = reel (4000pcs/reel) - moq = 4000pcs copyright ? azoteq iqs232 prelimanary datasheet v1.00 28of 33 i q s 2 3 2 x t z z z z z z p w w y y r e v i s i o n d a t e c o d e c o n f i g u r a t i o n m o d e t e m p e r a t u r e i q s 2 3 2 z z z z z z p p b i c n a m e c o n f i g u r a t i o n m o d e b u l k p a c k a g i n g p a c k a g e t y p e
iq switch ? proxsense ? series 14 contact information pretoria office paarl office physical address physical address 160 witch hazel avenue 109 main street hazel court 1, 1st floor paarl highveld techno park 7646 centurion, gauteng western cape republic of south africa republic of south africa tel: +27 12 665 2880 tel: +27 21 863 0033 fax: +27 12 665 2883 fax: +27 21 863 1512 postal address postal address po box 16767 po box 3534 lyttelton paarl 0140 7620 republic of south africa republic of south africa the following patents relate to the device or usage of the device: us 6,249,089 b1, us 6,621,225 b2, us 6,650,066 b2, us 6,952,084 b2, us 6,984,900 b1, us 7,084,526 b2, us 7,084,531 b2, us 7,119,459 b2, us 7,265,494 b2, us 7,291,940 b2, us 7,329,970 b2, us 7,336,037 b2, us 7,443,101 b2, us 7,466,040 b2, us 7,498,749 b2, us 7,528,508 b2, us 7,755,219 b2, us 7,772,781, us 7,781,980 b2, us 7,915,765 b2, ep 1 120 018 b1, ep 1 206 168 b1, ep 1 308 913 b1, ep 1 530 178 b1, zl 99 8 14357.x, aus 761094 iq switch ? , proxsense ? , lightsense tm , airbutton ? and the logo are trademarks of azoteq. the information in this datasheet is believed to be accurate at the time of publication. azoteq assumes no liability arising from the use of the information or the product. the applications mentioned herein are used solely for the purpose of illustration and azoteq makes no warranty or representation that such applications will be suitable without further modi?cation, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. azoteq products are not authorised for use as critical components in life support devices or systems. no licenses to patents are granted, implicitly or otherwise, under any intellectual property rights. azoteq reserves the right to alter its products without prior noti?cation. for the most up-to-date information, please refer to www.azoteq.com. copyright ? azoteq iqs232 prelimanary datasheet v1.00 29of 33
iq switch ? proxsense ? series 15 memory map 00h product number r/w bit 7 6 5 4 3 2 1 0 product number default 0x1f r 01h version number r/w bit 7 6 5 4 3 2 1 0 version number default 0x09 r 10h system flags r/w bit 7 6 5 4 3 2 1 0 system use lp ati busy nd zoom default 0 0 0 r 31h proximity channels r/w bit 7 6 5 4 3 2 1 0 ch2 ch1 ch0 default 0 0 0 r 35h touch channels r/w bit 7 6 5 4 3 2 1 0 ch2 ch1 ch0 default 0 0 0 r copyright ? azoteq iqs232 prelimanary datasheet v1.00 30of 33
iq switch ? proxsense ? series 36h system use r/w bit 7 6 5 4 3 2 1 0 default 0 r 37h system use r/w bit 7 6 5 4 3 2 1 0 default 0 r 39h filter halt r/w bit 7 6 5 4 3 2 1 0 ch2 ch1 ch0 default 0 0 0 r 3dh channel number r/w bit 7 6 5 4 3 2 1 0 default current channel r 42h current sample (cs) r/w bit 7 6 5 4 3 2 1 0 high byte default r 43h counts (cs) r/w bit 7 6 5 4 3 2 1 0 low byte default r copyright ? azoteq iqs232 prelimanary datasheet v1.00 31of 33
iq switch ? proxsense ? series 83h long term average (lta) r/w bit 7 6 5 4 3 2 1 0 high byte default r 84h long term average (lta) r/w bit 7 6 5 4 3 2 1 0 low byte default r c4h otp bank 0 r/w bit 7 6 5 4 3 2 1 0 details in table \ref default r/w c5h otp bank 1 r/w bit 7 6 5 4 3 2 1 0 details in table \ref default r/w c6h otp bank 2 r/w bit 7 6 5 4 3 2 1 0 details in table \ref default r/w c7h otp bank 3 r/w bit 7 6 5 4 3 2 1 0 details in table \ref default r/w copyright ? azoteq iqs232 prelimanary datasheet v1.00 32of 33
iq switch ? proxsense ? series references [1] azd013 - calculating rx for improving esd ratings . azoteq, 2008. [2] azd015 - rf immunity guidelines . azoteq, 2011. [3] azd051 - electrical fast transient burst guidelines . azoteq, 2011. [4] azd052 - conducted rf immunity guidelines . azoteq, 2011. [5] azd008 - design guidelines for touch pads . azoteq, 2011. [6] azd007 - usb prog overview . azoteq, 2008. [7] azd027 - auto tuning implementation . azoteq, 2009. copyright ? azoteq iqs232 prelimanary datasheet v1.00 33of 33
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