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doc.nr. 82 1566 00a murata electronic s oy subject to changes 1 / 14 www.muratamems .fi doc.nr. 82 1566 00 rev.a SCA1000 - n1000070 2 - axis high performance ana log accelerometer fe atures applications ? ? ? ? ? ? o true self test by deflecting the sensing element's proof mass with electrostatic force. o continuous sensing element interconnection failure check. o continuous memory parity check. ? ? ? ? ? ? ? ? ? ? general description the sca100 0 - n1000070 i s a 3d - mems - based dual axis accelerometer that enables tactical grade perform anc e for inertial measurement units (imus) operating in tough environmental conditions. the measuring axes of the sens or are parallel to the mounting plane and orthogonal to each other. wide measurement range and bandwidth, l ow repeatable temperature behavior , low output noise, together with a very robust sensing element and packaging design, make the SCA1000 - n1000 07 0 the ideal choice for challenging inertial sensing applications . product family specification da ta sheet figure 1 . functional block diagram self test 2 sensing element 1 sensing element 2 spi interface self test 1 signal conditioning and filtering a/d conversion signal conditioning and filtering eeprom calibration memory 9 st_2 10 st_1 12 vdd 6 gnd 11 out_1 5 out_2 1 sck 3 miso 4 mosi 7 csb temperature sensor
SCA1000 series murata electronic s oy subj ect to changes 2 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a table of contents SCA1000 - n1000070 2 - axis high performance analog accelerometer .............. 1 table of contents ................................ ................................ ................................ ...................... 2 1 electrical specifications ................................ ................................ ................................ ..... 3 1.1 absolute maximum ratings ................................ ................................ ................................ ... 3 1.2 performance characteristics ................................ ................................ ................................ .. 3 1.3 parameter ................................ ................................ ................................ ................................ 3 1.4 electrical characteristics ................................ ................................ ................................ ....... 4 1.5 spi interface dc characteristics ................................ ................................ ............................ 4 1.6 spi interface ac character istics ................................ ................................ ............................ 4 1.7 spi interface timing specifications ................................ ................................ ....................... 5 1.8 electrical connection ................................ ................................ ................................ .............. 6 2 functional description ................................ ................................ ................................ ....... 7 2.1 measuring directions ................................ ................................ ................................ .............. 7 2.2 ratiometric output ................................ ................................ ................................ .................. 7 2.3 spi serial interface ................................ ................................ ................................ .................. 7 2.4 self test and failure detection modes ................................ ................................ ................ 10 2.5 temperature measurement ................................ ................................ ................................ .. 11 3 application information ................................ ................................ ................................ .... 12 3.1 recommended circuit diagrams and printed circuit board layouts ............................... 12 3.2 recommended printed circuit board footprint ................................ ................................ . 13 4 mechanical specifications an d reflow soldering ................................ .......................... 13 4.1 mechanical specifications (reference only) ................................ ................................ ....... 13 4.2 reflow soldering ................................ ................................ ................................ ................... 14
SCA1000 series murata electronic s oy subj ect to changes 3 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 1 electrical s pecifications t he product version specific performance specifications are listed in the table sca100 0 perf ormance characteristics below. vdd=5.00v and ambient temperature unless otherwise specified. 1.1 absolute maximum ratings supply voltage (v dd ) voltage at input / output pins storage temperature operating temperature mechanical shock - 0.3 v to +5.5v - 0.3v to (v dd + 0.3v) - 55c to +125c - 40c to +125c drop from 1 meter onto a concrete surface (20000g). powered or non - powered 1.2 performance c haracteristics 1.3 parameter condition m in ( 1 typical max ( 1 units measuring range nominal - 4 + 4 g frequ ency response C 3db lp 60 115 170 hz offset (output at 0g) ratiometric output vdd/2 vdd/2 v offset digital output 1024 lsb offset calibration error - 20 20 mg offset temperature d ependency - 40+125 c 50 50 mg sensitivity 0.55 v/g se nsitivity digital output 226 lsb / g sensitivity calibration error - 2 +2 % sensitivity t emperature d ependency - 40+125 c - 2 .5 +2 % linearity error 4g range 80 mg 4g range 160 mg digi tal o utput r esolution 11 11 bits output n ois e d ensity from dc...100hz 95 120 ratiometric error vdd = 4.75...5.25v - 2 +2 % cross - axis sensitivity max. - 3.5 + 3.5 % note 1 . min/max values are +/ - 3 sigma of test population hz / g ?
SCA1000 series murata electronic s oy subj ect to changes 4 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 1.4 electrical c haracteristics parameter condition min. typ max. units supply voltage vdd 4.75 5.0 5.25 v current consumption vdd = 5 v; no load 4 5 ma operating temperature - 40 +125 c analog resistive output load vout to vdd or gnd 10 k analog capacitive output load vout to vdd or gnd 20 nf start - up delay reset and parity check 10 ms 1.5 spi interface dc characteristics parameter conditions symbol min typ . max unit input terminal csb pull up current v in = 0 v i pu 13 22 35 ? a inp ut high voltage v ih 4 vdd+0.3 v input low voltage v il - 0.3 1 v hysteresis v hyst 0.23*vdd v input capacitance c in 2 pf input terminal mosi, sck pull down current v in = 5 v i pd 9 17 29 ? a input high voltage v ih 4 vdd+0.3 v input low voltag e v il - 0.3 1 v hysteresis v hyst 0.23*vdd v input capacitance c in 2 pf output terminal miso output high voltage i > - 1ma v oh vdd - 0.5 v output low voltage i < 1 ma v ol 0.5 v tri - state leakage 0 < v miso < vdd i leak 5 100 pa 1.6 spi interface ac characteristics parameter condition min. typ. max. units output load @500khz 1 nf spi clock frequency 500 khz internal a/d conversion time 150 ? s data transfer time @500khz 38 ? s
SCA1000 series murata electronic s oy subj ect to changes 5 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 1.7 spi interface timing s pecifications parameter conditio ns symbol min. typ. max. unit terminal csb, sck time from csb (10%) to sck (90%) t ls1 120 ns time from sck (10%) to csb (90%) t ls2 120 ns terminal sck sck low time load capacitance at miso < 2 nf t cl 1 ? s sck high time load capacitance at m iso < 2 nf t ch 1 ? s terminal mosi, sck time from changing mosi (10%, 90%) to sck (90%). data setup time t set 30 ns time from sck (90%) to changing mosi (10%,90%). data hold time t hol 30 ns terminal miso, csb time from csb (10%) to stable mi so (10%, 90%). load capacitance at miso < 15 pf t val1 10 100 ns time from csb (90%) to high impedance state of miso. load capacitance at miso < 15 pf t lz 10 100 ns terminal miso, sck time from sck (10%) to stable miso (10%, 90%). load capacitance at miso < 15 pf t val2 100 ns terminal csb time between spi cycles, csb at high level (90%) t lh 15 ? s when using spi commands rdax, rday, and rwtr : time between spi cycles, csb at high level (90%) tlh 150 ? s figure 2 . timing diagram for spi communication csb sck mosi miso t ls1 t ch t hol t set t val1 t val2 t lz t ls2 t lh msb in msb out lsb in lsb out data out data in t cl
SCA1000 series murata electronic s oy subj ect to changes 6 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 1.8 electrical connection i f the spi interface is not used sck (pin1), miso (pin3), mosi (pin4) and csb (pin7) must be left floating. self - test can be activated applying logic 1 (positive supply voltage level) to st_1 or st_2 pins (pins 10 or 9). self - test must not be activated fo r both channels at the same time. if st feature is not used pins 9 and 10 must be left floating or connected to gnd. a c celeration signals are provided from pins out_1 and out_2. figure 3 . sca10 0 0 electrical connection no. node i/o description 1 sck input serial clock 2 nc input no connect, left floating 3 miso output master in slave out; data output 4 mosi input master out slave in; data input 5 out_2 output y axis output (ch 2) 6 gnd supply ground 7 csb input chip select (active low) 8 nc input no connect, left floating 9 st_2 input self test input for ch 2 10 st_1 input self test input for ch 1 11 out_1 output x axis output (ch 1) 12 vdd supply positive supply voltage (+5v dc ) sck miso mosi out_2 gnd vdd out_1 st_1 st_2 csb 1 2 3 4 5 6 7 8 9 10 11 12 sck ext_c_1 miso mosi out_2 vss csb ext_c_2 st_2 st_1/test_in out_1 vdd
SCA1000 series murata electronic s oy subj ect to changes 7 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 2 functional description 2.1 measuring d irections x - axis y - axis 2.2 ratiometric output ratiometric output means that the zero offset point and sensitivity of the sensor are proportional to th e supply voltage. if the SCA1000 supply vo ltage is fluctuating the SCA1000 output will also vary. when the same refere nce voltage for both the SCA1000 sensor and the measuring part (a/d - converter) is used, the error caused by reference voltage variation is automatically compensated for. 2.3 spi s erial in terface a serial peripheral interface (spi) system consists of one master device and one or more slave devices. the master is defined as a micro controller providing the spi clock and the slave as any integrated circuit receiving the spi clock from the mas ter. the asic in murata electronics products always operates as a slave device in master - slave operation mode. the spi has a 4 - wire synchronous serial interface. data communication is enabled by a low active slave select or chip select wire (csb). data i s transmitted by a 3 - wire interface consisting of wires for serial data input (mosi), serial data output (miso) and serial clock (sck). vout > vout =2.5v > vout fi gure 4 . the mea suring directions of the SCA1000
SCA1000 series murata electronic s oy subj ect to changes 8 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a figure 5 . typical spi connection the spi interface in mura ta products is designed to support any micro controller that uses spi bus. communication can be carried out by either a software or hardware based spi. please note that in the case of hardware based spi, the received acceleration data is 11 bits. the data transfer uses the following 4 - wire interface: mosi master out slave in p sca100 0 miso master in slave out sca100 0 p sck serial clock p SCA1000 csb chip select (low active) p sca100 0 each transmission starts with a falling edge of csb and ends with the rising edge. during transmission, commands and data ar e controlled by sck and csb according to the following rules: ? commands and data are shifted; msb first, lsb last ? each output data/status bits are shifted out on the falling edge of sck (miso line) ? each bit is sampled on the rising edge of sck (mosi line) ? after the device is selected with the falling edge of csb, an 8 - bit command is received. the command defines the operations to be performed ? the rising edge of csb ends all data transfer and resets internal counter and command register ? if an invalid command is received, no data is shifted into the chip and the miso remains in high impedance state until the falling edge of csb. this reinitializes the serial communication. ? data transfer to mosi continues immediately after receiving the command in all cases whe re data is to be written to sca100 0 s internal registers ? data transfer out from miso starts with the falling edge of sck immediately after the last bit of the spi command is sampled in on the rising edge of sck ? maximum spi clock frequency is 500khz ? maximu m data transfer speed for rdax and rday is 5300 samples per sec / channel data out (mosi) data in (miso) serial clock (sck) ss0 ss1 ss2 ss3 master microcontroller si so sck cs slave si so sck cs si so sck cs si so sck cs
SCA1000 series murata electronic s oy subj ect to changes 9 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a spi command can be either an individual command or a combination of command and data. in the case of combined command and data, the input data follows uninterruptedly the spi comman d and the output data is shifted out parallel with the input data . the spi interface uses an 8 - bit instruction (or command) register. the list of commands is given in table below. command name command format description: meas 00000000 measure mode (nor mal operation mode after power on) rwtr 00001000 read temperature data register stx 00001110 activate self test for x - channel sty 00001111 activate self test for y - channel rdax 00010000 read x - channel acceleration rday 00010001 read y - channel accelera tion measure mode (meas) is standard operation mode after power - up. during normal operation, the meas command is the exit command from self test. read temperature data register (rwtr) reads temperature data register during normal operation without affec ting the operation. the temperature data register is updated every 150 s. the load operation is disabled whenever the csb signal is low, hence csb must stay high at least 150 s prior to the rwtr command in order to guarantee correct data. the data transf er is presented in figure 10 below. the data is transferred msb first. in normal operation, it does not matter what data is written into temperature data register during the rwtr command and hence writing all zeros is recommended. figure 1. command and 8 bit temperature data transmission over the spi self test for x - channel (stx) activates the self test function for the x - channel (channel 1). the internal charge pump is activated and a high voltage is applied to the x - channel acceleration s ensor element electrode. this causes the electrostatic force that deflects the beam of the sensing element and simulates the acceleration to the positive direction. the self - test is de - activated by giving the meas command. the self test function must not b e activated for both channels at the same time. self test for y - channel (sty) activates the self test function for the y - channel (channel 2). the internal charge pump is activated and a high voltage is applied to the y - channel acceleration sensor element electrode. read x - channel acceleration (rdax) accesses the ad converted x - channel (channel 1) acceleration signal stored in acceleration data register x.
SCA1000 series murata electronic s oy subj ect to changes 10 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a read y - channel acceleration (rday) accesses the ad converted y - channel (channel 2) acceleration si gnal stored in acceleration data register y. during normal operation, acceleration data registers are reloaded every 150 s. the load operation is disabled whenever the csb signal is low, hence csb must stay high at least 150 s prior the rdax command in order to guarantee correct data. data output is an 11 - bit digital word that is fed out msb first and lsb last. figure 6 . command and 11 bit acceleration data transmission over the spi 2.4 self test and fa ilure detection m odes to ensure reliable measurement results the SCA1000 has continuous interconnection failure and calibration memory validity detection. a detected failure forces the output signal close to power supply ground or vdd level, outside the no rmal output range. the normal output ranges are: analog 0.25 - 4.75 v (@vdd=5v) and spi 102...1945 counts. the calibration memory validity is verified by continuously running parity check for the control register memory content. in the case where a parity e rror is detected, the control register is automatically re - loaded from the eeprom. if a new parity error is detected after re - loading data both analog output voltages are forced to go close to ground level (<0.25 v) and spi outputs go below 102 counts. t he sca100 0 also includes a separate self test mode. the true self test simulates acceleration, or deceleration, using an electrostatic force. the electrostatic force simulates acceleration that is high enough to deflect the proof mass to the extreme positi ve position, and this causes the output signal to go to the maximum value. the self test function is activated either by a separate on - off command on the self test input, or through the spi. the self - test generates an electrostatic force, deflecting the s ensing elements proof mass, thus checking the complete signal path. the true self test performs following checks: ? sensing element movement check ? asic signal path check ? pcb signal path check ? micro controller a/d and signal path check the created deflectio n can be seen in bo th the spi and analogue output. the self test function is activated digitally by a stx or sty command, and de - activated by a meas command. self test can be also activated applying logic1 (positive supply voltage level) to st pins (pins 9 & 10) of
SCA1000 series murata electronic s oy subj ect to changes 11 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a SCA1000 . the self test input high voltage level is 4 C vdd+0.3 v and input low voltage level is 0.3 C 1 v. the self test function must not be activated for both channels at the same time . figure 7 . se lf test wave forms v1 = initial output voltage before the self test function is activated. v2 = output voltage during the self test function. v3 = output voltage after the self test function has been de - activated and after stabilization time please note that the error band specified for v3 is to guarantee that the output is within 5% of the initial value after the specified stabilization time. after a longer time (max. 1 second) v1=v3. t1 = pulse length for self test activation t2 = saturation delay t3 = recovery time t4 = stabilization time =t2+t3 t5 = rise time during self test. self test characteristics: t1 [ms] t2 [ms] t3 [ms] t4 [ms] t5 [ms] v2: v3: 20 - 100 typ. 2 0 typ. 30 typ. 55 typ. 10 min 0.95*vdd (4.75v @vdd=5v) 0.95*v1 - 1.05*v1 2.5 tempe rature m easurement the sca100 0 has an internal temperature sensor, which is used for internal offset compensation. the temperature information is also available for additional external compensation. the temperature sensor can be accessed via the spi interf ace and the temperature reading is an 8 - bit word (0255). the transfer function is expressed with the following formula: where: counts temperature reading t temperature in c the temperature measurement output is not calibrated. the internal temperature compensation routine uses relative results where absolute accuracy is not needed. if the temperature vout 5v 0 v t5 t1 t2 t3 t4 v1 v2 v3 st pin voltage 0 v 5 v 083 . 1 197 ? ? ? counts t
SCA1000 series murata electronic s oy subj ect to changes 12 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a measurement results are used for additional external compensation then one point calibration in the system level is needed to remove the offse t. with external one point calibration the accuracy of the temperature measurement is about 1 c. 3 application information 3.1 recommended circuit d iagram s and printed circuit board l ayouts the SCA1000 should be powered from a well regulated 5 v dc power sup ply. coupling of digital noise to the power supply line should be minimized. 100nf filtering capacitor between vdd pin 12 and gnd plane must be used. the sca100 0 has a ratiometric output. to get the best performance use the same reference voltage for both the sca100 0 and analog/digital converter. use low pass rc filters with 5.11 k and 10nf on the sca100 0 outputs to minimize clock noise. locate the 100nf power supply filtering capacitor close to vdd pin 12. use as short a trace length as possible. conn ect the other end of capacitor directly to the ground plane. connect the gnd pin 6 to underlying ground plane. use as wide ground and power supply planes as possible. avoid narrow power supply or gnd connection strips on pcb. figure 8 . a nalog connection and layout example figure 9 . spi connection example
SCA1000 series murata electronic s oy subj ect to changes 13 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 3.2 recomme nded printed circuit board f ootprint figure 10 . recommended pcb footpr int 4 mechanical specifications and reflow s oldering 4.1 mechanical s pecifications (reference only) lead frame material: copper plating: nickel followed by gold solderability: jedec standard: jesd22 - b102 - c rohs compliance: rohs compliant lead free c omponent. co - planarity error : 0.1mm max. part weight: <1.2 g figure 11 . mechanical dimensions of the sca100 0 (dimensions in mm)
SCA1000 series murata electronic s oy subj ect to changes 14 / 14 www.muratamems .fi doc. nr. 82 1566 00 rev.a 4.2 reflow s oldering the SCA1000 is suitable for sn - pb eutectic and pb - free soldering process an d mounting with normal smd pick - and - place equipment. figure 12 . recommended sca100 0 body temperature profile during reflow soldering. ref. ipc/jedec j - std - 020b. profile feature sn - pb eutectic assembly pb - free assembly average r amp - up rate (t l to t p ) 3c/second max. 3c/second max. preheat - temperature min (t smin ) - temperature max (t smax ) - time (min to max) (ts) 100c 150c 60 - 120 seconds 150c 200c 60 - 180 seconds tsmax to t, ramp up rate 3c/second max time maintained above: - temperature (t l ) - time (t l ) 183c 60 - 150 seconds 217c 60 - 150 seconds peak temperature (t p ) 240 +0/ - 5c 250 +0/ - 5c time within 5c of actual peak temperature (t p ) 10 - 30 seconds 20 - 40 seconds ramp - down rate 6c/second max 6c/second max time 25 to p eak temperature 6 minutes max 8 minutes max the moisture sensitivity level of the part is 3 according to the ipc/jedec j - std - 020b. the part should be delivered in a dry pack. the manufacturing floor time (out of bag) in the customers end is 168 hours. notes: ? preheating time and temperatures according to guidance from solder paste manufacturer. ? it is important that the part is parallel to the pcb plane and that there is no angular alignment error from intended measuring direction during assembly process. ? wave soldering is not recommended. ? ultrasonic cleaning is not allowed . the sensing element may be damaged by an ultrasonic cleaning process.

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