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small, low power, 3 - axis 200 g accelerometer data sheet ADXL377 rev. 0 document feedback information furnished by analog devices is believed to be accurate and reliable. however, n o responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwis e under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062 - 9106, u.s.a. tel: 781.329.4700 ? 2012 analog devices, inc. all rights reserved. technical support www.analog.com features 3 - axis sensing small, low profile package 3 mm 3 mm 1.45 mm lfcsp low power: 300 a (typical) single - supply operation: 1.8 v to 3.6 v 10,000 g shock survival excellent temperature stability bandwidth adjustment with a single capacitor per axis rohs/weee and lead - free compliant applications concussion and head trauma detection high force event detection general description the ADXL377 is a small, thin, low power, complete 3 - axis accelerometer with s ignal conditioned voltage outputs. the ADXL377 measures acceleration resulting from motion, shock, or vibration with a typical full - scale range of 200 g . the user selects the bandwidth of the accelerometer us ing the c x , c y , and c z capacitors at the x out , y out , and z out pins. bandwidths can be selected to suit the application, with a range of 0.5 hz to 1 3 00 hz for the x - axis and y - a x i s and a range of 0.5 hz to 1 0 00 hz for the z - axis. the ADXL377 is available in a small, low profile, 3 mm 3 mm 1.45 mm, 16 - lead lead frame chip scale package (lfcsp_lq). functional block dia gram ADXL377 3-axis sensor demodulator output amplifiers ac amplifier gnd st +3v 32k? x out c x c y c z y out c dc v s z out 32k? 32k? 10765-001 figure 1.
ADXL377 data sheet rev. 0 | page 2 of 12 table of contents features .............................................................................................. 1 applications ....................................................................................... 1 general description ......................................................................... 1 functional block diagram .............................................................. 1 revision history ............................................................................... 2 specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 4 esd caution .................................................................................. 4 pin configuration and function descriptions ............................. 5 typical performance characteristics ............................................. 6 theory of operation ........................................................................ 8 mechanical sensor ........................................................................ 8 performance ...................................................................................8 applications information .................................................................9 power supply decoupling ............................................................9 setting the bandwidth using c x , c y , and c z .............................9 self - te st ..........................................................................................9 selecting fi lter characteristics: noise/bandwidth trade - off .... 9 axes of acceleration sensitivity ............................................... 10 layout and design recommendations ................................... 11 outline dimensions ....................................................................... 12 ordering guide .......................................................................... 12 revision history 9/12 revision 0: initial version
data sheet ADXL377 rev. 0 | page 3 of 12 specifications t a = 25c, v s = 3 v, c x = c y = c z = 0.1 f, acceleration = 0 g , unless otherwise noted. all minimum and maximum specifications are guaranteed. typical specifications are not guaranteed. table 1. parameter test conditions/comments min typ max unit sensor input each axis measurement range 200 g nonlinearity % of full scale up to 180 g 0.5 % cross-axis sensitivity 1 1.4 % sensitivity, ratiometric 2 each axis sensitivity at x out , y out , and z out v s = 3 v 5.8 6.5 7.2 mv/ g sensitivity change due to temperature 3 v s = 3 v 0.02 %/c zero g bias level, ratiometric zero g voltage v s = 3 v, t a = 25c 1.4 1.5 1.6 v zero g offset vs. temperature x-axis and y-axis 12 m g /c z-axis 30 m g /c noise performance noise density x out and y out 2.7 m g /hz z out 4.3 m g /hz frequency response 4 bandwidth 5 no external filter x out and y out 1300 hz z out 1000 hz r filt tolerance 32 15% k sensor resonant frequency 16.5 khz self-test 6 logic input low 0.6 v logic input high 2.4 v st actuation current 60 a output change self-test, 0 to 1 at x out ?6.5 mv at y out 6.5 mv at z out 11.5 mv output amplifier no load output swing low 0.1 v output swing high 2.8 v power supply operating voltage range 7 1.8 3.0 3.6 v supply current v s = 3 v 300 a turn-on time 8 no external filter 1 ms operating temperature range ?40 +85 c 1 defined as coupling between any two axes. 2 sensitivity is essentially ratiometric to v s . 3 defined as the output change from ambi ent temperature to maximum temp erature or from ambient temp erature to minimum temperatur e. 4 actual frequency response controlled by user-supplied external filter capacitors (c x , c y , and c z ). 5 bandwidth with external capacitors = 1/(2 32 k c x ). 6 self-test response changes cubically with v s . 7 tested at 3.0 v and guaranteed by design only (not tested) to work over the full voltage range from 1.8 v to 3.6 v. 8 turn-on time is dependent on c x , c y , and c z and is approximately 160 (c x or c y or c z ) + 1, where c x , c y , and c z are in f and the resulting turn-on time is in ms.
ADXL377 data sheet rev. 0 | page 4 of 12 absolute maximum rat ings table 2 . parameter rating acceleration (any axis ) unpowered 10,000 g powered 10,000 g v s ?0.3 v to +3.6 v all other pins (gnd ? 0.3 v) to (v s + 0.3 v) output short - circuit duration (any pin to ground ) indefinite operating temperature ra nge ?55c to +125c storage temperature range ?65c to +150c stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other cond itions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. esd caution
data sheet ADXL377 rev. 0 | page 5 of 12 pin configuration an d function descri ptions res 1 st 2 res 3 y out 4 nc 12 nc 11 nc 10 nc 9 x out gnd gnd nc 5 6 7 8 16 z out 15 v s 14 v s 13 nc ADXL377 top view (not to scale) +z +x +y notes 1. nc = no connect. 2. the exposed pad is not internally connected, but should be soldered for mechanical integrity. 10765-002 figure 2 . pin configuration table 3 . pin function descriptions pin no. mnemonic description 1, 3 res reserved. this pin must be connected to gnd or left open. 2 st self - test. 4 y out y channel o utput. 5 x out x channel output. 6, 7 gnd must be connected to ground. 8 to 13 nc no connect. not internally connected. 14, 1 5 v s supply voltage . 3.0 v typical . 16 z out z channel output. epad exposed pad. the exposed pad is n ot internally connected , but should be soldered for mechanical integrity.
ADXL377 data sheet rev. 0 | page 6 of 12 typical performance characteristics n > 250 for all typical performance figures, unless otherwise noted. n is the number of parts tested and used to produce the histograms. 35 30 0 5 10 15 20 25 percent of population (%) output voltage (v) 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925 1.4950 1.4975 1.5000 1.5025 1.5050 1.5075 1.5100 1.5125 1.5150 1.5175 1.5200 10765-003 figure 3. x - axis zero g output voltage at 25c, v s = 3 v 30 0 5 10 15 20 25 percent of population (%) output voltage (v) 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925 1.4950 1.4975 1.5000 1.5025 1.5050 1.5075 1.5100 1.5125 1.5150 1.5175 1.5200 10765-004 figure 4. y - axis zero g output voltage at 25c, v s = 3 v 90 80 70 60 50 40 30 20 10 0 percent of population (%) output voltage (v) 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925 1.4950 1.4975 1.5000 1.5025 1.5050 1.5075 1.5100 1.5125 1.5150 1.5175 1.5200 10765-005 figure 5. z - axis one g output voltage at 25c, v s = 3 v output voltage (v) temperature (c) ?60 ?40 ?20 0 20 40 60 80 100 1.480 1.485 1.490 1.495 1.500 1.505 1.510 1.515 1.520 1.525 10765-006 figure 6. x - axis zero g offset vs. temperature , v s = 3 v (14 parts soldered to pcb ) output voltage (v) temperature (c) ?60 ?40 ?20 0 20 40 60 80 100 1.480 1.485 1.490 1.495 1.500 1.505 1.510 1.515 1.520 1.525 10765-007 figure 7. y - axis zero g offset vs. temperature, v s = 3 v (14 parts soldered to pcb ) output voltage (v) temperature (c) ?60 ?40 ?20 0 20 40 60 80 100 1.480 1.485 1.490 1.495 1.500 1.505 1.510 1.515 1.520 1.525 10765-008 figure 8. z - axis zero g offset vs. temperature, v s = 3 v (14 parts soldered to pcb )
data sheet ADXL377 rev. 0 | page 7 of 12 25 0 5 10 15 20 percent of population (%) sensitivity (mv/ g) 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35 6.40 6.45 6.50 6.55 6.60 6.65 6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-009 figure 9. x - axis sensitivity at 25c, v s = 3 v 30 25 0 5 10 15 20 percent of population (%) sensitivity (mv/ g) 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35 6.40 6.45 6.50 6.55 6.60 6.65 6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-010 figure 10 . y - axis sensitivity at 25c, v s = 3 v 16 12 14 10 0 2 4 6 8 percent of population (%) sensitivity (mv/ g) 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35 6.40 6.45 6.50 6.55 6.60 6.65 6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-0 1 1 figure 11 . z - axis sen sitivity at 25c, v s = 3 v 250 200 150 100 50 0 output ( g) reference acceleration ( g) 0 50 100 150 200 z-axis x-axis y-axis 10765-012 figure 12 . typical output linearity over the dynamic range 10 1 sensitivity (mv/ g) frequency (hz) 10 100 1k 10k x-axis, y-axis response z-axis response 10765-013 figure 13 . typical frequency response
ADXL377 data sheet rev. 0 | page 8 of 12 theory of operation the ADXL377 is a complete 3 - axis acceleration measurement system with a typical measurement range of 200 g . the ADXL377 contains a polysilicon, surface - micromachined sensor and signal conditioning circuitry to implement an open - loop acceleration measurement architecture. the output signals are analog voltages that are proportional to acceleration. the accelerometer can mea - sure the static acceleration of gravity in tilt - sensing applications , as well as dynamic a cceleration resulting from motion, shock, or vibration. the sensor is a polysilicon , surface - micromachined structure built on top of a silicon wafer. polysilicon springs suspend the structure over the su rface of the wafer and provide resistance against acc eleration forces. deflection of the structure is mea - sured using a differential capacitor that consists of independent fixed plates and plates attached to the moving mass. the fixed plates are driven by 180 out - of - phase square waves. acceleration deflects the moving mass and unbalances the differential capacitor , resulting in a sensor output whose amplitude is proportional to acceleration. phase - sensitive demodulation techniques are then used to determine the magnitude and direction of the acceleration. t he demodulator output is amplified and brought off chip through a 32 k? resistor. the user then sets the signal band width of the device by adding a capacitor. this filtering improves measurement resolution and helps prevent aliasing. mechanical sensor the ADXL377 uses a si ngle structure for sensing the accelera - tion in the x - axis , y - axis , and z - ax i s. as a result, the three sense directions are highly orthogonal with little cross - axis sensitivity. mechanical misalignment of the sensor die to the package or misalignment of th e package to the pcb is the chief source of cross - axis sensitivity. mechanical misalignment can be calibrated at the system level. performance rather than using additional temperature compensation circuitry, the ADXL377 uses innovative design techniques to ensure high performance. as a result, there is neither quantization error nor nonmonotonic behavior, and temperature hysteresis is very low.
data sheet ADXL377 rev. 0 | page 9 of 12 applications informa tion power supply decoupl ing for most appli cations, a single 0.1 f capacitor, c dc , placed close to t he ADXL377 supply pins adequately decouples the accelerometer from noise on the power supply. however, in applications where noise is present at the 50 khz internal clock frequency (or any harmonic thereof), additional care in power supply bypassing is required because this noise can cause erro rs in acceleration measurement. if additional decoupling is needed, a 100 ? (or smaller) resistor or ferrite bea d can be inserted in the supply line. in a ddit ion , a larger bulk bypass capacitor (1 f or greater) can be added in parallel to c dc . ensure that the connection from t he ADXL377 ground to the power supply groun d is low impedance because noise transmitted through ground has a similar effect as noise transmitted through v s . setting the bandwidt h using c x , c y , and c z the ADXL377 has provisions for band - limiting the x ou t , y out , and z out pins. a c apacitor must be added at each of these pins to implement low - pass filtering for antialiasing and noise reduction. the equation for the ? 3 db bandwidth is f ?3 db = 1/(2 32 k? c x ) or more simply , f ?3 db = 5 f/ c x the toleranc e of the internal resistor (r filt ) typically varies by as much as 15% of its nominal value (32 k?), and the bandwidth varies accordingly. a minimum capacitance of 1000 p f for c x , c y , and c z is recommended in all cases. table 4 . fil ter capacitor selection for c x , c y , and c z bandwidth (hz) capacitor (f) 50 0.10 100 0.05 200 0.025 500 0.01 10 00 0.005 self - test the st pin controls the self - test feature. when this pin is set to v s , an electrostatic force is exerted on the accelero meter beam. the resulting movement of the beam allows the user to test whether the accelerometer is functional. the typical change in output is ?1.08 g (corresponding to ? 6.5 mv) for the x - axis, +1.08 g (or +6.5 mv) for the y - axis, and +1.83 g (or +11.5 mv) for the z - axis. th e st pin can be left open circuit or connected to ground ( gnd) in normal use. never expose the st pin to voltages greater than v s + 0.3 v. if the system design is such that this condition cannot be guaran - teed ( for example , if multiple supply voltages are present), it is recommended that a clamping diode with lo w forward voltage be connected between st and v s . se lecting filter chara cteristics: noise/ bandwidth trade - off the selected accelerometer bandwidth ultimately determines the measurement resolution (smallest detectable acceleration). filtering can be used to lower the noise floor , thereby improv ing the resolution of the accelerometer. resolution is dependent on the analog filter bandwidth at x out , y out , and z out . the output of the ADXL377 has a typical bandwidth of 1 0 00 hz. the user must filter the signal at this point to limit aliasing errors. the analog bandwidth must be no more than half the analog - to - digital sampling frequency to minimize aliasing. the analog bandwidth can be decreased further to reduce noise and improve resolution. the ADXL377 noise has the characteristics of white gaussian noise, which contributes equally at all frequencies and is described in terms of g /hz (th at is, th e noise is proportional to the square root of the accelerometer bandwidth). l imit the bandwidth to the lowest frequency requir ed by the application to maximize the resolution and dynamic range of the accelerometer. with the single - pole roll - off characteristic, the typical noise o f t he ADXL377 is determined by rms noise = noise density ) 1.6 ( bw it is often useful to know the peak value of the noise. peak - to - peak noise can only be estimated by statistical methods. table 5 can be used to estimate the probability of exceeding various peak values, given the rms value. table 5 . estimation of peak -to - peak noise peak - to - peak value percent age of time t hat noise ex ceeds nominal peak - to - peak value (%) 2 rms 32 4 rms 4.6 6 rms 0.27 8 rms 0.006
ADXL377 data sheet rev. 0 | page 10 of 12 axes of acceleration sensitivity figure 14 shows t he axes of sensitivity for the accelerometer . figure 15 shows the output response when the accelerometer is oriented parallel to each of these axes. a z a y a x 10765-014 figure 14 . axes of acceleration sensitivity ( corresponding output voltage increases when accelerated along the sensiti ve axis ) x out = ?1 g y out = 0 g z out = 0 g gravity x out = 0 g y out = 1 g z out = 0 g x out = 0 g y out = ?1 g z out = 0 g x out = 1 g y out = 0 g z out = 0 g x out = 0 g y out = 0 g z out = 1 g x out = 0 g y out = 0 g z out = ?1 g top top top top 10765-015 figure 15 . output response vs. orientation to gravity
data sheet ADXL377 rev. 0 | page 11 of 12 layout and design recommendations figure 16 shows the recommended soldering profile; table 6 describes the profile features. figure 17 shows the recommended pcb layout or solder land drawing. t p t l t 25c t s preheat critical zone t l to t p temperature time ramp-down ramp-up t smin t smax t p t l 10765-016 figure 16. recommended soldering profile table 6. recommended soldering profile profile feature sn63/pb37 pb-free average ramp rate (t l to t p ) 3c/sec max 3c/sec max preheat minimum temperature (t smin ) 100c 150c maximum temperature (t smax ) 150c 200c time, t smin to t smax (t s ) 60 sec to 120 sec 60 sec to 180 sec ramp-up rate (t smax to t l ) 3c/sec max 3c/sec max time maintained above liquidous (t l ) 60 sec to 150 sec 60 sec to 150 sec liquidous temperature (t l ) 183c 217c peak temperature (t p ) 240c + 0c/?5c 260c + 0c/?5c time within 5c of actual peak temperature (t p ) 10 sec to 30 sec 20 sec to 40 sec ramp-down rate (t p to t l ) 6c/sec max 6c/sec max time 25c to peak temperature (t 25c ) 6 minutes max 8 minutes max c enter pad is not internally connected but should be soldered for mechanical integrity 0.40 max 0.50 0.25 1.60 0.50 0.25 3 3 0.30 max 1.60 dimensions shown in millimeters 10765-017 figure 17. recommended pcb layout
ADXL377 data sheet rev. 0 | page 12 of 12 outline dimensions 3.10 3.00 sq 2.90 0.30 0.25 0.18 1.70 1.60 sq 1.50 1 0.50 bsc b o t t o m v i e w t o p v i e w 1 6 5 8 9 1 2 1 3 4 e x p o s e d p a d pin 1 ind ica t or 0.45 0.40 0.35 sea ting plane 0.05 max 0.02 nom 0.152 ref 0.20 min copla narit y 0.08 pin 1 indic a t or 1.50 1.45 1.40 for prope r conne ction of the expos ed pad, refer to the pin confi gurat ion and funct ion descr iptio ns sect ion of this data sheet . 04-27- 2010-a figure 18 . 16 - lead lead frame chip scale package [lfcsp_lq] 3 mm 3 mm body, thick quad (cp - 16 - 28) dimensions shown in millimeters ordering guide model 1 measurement range specified voltage temperature range package description package option branding ADXL377 bcpz -rl 200 g 3 v ?40c to +85c 16- lead lfcsp_lq cp -16-28 y4p ADXL377bcpz - rl7 200 g 3 v ?40c to +85c 16- lead lfcsp_lq cp -16-28 y4p eval - ADXL377z evaluation board 1 z = rohs compliant part. ? 2012 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. d10765 - 0 - 9/12(0)

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