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300/sec yaw rate gyro ADXRS620 rev. 0 information furnished by analog devices is belie responsibility is assumed by analog devices for it rights of third parties that may result from its use. sp license is granted by implication or otherwise unde trademarks and registered trademarks are the prop 06, norwood, ma 02062-9106, u.s.a. www.analog.com nalog devices, inc. all rights reserved. ved to be accurate and reliable. however, no s use, nor for any infringements of patents or other ecifications subject to change without notice. no r any patent or patent rights of analog devices. erty of their respective owners. one technology way, p.o. box 91 tel: 781.329.4700 fax: 781.461.3113 ?2010 a features complete rate gyroscope on a single chip z-axis (yaw rate) response high vibration rejection over wide frequency 2000 g powered shock survivability ratiometric to referenced supply 5 v single-supply operation 105 c operation self-test on digital command ultrasmall and light (<0.15 cc, <0.5 gram) temperature sensor output rohs compliant applications vehicle chassis rollover sensing inertial measurement units platform stabilization general description the ADXRS620 is a complete angular rate sensor (gyroscope) that uses the analog devices, inc., surface-micromachining process to create a functionally complete and low cost angular rate sensor integrated with all required electronics on one chip. the manufacturing technique for this device is the same high volume bimos process that is used for high reliability automotive airbag accelerometers. the output signal, rateout (1b, 2a), is a voltage that is proportional to angular rate about the axis normal to the top surface of the package. the output is ratiometric with respect to a provided reference supply. an external capacitor sets the bandwidth. other external capacitors are required for operation. a temperature output is provided for compensation techniques. two digital self-test inputs electromechanically excite the sensor to test proper operation of both the sensor and the signal condi- tioning circuits. the ADXRS620 is available in a 7 mm 7 mm 3 mm bga ceramic package. functional block diagram v dd pgnd agnd av cc st2 st1 temp v ratio demod 180k ? 1% 100nf 100nf cp1 cp2 cp3 cp4 cp5 sumj rateout 22nf 100nf 22nf 100nf drive amp mechanical sensor +5v +5v +5 v charge pump and voltage regulator c out (adc ref) ac amp vga 25k? @ 25c ADXRS620 25k? self-test 08887-001 figure 1.
ADXRS620 rev. 0 | page 2 of 1 2 table of contents features .............................................................................................. 1 ? applications ....................................................................................... 1 ? general description ......................................................................... 1 ? functional block diagram .............................................................. 1 ? revision history ............................................................................... 2 ? specifications ..................................................................................... 3 ? absolute maximum ratings ............................................................ 4 ? rate sensitive axis ....................................................................... 4 ? esd caution .................................................................................. 4 ? pin configuration and function descriptions ............................. 5 ? typical performance characteristics ............................................. 6 ? theory of operation .........................................................................9 ? setting bandwidth .........................................................................9 ? temperature output and calibration .........................................9 ? calibrated performance ................................................................9 ? ADXRS620 and supply ratiometricity ................................... 10 ? null adjustment ......................................................................... 10 ? self-test function ...................................................................... 10 ? continuous self-test .................................................................. 10 ? outline dimensions ....................................................................... 11 ? ordering guide .......................................................................... 11 ? revision history 3/10revision 0: initial version
ADXRS620 rev. 0 | page 3 of 12 specifications all minimum and maximum specifications are guaranteed. typical specifications are not guaranteed. t a = ?40c to +105c, v s = av cc = v dd = 5 v, v ratio = av cc , angular rate = 0/sec, bandwidth = 80 hz (c out = 0.01 f), i out = 100 a, 1 g , unless otherwise noted. table 1. parameter onitions in typ a nit sensitivity 1 clockwise rotation is positive output measurement range 2 full-scale range over specifications range 300 /sec initial and over temperature ?40c to +105c 5.52 6 6.48 mv//sec temperature drift 3 2 % nonlinearity best fit straight line 0.1 % of fs null 1 null ?40c to +105c 2.2 2.5 2.8 v linear acceleration effect any axis 0.1 /sec/ g noise performance rate noise density t a 25 c 0.05 /sec/ hz frequency response bandwidth 4 0.01 2500 hz sensor resonant frequency 12 14.5 17 khz self-test 1 st1 rateout response st1 pin from logic 0 to logic 1 ?650 ?450 ?250 mv st2 rateout response st2 pin from logic 0 to logic 1 250 450 650 mv st1 to st2 mismatch 5 ?5 +5 % logic 1 input voltage 3.3 v logic 0 input voltage 1.7 v input impedance to common 40 50 100 k temperature sensor 1 v out at 25c load = 10 m 2.35 2.5 2.65 v scale factor 6 @ 25c, v ratio = 5 v 9 mv/ c load to v s 25 k ? load to common 25 k ? turn-on time power on to ?/sec of final 50 ms output drive capability current drive for rated specifications 200 a capacitive load drive 1000 pf power supply operating voltage (v s ) 4.75 5.00 5.25 v quiescent supply current 3.5 4.5 ma temperature range specified performance ?40 +105 c 1 parameter is linearly ratiometric with v ratio . 2 the maximum range possible, including output swing range, initial offset, sensitivity, offset drift, and sensitivity drift at 5 v supplies. 3 from +25c to ?40c or from +25c to 105c. 4 adjusted by external capacitor, c out . reducing bandwidth below 0.01 hz does not reduce noise further. 5 self-test mismatch is described as (st2 + st1)/((st2 ? st1)/2). 6 for a change in temperature from 25c to 26c. v temp is ratiometric to v ratio . see the tem section for more details. perature output and calibration
ADXRS620 rev. 0 | page 4 of 12 absolute maximum ratings table 2. parameter rating acceleration (any axis, 0.5 ms) unpowered 2000 g powered 2000 g v dd , av cc ?0.3 v to +6.0 v v ratio av cc st1, st2 av cc output short-circuit duration (any pin to common) indefinite operating temperature range ?55c to +125c storage temperature range ?65c to +150c stresses above those listed under the 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 conditions 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. drops onto hard surfaces can cause shocks of greater than 2000 g and can exceed the absolute maximum rating of the device. exercise care during handling to avoid damage. rate sensitive axis the ADXRS620 is a z-axis rate-sensing device (also called a yaw rate sensing device). it produces a positive going output voltage for clockwise rotation about the axis normal to the package top, that is, clockwise when looking down at the package lid. rate axis longitudinal axis lateral axis + abcd g 1 7 ef a1 rate out rate in 4.75v 0.25v v cc = 5v v ratio /2 gnd 08887-002 figure 2. rateout signal incr eases with clockwise rotation esd caution
ADXRS620 rev. 0 | page 5 of 12 pin configuration and fu nction descriptions pgnd st1 st2 temp a gnd v ratio nc sumj rateout av cc cp2 cp1 cp4 cp3 cp5 v dd gfedcba 08887-003 7 6 5 4 3 2 1 figure 3. pin configuration table 3. pin function descriptions pin no. mnemonic description 6d, 7d cp5 hv filter capacitor (0.1 f). 6a, 7b cp4 charge pump capacitor (22 nf). 6c, 7c cp3 charge pump capacitor (22 nf). 5a, 5b cp1 charge pump capacitor (22 nf). charge pump capacitor (22 nf). 4a, 4b cp2 3a, 3b av cc positive analog supply. 1b, 2a rateout rate signal output. 1c, 2c sumj output amp summing junction. 1d, 2d nc no connect. 1e, 2e v ratio reference supply for ratiometric output. 1f, 2g agnd analog supply return. 3f, 3g temp temperature voltage output. 4f, 4g st2 self-test for sensor 2. 5f, 5g st1 self-test for sensor 1. 6g, 7f pgnd charge pump supply return. 6e, 7e v dd positive charge pump supply.
ADXRS620 rev. 0 | page 6 of 12 2.2 2.2 2.3 2.3 2.4 2.4 2.8 2.7 2.7 2.6 2.6 2.5 2.5 rate out (v) 08887-0 typical performance characteristics n > 1000 for all typical performance plots, unless otherwise noted. 20 18 16 14 12 10 8 6 4 2 0 0 5 0 5 0 5 0 5 0 5 0 5 0 percentage of population (%) 04 figure 4. null output at 25c (v ratio = 5 v) 45 40 35 30 25 20 15 10 0 5 percentage of population (%) ?0.5 ?0.4 ?0.3 ?0.2 ?0.1 0 0.1 0.2 0.3 0.4 0.5 (/sec/c) 0 8887-005 figure 5. null drift over temperature (v ratio = 5 v) 16 14 12 10 8 6 4 2 0 % of population 6 sensitivity (mv//sec) 08887-00 5.5 5.6 5.7 5.8 5.9 6 6.1 6.5 6.46.3 6.2 figure 6. sensitivity at 25c (v ratio = 5 v) 30 25 20 15 10 5 0 ?10 ?8 ?6 ?4 ?2 0 2 4 6 8 10 percentage of population (%) drift (%) 08887-007 figure 7. sensitivity drift over temperature 35 0 5 10 15 20 25 30 ?650 ?610 ?570 ?530 ?490 ?450 ?410 ?370 ?330 ?290 ?250 percentage of population (%) st1 (mv) 08887-008 figure 8. st1 output change at 25c (v ratio = 5 v) 40 35 30 25 20 15 10 5 0 percentage of population (%) st2 (mv) 08887-009 250 290 330 370 410 450 490 650610570530 figure 9. st2 output change at 25c (v ratio = 5 v)
ADXRS620 rev. 0 | page 7 of 12 0 percentage of population (%) 0 70 60 50 40 30 20 10 ?5 ?4 ?3 ?2 ?1 5 43210 self-test mismatch (%) 08887-01 figure 10. self-test mismatch at 25c (v ratio = 5 v) 600 400 200 0 ?400 ?200 self-test (mv) ?600 ?40 ?20 0 20 40 80 100 120 60 temperature (c) st1 st2 08887-011 figure 11. typical self-test change over temperature 0 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 current consumption (m a) 08887-012 5 10 15 20 25 30 percentage of population (%) figure 12. current consumption at 25c (v ratio = 5 v) 40 35 30 25 0 5 10 15 20 2.40 2.42 2.44 2.46 2.48 2.50 2.54 2.56 2.58 2.60 2.52 percentage of population (%) voltage (v) 08887-015 figure 13. v temp output at 25c (v ratio = 5 v) 3.3 3.1 2.9 2.7 1.5 2.1 1.9 1.7 2.3 2.5 ?40 ?20 0 20 40 60 100 120 80 voltage (v) temperature (c) 256 parts 08887-013 figure 14. v temp output over temperature (v ratio = 5 v) 60 50 30 40 10 20 ?20 ?10 0 750 770 810 830 850 790 g or /se c time (ms) y ref x +45 ?45 08887-014 figure 15. g and g g sensitivity for a 50 g , 10 ms pulse
ADXRS620 rev. 0 | page 8 of 12 0 0.2 peak rateout (/s) 0.4 0.6 0.8 1.0 1.2 1.6 2.0 1.4 1.8 100 1k 10k frequency (hz) lat long rate 08887- 116 figure 16. typical response to 10 g sinusoidal vibration (sensor bandwidth = 2 khz) 400 300 200 100 0 ?100 ?200 ?300 ?400 rate of rotation (/sec) 0 250 150 100 200 50 time (ms) dut1 offset by +200/sec dut2 offset by ?200/sec 08887-0 16 figure 17. typical high g (2500 g ) shock response (sensor bandwidth = 40 hz) 1 0.1 0.01 root allan deviation (/sec rms) 0.001 0.01 0.1 100k 10k 1k 100 10 1 average time (seconds) 08887-017 figure 18. typical root allan deviation at 25c vs. averaging time 0.10 ?0.05 0 0.05 ?0.10 0 140 120 100 80 60 40 20 time (hours) rate of rotation (/sec) 08887-018 figure 19. typical shift in 90 sec null averages accumulated over 140 hours 0.10 0.05 0 ?0.05 ?0.10 03 1800 1200 3000 2400 600 time (seconds) rate of rotation (/sec) 6 0 0 08887-019 figure 20. typical shift in short-term null (bandwidth = 1 hz) 0.1 0.001 0.01 0.0001 10 100k 1k 100 frequency (hz) noise spectral density(/sec/ hz rms) 10k 08887-020 figure 21. typical noise spectral density (bandwidth = 40 hz)
ADXRS620 rev. 0 | page 9 of 12 () theory of operation figure 22 shows the effect of adding a 250 hz filter to the output of an ADXRS620 set to 40 hz bandwidth (as shown in figure 21 ). high frequency demodulation artifacts are attenuated by approximately 18 db. the ADXRS620 operates on the principle of a resonator gyro. two polysilicon sensing structures each contain a dither frame that is electrostatically driven to resonance, producing the necessary velocity element to produce a coriolis force during angular rate. at two of the outer extremes of each frame, orthogonal to the dither motion, are movable fingers that are placed between fixed pickoff fingers to form a capacitive pickoff structure that senses coriolis motion. the resulting signal is fed to a series of gain and demodulation stages that produces the electrical rate signal output. the dual-sensor design rejects external g -forces and vibration. fabricating the sensor with the signal conditioning electronics preserves signal integrity in noisy environments. 0.1 0.01 0.000001 0.00001 0.0001 0.001 10 100k 1k 100 frequency (hz) noise spectral density(/sec/ hz rms) 10k 08887-021 the electrostatic resonator requires 18 v to 20 v for operation. because only 5 v are typically available in most applications, a charge pump is included on chip. if an external 18 v to 20 v supply is available, the two capacitors on cp1 through cp4 can be omitted and this supply can be connected to cp5 (pin 6d, pin 7d). note that cp5 should not be grounded when power is applied to the ADXRS620. although no damage occurs, under certain conditions the charge pump may fail to start up after the ground is removed without first removing power from the ADXRS620. figure 22. noise spectral density with additional 250 hz filter temperature output and calibration it is common practice to temperature-calibrate gyros to improve their overall accuracy. the ADXRS620 has a temperature propor- tional voltage output that provides input to such a calibration method. the temperature sensor structure is shown in figure 23 . the temperature output is characteristically nonlinear, and any load resistance connected to the temp output results in decreasing the temp output and temperature coefficient. therefore, buf- fering the output is recommended. setting bandidth external capacitor c out is used in combination with the on- chip r out resistor to create a low-pass filter to limit the bandwidth of the ADXRS620 rate response. the ?3 db frequency set by r out and c out is out out ut o cr f = 2 1 the voltage at the temp pin (3f, 3g) is nominally 2.5 v at 25c, and v ratio = 5 v. the temperature coefficient is ~9 mv/c at 25c. although the temp output is highly repeatable, it has only modest absolute accuracy. this frequency can be well controlled because r out has been trimmed during manufacturing to be 180 k 1%. any external resistor applied between the rateout pin (1b, 2a) and sumj pin (1c, 2c) results in v ratio v temp r fixed r temp 0 8887-022 ( ) () ext ut o r r + = k 180 ext r k 180 figure 23. temperature sensor structure calibrated performance in general, an additional hardware or software filter is added to attenuate high frequency noise arising from demodulation spikes at the gyros 14 khz resonant frequency. (the noise spikes at 14 khz can be clearly seen in the power spectral density curve shown in figure 21 ). typically, this additional filters corner frequency is set to greater than 5 the required bandwidth to preserve good phase response. using a three-point calibration technique, it is possible to calibrate the null and sensitivity drift of the ADXRS620 to an overall accuracy of nearly 200/hour. an overall accuracy of 40/hour or better is possible using more points. limiting the bandwidth of the device reduces the flat-band noise during the calibration process, improving the measure- ment accuracy at each calibration point.
ADXRS620 rev. 0 | page 10 of 1 2 ADXRS620 and supply ratiometricity the ADXRS620 rateout and temp signals are ratiometric to the v ratio voltage, that is, the null voltage, rate sensitivity, and temperature outputs are proportional to v ratio . thus, the ADXRS620 is most easily used with a supply-ratiometric adc that results in self-cancellation of errors due to minor supply variations. there is some small error due to nonratiometric behavior. typical ratiometricity error for null, sensitivity, self- test, and temperature output is outlined in tabl e 4 . note that v ratio must never be greater than av cc. table 4. ratiometricity error for various parameters parameter v s = v ratio = 4.85 v v s = v ratio = 5.15 v st1 mean 0.3% 0.09% sigma 0.21% 0.19% st2 mean ?0.15% ?0.2% sigma 0.22% 0.2% null mean ?0.3% ?0.05% sigma 0.2% 0.08% sensitivity mean 0.003% ?0.25% sigma 0.06% 0.06% v temp mean ?0.2% ?0.04% sigma 0.05% 0.06% null adjustment the nominal 2.5 v null is for a symmetrical swing range at rateout (1b, 2a). however, a nonsymmetrical output swing may be suitable in some applications. null adjustment is possible by injecting a suitable current to sumj (1c, 2c). note that supply disturbances may reflect some null instability. digital supply noise should be avoided, particularly in this case. self-test function the ADXRS620 includes a self-test feature that actuates each of the sensing structures and associated electronics as if subjected to angular rate. it is activated by standard logic high levels applied to input st1 (5f, 5g), input st2 (4f, 4g), or both. st1 causes the voltage at rateout to change about ?0.450 v, and st2 causes an opposite change of +0.450 v. the self-test response follows the viscosity temperature dependence of the package atmosphere, approximately 0.25%/c. activating both st1 and st2 simultaneously is not damaging. st1 and st2 are fairly closely matched (5%), but actuating both simultaneously may result in a small apparent null bias shift proportional to the degree of self-test mismatch. st1 and st2 are activated by applying a voltage equal to v ratio to the st1 and st2 pins. the voltage applied to st1 and st2 must never be greater than av cc . continuous self-test the on-chip integration of the ADXRS620 gives it higher reliability than is obtainable with any other high volume manufacturing method. in addition, it is manufactured under a mature bimos process with field-proven reliability. as an additional failure detection measure, a power-on self-test can be performed. however, some applications may warrant continuous self-test while sensing rate. details outlining continuous self-test techniques are also available in the an-768 application note at analog.com .
ADXRS620 rev. 0 | page 11 of 1 2 outline dimensions a b c d e f g 76543 top view detail a ball diameter 21 * a1 corner index area 0.60 0.55 0.50 0.60 max 0.25 min coplanarity 0.15 3.20 max 2.50 min * ball a1 identifier is gold plated and connected to the d/a pad internally via holes. 10-26-2009-b 7.05 6.85 sq 6.70 a1 ball corner bottom view detail a 0.80 bsc 4.80 bsc sq 3 .80 max sea ting plane figure 24. 32-lead ceramic ball grid array [cbga] (bg-32-3) dimensions shown in millimeters ordering guide model 1 temperature range package description package option ADXRS620wbbgza C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 ADXRS620wbbgza-rl C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 eval-ADXRS620z evaluation board 1 z = rohs compliant part.
ADXRS620 rev. 0 | page 12 of 12 notes ?2010 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. d08887-0-3/10(0)

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