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50/s yaw rate gyro adxrs614 rev. a information furnished by analog devices is believed to be accurate and reliable. however, no 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 otherwise 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 www.analog.com fax: 781.461.3113 ?2007C2010 analog devices, inc. all rights reserved. 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 navigation systems inertial measurement units platform stabilization robotics general description t he adxrs614 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 used for high reliability automotive airbag accelerometers. the output signal, rateout (1b, 2a), is a voltage 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. a single external resistor between sumj and rateout can be used to lower the scale factor. 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 conditioning circuits. the adxrs614 is available in a 7 mm 7 mm 3 mm bga chip scale package. functional block diagram v dd agnd pgnd av cc st2 st1 temp v ratio cp1 cp2 cp3 cp4 cp5 sumj rateout demod 200k ? 5% 22nf 100nf 22nf 100nf 100nf 100nf drive amp mechanical sensor charge pump and voltage regulator c out +5v +5v +5 v (adc ref) ac amp vga 25k? @ 25c adxrs614 25k? self-test 06748-001 figure 1. adxrs614 block diagram
adxrs614 rev. a | 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 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 adxrs614 and supply ratiometricity ......................................9 null adjustment ......................................................................... 10 self-test function ...................................................................... 10 continuous self-test .................................................................. 10 outline dimensions ....................................................................... 11 ordering guide .......................................................................... 11 revision history 2/10rev. 0 to rev. a updated outline dimensions ....................................................... 11 changes to ordering guide .......................................................... 11 4/07revision 0: initial version adxrs614 rev. a | page 3 of 12 specifications all minimum and maximum specifications are guaranteed. typical specifications are not guaranteed. @t a = ?40 c to +105 c, v s = av cc = v dd = 5 v, v ratio = av cc , angular rate = 0/s, bandwidth = 80 hz (c out = 0.01 f), i out = 100 a, 1 g , unless otherwise noted. table 1. parameter conditions adxrs614bbgz unit min typ max sensitivity (ratiometric) 1 clockwise rotation is positive output measurement range 2 full-scale range over specifications range 50 75 /sec initial and over temperature 22.5 25 27.5 mv//sec temperature drift 3 3 % nonlinearity best fit straight line 0.1 % of fs null (ratiometric) 1 null ?40c to +105c 2.5 v linear acceleration effect any axis 0.1 /sec/ g noise performance rate noise density t a = 25 c 0.04 /sec/ hz frequency response bandwidth 4 1 1000 hz sensor resonant frequency 14.5 khz self-test (ratiometric) 1 st1 rateout response st1 pin from logic 0 to logic 1 ?1.9 v st2 rateout response st2 pin from logic 0 to logic 1 1.9 v logic 1 input voltage 0.8 v ratio v logic 0 input voltage 0.2 v ratio v input impedance to common 50 k temperature sensor (ratiometric) 1 v out at 25c load = 100 m 2.35 2.5 2.65 v scale factor 5 @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 v ratio input 3 v s v supply current 3.5 5.0 ma temperature range specified performance C40 +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, cout. 5 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 adxrs614 rev. a | 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 C0.3 v to +6.0 v v ratio av cc output short-circuit duration (any pin to common) indefinite operating temperature range C55c to +125c storage temperature C65c 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 adxrs614 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 06748-002 figure 2. rateout signal incr eases with clockwise rotation esd caution adxrs614 rev. a | 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 gf e d c ba 7 6 5 4 3 2 1 06748-003 figure 3. pin configuration table 4. pin function descriptions pin no. mnemonic description 6d, 7d cp5 hv filter capacitor (0.1 n 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). 4a, 4b cp2 charge pump capacitor (22 nf). 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. adxrs614 rev. a | page 6 of 12 typical performance characteristics n > 1000 for all typical performance plots, unless otherwise noted. 18 16 14 12 10 8 6 4 2 0 06748-004 volts % of population 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 figure 4. null output at 25c (v ratio = 5 v) 30 0 ?0.6 0.6 ?0.5 0.1 ?0.4 ?0.3 0 ?0.2 0.50.40.30.2 ?0.1 06748-005 o/s/oc % of population 25 20 15 10 5 figure 5. null drift over temperature (v ratio = 5 v) 50 0 22 06748-006 mv/o/s % of population 45 40 35 30 25 20 15 10 5 22.52323.52424.52525.52626.52727.528 figure 6. sensitivity at 25c (v ratio = 5 v) 35 0 06748-007 drift (%) % of population 30 25 20 15 10 5 ?10 ?9 ?8 ?7 ?6 ?5 ?4 ?3 ?2 ?1 0 3 6 8 9 5 12 4 7 10 figure 7. sensitivity drift over temperature 40 0 ?1.3 06748-008 volts % of population 35 30 25 20 15 10 5 ?2.5 ?2.4 ?2.3 ?2.2 ?2.1 ?2 ?1.9 ?1.8 ?1.7 ?1.6 ?1.5 ?1.4 figure 8. st1 output change at 25c (v ratio = 5 v) 40 0 06748-009 volts % of population 35 30 25 20 15 10 5 2.5 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 figure 9. st2 output change at 25c (v ratio = 5 v) adxrs614 rev. a | page 7 of 12 14 0 50 54 58 62 66 70 74 78 82 86 90 94 98 06748-010 o/s % of population 12 10 8 6 4 2 figure 10 .measurement range 2.5 ?2.5 ?40 120 06748-011 temperature (oc) volts 2 1.5 1 0.5 0 ?0.5 ?1 ?1.5 ?2 ?20 0 20 40 60 80 100 figure 11. typical self-test change over temperature 30 0 06748-012 (ma) % of population 25 20 15 10 5 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 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 % of population volts 06748-013 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 volts temperature (c) 256 parts 06748-014 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 /s time (ms) y ref x +45 ?45 06748-015 figure 15. g and g g sensitivity for a 50 g , 10 ms pulse adxrs614 rev. a | page 8 of 12 1.6 0 100 10k (hz) (/s) 1k 1.4 1.2 1.0 0.8 0.4 0.2 0.6 long lat rate 06748-016 figure 16. typical response to 10 g sinusoidal vibration (sensor bandwidth = 2 khz) 400 300 200 100 0 ?100 ?200 ?300 ?400 02 5 0 150 100 200 50 (ms) (/s) dut1 offset by +200/s dut2 offset by ?200/s 06748-017 figure 17. typical high g (2500 g ) shock response (sensor bandwidth = 40 hz) 1 0.1 0.01 0.001 0.01 0.1 100k 10k 1k 100 10 1 average time (seconds) (/s rms) 06748-018 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) (/s) 06748-019 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) (/s) 6 0 0 06748-020 figure 20. typical shift in short term null (bandwidth = 1 hz) 0.1 0.001 0.01 0.0001 10 100k 1k 100 (hz) (/s/ hz rms) 10k 06748-021 figure 21. typical noise spectral density (bandwidth = 40 hz) adxrs614 rev. a | page 9 of 12 theory of operation 0.1 0.01 0.000001 0.00001 0.0001 0.001 10 100k 1k 100 (hz) (/s/ hz rms) 10k 0 6748-022 the adxrs614 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 produce 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. 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 adxrs614. 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 adxrs614. 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 adxrs614 has a temperature proportional 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, buffering the output is recommended. setting bandwidth 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. 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 adxrs614 rate response. the C3 db frequency set by r out and c out is: 0 6748-023 v ratio r temp r fixed v temp () out out out cr f = 2 1 and can be well controlled because r out has been trimmed during manufacturing to be 200 k 1%. any external resistor applied between the rateout pin (1b, 2a) and sumj pin (1c, 2c) results in: figure 23. adxrs614 temperature sensor structure calibrated performance using a 3-point calibration technique, it is possible to calibrate the null and sensitivity drift of the adxrs614 to an overall accuracy of nearly 200/hour. an overall accuracy of 40/hour or better is possible using more points. ( ) () ext ext out r r r + = k 200 k 200 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. limiting the bandwidth of the device reduces the flat-band noise during the calibration process, improving the measurement accuracy at each calibration point. adxrs614 and supply ratiometricity the adxrs614 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 adxrs614 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 figure 22 shows the effect of adding a 250 hz filter to the output of an adxrs614 set to 40 hz bandwidth (as shown in figure 21 ). high frequency demodulation artifacts are attenuated by approximately 18 db. adxrs614 rev. a | page 10 of 12 behavior. typical ratiometricity error for null, sensitivity, self- test, and temperature output is outlined in tabl e 3 . note that v ratio must never be greater than av cc. table 3. ratiometricity error for various parameters parameter v s = v ratio = 4.75 v v s = v ratio = 5.25 v st1 mean ?0.4% ?0.3% sigma 0.6% 0.6% st2 mean ?0.4% ?0.3% sigma 0.6% 0.6% null mean ?0.04% ?0.02% sigma 0.3% 0.2% sensitivity mean 0.03% 0.1% sigma 0.1% 0.1% v temp mean ?0.3% ?0.5% sigma 0.1% 0.1% 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 adxrs614 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 ?1.9 v, and st2 causes an opposite change of +1.9 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 of greater than 0.8 v ratio to the st1 and st2 pins. st1 and st2 are deactivated by applying a voltage of less than 0.2 v ratio to the st1 pin and the st2 pin. the voltage applied to st1 and st2 must never be greater than av cc . continuous self-test the one-chip integration of the adxrs614 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 a separate application note. adxrs614 rev. a | page 11 of 12 outline dimensions a b c d e f g 76543 top view detail a ball diameter 0.60 0.55 0.50 0.60 max 0.25 min coplanarity 0.15 21 * a1 corner index area 3.20 max 2.50 min * ball a1 identifier is gold plated and connected to the d/a pad internally via holes. 102609-b 7.05 6.85 sq 6.70 a1 ball corner bottom view detail a 0.80 bsc 4.80 bsc sq seating plane 3 .80 max 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 adxrs614bbgz C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 adxrs614bbgz-rl C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 adxrs614wbbgza C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 adxrs614wbbgza-rl C40c to +105c 32-lead ceramic ball grid array (cbga) bg-32-3 eval-adxrs614z evaluation board 1 z = rohs compliant part. adxrs614 rev. a | page 12 of 12 notes ?2007C2010 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. d06748-0-2/10(a) |
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