vibration rejecting 250/s yaw rate gyro preliminary technical data ADXRS642 rev. pr 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 ?201 analog devices, inc. all rights reserved. features complete rate gyroscope on a single chip z-axis (yaw rate) response 20/hour bias stability 0.02/second angle random walk high vibration rejection over wide frequency 10,000 g powered shock survivability ratiometric to referenced supply 5 v single-supply operation ?40c to +105c operation self-test on digital command ultrasmall and light (<0.15 cc, <0.5 gram) temperature sensor output rohs compliant applications industrial applications inertial measurement units severe mechanical environments platform stabilization general description the ADXRS642 is a complete angular rate sensor (gyroscope) that uses the analog devices, inc., surface-micromachining process to make a functionally complete and low cost angular rate sensor integrated with all of the required electronics on one chip. the manufacturing technique for this device is a patented high volume bimos process with years of proven field reliability. the ADXRS642 is an industrial grade gyroscope that is 100% pin, package, temperature, and function compatible with the adxrs622 and adxrs652 C while offering enhanced vibration rejection the output signal, rateout (1b, 2a), is a voltage propor- tional to angular rate about the axis normal to the top surface of the package. the measurement range is a minimum of 250/s. the output is ratiometric with respect to a provided reference supply. 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 ADXRS642 is available in a 7 mm 7 mm 3 mm bga chip-scale package. functional block diagram figure 1. block diagram v dd agnd pgnd av cc st2 st1 temp v ratio cp1 cp2 cp3 cp4 cp5 sumj rateout demod 180k ? 1% 22nf 100nf 22nf 100nf 100nf 100nf drive amp mechanical sensor charge pump and voltage regulator c out 5v 5v (adc ref) ac amp vga 25k ? @ 25c ADXRS642 25k ? self-test 08820-001 3 to 5v
ADXRS642 preliminary technical data rev. pr. a | page 2 of 10 table of contents features .............................................................................................. 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?
preliminary technical data ADXRS642 rev. pr. a | page 3 of 10 specifications all minimum and maximum specifications are guaranteed. typical specifications are not guaranteed. t a = 25c, 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 table 1. paraeter onitions in tp a nit tt 1 locise rotation is positie output easureent ane 2 fullscale rane oer speciications rane 2 3 sec nitial an er teperature to 1 . sec teperature drit 3 2 onlinearit est it strait line .1 o f 1 ull to 1 2. alibrate ull to 1 .1 sec teperature drit to 1 1 sec inear cceleration ect n ais .3 sec ibration ectiication 2 to .2 s 2 pf ate oise densit t 2 .2 sec esolution floor t 2 1 inute to 1 our inrun 2 r f p anit 3 user austable up to 2 ensor esonant freuenc 1 1 2 ftt 1 t1 tt esponse t1 pin ro oic to oic 1 sec t2 tt esponse t2 pin ro oic to oic 1 sec t1 to t2 isatc 2 oic 1 nput oltae 3.3 oic nput oltae 1. nput peance to coon 1 tpt 1 t at 2 oa 1 2.3 2. 2. cale factor 2 t oa to 2 oa to oon 2 t t poer on to .s o inal it p 1nf s tpt d pt urrent drie for rate speciications 2 apacitie oa drie 1 pf p pp peratin oltae . . .2 uiescent uppl urrent 3. . tpt peciie perorance 1 1 paraeter is linearl ratioetric it t . 2 easureent rane is te aiu rane possible incluin output sin rane initial oset sensitiit oset rit an sensitiit rit at supplies. 3 fro 2 to or 2 to 1. uste b eternal capacitor t . eucin banit belo .1 oes not result in urter noise iproeent. eltest isatc is escribe as t2 t1t2 t12. cale actor or a cane in teperature ro 2 to 2. tp is ratioetric to t . ee te teperature utput an alibr ation section or o re inoration. ase on caracteriation
ADXRS642 preliminary technical data rev. pr. a | page 4 of 10 absolute maximum ratings table 2. paraeter atin cceleration n is . s npoere 3 poere 3 dd .3 to . t t1 t2 utput ortircuit duration n pin to oon neinite peratin teperature ane to 12 torae teperature ane to 1 tresses aboe tose liste uner te bsolute aiu atins a cause peranent aae to te eice. tis is a stress ratin onl unctional operation o te eice at tese or an oter conitions aboe tose inicate in te operational section o tis speciication is not iplie. posure to absolute aiu ratin conitions or etene perios a aect eice reliabilit. drops onto ar suraces can cause socs o reater tan 1 g gf cgg rteetex tg gggg fg gg grteoutg cr ecuto rte x otu x terx c e rteout rte cc rto
preliminary technical data ADXRS642 rev. pr. a | page 5 of 10 pin configuration and fu nction descriptions figure 3. pin configuration table 3. pin function descriptions pin o. neonic description d d p filter apacitor 1nf. p are pup apacitor 22 nf. p3 are pup apacitor 22 nf. p1 are pup apacitor 22 nf. p2 are pup apacitor 22 nf. 3 3 positie nalo uppl. 1 2 tt ate inal utput. 1 2 utput p uin unction. 1d 2d do ot onnect. 1 2 t eerence uppl or atioetric utput. 1f 2 d nalo uppl eturn. 3f 3 tp teperature oltae utput. f t2 eltest or ensor 2. f t1 eltest or ensor 1. f pd are pup uppl eturn. dd positie are pup uppl. pd t1 t2 tp d t tt p2 p1 p p3 p dd fd 3 2 1 223
ADXRS642 preliminary technical data rev. pr. a | page 6 of 10 theory of operation the ADXRS642 operates on the principle of a resonator gyro. figure 4 shows a simplified version of one of four polysilicon sensing structures. each sensing structure contains a dither frame that is electrostatically driven to resonance. this produces the necessary velocity element to produce a coriolis force when experiencing angular rate. the ADXRS642 is designed to sense a z-axis (yaw) angular rate. when the sensing structure is exposed to angular rate, the resulting coriolis force couples into an outer sense frame, which contains movable fingers that are placed between fixed pickoff fingers. this forms 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 quad sensor design rejects linear and angular acceleration, including external g ft gfg g fg fff xr gfgoc tf gf cc c cg xrg gffg fgfxr ettt ecc out r out f fxrtf r out c out out out out c r f r out gfg rteoutu cc ext ext out r r r gff gfgf ffg rcfgf teertureoututcrto g txr g tg t teg tefftf ffg tgtec rto tffcc gteg gt urtoetrct trteoutttteg rto gg rto c ff tgg gf g rto g cc x rto te r xe r te
preliminary technical data ADXRS642 rev. pr. a | page 7 of 10 modifying the measurement range the ADXRS642 scale factor can be reduced to extend the measurement range to as much as 450/s by adding a single 225k resistor between the rateout and sumj. if an external resistor is added between rateout and sumj c out must be proportionally reduced to maintain correct bandwidth.
ADXRS642 preliminary technical data rev. pr. a | page 8 of 10 null adjustment the nominal 2.5 v null is for a symmetrical swing range at rateout (1b, 2a). however, a nonsymmetric 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 ADXRS642 includes a self-test feature that actuates each of the sensing structures and associated electronics in the same manner, 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 ?0.3 v, and st2 causes an opposite change of +0.3 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 (2%), 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 pin and the st2 pin. the voltage applied to st1 and st2 must never be greater than av cc . continuous self-test the on-chip integration of the ADXRS642 gives it higher reliability than is obtainable with any other high volume manufacturing method. also, it is manufactured under a mature bimos process that has field-proven reliability. as an additional failure detection measure, 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. mechanical performance the ADXRS642 excellent vibration rejection is demonstrated in the graphs below. figure 6 shows the ADXRS642 output response with and without 15g rms 50hz to 5khz of random vibration. bandwidth of the gyro was limited to 1600hz. performance is similar regardless of the direction of input vibration. figure 6. ADXRS642 output response with and without random vibration (15g rms, 50hz to 5khz) figure 7 demonstrates the ADXRS642 dc bias response to 5g sine vibration over the 20hz to 5khz range. as can be seen, there are no sensitive frequencies present and vibration rectification is vanishingly small. as in the previous example gyro bandwidth was set to 1600hz. figure 7. ADXRS642 sine vibration output response (5g, 20hz to 5khz) 0.00001 0.0001 0.001 0.01 0.1 1 10 100 1000 10000 frequency (/s) 2 /root hz \ 0.04 \ 0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 10 100 1000 10000 hz deg/sec
preliminary technical data ADXRS642 rev. pr. a | page 9 of 10 outline dimensions figure 8. 32-lead ceramic ball grid array [cbga] (bc-32-3) dimensions shown in millimeters ordering guide model 1 temperature range package description package option ADXRS642bbgz ?40c to +105c 32-lead ceramic ball grid array [cbga] bc-32-3 ADXRS642bbgz-rl ?40c to +105c 32-lead ceramic ball grid array [cbga] bc-32-3 eval-ADXRS642z evaluation board 1 z = rohs compliant part. 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. 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 seating plane 3 .80 max
ADXRS642 preliminary technical data rev. pra | page 10 of 10 notes ?2011 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. pr09770-0-2/11(pra)
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