functional block diagram ad22055 out gain in+ in +v s ofs filt a1 8 1 7 3 2 a2 4 5 6 gnd rev. 0 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 which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. a single supply bridge transducer amplifier ad22055 features gain of 400. alterable from 40 to 1000 output span 20 mv to (v s C 0.25) v 1 pole low-pass filtering available offset capability differential input resistance 230 k v drives 1 k v load to +4 v using v s = +5 v supply voltage: +3 v to +36 v transient spike protection and rfi filters included peak input voltage (40 ms): 60 v reversed supply protection: C34 v operating temperature range: C40 8 c to +125 8 c applications interface for pressure transducers, position indicator, strain gages and other low level signal sources general description the ad22055 accepts a differential signal from a bridge trans- ducer whose common-mode signal can be anywhere between the power supplies. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 617/329-4700 world wide web site: http://www.analog.com fax: 617/326-8703 ? analog devices, inc., 1997 the extended temperature range allows for local signal condi- tioning for oil and hydraulic pressure sensors as well as other automotive sensors. the use of an external gain resistor allows the user to compen- sate transducer gain error and temperature drift. v ref ad22055 in+ ofs +v s out in gnd filt gain 1234 5 6 7 8 1k w +5 volt output analog ground gain = 400 figure 1. typical application circuit for a pressure sensor interface
ad22055Cspecifications rev. 0 C2C (@ t a = + 25 8 c, v s = +5 v, v cm = 0, unless otherwise noted) parameter comments test conditions min typ max units inputs (pins 1 and 8) v cm common-mode range 0 5 v cmrr lf common-mode rejection ratio f 10 hz C80 C90 db cmrr hf common-mode rejection ratio f = 10 khz C60 C75 db r incm common-mode input resistance pin 1 or pin 8 to pin 2 180 230 k w r match matching of input resistances 0.5 % r indiff differential input resistance pin 1 to pin 8 180 230 300 k w preamplifier g cl closed-loop gain 1 40 v/v v o output voltage range (pin 3) +0.02 +4.75 v r o output resistance 2 77.6 80 82.4 k w output buffer g cl closed-loop gain 1 r load 3 10 k w 9.95 10 10.05 v/v v o output voltage range +0.02 +4.75 v r o output resistance (pin 5) v o 3 0.1 v dc 2.0 w overall system g cl gain 1 v o 3 0.1 v dc 398 400 402 v/v gain drift C40 c to +125 c C60 ppm/ c gain drift C125 c to +150 c C500 ppm/ c v os initial offset voltage 3 C1 0.05 1 mv offset drift C40 c to +125 c1 m v/ c offset drift C125 c to +150 c C10 m v/ c input resistance pin 7 to pin 2 2.5 3.0 k w i osc short-circuit output current 7 11 25 ma bw C3 db C3 db bandwidth v o = + 1 v dc 20 30 khz sr slew rate 0.2 v/ m s n sd noise spectral density 3 f = 100 hz to 10 khz 0.2 m v/ ? hz power supply v s operating range t a = t min to t max 3 5 36 v i s quiescent supply current 4 200 500 m a temperature range t op operating temperature range C40 +125 c notes 1 a2 gain is trimmed to 0.5% with a 0.01% 1 k w resistor to ground from pin 4. the overall gain is trimmed to a gain of 400 0.5% with the same 1 k w resistor. the gain of a1 (the ratio of overall gain to a2 gain) is used to adjust the overall gain and, therefore, is not trimmed explicitly to 40. note that the actual gain to a particu- lar application can be modified by the use of an external resistor at pin 4. 2 the actual output resistance of a1 is only a few ohms, but access to this output, via pin 3, is always through an 80 k w resistor, which is trimmed to 3%. 3 referred to the input (pins 1 and 8). 4 with v dm = 0 v. differential mode signals are referred to as v dm , while v cm refers to common-mode voltages. all min and max specifications are guaranteed, although only those marked in boldface are tested on all production units at final test. specifications subject to change without notice.
ad22055 rev. 0 C3C absolute maximum ratings 1 supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . +3 v to +36 v peak input voltage (40 ms) . . . . . . . . . . . . . . . . . . . . . . . . 60 v reversed continuous supply voltage . . . . . . . . . . . . . . C34 v operating temperature . . . . . . . . . . . . . . . . C40 c to +125 c storage temperature . . . . . . . . . . . . . . . . . . C65 c to +150 c output short circuit duration . . . . . . . . . . . . . . . . indefinite lead temperature (soldering, 60 sec) . . . . . . . . . . . . . +300 c 1 stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; the functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. ordering guide temperature package package model range description option* AD22055N plastic dip n-8 ad22055r C40 c to +125 c plastic soic so-8 *n = plastic dip; so = small outline package. pin connection 1 2 3 4 8 7 6 5 top view (not to scale) ad22055 in out +v s ofs in+ gnd filt gain pin description 8-pin soic pin function 1 inC 2 ground 3 filter 4 gain 5 out 6+v s 7 ofs 8 in+ product description the ad22055 is a single supply difference amplifier consisting of a precision balanced attenuator, a very low drift preamplifier and an output buffer amplifier (a1 and a2, respectively, in the functional block diagram). it has been designed so that small differential signals, v dm , can be accurately amplified and fil- tered in the presence of large common-mode voltages, v cm , without the use of any other active components. the common-mode range resistors in this network are trimmed to match better than one part in 10,000. the resistive attenua- tor network is situated at the input to the ad22055 (pins 1 and 8) allowing the common-mode voltage at pins 1 and 8 to be two times greater than that which can be tolerated by the actual input of a1. as a result, the input common-mode range extends from ground to the power supply voltage. two small filter capacitors (not shown) have been included at the inputs to a1 to minimize the effects of any spurious rf sig- nals present in the signal. internal feedback around a1 sets the closed-loop gain of the preamplifier to 40 v/v from the input pins, and the output of a1 is connected to pin 3 via a 80 k w resistor, which is trimmed to 3% to facilitate the low-pass filtering of the signal. the out- put buffer a2 has a gain of 10 v/v (using a precise 1 k w resistor from pin 4 to ground) setting the precalibrated, overall gain of the ad22055, to 400 v/v. this gain is easily user-configurable. overall gain is programmed using the following equation: gain = 40 1 + 9 k w r gain ? ? ? ? v / v (1) the dynamic properties of the ad22055 are optimized for interf acing to transducers, particularly those with a wheatstone bridge co nfiguration. its r ejection of large, high frequency, common-mode signals makes it superior to that of many alter- native approaches. this is due to the very careful design of the input attenuator and the integration of this highly balanced, high impedance system with the preamplifier. warning! esd sensitive device caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the ad22055 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality.
rev. 0 C4C ad22055 outline dimensions dimensions shown in inches and (mm). 8-lead plastic dip (n-8) 8 14 5 0.430 (10.92) 0.348 (8.84) 0.280 (7.11) 0.240 (6.10) pin 1 seating plane 0.022 (0.558) 0.014 (0.356) 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) max 0.130 (3.30) min 0.070 (1.77) 0.045 (1.15) 0.100 (2.54) bsc 0.160 (4.06) 0.115 (2.93) 0.325 (8.25) 0.300 (7.62) 0.015 (0.381) 0.008 (0.204) 0.195 (4.95) 0.115 (2.93) 8-lead plastic soic package (so-8) 0.1968 (5.00) 0.1890 (4.80) 8 5 4 1 0.2440 (6.20) 0.2284 (5.80) pin 1 0.1574 (4.00) 0.1497 (3.80) 0.0688 (1.75) 0.0532 (1.35) seating plane 0.0098 (0.25) 0.0040 (0.10) 0.0192 (0.49) 0.0138 (0.35) 0.0500 (1.27) bsc 0.0098 (0.25) 0.0075 (0.19) 0.0500 (1.27) 0.0160 (0.41) 8 0 0.0196 (0.50) 0.0099 (0.25) x 45 printed in u.s.a. c2978C12C1/97
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