one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 617/329-4700 fax: 617/326-8703 functional block diagram input power supply 19 14 15 16 17 18 v o 30 29 t2 power power oscillator input output mod demod filter 1 2 output power supply 3 4 o com +v oss ? oss ad210 pwr com pwr t3 t1 ? iss +v iss i com +in ?n fb a precision, wide bandwidth 3-port isolation amplifier ad210 features high cmv isolation: 2500 v rms continuous 6 3500 v peak continuous small size: 1.00" 3 2.10" 3 0.350" three-port isolation: input, output, and power low nonlinearity: 6 0.012% max wide bandwidth: 20 khz full-power (C3 db) low gain drift: 6 25 ppm/ 8 c max high cmr: 120 db (g = 100 v/v) isolated power: 6 15 v @ 6 5ma uncommitted input amplifier applications multichannel data acquisition high voltage instrumentation amplifier current shunt measurements process signal isolation general description the ad210 is the latest member of a new generation of low cost, high performance isolation amplifiers. this three-port, wide bandwidth isolation amplifier is manufactured with sur- face-mounted components in an automated assembly process. the ad210 combines design expertise with state-of-the-art manufacturing technology to produce an extremely compact and economical isolator whose performance and abundant user features far exceed those offered in more expensive devices. the ad210 provides a complete isolation function with both signal and power isolation supplied via transformer coupling in- ternal to the module. the ad210s functionally complete de- sign, powered by a single +15 v supply, eliminates the need for an external dc/dc converter, unlike optically coupled isolation devices. the true three-port design structure permits the ad210 to be applied as an input or output isolator, in single or multichannel applications. the ad210 will maintain its high performance under sustained common-mode stress. providing high accuracy and complete galvanic isolation, the ad210 interrupts ground loops and leakage paths, and rejects common-mode voltage and noise that may other vise degrade measurement accuracy. in addition, the ad210 provides pro- tection from fault conditions that may cause damage to other sections of a measurement system. product highlights the ad210 is a full-featured isolator providing numerous user benefits including: high common-mode performance: the ad210 provides 2500 v rms (continuous) and 3500 v peak (continuous) common- mode voltage isolation between any two ports. low input capacitance of 5 pf results in a 120 db cmr at a gain of 100, and a low leakage current (2 m a rms max @ 240 v rms, 60 hz). high accuracy: with maximum nonlinearity of 0.012% (b grade), gain drift of 25 ppm/ c max and input offset drift of ( 10 30/g) m v/ c, the ad210 assures signal integrity while providing high level isolation. wide bandwidth: the ad210s full-power bandwidth of 20 khz makes it useful for wideband signals. it is also effective in applications like control loops, where limited bandwidth could result in instability. small size: the ad210 provides a complete isolation function in a small dip package just 1.00" 2.10" 0.350". the low profile dip package allows application in 0.5" card racks and assemblies. the pinout is optimized to facilitate board layout while maintaining isolation spacing between ports. three-port design: the ad210s three-port design structure allows each port (input, output, and power) to remain inde- pendent. this three-port design permits the ad210 to be used as an input or output isolator. it also provides additional system protection should a fault occur in the power source. isolated power: 15 v @ 5 ma is available at the input and output sections of the isolator. this feature permits the ad210 to excite floating signal conditioners, front-end amplifiers and remote transducers at the input as well as other circuitry at the output. flexible input: an uncommitted operational amplifier is pro- vided at the input. this amplifier provides buffering and gain as required and facilitates many alternative input functions as required by the user. 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. rev. a
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ad210 pin designations pin designation function 1 v o output 2o com output common 3+v oss +isolated power @ output 4ev oss eisolated power @ output 14 +v iss +isolated power @ input 15 ev iss eisolated power @ input 16 fb input feedback 17 ein einput 18 i com input common 19 +in +input 29 pwr com power common 30 pwr power input ad210especifications (typical @ +25 8 c, and v s = +15 v unless otherwise noted) model ad210an ad210bn ad210jn gain range 1 v/v e 100 v/v * * error 2% max 1% max * vs. temperature(0 c to +70 c) +25 ppm/ c max * * (e25 c to +85 c) 50 ppm/ c max * * vs. supply voltage 0.002%/v * * nonlinearity 1 0.025% max 0.012% max * input voltage ratings linear differential range 10 v * * maximum safe differential input 15 v * * max. cmv input-to-output * ac, 60 hz, continuous 2500 v rms * 1500 v rms dc, continuous 3500 v peak * 2000 v peak common-mode rejection * 60 hz, g = 100 v/v * r s 500 w impedance imbalance 120 db * * leakage current input-to-output * @ 240 v rms, 60 hz 2 m a rms max * * input impedance differential l0 12 w ** common mode 5 g w i 5pf * * input bias current initial, @ +25 c 30 pa typ (400 pa max) * * vs. temperature (0 c to +70 c) 10 na max * * (e25 c to +85 c) 30 na max * * input difference current initial, @ +25 c 5 pa typ (200 pa max) * * vs. temperature(0 c to + 70 c) 2 na max * * (e25 c to +85 c) 10 na max * * input noise voltage (l khz) 18 nv/ ? hz ** (10 hz to 10 khz) 4 m v rms * * current (1 khz) 0.01 pa/ hz ** frequency response bandwidth (C3 db) * g = 1 v/v 20 khz * * g = 100 v/v 15 khz * * settling time ( 10 mv, 20 v step) * g = 1 v/v 150 m s* * g = 100 v/v 500 m s* * slew rate (g = 1 v/v) 1 v/ m s* * offset voltage (rti) 2 initial, @ +25 c 15 45/g) mv max ( 5 15/g) mv max * vs. temperature (0 c to +70 c) ( 10 30/g) m v/ c* * (C25 c to +85 c) ( 10 50/g) m v/ c* * rated output 3 voltage, 2 k w load 10 v min * * impedance 1 w max * * ripple (bandwidth = 100 khz) 10 mv p-p max * * isolated power outputs 4 voltage, no load 15 v * * accuracy 10% * * current 5ma * * regulation, no load to full load see text * * ripple see text * * power supply voltage, rated performance +15 v dc 5% * * voltage, operating +15 v dc 10% * * current, quiescent 50 ma * * current, full load C full signal 80 ma * * temperature range rated performance C25 c to +85 c* * operating C40 c to +85 c* * storage C40 c to +85 c* * package dimensions inches 1.00 2.10 0.350 * * millimeters 25.4 53.3 8.9 * * notes *specifications same as ad210an. 1 nonlinearity is specified as a % deviation from a best straight line.. 2 rti C referred to input. 3 a reduced signal swing is recommended when both v iss and v oss supplies are fully loaded, due to supply voltage reduction. 4 see text for detailed information. _ specifications subject to change without notice. rev. a C2C outline dimensions dimensions shown in inches and (mm). ac1059 mating socket caution esd (electrostatic discharge) sensitive device. elec- trostatic charges as high as 4000 v readily accumu- late on the human body and test equipment and can discharge without detection. although the ad210 features proprietary esd protection circuitry, per- manent 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. warning! esd sensitive device
ad210 rev. a e3e inside the ad210 the ad210 basic block diagram is illustrated in figure 1. a +15 v supply is connected to the power port, and 15 v isolated power is supplied to both the input and output ports via a 50 khz carrier frequency. the uncom- mitted input amplifier can be used to supply gain or buff- ering of input signals to the ad210. the fullwave modulator translates the signal to the carrier frequency for application to transformer t1. the synchronous demodu- lator in the output port reconstructs the input signal. a 20 khz, three-pole filter is employed to minimize output noise and ripple. finally, an output buffer provides a low impedance output capable of driving a 2 k w load. input power supply 19 14 15 16 17 18 v o 30 29 t2 power power oscillator input output mod demod filter 1 2 output power supply 3 4 o com +v oss ev oss ad210 pwr com pwr t3 t1 ev iss +v iss i com +in ein fb figure 1. ad210 block diagram using the ad210 the ad210 is very simple to apply in a wide range of ap- plications. powered by a single +15 v power supply, the ad210 will provide outstanding performance when used as an input or output isolator, in single and multichannel configurations. input configurations: the basic unity gain configura- tion for signals up to 10 v is shown in figure 2. addi- tional input amplifier variations are shown in the following figures. for smaller signal levels figure 3 shows how to obtain gain while maintaining a very h igh input impedance. 19 14 15 16 17 18 v out ( 10v) 30 29 +v oss v sig 10v ad210 +v iss ev iss +15v 2 3 4 ev oss 1 v out figure 2. basic unity gain configuration the high input impedance of the circuits in figures 2 and 3 can be maintained in an inverting application. since the ad210 is a three-port isolator, either the input leads or the output leads may be interchanged to create the signal inversion. 19 14 15 16 17 18 30 29 +v oss v sig ad210 +v iss ev iss +15v 2 3 4 ev oss 1 v out = v sig 1+ ( ) r f r g r g r f figure 3. input configuration for g > 1 figure 4 shows how to accommodate current inputs or sum cur- rents or voltages. this circuit configuration can also be used for signals greater than 10 v. for example, a 100 v input span can be handled with r f = 20 k w and r s1 = 200 k w . 19 14 15 16 17 18 30 29 +v oss ad210 +v iss ? iss +15v 2 3 4 ? oss 1 r s1 i s v s2 v s1 r s2 r f v out v out = ? f v s1 r s1 ( ) v s2 r s2 + + i s + ... figure 4. summing or current input configuration adjustments when gain and offset adjustments are required, the actual cir- cuit adjustment components will depend on the choice of input configuration and whether the adjustments are to be made at the isolator? input or output. adjustments on the output side might be used when potentiometers on the input side would represent a hazard due to the presence of high common-mode voltage during adjustment. offset adjustments are best done at the input side, as it is better to null the offset ahead of the gain. figure 5 shows the input adjustment circuit for use when the in- put amplifier is configured in the noninverting mode. this offset adjustment circuit injects a small voltage in series with the 19 15 16 17 18 30 29 +v oss ad210 +v iss ? iss +15v 2 3 4 ? oss r g hi v out v sig 14 200 w 47.5k w 5k w 100k w 50k w lo gain offset 1 figure 5. adjustments for noninverting input
ad210 rev. a C4C low side of the signal source. this will not work if the source has another current path to input common or if current flows in the signal source lo lead. to minimize cmr degradation, keep the resistor in series with the input lo below a few hundred ohms. figure 5 also shows the preferred gain adjustment circuit. the circuit shows r f of 50 k w , and will work for gains of ten or greater. the adjustment becomes less effective at lower gains (its effect is halved at g = 2) so that the pot will have to be a larger fraction of the total r f at low gain. at g = 1 (follower) the gain cannot be adjusted downward without compromising input impedance; it is better to adjust gain at the signal source or after the output. figure 6 shows the input adjustment circuit for use when the input amplifier is configured in the inverting mode. the offset adjustment nulls the voltage at the summing node. this is pref- erable to current injection because it is less affected by subse- quent gain adjustment. gain adjustment is made in the feedback and will work for gains from 1 v/v to 100 v/v. 19 15 16 17 18 30 29 +v oss ad210 +v iss ? iss +15v 2 3 4 ? oss v out v sig 14 200w 47.5k w 5kw 100kw gain offset 50kw r s 1 figure 6. adjustments for inverting input figure 7 shows how offset adjustments can be made at the out- put, by offsetting the floating output port. in this circuit, 15 v would be supplied by a separate source. the ad210s output amplifier is fixed at unity, therefore, output gain must be made in a subsequent stage. 19 15 16 17 18 30 29 +v oss ad210 +v iss ? iss +15v 2 3 4 ? oss v out 14 200w 1 0.1? 100k offset 50kw +15v ?5v figure 7. output-side offset adjustment pcb layout for multichannel applications: the unique pinout positioning minimizes board space constraints for multi- channel applications. figure 8 shows the recommended printed circuit board layout for a noninverting input configuration with gain. r f r g r f r g r f r g power channel inputs 1 2 3 0.1" grid channel outputs 1 2 3 figure 8. pcb layout for multichannel applications with gain synchronization: the ad210 is insensitive to the clock of an adjacent unit, eliminating the need to synchronize the clocks. however, in rare instances channel to channel pick-up may occur if input signal wires are bundled together. if this happens, shielded input cables are recommended. performance characteristics common-mode rejection: figure 9 shows the common- mode rejection of the ad210 versus frequency, gain and input source resistance. for maximum common-mode rejection of unwanted signals, keep the input source resistance low and care- fully lay out the input, avoiding excessive stray capacitance at the input terminals. 180 140 40 10 20 50 60 100 200 500 1k 2k 5k 10k 160 100 120 60 80 frequency ?hz r lo = 0w r lo = 500 w r lo = 0w r lo = 10k w r lo = 10k w g = 100 g = 1 cmr ?db figure 9. common-mode rejection vs. frequency
ad210 rev. a e5e +0.04 +0.03 +0.02 +0.01 0 e0.01 e0.02 e0.03 e0.04 e10 e8 e6 e4 e2 0 +2 +4 +6 +8 +10 output voltage swing e volts +8 +6 +4 +2 0 e2 e4 e6 e8 error e mv error e % figure 12. gain nonlinearity error vs. output 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0.000 100 90 80 70 60 50 40 30 20 10 0 0 2 4 6 8 10 12 14 16 18 20 total signal swing e volts error e % of signal swing error e ppm of signal swing figure 13. gain nonlinearity vs. output swing gain vs. temperature: figure 14 illustrates the ad210?s gain vs. temperature performance. the gain versus temperature performance illustrated is for an ad210 configured as a unity gain amplifier. 400 200 0 e200 e400 e600 e800 e1000 e1200 e1400 e1600 e25 0 +25 +50 +70 +85 temperature e c gain error e ppm of span g = 1 figure 14. gain vs. temperature phase shift: figure 10 illustrates the ad210?s low phase shift and gain versus frequency. the ad210?s phase shift and wide bandwidth performance make it well suited for applications like power monitors and controls systems. 60 20 e80 100 100k 10k 1k 10 40 e20 0 e60 e40 frequency e hz 0 e20 e40 e60 e80 e100 e120 e140 phase shift e degrees gain e db f g = 1 f g = 100 figure 10. phase shift and gain vs. frequency input noise vs. frequency: voltage noise referred to the input is dependent on gain and signal bandwidth. figure 11 illustrates the typical input noise in nv/ ? hz of the ad210 for a frequency range from 10 to 10 khz. 60 40 0 100 10k 1k 10 50 20 30 10 frequency C hz noise C nv/ hz figure 11. input noise vs. frequency gain nonlinearity vs. output: gain nonlinearity is defined as the deviation of the output voltage from the best straight line, and is specified as % peak-to-peak of output span. the ad210b provides guaranteed maximum nonlinearity of 0.012% with an output span of 10 v. the ad210s nonlinearity performance is shown in figure 12. gain nonlinearity vs. output swing: the gain nonlinearity of the ad210 varies as a function of total signal swing. when the output swing is less than 20 volts, the gain nonlinearity as a fraction of signal swing improves. the shape of the nonlinearity remains constant. figure 13 shows the gain nonlinearity of the ad210 as a function of total signal swing.
ad210 rev. a C6C isolated power: the ad210 provides isolated power at the input and output ports. this power is useful for various signal conditioning tasks. both ports are rated at a nominal 15 v at 5 ma. the load characteristics of the isolated power supplies are shown in figure 15. for example, when measuring the load rejection of the input isolated supplies v iss , the load is placed between +v iss and Cv iss . the curves labeled v iss and v oss are the individual load rejection characteristics of the input and the output supplies, respectively. there is also some effect on either isolated supply when loading the other supply . the curve labeled crossload indicates the sensitivity of either the input or output supplies as a function of the load on the opposite supply . 30 20 510 0 25 current ?ma voltage v oss v oss v iss v iss simultaneous simultaneous crossload figure 15. isolated power supplies vs. load lastly, the curves labeled v oss simultaneous and v iss simulta- neous indicate the load characteristics of the isolated power sup- plies when an equal load is placed on both supplies. the ad210 provides short circuit protection for its isolated power supplies. when either the input supplies or the output supplies are shorted to input common or output common, respectively, no damage will be incurred, even under continuous application of the short. however, the ad210 may be damaged if the input and output supplies are shorted simultaneously. 100 50 10 75 load ?ma ripple ?mv p-p ? oss +v iss 25 0 +v oss ? iss 234567 figure 16a. isolated supply ripple vs. load (external 4.7 m f bypass) under any circumstances, care should be taken to ensure that the power supplies do not accidentally become shorted. the isolated power supplies exhibit some ripple which varies as a function of load. figure 16a shows this relationship. the ad210 has internal bypass capacitance to reduce the ripple to a point where performance is not affected, even under full load. since the internal circuitry is more sensitive to noise on the negative supplies, these supplies have been filtered more heavily. should a specific application require more bypassing on the iso- lated power supplies, there is no problem with adding external capacitors. figure 16b depicts supply ripple as a function of external bypass capacitance under full load. 1v 10mv 0.1? 100mv 1mv capacitance ripple ?peak-peak volts 1? 10? 100? ( ) +v iss +v oss ( ) ? iss ? oss figure 16b. isolated power supply ripple vs. bypass capacitance (volts p-p, 1 mhz bandwidth, 5 ma load) applications examples noise reduction in data acquisition systems: transformer coupled isolation amplifiers must have a carrier to pass both ac and dc signals through their signal transformers. therefore, some carrier ripple is inevitably passed through to the isolator output. as the bandwidth of the isolator is increased more of the carrier signal will be present at the output. in most cases, the ripple at the ad210s output will be insignificant when com- pared to the measured signal. however, in some applications, particularly when a fast analog-to-digital converter is used fol- lowing the isolator, it may be desirable to add filtering; other- wise ripple may cause inaccurate measurements. figure 17 shows a circuit that will limit the isolators bandwidth, thereby reducing the carrier ripple. v out 15 30 29 +v oss +v iss ? iss +15v 2 4 ? oss 14 1 0.001? 0.002? r (kw) = ( ) 112.5 f c (khz) ad542 +v oss ? oss 3 v sig 19 18 ad210 r r 16 17 figure 17. 2-pole, output filter self-powered current source the output circuit shown in figure 18 can be used to create a self-powered output current source using the ad210. the 2 k w resistor converts the voltage output of the ad210 to an equiva-
ad210 rev. a e7e lent current v out /2 k w . this resistor directly affects the output gain temperature coefficient, and must be of suitable stability for the application. the external low power op amp, powered by +v oss and ev oss, maintains its summing junction at output common. all the current flowing through the 2 k w resistor flows through the output darlington pass devices. a darlington con- figuration is used to minimize loss of output current to the base. i out 15 +v oss +v iss ev iss +15v 2 ev oss 14 1 lf441 +v oss ev oss 3 v sig 0-10v 19 18 ad210 2k w 2n3906 (2) 16 17 4 fdh333 i out return 30 29 figure 18. self-powered isolated current source the low leakage diode is used to protect the base-emitter junc- tion against reverse bias voltages. using ev oss as a current return allows more than 10 v of compliance. offset and gain control may be done at the input of the ad210 or by varying the 2 k w resistor and summing a small correction current directly into the summing node. a nominal range of 1 mae 5 ma is recommended since the current output cannot reach zero due to reverse bias and leakage currents. if the ad210 is powered from the input potential, this circuit provides a fully isolated, wide bandwidth current output. this configuration is limited to 5 ma output current. isolated v-to-i converter illustrated in figure 19, the ad210 is used to convert a 0 v to +10 v input signal to an isolated 4e20 ma output current. the ad210 isolates the 0 v to +10 v input signal and provides a proportional voltage at the isolator?s output. the output circuit converts the input voltage to a 4e20 ma output current, which in turn is applied to the loop load r load . r load 15 +v oss +v iss ev iss +15v 2 ev oss 14 1 +v s ev s 3 v sig 19 18 ad210 500 w 2n2907 16 17 4 current loop 143 w 3.0k adjust to 4ma with 0v in +28v current loop 2n2219 576 w 1n4149 span adj 100 w 30 29 ad308 figure 19. isolated voltage-to-current loop converter isolated thermocouple amplifier the ad210 application shown in figure 20 provides amplifica- tion, isolation and cold-junction compensation for a standard j type thermocouple. the ad590 temperature sensor accurately monitors the input terminal (cold-junction). ambient tempera- ture changes from 0 c to +40 c sensed by the ad590, are can- celled out at the cold junction. total circuit gain equals 183; 100 and 1.83, from a1 and the ad210 respectively. calibration is performed by replacing the thermocouple junction with plain thermocouple wire and a millivolt source set at 0.0000 v (0 c) and adjusting r o for e out equal to 0.000 v. set the millivolt source to +0.02185 v (400 c) and adjust r g for v out equal to +4.000 v. this application circuit will produce a nonlinearized output of about +10 mv/ c for a 0 c to +400 c range. +v oss +v iss ev iss +15v 2 ev oss 3 18 ad210 16 17 4 13.7k 30 29 10k r g 5k a1 19 ev iss 10k 220pf 100k thermal contact 52.3 w cold junction ev iss +v iss 1k -20k- "j" 15 14 1000pf 1 v out ad590 ad op-07 r g figure 20. isolated thermocouple amplifier precision floating programmable reference the ad210, when combined with a digital-to-analog converter, can be used to create a fully floating voltage output. figure 21 shows one possible implementation. the digital inputs of the ad7541 are ttl or cmos compat- ible. both the ad7541 and ad581 voltage reference are pow- ered by the isolated power supply + v iss . i com should be tied to input digital common to provide a digital ground reference for the inputs. the ad7541 is a current output dac and, as such, requires an external output amplifier. the uncommitted input amplifier internal to the ad210 may be used for this purpose. for best results, its input offset voltage must be trimmed as shown. the output voltage of the ad210 will go from 0 v to C10 v for digital inputs of 0 and full scale, respectively. however, since the output port is truly isolated, v out and o com may be freely interchanged to get 0 v to +10 v. this circuit provides a precision 0 vC10 v programmable refer- ence with a 3500 v common-mode range. +v oss +v iss Cv iss +15v Cv oss ad210 200 w 1k w +v iss v out 0 - C10v 100k w 50k w 17 1 3 2 18 16 12-bit digital input ad7541 2k w gain hp5082-2811 or equivalent +v iss ad581 offset 17 15 4 1 3 2 18 16 4 15 19 14 30 29 figure 21. precision floating programmable reference
ad210 rev. a C8C multichannel data acquisition front-end illustrated in figure 22 is a four-channel data acquisition front- end used to condition and isolate several common input signals found in various process applications. in this application, each ad210 will provide complete isolation from input to output as well as channel to channel. by using an isolator per channel, maximum protection and rejection of unwanted signals is obtained. the three-port design allows the ad210 to be configured as an input or output isolator. in this application the isolators are configured as input devices with the power port providing additional protection from possible power source faults. channel 1: the ad210 is used to convert a 4C20 ma current loop input signal into a 0 vC10 v input. the 25 w shunt resistor converts the 4-20 ma current into a +100 mv to +500 mv signal. the signal is offset by C100 mv via r o to produce a 0 mv to +400 mv input. this signal is amplified by a gain of 25 to produce the desired 0 v to +10 v output. with an open circuit, the ad210 will show C2.5 v at the output. channel 2: in this channel, the ad210 is used to condition and isolate a current output temperature transducer, model ad590. at +25 c, the ad590 produces a nominal current of 298.2 m a. this level of current will change at a rate of 1 m a/ c. at C17.8 c (0 f), the ad590 current will be reduced by 42.8 m a to +255.4 m a. the ad580 reference circuit provides an equal but opposite current, resulting in a zero net current flow, producing a 0 v output from the ad210. at +100 c (+212 f), the ad590 current output will be 373.2 m a minus the 255.4 m a offsetting current from the ad580 circuit to yield a +117.8 m a input current. this current is converted to a voltage via r f and r g to produce an output of +2.12 v. channel 2 will produce an output of +10 mv/ f over a 0 f to +212 f span. channel 3: channel 3 is a low level input channel configured with a high gain amplifier used to condition millivolt signals. with the ad210s input set to unity and the input amplifier set for a gain of 1000, a 10 mv input will produce a 10 v at the ad210s out put. channel 4: channel 4 illustrates one possible configuration for conditioning a bridge circuit. the ad584 produces a +10 v excitation voltage, while a1 inverts the voltage, producing negative excitation. a2 provides a gain of 1000 v/v to amplify the low level bridge signal. additional gain can be obtained by reconfiguration of the ad210s input amplifier. v iss provides the complete power for this circuit, eliminating the need for a separate isolated excita- tion source. each channel is individually addressed by the multiplexers chan- nel select. additional filtering or signal conditioning should follow the multiplexer, prior to an analog-to-digital conversion stage . +v oss +v iss ? iss ? oss ad210 r o 50k 17 15 18 16 19 14 4 3 29 com +v to a/d +v oss +v iss ? iss ? oss offset 50k 17 15 18 16 19 14 4 3 2 30 29 +v iss ? iss 15 +v oss ? oss ad210 18 19 14 4 3 2 1 30 +v oss ? oss ad210 17 18 16 19 4 3 1 30 29 r g 1k w 1 200kw 8.25k ad210 1 10t 4-20ma 25w 50k 1kw r g 5k 10t r f 15.8k 10t 50k 30 16 17 100w ad590 ad580 ? iss +v iss r o 1kw 10t 9.31k ad op-07 +v iss ? iss +v iss ? iss 15 14 0.47? 50kw 50w 1.0? 39k e in 1m 1k 20k 20k 20k 20k +v iss ? iss 29 +v iss ? iss a2 a1 ad584 +v iss com +15v dc power source 2 2 ad7502 multiplexer ? channel select channel 3 channel 1 channel 2 channel 4 +10v a1 a2 = ad547 figure 22. multichannel data acquisition front-end c1005C9C9/86 printed in u.s.a.
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