AD698 Analog Devices, AD698 Datasheet
AD698
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AD698 Summary of contents
Page 1
... Multiple LVDTs can be driven by a single AD698 either in series or parallel as long as power dissipation limits are not exceeded. The excitation output is thermally protected. 6. The AD698 may be used as a loop integrator in the design of simple electromechanical servo loops. 7. The sum of the transducer secondary voltages do not need to Package be constant ...
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... AD698AP Min Typ Max Unit R2 V 0.4 1. 500 ppm of FS 0.1 1 100 ppm 0. ppm 100 ppm/dB ...
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... Storage Temperature Range P Package . . . . . . . . . . . . . . . . . . . . . . . . . – +150 C Q Package . . . . . . . . . . . . . . . . . . . . . . . . – +150 C Operating Temperature Range AD698SQ . . . . . . . . . . . . . . . . . . . . . . . . – +125 C AD698AP . . . . . . . . . . . . . . . . . . . . . . . . . – +85 C Lead Temperature Range (Soldering 60 sec +300 C Power Dissipation Derates above + Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mW Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mW/ C THERMAL CHARACTERISTICS ...
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... AD698 Typical Characteristics (at +25 C and V 240 200 160 GAIN PSRR 15–18V 120 80 40 GAIN PSRR 12–15V 20 OFFSET PSRR 12–15V 0 OFFSET PSRR 15–18V –20 –60 –40 – TEMPERATURE – C Figure 1. Gain and Offset PSRR vs. Temperature 0 OFFSET CMRR –05 –10 –15 – ...
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... The AD698 energizes the LVDT coil, senses the LVDT output voltages and produces a dc output voltage proportional to core position. The AD698 has a sine wave oscillator and power am- plifier to drive the LVDT. Two synchronous demodulation stages are available for decoding the primary and secondary voltages ...
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... AD698 CONNECTING THE AD698 The AD698 can easily be connected for dual or single supply operation as shown in Figures 7, 8 and 13. The following gen- eral design procedures demonstrate how external component values are selected and can be used for any LVDT that meets AD698 input/output criteria. The connections for the A and B channels and the A channel comparators will depend on which transducer is used ...
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... Farad Hz/250 Hz = 0.4 F See Figures 14, 15 and 16 for more information about AD698 bandwidth and phase characterization. D. Set the Full-Scale Output Voltage 8. To compute R2, which sets the AD698 gain or full-scale output range, several pieces of information are needed: a. LVDT sensitivity, S REV Full-scale core displacement from null, d ...
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... SIGNAL to respond once the core is moved. The dynamics arise prima- REFERENCE rily from the interface electronics. Figures 14, 15 and 16 show the frequency response of the AD698 LVDT Signal Conditioner Note that Figures 15 and 16 are basically the same; the differ- OUT 19 ence is frequency range covered ...
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... The figures are transfer functions with the input to be 0.033µF considered as a sinusoidally varying mechanical position and the output as the voltage from the AD698; the units of the transfer function are volts per inch. The value of C2, C3, and C4, from 0.01µF Figure 7, are all equal and designated as a parameter in the fig- ures ...
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... V by the gain stage created by A1 provide a differential in- A 1.71V rms put to the A Channel of the AD698. The signal is then synchro- nously detected by A Channel. The B Channel is used to detect the level of the bridge excitation. The ratio of A/B is then calcu- 0.99V rms lated and converted to an output voltage by R2 ...
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... The other components, C1, C2, C3, C4 may be selected by following the guidelines on general device operation men- tioned earlier gain trim is required, then a trim resistor can be used to ad- just either network on the OFFSET 1 and OFFSET 2 pins of the AD698. 6.8µF 100nF 100nF –V ...
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... AD698 0.005 (0.13) MIN PIN 1 0.200 (5.08) MAX 0.200 (5.08) 0.125 (3.18) 0.023 (0.58) 0.014 (0.36) 0.048 (1.21) 0.042 (1.07) OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 24-Pin Cerdip (Wide) 0.098 (2.49) MAX 24 13 0.610 (15.5) 0.520 (13. 1.280 (32.51) MAX 0.060 (1.52) 0.015 (0.38) 0.150 (3.81) MIN SEATING 0.100 0.070 (1.78) PLANE (2.54) 0.030 (0.76) BSC 28-Pin PLCC ...