Datasheet AD7714 (Analog Devices) - 38

AD7714 Data Acquisition
The AD7714 with its three differential channels (or five pseudo- from a single +3␣ V or +5 V supply provided that the input sig- differential channels) is suited to low bandwidth, high resolution nals to the AD7714’s analog inputs are all of positive polarity. data acquisition systems. In addition, the three-wire digital The low power operation of the AD7714 ensures that very little interface allows this data acquisition front end to be isolated power has to be brought across the isolation barrier. Figure 15 with just three optoisolators. The entire system can be operated shows the AD7714 in an isolated data acquisition system.
+5V 2 AVDD DVDD AVDD AD7714 1
m
A AIN1 CHARGE BALANCING A/D IN1+ STANDBY CONVERTER AIN2 IN1– AIN3 AUTO-ZEROED DIGITAL IN2+ SYNC AIN4 BUFFER PGA
SD
FILTER IN2– MODULATOR AIN5 MATRIX IN3+ SWITCHING AIN6 A = 1–128 MCLK IN IN3– CLOCK GENERATION 1
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A +5V SERIAL INTERFACE MCLK OUT +V AGND REGISTER BANK IN REF IN (+) RESET VOUT AD780 DRDY REF IN (–) POL GND AGND DGND BUFFER DOUT DIN CS SCLK DVDD MICROCONTROLLER OPTO-ISOLATORS
Figure 15. Data Acquisition System Using the AD7714 REV. C –37–