AD7714Data 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. +5V2AVDDDVDDAVDDAD77141 m AAIN1CHARGE BALANCING A/DIN1+STANDBYCONVERTERAIN2IN1–AIN3AUTO-ZEROEDDIGITALIN2+SYNCAIN4BUFFERPGA SD FILTERIN2–MODULATORAIN5MATRIXIN3+SWITCHINGAIN6A = 1–128MCLK ININ3–CLOCKGENERATION1 m A+5VSERIAL INTERFACEMCLK OUT+VAGNDREGISTER BANKINREF IN (+)RESETVOUTAD780DRDYREF IN (–)POLGNDAGNDDGNDBUFFERDOUTDINCSSCLKDVDDMICROCONTROLLEROPTO-ISOLATORS Figure 15. Data Acquisition System Using the AD7714 REV. C –37–