GENERAL DESCRIPTION
The AD7708/AD7718 are complete analog front-ends for low frequency measurement applications. The AD7718 contains a 24-bit Σ-∆ ADC with PGA and can be configured as 4/5 fully-differential input channels or 8/10 pseudo-differential input channels. Two pins on the device are configurable as analog inputs or reference inputs. The AD7708 is a 16-bit version of the AD7718. Input signal ranges from 20 mV to 2.56 V can be directly converted using these ADCs. Signals can be converted directly from a transducer without the need for signal conditioning.
   
FEATURES
    8-/10-Channel, High Resolution Σ-∆ ADCs
    AD7708 Has 16-Bit Resolution
    AD7718 Has 24-Bit Resolution
    Factory-Calibrated
    Single Conversion Cycle Setting
    Programmable Gain Front End
    Simultaneous 50 Hz and 60 Hz Rejection
    VREF Select™ Allows Absolute and Ratiometric
        Measurement Capability
    Operation Can Be Optimized for
        Analog Performance (CHOP = 0) or
        Channel Throughput (CHOP = 1)
   
INTERFACE
    3-Wire Serial
    SPITM, QSPITM, MICROWIRETM, and DSP-Compatible
    Schmitt Trigger on SCLK
   
POWER
    Specified for Single 3 V and 5 V Operation
    Normal: 1.28 mA Typ @ 3 V
    Power-Down: 30 μA (32 kHz Crystal Running)
    On-Chip Functions
        Rail-to-Rail Input Buffer and PGA
        2-Bit Digital I/O Port
   
APPLICATIONS
    Industrial Process Control
    Instrumentation
    Pressure Transducers
    Portable Instrumentation
    Smart Transmitters