GENERAL DESCRIPTION
The AD7877 is a 12-bit successive approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The AD7877 operates from a single 2.7 V to 5.25 V power supply (functional operation to 2.2V), and features throughput rates of 125 kSPS. The AD7877 features direct battery measurement on two inputs, temperature and touch-pressure measurement.

FEATURES
    4-wire touch screen interface
    LCD noise reduction feature (STOPACQ pin)
    Automatic conversion sequencer and timer
    User-programmable conversion parameters
    On-chip temperature sensor: −40°C to +85°C
    On-chip 2.5 V reference
    On-chip 8-bit DAC
    3 auxiliary analog inputs
    1 dedicated and 3 optional GPIOs
    2 direct battery measurement channels (0.5 V to 5 V)
    3 interrupt outputs
    Touch-pressure measurement
    Wake up on touch function
    Specified throughput rate of 125 kSPS
    Single supply, VCC of 2.7 V to 5.25 V
    Separate VDRIVE level for serial interface
    Shutdown mode: 1 µA maximum
    32-lead LFCSP 5 mm x 5 mm package

APPLICATIONS
    Personal digital assistants
    Smart hand-held devices
    Touch screen monitors
    Point-of-sale terminals
    Medical devices
    Cell phones
    Pagers