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 2.2 V), 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 × 5 mm package

25-ball,WLCSP, 2.5 mm × 2.8 mm package

Qualified for automotive applications

APPLICATIONS

Personal digital assistants

Smart hand-held devices

Touch screen monitors

Point-of-sale terminals

Medical devices

Cell phones

Pagers