GENERAL DESCRIPTION

The AD7879/AD7889 are 12-bit successive approximation analog-to-digital converters (SAR ADCs) with a synchronous serial interface and low on-resistance switches for driving 4-wire resistive touch screens. The AD7879/AD7889 work with a very low power supply—a single 1.6 V to 3.6 V supply—and feature a throughput rate of 105 kSPS. The devices include a shutdown mode that reduces current consumption to less than 6 μA.

FEATURES

4-wire touch screen interface

1.6 V to 3.6 V operation

Median and averaging filter to reduce noise

Automatic conversion sequencer and timer

User-programmable conversion parameters

Auxiliary analog input/battery monitor (0.5 V to 5 V)

1 optional GPIO

Interrupt outputs (INT, PENIRQ)

Touch-pressure measurement

Wake-up on touch function

Shutdown mode: 6 μA maximum

12-ball, 1.6 mm × 2 mm WLCSP

16-lead, 4 mm × 4 mm LFCSP

APPLICATIONS

Personal digital assistants

Smart handheld devices

Touch screen monitors

Point-of-sale terminals

Medical devices

Cell phones