ADS7845

FEATURES

q 5-WIRE TOUCH SCREEN INTERFACE

q RATIOMETRIC CONVERSION

q SINGLE SUPPLY: 2V to 5V

q UP TO 125kHz CONVERSION RATE

q SERIAL INTERFACE

q PROGRAMMABLE 8- OR 12-BIT RESOLUTION

q AUXILIARY ANALOG INPUTS

q FULL POWER-DOWN CONTROL

®

DESCRIPTION

The ADS7845 is a 12-bit sampling analog-to-digital

converter (ADC) with a synchronous serial interface

and low on-resistance switches for driving touch

screens. Typical power dissipation is 750

µW at a

125kHz throughput rate and a +2.7V supply. The

reference voltage (V

+V

of 0V to V

which reduces typical power dissipation to under

0.5

µW. The ADS7845 is guaranteed down to 2.7V

operation.

Low power, high speed, and on-board switches make

the ADS7845 ideal for battery-operated systems such

as personal digital assistants with resistive touch screens

and other portable equipment. The ADS7845 is avail-

able in a 16-lead SSOP package and is guaranteed

over the –40

°C to +85°C temperature range.

APPLICATIONS

q PERSONAL DIGITAL ASSISTANTS

q PORTABLE INSTRUMENTS

q POINT-OF-SALES TERMINALS

q PAGERS

q TOUCH-SCREEN MONITORS

PDS-1497A

Printed in U.S.A. December, 1998

TOUCH SCREEN CONTROLLER

CDAC

SAR

ADS7845

Comparator

MUX

Serial

Data

Interface

and

Control

DOUT

BUSY

CS

DCLK

DIN

UR

LR

UL

LL

AUX IN

WIPER

PENIRQ

V

REF

GND

Driver

+V

CC

+V

CC

GND

+V

CC

GND

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111

Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132

ADS7845

SBAS104