®
ADS7843
TOUCH SCREEN CONTROLLER
FEATURES
q
4-WIRE TOUCH SCREEN INTERFACE
q
RATIOMETRIC CONVERSION
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SINGLE SUPPLY: 2.7V to 5V
q
UP TO 125kHz CONVERSION RATE
q
SERIAL INTERFACE
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PROGRAMMABLE 8- OR 12-BIT RESOLUTION
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2 AUXILIARY ANALOG INPUTS
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FULL POWER-DOWN CONTROL
DESCRIPTION
The ADS7843 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 750µW at a
125kHz throughput rate and a +2.7V supply. The
reference voltage (V
REF
) can be varied between 1V and
+V
CC
, providing a corresponding input voltage range
of 0V to V
REF
. The device includes a shutdown mode
which reduces typical power dissipation to under
0.5µW. The ADS7843 is guaranteed down to 2.7V
operation.
Low power, high speed, and on-board switches make
the ADS7843 ideal for battery operated systems such
as personal digital assistants with resistive touch screens
and other portable equipment. The ADS7843 is avail-
able in a 16-lead SSOP package and is guaranteed
over the –40°C to +85°C temperature range.
APPLICATIONS
q
q
q
q
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PERSONAL DIGITAL ASSISTANTS
PORTABLE INSTRUMENTS
POINT-OF-SALES TERMINALS
PAGERS
TOUCH-SCREEN MONITORS
PENIRQ
+V
CC
X+
X–
SAR
DCLK
Y+
Y–
Four
Channel
Multiplexer
Comparator
CDAC
Serial
Interface
and
Control
CS
DIN
DOUT
IN3
IN4
BUSY
V
REF
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/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
©
1997 Burr-Brown Corporation
PDS-1441C
Printed in U.S.A. June, 1998
BURR-BROWN [ BURR-BROWN CORPORATION ]
