ADS7843
SBAS090B – SEPTEMBER 2000 – REVISED MAY 2002
TOUCH SCREEN CONTROLLER
FEATURES
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4-WIRE TOUCH SCREEN INTERFACE
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RATIOMETRIC CONVERSION
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SINGLE SUPPLY: 2.7V to 5V
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UP TO 125kHz CONVERSION RATE
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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 Con-
verter (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 specified down to 2.7V operation.
Low power, high speed, and onboard switches make the
ADS7843 ideal for battery-operated systems such as per-
sonal digital assistants with resistive touch screens and other
portable equipment. The ADS7843 is available in an
SSOP-16 package and is specified over the –40°C to +85°C
temperature range.
US Patent No. 6246394
APPLICATIONS
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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
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright © 2001, Texas Instruments Incorporated
www.ti.com
TI [ TEXAS INSTRUMENTS ]
