ADS7845 Datasheet, PDF (1/16 Pages) Burr-Brown (TI) – TOUCH SCREEN CONTROLLER

®
ADS7845
ADS7845
TOUCH SCREEN CONTROLLER
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
APPLICATIONS
q PERSONAL DIGITAL ASSISTANTS
q PORTABLE INSTRUMENTS
q POINT-OF-SALES TERMINALS
q PAGERS
q TOUCH-SCREEN MONITORS
GND
+V_CC
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 750µW at a
125kHz throughput rate and a +2.7V supply. The
reference voltage (V ) can be varied between 1V and
REF
+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 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.
UR
LR
Driver
GND
+V_CC
UL
LL
AUX IN
WIPER
PENIRQ
+V_{CC GND}
MUX
SAR
ADS7845
CDAC
Comparator
Serial
Data
Interface
and
Control
DOUT
BUSY
CS
DCLK
DIN
SBAS104
V_REF
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©_{1998 Burr-Brown Corporation}
PDS-1497A
Printed in U.S.A. December, 1998