FEATURES
a71 SAME PINOUT AS ADS7843
a71 2.2V TO 5.25V OPERATION
a71 INTERNAL 2.5V REFERENCE
a71 DIRECT BATTERY MEASUREMENT (0V to 6V)
a71 ON-CHIP TEMPERATURE MEASUREMENT
a71 TOUCH-PRESSURE MEASUREMENT
a71 QSPI
TM
/SPI
TM
3-WIRE INTERFACE
a71 AUTO POWER-DOWN
a71 TSSOP-16, SSOP-16, QFN-16,
AND VFBGA-48 PACKAGES
APPLICATIONS
a71 PERSONAL DIGITAL ASSISTANTS
a71 PORTABLE INSTRUMENTS
a71 POINT-OF-SALE TERMINALS
a71 PAGERS
a71 TOUCH SCREEN MONITORS
a71 CELLULAR PHONES
TOUCH SCREEN CONTROLLER
DESCRIPTION
The ADS7846 is a next-generation version to the industry
standard ADS7843 4-wire touch screen controller. The
ADS7846 is 100% pin-compatible with the existing ADS7843,
and drops into the same socket. This allows for easy upgrade
of current applications to the new version. Only software
changes are required to take advantage of the added fea-
tures of direct battery measurement, temperature measure-
ment, and touch-pressure measurement. The ADS7846 also
has an on-chip 2.5V reference that can be used for the
auxiliary input, battery monitor, and temperature measure-
ment modes. The reference can also be powered down when
not used to conserve power. The internal reference operates
down to 2.7V supply voltage while monitoring the battery
voltage from 0V to 6V.
The low-power consumption of < 0.75mW (typ at 2.7V,
reference off), high speed (up to 125kHz clock rate), and on-
chip drivers make the ADS7846 an ideal choice for battery-
operated systems such as personal digital assistants (PDAs)
with resistive touch screens, pagers, cellular phones, and
other portable equipment. The ADS7846 is available in the
small TSSOP-16, SSOP-16, QFN-16, and VFBGA-48 pack-
ages and is specified over the –40°C to +85°C temperature
range.
CDAC
Internal 2.5V
Reference
SAR
ADS7846
Comparator
6-Channel
MUX
Serial
Data
Out
Temperature
Sensor
Battery
Monitor
DOUT
BUSY
CS
DCLK
DIN
V
BAT
AUX
V
REF
+V
CC
X+
X–
Y+
Y–
PENIRQ
ADS7846
SBAS125H – SEPTEMBER 1999 – REVISED JANUARY 2005
www.ti.com
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 © 1999-2005, Texas Instruments Incorporated
US Patent No. 6246394
QSPI and SPI are registered trademarks of Motorola.
®ADS
78
46
AD
S7
846
AD
S7
846
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.
All trademarks are the property of their respective owners.