TSC2046E-Q1 Datasheet, PDF (9/28 Pages) Texas Instruments – LOW-VOLTAGE I/O TOUCH SCREEN CONTROLLER

TSC2046E-Q1
www.ti.com
THEORY OF OPERATION
SBAS510 – JUNE 2010
The TSC2046E is a classic successive approximation register (SAR) analog-to-digital converter (ADC). The
architecture is based on capacitive redistribution, which inherently includes a sample-and-hold function. The
converter is fabricated on a 0.6µm CMOS process.
The basic operation of the TSC2046E is shown in Figure 1. The device features an internal 2.5-V reference and
an internal clock. Operation is maintained from a single supply of 2.7 V to 5.25 V. The internal reference can be
overdriven with an external, low-impedance source between 2 V and +V_CC. The value of the reference voltage
directly sets the input range of the converter.
The analog input (X-, Y-, and Z-position coordinates, auxiliary inputs, battery voltage, and chip temperature) to
the converter is provided via a multiplexer. A unique configuration of low on-resistance switches allows an
unselected ADC input channel to provide power and an accompanying pin to provide ground for an external
device. By maintaining a differential input to the converter and a differential reference architecture, it is possible
to negate the error from each touch panel driver switch on-resistance (if this is a source of error for the particular
measurement).
Touch
Screen
1µF
to
+
10µF
(Optional)
+2.7V to +5V
TSC2046E
0.1µF
B1 +V_CC
C1 +V_CC
D1 X+
DCLK A2
CS A3
DIN A4
E1 Y+
BUSY A5
G2 X−
DOUT A6
To Battery
Auxiliary Input
G3 Y−
G6 V_BAT
E7 AUX
PENIRQ B7
IOVDD C7
V_REF D7
Serial/Conversion Clock
Chip Select
Serial Data In
Converter Status
Serial Data Out
Pen Interrupt
Voltage
Regulator
GND ^{G4 G5} GND
Figure 1. Basic Operation
NOTE: VFBGA package and pin names shown.
Copyright © 2010, Texas Instruments Incorporated
Product Folder Link(s): TSC2046E-Q1
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