PENIRQ
TEMP1
TEMP0
+V
DD
V
REF
C2-C0
(Shown 101
B
)
C3
(Shown HIGH)
X+
X–
Ref ON/OFF
Y+
Y–
2.5V
Reference
+IN
–IN
–REF
+REF
Converter
7.5kΩ
V
BAT1
7.5kΩ
V
BAT2
2.5kΩ
2.5kΩ
Battery
On
IN1
IN2
GND
Battery
On
FIGURE 2. Simplified Diagram of the Analog Input.
INTERNAL REFERENCE
The TSC2003 has an internal 2.5V voltage reference that
can be turned ON or OFF with the power-down control bits,
PD0 and PD1 (see Table II and Figure 3). The internal
reference is powered down when power is first applied to the
device.
The internal reference voltage is only used in the
single-ended reference mode for battery monitoring, tem-
perature measurement, and for measuring the auxiliary in-
put. Optimal touch screen performance is achieved when
using a ratiometric conversion; thus, all touch screen mea-
surements are done automatically in the differential mode.
Reference
Power Down
Band
Gap
V
REF
Buffer
To
CDAC
Optional
FIGURE 3. Simplified Diagram of the Internal Reference.
10
www.ti.com
TSC2003
SBAS162D
TI [ TEXAS INSTRUMENTS ]
