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ADD8701
12-Channel Gamma Buffers
with VCOM Buffer
PANEL
TIMING
CONTROLLER
TIMING AND CONTROL
SCAN DRIVER CONTROL
GAMMA
REFERENCE
VOLTAGES
V12
VCOM IN
VCOM OUT V1
GND
V
DD
V
DD
RESISTOR
LADDER
R
384
SOURCE DRIVER
NO. 1
768
SCAN
DRIVERS
TFT COLOR PANEL
1024 H11547 768
384
SOURCE DRIVER
NO. 2
384
SOURCE DRIVER
NO. 8
ADD8701
G B
Figure 1. Typical SVGA TFT-LCD Application
FUNCTIONAL BLOCK DIAGRAM
GND
V
DD
V6
V5
V
DD
VCOM

IN
VCOM

OUT
IN12
V4
V3
V2
V1
IN6 IN5 IN4 IN3 IN2 IN1
V
DD
GND
IN11
IN10
IN9
IN8
IN7
GND V12 V11 V10 V9 V8 V7
9 10 11 12 13 14 15 16
32 31 30 26 28 27 26 25
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
FEATURES
Single-Supply Operation: 7 V to 16 V
Dual-Supply Operation: H115503.5 V to H115508 V
Supply Current: 13 mA Max
Upper/Lower Buffers Swing to V
DD
/GND
Continuous Output Current: 10 mA
VCOM Peak Output Current: 250 mA
Offset Voltage: 15 mV Max
Slew Rate: 6 V/H9262s
Fast Settling Time with Large C-Load
APPLICATIONS
TFT LCD Panels
GENERAL DESCRIPTION
The ADD8701 is a low cost, 12-channel buffer amplifier and
VCOM driver that operates from a single supply. The part is
designed for high resolution TFT LCD panels, and is built on
an advanced, high voltage, CBCMOS process.
The buffers have high slew rate, 10 mA continuous output current,
and high capacitive load drive capability. The VCOM buffer has
increased drive of 35 mA and can drive large capacitive loads. The
ADD8701 offers wide supply range and offset voltages below 15 mV.
The ADD8701 is specified over the –40ºC to +85ºC tempera-
ture range and is available in a 32-lead lead frame chip scale
package (LFCSP).
All inputs and outputs incorporate internal ESD protection
circuits.