ADD8702 Analog Devices, Inc., ADD8702 Datasheet

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ADD8702

Manufacturer Part Number
ADD8702
Description
12-channel Gamma Buffers With Vcom Buffer
Manufacturer
Analog Devices, Inc.
Datasheet
GENERAL DESCRIPTION
The ADD8702 is a low cost, mask programmable, 12-channel
gamma reference generator, plus an adjustable V
part is designed to provide gamma correction for high resolution
TFT LCD panels. The 12 gamma reference levels and V
mask programmable to 0.3% resolution using the on-chip 500
chain resistor string. This reduces component and board costs.
The ADD8702 provides a complete programmed set of gamma
voltage references for the LCD source drivers. These references
settle quickly to load change. The V
high capacitive loads and can source or sink 250 mA peak cur-
rent. The V
trim-potentiometer or discrete resistors.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
FEATURES
Programmable 12-Channel Gamma Reference Generator
Mask Programmable Adjustable V
Upper/Lower Outputs Swing to V
Continuous Output Current: 10 mA
V
Outputs with Fast Settling Time for Load Change
Output Pins Are Compatible with ADD8701
Single-Supply Operation: 7 V to 16 V
Supply Current: 15 mA Max
APPLICATIONS
TFT LCD Panels
COM
Peak Output Current: 250 mA
COM
output level can be adjusted using an external
CONTROLLER
TIMING
PANEL
SCAN DRIVER CONTROL
DRIVERS
SCAN
TIMING AND CONTROL
COM
768
DD
COM
output is stable with
SOURCE DRIVER
R
Figure 1. Typical SVGA TFT LCD Application
/GND
G B
Buffer
NO. 1
384
COM
driver. This
COM
are
TFT COLOR PANEL
SOURCE DRIVER
1024
NO. 2
384
The output pins are compatible with the ADD8701. This allows
for single board design and fast turns for prototyping using the
initial ADD8701 board design.
The ADD8702 is specified over the temperature range of –40°C
to +85°C and comes in the 32-lead lead frame chip scale pack-
age (LFCSP) for compact board space.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
768
12-Channel Gamma Buffers
V
COM
V
V
V
HIGH
V
V
V
ADJ
V
IN
IN
IN
IN
IN
FUNCTIONAL BLOCK DIAGRAM
DD
11
10
9
8
7
SOURCE DRIVER
1
2
3
4
5
6
7
8
NO. 8
384
© 2003 Analog Devices, Inc. All rights reserved.
32
REFERENCE
9
VOLTAGES
GAMMA
31
10
30
11
26
12
with V
28
13
27
14
ADD8702
GAMMA
26
15
V
COM
ADD8702
25
16
COM
www.analog.com
24
23
22
21
20
19
18
17
GND
V
VGMA6
VGMA5
VGMA4
VGMA3
VGMA2
VGMA1
Buffer
DD

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ADD8702 Summary of contents

Page 1

... COM initial ADD8701 board design. The ADD8702 is specified over the temperature range of –40°C to +85°C and comes in the 32-lead lead frame chip scale pack- age (LFCSP) for compact board space. ...

Page 2

... ADD8702–SPECIFICATIONS ELECTRICAL CHARACTERISTICS Parameter Symbol OUTPUT ACCURACY V ERROR V SYSTEM MASK PROGRAMMABLE RESISTOR STRING Total Resistor String R Resistor Matching R OUTPUT CHARACTERISTICS Output Voltage High V (VGMA11, VGMA12) Output Voltage Mid V (VGMA3 to VGMA10) Output Voltage Low V (VGMA1, VGMA2) Continuous Output Current I OUT Peak Output Current ...

Page 3

... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the ADD8702 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...

Page 4

... ADD8702–Typical Performance Characteristics SUPPLY VOLTAGE (V) TPC 1. Supply Current vs. Supply Voltage 16V DD GAMMA 10k 0 –10 150 –20 –30 –40 100k 1M 10M 30M FREQUENCY (Hz) TPC 4. Frequency Response vs. Resistive Loading 16V ...

Page 5

... GAMMA 1,200 SINK 1,000 800 600 400 SOURCE 200 0 0.001 0.01 0 100 LOAD CURRENT (mA) TPC 17. Output Voltage Error vs. Load Current –5– ADD8702 7V < V < 16V NULL TIME (20 s/DIV) TPC 12. Small Signal Transient Response 16V COM ...

Page 6

... ADD8702 6,000 V = 16V 5,000 ALL CHANNELS 4,000 3,000 2,000 1,000 0 –22 –14 – OUTPUT VOLTAGE ERROR (mV) TPC 19. Output Voltage Error Distribution 16V AND BUFFERS COM MARKER SET @ 10kHz MARKER READING = 25.7nV – ...

Page 7

... LOW V DD buffer can COM GND V ADJUST COM Table I. ADD8702 – 000 Mask Option, Resistor Tap Points (0 ≤ ≤ 500) V VGMA1 VGMA2 VGMA3 VGMA4 VGMA5 VGMA6 VGMA7 VGMA8 VGMA9 VGMA10 VGMA11 VGMA12 V COM –7– ADD8702 ...

Page 8

... ADD8702 PIN 1 INDICATOR 12 MAX 1.00 0.90 0.80 SEATING PLANE OUTLINE DIMENSIONS 32-Lead Lead Frame Chip Scale Package [LFCSP] (CP-32) Dimensions shown in millimeters 5.00 BSC SQ 0.60 MAX 24 0.50 BSC 4.75 TOP BSC SQ VIEW 0.50 0.40 17 0.30 0.80 MAX 0.65 NOM 0.05 MAX 0.02 NOM 0.30 COPLANARITY 0.20 REF 0.23 0.08 0.18 COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2 –8– 0.60 MAX PIN 1 INDICATOR 3.25 BOTTOM 3 ...

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