Analog Devices ADD8702 Datasheet
12-Channel Gamma Buffers
FEATURES
Programmable 12-Channel Gamma Reference Generator
Mask Programmable Adjustable V
Upper/Lower Outputs Swing to V
COM
/GND
DD
Buffer
Continuous Output Current: 10 mA
V
Peak Output Current: 250 mA
COM
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
GENERAL DESCRIPTION
The ADD8702 is a low cost, mask programmable, 12-channel
gamma reference generator, plus an adjustable V
driver. This
COM
part is designed to provide gamma correction for high resolution
TFT LCD panels. The 12 gamma reference levels and V
COM
are
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
output is stable with
COM
high capacitive loads and can source or sink 250 mA peak current. The V
output level can be adjusted using an external
COM
trim-potentiometer or discrete resistors.
with V
Buffer
COM
ADD8702
FUNCTIONAL BLOCK DIAGRAM
OUT
COM
V
GND
VGMA12
VGMA11
VGMA10
VGMA9
VGMA8
LOW
V
DD
V
VGMA7
GND
24
23
22
21
20
19
18
17
GND
V
DD
VGMA6
VGMA5
VGMA4
VGMA3
VGMA2
VGMA1
32 31 30 26 28 27 26 25
V
1
DD
V
ADJ
V
HIGH
VIN11
V
IN
V
V
V
2
3
4
10
5
6
9
IN
7
8
IN
7
8
IN
9 10 11 12 13 14 15 16
6
5
4
3
IN
IN
V
V
2
IN
IN
IN
V
V
V
COM
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 package (LFCSP) for compact board space.
PAN E L
TIMING
CONTROLLER
TIMING AND CONTROL
SCAN DRIVER CONTROL
SCAN
DRIVERS
768
SOURCE DRIVER
NO. 1
384
R
G B
Figure 1. Typical SVGA TFT LCD Application
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.
ADD8702
SOURCE DRIVER
NO. 2
384
TFT COLOR PANEL
1024 768
GAMMA
REFERENCE
VOLTAG ES
SOURCE DRIVER
NO. 8
384
GAMMA
V
COM
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 www.analog.com
Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved.
ADD8702–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
(VDD = 16 V, TA = 25ⴗC, unless otherwise specified.)
Parameter Symbol Conditions Min Typ Max Unit
OUTPUT ACCURACY
V
ERROR V
SYSTEM
SY ERROR
10 50 mV
MASK PROGRAMMABLE
RESISTOR STRING
Total Resistor String R
Resistor Matching R
TOTAL
MATCH
500 Elements V
LOW
to V
HIGH
22.5 kΩ
Any Two Segments 1 %
OUTPUT CHARACTERISTICS
Output Voltage High V
OUT
(VGMA11, VGMA12) I
Output Voltage Mid V
OUT
IL = 100 µA 15.995 V
= 5 mA 15.85 15.95 V
L
–40°C ≤ T
≤ +85°C 15.75 V
A
IL = 5 mA 14.6 V
(VGMA3 to VGMA10)
Output Voltage Low V
OUT
IL = 100 µA5mV
(VGMA1, VGMA2) IL = 5 mA 50 150 mV
Continuous Output Current I
Peak Output Current I
Settling Time—Voltage t
CHARACTERISTICS
V
COM
Continuous Output Current I
Peak Output Current I
Settling Time—Voltage t
OUT
PK
S
OUT
PK
S
–40°C ≤ T
1 V Step 0.1%, RL = 10 kΩ, CL = 200 pF 1 µs
1 V Step 0.1%, RL = 10 kΩ, CL = 200 pF 0.8 µs
≤ +85°C 250 mV
A
10 mA
150 mA
35 mA
250 mA
SUPPLY CHARACTERISTICS
Supply Voltage V
DD
716V
Power Supply Rejection Ratio PSRR VS = 6 V to 17 V, –40°C ≤ TA ≤ +85°C6875 dB
SUPPLY CURRENT I
SYS
No Load 11 15 mA
–40°C ≤ TA ≤ +85°C16mA
Specifications subject to change without notice.
REV. 0–2–
ADD8702
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage (VS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Operating Temperature Range . . . . . . . . . . . .–40°C to +85°C
Junction Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering, 60 sec.) . . . . . . . . 300°C
ESD Tolerance (HBM) . . . . . . . . . . . . . . . . . . . . . . . ± 1,000 V
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
ORDERING GUIDE
Temperature Package Package
Model Range Description Option
ADD8702ACP-R2 –40°C to +85°C 32-Lead LFCSP CP-32
ADD8702ACP-REEL –40°C to +85°C 32-Lead LFCSP CP-32
ADD8702ACP-REEL7 –40°C to +85°C 32-Lead LFCSP CP-32
PIN CONFIGURATION
OUT
COM
32 V
31 GND
30 VGMA12
29 VGMA11
Package Type
1
JA
2
JB
Unit
32-Lead LFCSP (CP) 35 13 °C/W
NOTES
1
θJA is specified for worst-case conditions, i.e., θ
in circuit board for surface-mount packages.
2
ψJB is applied for calculating the junction temperature by reference to the board
temperature.
28 VGMA10
27 VGMA9
26 VGMA8
25 VGMA7
is specified for device soldered
JA
V
1
DD
ADJ 2
V
COM
V
HIGH
VIN11 4
V
10 5
IN
9 6
V
IN
V
8 7
IN
7 8
V
IN
PIN 1
INDICATOR
3
ADD8702
TOP VIEW
6 9
5 10
4 11
3 12
2 13
IN
IN
IN
IN
V
IN
V
V
V
V
14
LOW
V
15
V
DD
24 GND
23 V
22 VGMA6
21 VGMA5
20 VGMA4
19 VGMA3
18 VGMA2
17 VGMA1
GND 16
DD
PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic Description
1, 15, 23 V
2V
3V
4–13 V
14 V
DD
ADJ V
COM
HIGH
11–VIN2Gamma Buffer Inputs
IN
LOW
Power (+)
Adjust Input
COM
Highest Gamma Input Voltage
Lowest Gamma Input Voltage
16, 24, 31 GND Power (–)
17–22, 25–30 VGMA1–VGMA12 Gamma Buffer Outputs
32 V
OUT V
COM
Buffer Output
COM
CAUTION
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.
REV. 0
–3–
Loading...