Analog Devices ADD8707 a Datasheet
12-Channel Gamma Buffers
FEATURES
12 precision gamma reference outputs
Mask-programmable gamma resistors:
0.2% resolution and 0.1% accuracy
Mask programmable voltage regulator: 0.4% accuracy
Upper 6 buffers swing to V
Lower 6 buffers swing to GND
Single-supply operation: 7.5 V to 16 V
Gamma current drive: 15 mA per channel
peak output current: 250 mA
V
COM
Outputs stable under load conditions
48-lead, Pb-free LFCSP package
APPLICATIONS
LCD TV panels
LCD monitor panels
PRODUCT OVERVIEW
The ADD8707 is a 12-channel integrated gamma reference with
VCOM for use in LCD TV and monitor panels. The output
buffers feature high current drive and low offset voltage to
provide an accurate and stable gamma curve. The top six
channels swing to VDD and the lower six channels swing to
GND.
Integrating the gamma setup resistors drastically reduces the
external component count while increasing the gamma curve
accuracy. To accommodate multiple column drivers and panel
architectures, the ADD8707 is mask-programmable to a 0.2%
resolution using the on-chip 500 resistor string. An on-board
voltage regulator provides a fixed input for the resistor string,
isolating the gamma curve from supply ripple.
The ADD8707 is specified over the temperature range of
–40°C to +105°C and comes in a 48-lead, Pb-free, lead frame
chip-scale package.
DD
with V
FUNCTIONAL BLOCK DIAGRAM
MASK-PROGRAMMABLE
REGULATOR RESISTORS
GND
V
11
IN
V
10
IN
V
8
IN
V
7
IN
V
6
IN
V
5
IN
V
3
IN
V
2
IN
1
V
IN
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
*ESD PROTECTION RESISTORS
and Regulator
COM
FB
700Ω*
+
1.2V
–
PROGRAMMABLE
GAMMA RESISTORS
MASK-
Figure 1. 48-Lead LFCSP
ADD8707
COM IN–
V
V
GAMMA
BUFFERS
COM IN+
V
COM
V
COM OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
V
OUT
12
11
10
9
8
7
6
5
4
3
2
1
04712-001
REG OUT
V
Rev. A
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.
Specifications subject to change without notice. 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 owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.
www.analog.com
ADD8707
TABLE OF CONTENTS
Electrical Characteristics ................................................................. 3
Absolute Maximum Ratings............................................................ 5
Pin Configuration and Function Description .............................. 6
Typical Performance Characteristics ............................................. 8
Application Notes ........................................................................... 12
Tap Point Selection ..................................................................... 12
Volt a ge R e gu l ator ....................................................................... 13
Maximum Power Dissipation ...................................................13
Land Pattern................................................................................ 13
Operating Temperature Range ................................................. 14
Typical Applications Ci r c u it ..........................................................16
Development Circuit...................................................................... 17
Tap Point and Regulator Voltage Request Form......................... 19
Regulator Section—V
...................................................... 19
REG OUT
Tap Point S ec t ion ........................................................................ 19
Outline Dimensions ....................................................................... 20
Ordering Guide........................................................................... 20
REVISION HISTORY
10/04—Data Sheet Changed from Rev. 0 to Rev. A
Changes to Product Overview Section .......................................... 1
Changes to Figure 1.......................................................................... 1
Changes to Electrical Characteristics Section .............................. 3
Changes to Absolute Maximum Ratings Section......................... 5
Changes to Pin Configuration and Function Description.......... 6
Changes to Typical Performance Characteristics Section........... 8
Changes to Applications Notes Section....................................... 12
Changes to Figure 28, Typical Applications Circuit................... 16
Added Development Circuit Section........................................... 17
Added Tap Point and Regulator Voltage Request Form............ 19
Changes to Ordering Guide.......................................................... 20
7/04—Revision 0: Initial Version
Rev. A | Page 2 of 20
ADD8707
ELECTRICAL CHARACTERISTICS
VDD = 16 V, TA @ +25oC, unless otherwise noted.
Table 1.
Parameter Symbol Condition Min Typ Max Unit
GAMMA CURVE CHARACTERISTICS
Accuracy R
Programming Resolution R
Total Resistor String Value R
BUFFER CHARACTERISTICS
OUTPUTS
Output Voltage Range (Ch12 to Ch7) V
Output Voltage Range (Ch6 to Ch1) V
Output vs. Load (Ch12, Ch11, Ch2, Ch1)
Output vs. Load (Ch10 to Ch3)
INPUTS
Offset Voltage V
Offset Voltage Drift
Input Bias Current I
Input Voltage Range (Ch12 to Ch7) V
Input Voltage Range (Ch6 to Ch1) V
V
CHARACTERISTICS
COM
Offset Voltage V
Input Range V
Peak Output Current I
Continuous Output Current I
Output vs. Load
BUFFER AND V
DYNAMIC PERFORMANCE
COM
Slew Rate SR RL = 10 kΩ, CL = 200 pF 4 6 V/µs
Bandwidth BW −3dB, RL = 10 kΩ, CL = 200 pF 4.5 MHz
Settling Time to 0.1%
Phase Margin
Power Supply Rejection Ratio PSRR
VOLTAGE REGULATOR
Programmable Range V
Initial Regulator Accuracy V
Dropout Voltage V
I
Line Regulation REG
Load Regulation REG
Maximum Load Current I
Feedback Reference Voltage V
Feedback Input Bias Current I
ACC
RES
TOTAL
OUT
OUT
∆V
∆V
OS
∆V
B
IN
IN
OS
IN
PK
OUT
∆V
t
S
φ
o
REG OUT
ACC
DO
O
REF
B FB
OUT
OUT
OS
COM
1
/∆T
LINE
LOAD
0.1 0.4 %
500 segments 0.2 %
15 kΩ
IL = 100 µA
IL = 100 µA
2
IL = 20 mA 15 mV
2
IL = 5 mA 5 mV
1.4 V
0
V
DD
DD
− 1.4
V
V
5 15 mV
−40°C ≤ T
≤ +105°C
A
−40°C ≤ TA ≤ +105°C
1.4 V
0
20
0.5 1.5
DD
V
− 1.4
DD
µV/°C
µA
V
V
5 15 mV
1.4
V
DD
− 1.4
V
250 mA
50 mA
2
IL = 30 mA 10 mV
1V step, RL = 10 kΩ, CL = 200 pF 1.1 µs
RL = 10 kΩ, CL = 200 pF 55 Degrees
V
= 7 V to 17 V, −40°C ≤ TA ≤ +105°C
DD
5
No Load. V
= 14.4V 0.4 1.5 %
REG OUT
IL = 100 µA
= 5 mA 310 350 mV
L
VIN = 8.5 V to 16.5 V, V
= 8V 0.01 0.20 %/V
OUT
IO = 100 µA to 5 mA
−40°C ≤ TA ≤ +105°C
68 90 dB
V
DD
− 0.6
V
100 150 mV
0.02 0.10 %/mA
5 mA
1.2 V
−40°C ≤ TA ≤ +105°C −150
10 150 nA
Rev. A | Page 3 of 20
ADD8707
Parameter Symbol Condition Min Typ Max Unit
SYSTEM ACCURACY 10
Total Error3,
POWER SUPPLY
Supply Voltage V
Supply Current I
1
Gamma curve accuracy includes resistor matching and buffer errors, but excludes the regulator error.
2
∆V
is the shift from the desired output voltage under the specified current load.
COM
3
Total error is defined as the difference between the designed and actual output voltage divided by the actual regulator output voltage or full-scale voltage.
4
Total error includes regulator error, resistor string error, bias current effects, and buffer offset voltage.
4
V
TOTAL ERROR
DD
SY
–40°C ≤ TA ≤ +105°C 0.5 3 %
7.5 16 V
No load, –40°C ≤ TA ≤ +105°C 8.3 15 mA
Rev. A | Page 4 of 20
ADD8707
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Supply Voltage (VDD) 18 V
Input Voltage
Storage Temperature Range
Operating Temperature Range
1
−0.5 V to V
DD
−65°C to +150°C
−40°C to +105°C
Lead Temperature Range (Soldering 10 sec) 300°C
Junction Temperature 150°C
ESD Tolerance (HBM) ±3000 V
ESD Tolerance (MM) ±100 V
Table 3. Thermal Resistance
Package Type
2
θ
JA
3
θ
JA
Unit
48-Lead LFCSP (CP) 28.3 47.7 °C/W
1
See the Applications Information section.
2
θJA for exposed pad soldered to JEDEC 4-layer board.
3
θJA for exposed pad not soldered down.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent 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
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD 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 this product 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. A | Page 5 of 20
ADD8707
PIN CONFIGURATION AND FUNCTION DESCRIPTION
12
11
10
9
8
7
OUT
OUT
OUT
OUT
OUT
OUT
DD
GND
V
V
2
1
–
IN
IN
V
V
COM IN
V
V
REG OUT
GND
V
V
V
V
V
ADD8707
TOP VIEW
(Not to Scale)
5
IN
NC
V
V
3
IN
V
NC
V
48 47 46 45 44 43 42 41 40 39 38 37
1
NC
2
V
3
DD
4
5
FB
NC
6
NC
7
8
11
IN
9
10
IN
10
NC
V
11
8
IN
12
NC
13 14 15 16 17 18 19 20 21 22 23 24
7
6
IN
IN
NC
V
V
Figure 2. 48-Lead LFCSP
6
OUT
V
+
COM IN
V
5
V
NC
OUT
NC
NC
36
35
34
33
32
31
30
29
28
27
26
25
NC
NC
NC
V
OUT
V
OUT
V
OUT
V
OUT
V
DD
GND
V
COM OUT
NC
NC
4
3
2
1
04712-0-002
Table 4. Pin Function Descriptions
Pin No. Name Description
1 NC
2 GND Ground. Normally 0 V.
3 V
4 V
DD
REG OUT
Supply voltage. Normally 16 V.
Regulator output voltage. Provides reference voltage to resistor string and is internally connected to the top of
the resistor string.
5 FB
Regulator feedback pin. Compares a percentage of the regulator output to the internal 1.2V voltage reference.
Internal resistors are used to program the desired regulator output voltage.
6 NC
7 NC
8 VIN11
9 VIN10
Buffer inputs. Normally floating.
1
10 NC
11 VIN8 Buffer inputs. Normally floating.1
12 NC
13 NC
14 VIN7
15 VIN6
Buffer inputs. Normally floating.
1
16 VIN5
17 NC
18 VIN3
19 VIN2
Buffer inputs. Normally floating.
1
20 VIN1
21 V
22 V
COM IN
COM IN
- V
+ V
amplifier inverting input.
COM
amplifier non-inverting input.
COM
23 NC
24 NC
1
External resistors can be added to modify the internal resistor string to change the gamma voltage. An external resistor calculator is available upon request.
Rev. A | Page 6 of 20
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