Analog Devices ADD8709 a Datasheet

18-Channel Gamma Buffer

FEATURES

18 precision gamma reference outputs
Mask-programmable voltage regulator: 0.4% accuracy
Upper 9 buffers swing to V
Lower 9 buffers swing to GND
Single-supply operation: 7.5 V to 16.5 V
Gamma current drive: 15 mA per channel
Peak output current: 150 mA
Output voltage stable under load conditions
48-lead, Pb-free LQFP package

APPLICATIONS

LCD TV panels
LCD monitor panels

GENERAL DESCRIPTION

The ADD8709 is an 18-channel integrated gamma reference for
use in LCD TV and monitors panels. The output buffers feature
high current drive and low offset voltage to provide an accurate
and stable gamma curve. The top nine channels swing to V
and the lower nine channels swing to GND.

An on-board voltage regulator provides a fixed input for the
gamma buffers, isolating the gamma curve from supply ripple.

The ADD8709 is specified over the temperature range of
–40°C to +105°C and comes in a 48-lead, Pb-free, low-profile
quad flat package.

DD

DD

V

REG OUT

with Regulator

FUNCTIONAL BLOCK DIAGRAM

V

GND

DD

700Ω*

FB

18

V

IN

17

V

IN

16

V

IN

15

V

IN

V

14

IN

V

13

IN

V

12

IN

V

11

IN

V

10

IN

V

9

IN

V

8

IN

V

7

IN

V

6

IN

V

5

IN

V

4

IN

V

3

IN

V

2

IN

V

1

IN

VOLTAGE

REGULATOR

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

700Ω*

ADD8709

VDDV

DD

GAMMA
BUFFERS

V

18

OUT

V

17

OUT

V

16

OUT

V

15

OUT

V

14

OUT

V

13

OUT

V

12

OUT

V

11

OUT

V

10

OUT

V

9

OUT

V

8

OUT

V

7

OUT

V

6

OUT

V

5

OUT

V

4

OUT

V

3

OUT

V

2

OUT

V

1

OUT

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.

*ESD PROTECTION RESISTORS

GND GND

Figure 1. 48-Lead LQFP

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

04715-001

ADD8709

TABLE OF CONTENTS

Electrical Characteristics................................................................. 3

Absolute Maximum Ratings............................................................ 4

ESD Caution.................................................................................. 4

Pin Configuration and Function Descriptions............................. 5

Typical Performance Characteristics ............................................. 7

Application Notes ........................................................................... 10

Volt a ge R e gu l ator ....................................................................... 10

Maximum Power Dissipation ...................................................10

Operating Temperature Range ................................................. 10

Typical Applications Ci r c u it ..........................................................12

Outline Dimensions ....................................................................... 13

Ordering Guide........................................................................... 13

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......................... 4

Changes to Pin Configuration and Function Description.......... 5

Changes to Typical Performance Characteristics Section........... 7

Changes to Applications Notes Section....................................... 10

Changes to Figure 28, Typical Applications Circuit................... 12

Changes to Ordering Guide.......................................................... 13

8/04—Revision 0: Initial Version

Rev. A | Page 2 of 16

ADD8709

ELECTRICAL CHARACTERISTICS

VDD = 16 V, TA @ 25°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

BUFFER CHARACTERISTICS

OUTPUTS

Output Voltage Range (Ch18 to Ch10) V
Output Voltage Range (Ch9 to Ch1) V

Output vs. Load (Ch18, Ch17, Ch2, Ch1) ∆V
Output vs. Load (Ch16 to Ch3) ∆V

OUT

OUT

OUT

OUT

INPUTS

Offset Voltage V

OS

Offset Voltage Drift ∆VOS/∆T

Input Bias Current I
Input Voltage Range (Ch18 to Ch10) V
Input Voltage Range (Ch9 to Ch1) V

B

IN

IN

DYNAMIC PERFORMANCE

Slew Rate SR RL = 10 kΩ, CL = 200 pF 4 6 V/µs
Bandwidth BW –3 dB, RL = 10 kΩ, CL = 200 pF 4.5 MHz
Settling Time to 0.1% t
Phase Margin Ф

S

o

Power Supply Rejection Ratio PSRR VDD = 7 V to 17 V, −40°C ≤ TA ≤ +105°C 68 90 dB

VOLTAGE REGULATOR

Programmable Range V

Initial Regulator Accuracy V
Dropout Voltage V

REG OUT

ACC

DO

I

Line Regulation REG
Load Regulation REG
Maximum Load Current I
Feedback Reference Voltage V
Feedback Input Bias Current I

LINE

LOADIO

O

REF

BFB

POWER SUPPLY

Supply Voltage V
Supply Current I

S

SY

1

∆V

is the shift from the desired output voltage under the specified current load.

OUT

IL = 100 µA 1.4 V
IL = 100 µA 0

1

IL = 20 mA 15 mV

1

IL = 5 mA 5 mV

DD

V

DD

− 1.4

V
V

5 15 mV

−40°C ≤ T

≤ +105°C

A

20 µV/°C

−40°C ≤ TA ≤ +105°C 0.5 1.5 µA

1.4 V
0

V

DD

− 1.4

DD

V
V

1 V step, RL = 10 kΩ, CL = 200 pF 1.1 µs
RL = 10 kΩ, CL = 200 pF 55 Degrees

5

No load; V

= 14.4 V 0.4 1.5 %

REG OUT

V

− 0.6

DD

V

IL = 100 µA 100 150 mV

= 5 mA 310 350 mV

L

VIN = 8.5 V to 16.5 V, V

= 8 V 0.01 0.20 %/V

OUT

= 100 µA to 10 mA 0.02 0.10 %/mA

−40°C ≤ TA ≤ +105°C 5 mA

1.2 V

−40°C ≤ TA ≤ +105°C −150 10 150 nA

7.5 16.5 V
No load, −40°C ≤ TA ≤ +105°C 10.5 17 mA

Rev. A | Page 3 of 16

ADD8709

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage (VDD) 18 V
Input Voltage –0.5 V to V
Storage Temperature Range –65°C to +150°C
Operating Temperature Range
Junction Temperature Range –65°C to +150°C
Lead Temperature Range (Soldering, 60 sec) 300°C
ESD Tolerance (HBM) ±2000 V
ESD Tolerance (MM) ±150 V

1

−40°C to +105°C

DD

Table 3. Package Characteristics

Package Type θ

LQFP (ST) 74.57 °C/W

JA

Unit

1

See section. Application Notes

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
sections 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 4 of 16

ADD8709

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

18

17

16

15

14

48 47 46 45 44 43 42 41 40 39 38 37

1

REG

FB

2

GND

3

V

DD

REG OUT

VIN18
VIN17
V

IN

V

IN

V

IN

V

IN

V

IN

V

IN

4

5

6

7

16

8

15

9

14

10

13

11

12

12

11

13 14 15 16 17 18 19 20 21 22 23 24

V

Figure 2. 48-Lead Low-Profile Quad Flat Package (ST-48)

Table 4. Pin Function Descriptions

Pin No. Name Description

1 REG

FB

Regulator feedback. Compares a percentage of the regulator output to the internal 1.2 V voltage

reference.
2 GND Ground. Normally 0 V.
3 V

DD

4 REG

OUT

Supply voltage. Normally 16 V.

Regulator output voltage. Provides a regulated output voltage for use as a reference for the gamma

resistors.
5 VIN18
6 VIN17
7 VIN16
8 VIN15
9 VIN14
10 VIN13
11 VIN12
12 VIN11
13 VIN10
14 VIN9

Buffer inputs. An external resistor calculator is available upon request from your local sales office.

15 VIN8
16 VIN7
17 VIN6
18 VIN5
19 VIN4
20 VIN3
21 VIN2
22 VIN1
23 GND Ground. Normally 0 V.
24 V
25 V
26 V

DD

OUT

OUT

1
2

Supply voltage. Normally 16 V.

Buffer outputs. These buffers can swing to ground.

VDDGND

9

10

IN

IN

V

V

8
V

OUT

IN

OUT

OUT

V

V

ADD8709

TOP VIEW

(Not to Scale)

7

6

IN

IN

V

V

V

5
V

OUT

IN

V

4
V

OUT

IN

13

V

3
V

OUT

IN

12

11

DD

OUT

GND

1

IN

V

V

GND

V

V

OUT

DD

36

V

10

OUT

35

V

9

OUT

34

8

V

OUT

33

7

V

OUT

32

V

DD

31

GND

30

6

V

OUT

29

5

V

OUT

28

4

V

OUT

27

3

V

OUT

26

2

V

OUT

25

V

1

OUT

04715-002

V

2

IN

V

Rev. A | Page 5 of 16