ADD8708 Analog Devices, Inc., ADD8708 Datasheet

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ADD8708

Manufacturer Part Number
ADD8708
Description
18-channel Gamma Buffer With Regulator
Manufacturer
Analog Devices, Inc.
Datasheet
FEATURES
18 precision gamma reference outputs
Mask-programmable gamma resistors:
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
Pin-to-pin compatible with ADD8709
48-lead, Pb-free LQFP and LFCSP
APPLICATIONS
LCD TV panels
LCD monitor panels
GENERAL DESCRIPTION
The ADD8708 is an 18-channel integrated gamma reference for
use in high resolution LCD TV and monitors panels. The out-
put buffers feature high current drive and low offset voltage to
provide an accurate and stable gamma curve. The top nine
channels swing to V
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 ADD8708 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 the supply ripple.
The ADD8708 is specified over the temperature range of
–40°C to +105°C and comes in both a 48-lead, Pb-free,
lead-frame chip-scale package and a Pb-free, low-profile,
quad flat package.
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.
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.
0.2% resolution and 0.1% accuracy
DD
; the lower nine channels swing to GND.
DD
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
MASK-PROGRAMMABLE
REGULATOR RESISTORS
V
V
V
V
V
V
V
V
V
GND
V
V
V
V
V
V
V
V
V
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
IN
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
*ESD PROTECTION RESISTORS
18-Channel Gamma Buffer
MASK-PROGRAMMABLE
RESISTOR STRING
FUNCTIONAL BLOCK DIAGRAM
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
700Ω*
Figure 1. 48-Lead LQFP or LFCSP
1.2V
© 2004 Analog Devices, Inc. All rights reserved.
FB
+
700Ω*
V
REG OUT
with Regulator
V
GND GND
DD
V
DD
ADD8708
GAMMA
BUFFERS
www.analog.com
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
OUT
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1

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ADD8708 Summary of contents

Page 1

... An on-board voltage regulator provides a fixed input for the resistor string, isolating the gamma curve from the supply ripple. The ADD8708 is specified over the temperature range of –40°C to +105°C and comes in both a 48-lead, Pb-free, lead-frame chip-scale package and a Pb-free, low-profile, quad flat package ...

Page 2

... ADD8708 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 Tap Point Selection..................................................................... 10 Voltage Regulator ....................................................................... 11 Maximum Power Dissipation ................................................... 11 Land Pattern................................................................................ 11 Operating Temperature Range ................................................. 12 Typical Applications Circuit.......................................................... 14 Tap Point and Regulator Voltage Request Form......................... 15 Outline Dimensions ...

Page 3

... REF I −40°C ≤ T ≤ +105° −40°C ≤ T ≤ +105°C Total Error load; −40°C ≤ T ≤ +105° Rev Page ADD8708 Min Typ Max Unit 0.1 0 kΩ 1 − 1.4 ...

Page 4

... ADD8708 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Supply Voltage ( Input Voltage Storage Temperature Range 1 Operating Temperature Range Junction Temperature Range Lead Temperature Range (Soldering, 60 sec) ESD Tolerance (HBM) ESD Tolerance (MM) Table 3. Package Characteristics 2 3 Package Type θ θ LFCSP (CP) 28 ...

Page 5

... Figure 2. Pin Configuration 1 Rev Page OUT OUT OUT OUT GND OUT OUT OUT OUT OUT OUT ADD8708 ...

Page 6

... ADD8708 Pin No. Name Description OUT OUT OUT Buffer Outputs. These buffers can swing to ground OUT OUT OUT 31 GND Ground. Normally Supply voltage. Normally OUT Buffer Output. These buffers can swing to ground. ...

Page 7

... CH1 SINK 0 LOAD CURRENT (mA –200 0 200 400 600 800 1000 1200 1400 TIME (ns) ADD8708 CH9 SOURCE CH9 SINK 100 CH2 SOURCE CH2 SINK 100 10V PULSE 120pF 320pF 520pF 1nF 10nF 1600 1800 ...

Page 8

... ADD8708 1000 900 800 700 600 500 400 300 200 100 0 –0.30 –0.18 –0.10 –0.02 0.06 GAMMA OUTPUT ERROR DUE TO OFFSET AND RESISTOR MATCHING (% OF FS) Figure 9. Gamma Output Voltage Error 0.3 MAX ERROR EACH STEP 0.2 TYPICAL UNIT B TYPICAL UNIT C 0.1 0 TYPICAL UNIT A –0.1 – ...

Page 9

... LOAD –20 –40 Rev Page SUPPLY VOLTAGE (V) Figure 18. Supply Current vs. Supply Voltage – TEMPERATURE (°C) Figure 19. Supply Current vs. Temperature ADD8708 16 18 100 120 ...

Page 10

... OUT V 4 OUT V 3 OUT V 2 OUT V 1 OUT _______________________________ 1 ADD8708 release samples do not have these typical values. The values on the samples are nonmonotonic and can be provided upon request. Rev Page REG OUT 500– OUT TP X Figure 22 ...

Page 11

... V pattern is critical to heat dissipation. A suggested land pattern is REG OUT shown in Figure 22. The thermal pad is attached to the substrate. In the ADD8708, the substrate is connected to V thermal pad should be soldered to an area on the board that is electrically isolated or connected to V pad to ground adversely affects the performance of the part. ...

Page 12

... P J AMB JA DIS where ambient temperature. AMB θ = junction-to-ambient thermal resistance, in °C/watt power dissipated in the device, in watts. DIS For the ADD8708, P can be calculated by this equation: DIS × Σ(I × (V − V DIS DD DQ OUT X(+) DD Σ(−I × ...

Page 13

... The thermal pad is electrically active. The solder mask opening should be 0.150 mm larger than the pad size, resulting in 0.075 mm of clearance between the copper pad and solder mask. 7.31mm 5.40mm 0.5mm 0.075mm 1.60mm 0.075mm 0.33mm DIAMETER 0.28mm THERMAL VIA Rev Page ADD8708 1.60mm 5.78mm 0.69mm ...

Page 14

... ADD8708 TYPICAL APPLICATIONS CIRCUIT NORMALLY OPEN ESD PROTECTION RESISTOR ESD PROTECTION V REG OUT V DD 16V 0.1 µ ...

Page 15

... CUSTOMER INFORMATION Name: ____________________________________________ Company: ____________________________________________ Address: ____________________________________________ ____________________________________________ Date: ____________________________________________ Please return this form to your local sales office. must exceed V by 600 mV minimum—that is REG Rev Page ADD8708 = 14.4 V requires a minimum REG and the desired output REG OUT ...

Page 16

... Lead Frame Chip Scale Package 48-Lead Low Profile Quad Flat Package Rev Page 0.30 0.23 0.60 MAX 0.18 PIN 1 INDICATOR 48 1 EXPOSED 5.25 PAD 5.10 SQ (BOTTOM VIEW) 4. 0.25 MIN 5.50 REF 9.00 BSC PIN 1 7.00 TOP VIEW BSC SQ (PINS DOWN 0.27 0.50 BSC 0.22 0.17 Package Option CP-48 ST-48 ADD8708 ...

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