Datasheet ADD8707 Datasheet (Analog Devices)

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*

*ESD PROTECTION RESISTORS

and Regulator

COM

FB

700Ω*

+

1.2V –

PROGRAMMABLE

GAMMA RESISTORS

MASK-

Figure 1. 48-Lead LFCSP

ADD8707

COM IN–

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.

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

∆V ∆V

OS

∆V

B

IN

OS

IN

PK

OUT

∆V

t

S

φ

o

REG OUT

ACC

DO

O

REF

B FB

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

− 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

DD

GND

V

2

1

–

IN

V

COM IN

V

REG OUT

GND

V V

V

ADD8707

TOP VIEW

(Not to Scale)

5

IN

NC

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

NC

V

Figure 2. 48-Lead LFCSP

6

OUT

V

+

COM IN

V

5

V

NC

OUT

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

- 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

ADD8707

Pin No. Name Description

25 NC 26 NC 27 V

COM OUT

28 GND Ground. Normally 0 V. 29 V 30 V 31 V 32 V 33 V

DD

OUT

1 2 3

4 34 NC 35 NC 36 NC 37 NC 38 V 39 V

OUT

5

6 40 GND Ground. Normally 0 V. 41 V 42 V 43 V 44 V 45 V 46 V 47 V

DD

OUT

7

8

9

10

11

12 48 NC

V

amplifier output.

COM

Supply voltage. Normally 16 V.

Buffer outputs. These buffers can swing to ground.

Supply voltage. Normally 16 V.

Buffer outputs. These buffers can swing to V

.

DD

Rev. A | Page 7 of 20

ADD8707

TYPICAL PERFORMANCE CHARACTERISTICS

20 15 10

5 0

–5 –10 –15 –20 –25

OUTPUT VOLTAGE ERROR (mV)

–30 –35

–20–100102030405060708090100110120

I

SOURCE

I

SINK

= 25mA

Figure 3. Output Voltage Error vs. Temperature

35

I

= 25mA

SINK

= 15mA

I

SOURCE

TEMPERATURE (°C)

= 15mA

I

LOAD

I

= 0mA

I

SOURCE

SINK

= 5mA

04712-003

30

25

20

15

10

OUTPUT VOLTAGE ERROR (mV)

5

0

0.1 1 10 100

CH6 SOURCE

CH3 SOURCE

CH6 SINK

CH3 SINK

LOAD CURRENT (mA)

Figure 6. Output Voltage Error vs. Load Current (Channels 3 and 6)

30

04712-006

30

25

20

15

10

OUTPUT VOLTAGE ERROR (mV)

5

0

0.1 1 10 100 LOAD CURRENT (mA)

CH11 SOURCE

CH12 SOURCE

CH11 SINK

CH12 SINK

Figure 4. Output Voltage Error vs. Load Current (Channels 11 and 12)

30

25

20

15

10

OUTPUT VOLTAGE ERROR (mV)

5

0

0.1 1 10 100

CH7 SOURCE

CH10 SOURCE

CH10 SINK

CH7 SINK

LOAD CURRENT (mA)

Figure 5. Output Voltage Error vs. Load Current (Channels 7 and 10)

04712-004

04712-005

25

20

15

10

OUTPUT VOLTAGE ERROR (mV)

5

0

0.1 1 10 100

CH2 SOURCE

CH1 SOURCE

CH1 SINK

CH2 SINK

LOAD CURRENT (mA)

Figure 7. Output Voltage Error vs. Load Current (Channels 1 and 2)

15 14 13 12 11 10

9 8 8 7 6 5 4 3

OUTPUT VOLTAGE ERROR (mV)

2 1 0

0.1 1 10 100 LOAD CURRENT (mA)

Figure 8. Output Voltage Error vs. Load Current ( V

V

SINK

COM

V

SOURCE

COM

)

COM

04712-007

04712-008

Rev. A | Page 8 of 20

ADD8707

1000

900

800

700

600

500

400

300

NUMBER OF AMPLIFIERS

200

100

0

–0.30 –0.18 –0.10 –0.02 0.06 0.14 0.22 0.30

GAMMA OUTPUT ERROR DUE TO OFFSET AND

RESISTOR MATCHING (% OF FS)

Figure 9. Gamma Output Voltage Error

35

30

25

20

15

10

NUMBER OF AMPLIFIERS

5

0

–10.0 –7.5 2.5 10.0

–5.0 –2.5 7.55.0

OUTPUT VOLTAGE ERROR (mV)

Figure 10. V

0

Offset Voltage

COM

04712-009

04712-010

0.3 MAX ERROR EACH STEP

0.2

0.1

0

ERROR (%)

–0.1

–0.2

–0.3

TYPICAL UNIT B

TYPICAL UNIT A

0123456789101112

OUTPUT CHANNEL

TYPICAL UNIT C

MIN ERROR EACH STEP

Figure 12. Gamma Output Error per Channel (920 Parts)

15 14 13 12 11 10

9 8 7 6 5

OUTPUT VOLTAGE (V)

4 3 2 1 0

17 012345678910111213141516

INPUT VOLTAGE (V)

I

LOAD

I

LOAD

= 10mA

= 0mA

I

LOAD

= 5mA

Figure 13. Dropout Characteristics

04712-012

04712-013

35

30

25

20

15

10

NUMBER OF AMPLIFIERS

5

0

–500 –470 –440 –410 –380 –350 –320

Figure 11. V

INPUT BIAS CURRENT (nA)

Input Bias Current Distribution

COM

04712-0-011

Rev. A | Page 9 of 20

0

100

200

300

400

500

600

700

DROPOUT VOLTAGE (mV)

800

900

1000

01234567891011121314151617181920

OUTPUT CURRENT (mA)

Figure 14. Dropout Voltage vs. Output Current

04712-014

ADD8707

800 750 700 650 600 550 500 450 400 350 300 250 200

DROPOUT VOLTAGE (mV)

150 100

50

0

–25–15–5 5 152535455565758595105115

14.5

14.4

14.3

14.2

14.1

14.0

13.9

REGULATOR OUTPUT (V)

13.8

13.7

13.6 0 2 4 6 8 10 12 14 16 18 20

Figure 16. Regulator Output vs. I

14.45

14.40

14.35

14.30

REGULATOR OUTPUT (V)

14.25

14.20 –20–100 102030405060708090100110

10mA

TEMPERATURE (°C)

Figure 15. Dropout Voltage vs. Temperature

+25°C

+55°C

+85°C

+95°C

+105°C

LOAD CURRENT (mA)

over Temperature

LOAD

TEMPERATURE (°C)

Figure 17. Regulator Output vs. Temperature

5mA

0mA

5mA

–20°C

0°C

10mA

04712-015

04712-016

04712-017

18

17

16

INPUT VOLTAGE (V)

15

14

TIME (100µs/DIV)

C

LOAD

= 1µF

Figure 18. Regulator Line Transient Response

C

= 1µF

LOAD

0.1

LOAD CURRENT (mA)

5

TIME (100µs/DIV)

Figure 19. Regulator Load Transient Response

11 10

9 8 7 6 5 4 3

SUPPLY CURRENT (mA)

2 1 0

024681012141618

SUPPLY VOLTAGE (V)

Figure 20. Supply Current vs. Supply Voltage

400

200

0

–200

–400

OUTPUT VOLTAGE CHANGE (mV)

04712-0-018

40

20

0

–20

–40

OUTPUT VOLTAGE CHANGE (mV)

04712-0-019

04712-020

Rev. A | Page 10 of 20

ADD8707

8.8

8.7

8.6

8.5

8.4

8.3

SUPPLY CURRENT (mA)

8.2

8.1 –20 120100806040200

TEMPERATURE (°C)

Figure 22. Supply Current vs. Temperature

04712-022

AMPLITUDE (V)

11 10

9 8 7 6 5 4 3 2 1 0

–200 180016001400120010008006004002000

TIME (ns)

10V PULSE 120pF 320pF 520pF 1nF 10nF

04712-021

Figure 21. Gamma Buffers Transient Load Response vs. Capacitive Loading

Rev. A | Page 11 of 20

ADD8707

V

APPLICATION NOTES

The ADD8707 is a mask-programmable gamma reference generator that allows source drivers to be optimized for the different combinations of liquid crystals, glass sizes, etc. in large LCD panels. It generates 12 gamma reference outputs that can be mask-programmed in 0.2% increments using the 500 matched internal resistors (Figure 23), so that every point on the curve can be targeted within 0.1% of the desired value.

TAP POINT 4

TAP POINT 3

TAP POINT 2

TAP POINT 1

EACH R = 30Ω TYPICALLY

Figure 23. 500 Mask-Programmable Resistor String

In a typical panel application, the selected source drivers have an internal gamma curve that is not ideal for the specific panel (Figure 24). The ADD8707 allows the gamma curve in the source drivers to be adjusted appropriately, and also insures that all the source drivers have the same gamma curve.

16

14

12

10

8

6

PANEL GAMMA CURVE

CORRECTED BY ADD8707

GAMMA VOLTAGE (V)

4

2

0

Figure 24. Original and Corrected Gamma Cur ves

ORIGINAL GAMMA CURVE

IN SOURCE DRIVERS

GAMMA REFERENCE INPUT POINTS

TAP POINT 500

TAP POINT 499

TAP POINT 498

TAP POINT 497

04712-023

04712-024

The matching and tracking accuracy of the internal resistors is typically 0.1% with worst-case deviation from the desired curve within 0.4% of the ideal gamma curve, over temperature.

The ADD8707 also includes a low dropout linear regulator to provide a stable reference level for the gamma curve for optimum panel performance.

TAP POINT SELECTION

The ADD8707 uses a single resistor string consisting of 500 individual elements. The tap points are mask programmable and completely independent of each other. Refer to the Tap Point and Regulator Voltage Request Form in this data sheet.

V

REG OUT

500–TP

X

IN

X

TP

X

V

X

OUT

04712-025

Figure 25. Gamma Buffers Tap Point Circuit.

Tap point voltages can be derived from the following equation:

TP

X

V ×=

where TP

XOUT

is the desired tap point for the Xth channel.

X

500

V

OUTREG

Table 5. Typical Mask Implementation

= 16 V, V

V

DD

= 14.4 V, 0 ≤ X ≤ 500

REG OUT

Tap Point (X) Voltage Units

V

12 500 14.400 V

OUT

V

11 419 12.067 V

OUT

V

10 365 10.512 V

OUT

V

9 349 10.051 V

OUT

V

8 343 9.878 V

OUT

V

7 297 8.554 V

OUT

V

6 213 6.134 V

OUT

V

5 173 4.982 V

OUT

V

4 163 4.694 V

OUT

V

3 146 4.205 V

OUT

V

2 95 2.736 V

OUT

V

1 7 0.202 V

OUT

Rev. A | Page 12 of 20

ADD8707

VOLTAGE REGULATOR

The on-board voltage regulator provides a regulated voltage to the resistor chain to provide stable gamma voltages.

The output of the regulator is set by the two mask programmable internal resistors R1 and R2, and a reference voltage. In the ADD8707, the typical values of these parts are shown in Figure 26. To request a different regulator voltage, please refer to the Tap Point and Regulator Voltage Request Form in this data sheet.

R

2

R

5kΩ

V

REF

1.2V

Figure 26. Voltage Regulator

The internal resistors have a typical accuracy of 0.1%. External resistors can be used to adjust the regulator voltage, though it is not recommended. Contact a sales office for further details.

55kΩ

1

V

REG OUT

+ –

04712-026

LAND PATTERN

The LFCSP package comes with a thermal pad. Soldering down this thermal pad dramatically improves the heat dissipation of the package. It is necessary to attach vias that connect the soldered thermal pad to another layer on the board. This provides an avenue to dissipate the heat away from the part. Without vias, the heat is isolated directly under the part.

Subdivide the solder paste, or stencil layer, for the thermal pad. This reduces solder balling and splatter. It is not critical how the subdivisions are arranged, as long as the total coverage of the solder paste for the thermal pad is greater than 50%. The land pattern is critical to heat dissipation. A suggested land pattern is shown in Figure 27.

The thermal pad is attached to the substrate. In the ADD8707, 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.

. To be electrically safe, the

DD

. Attaching the thermal

DD

MAXIMUM POWER DISSIPATION

The maximum safe power dissipation in the ADD8707 package is limited by the associated rise in junction temperature (TJ) on the die. At approximately 150°C, the glass transition temperature, the properties of the plastic change. Even temporarily exceeding this temperature limit may change the stresses that the package exerts on the die, permanently shifting the parametric performance of the ADD8707. Exceeding a junction temperature of 175°C for an extended period can result in changes in the silicon devices, potentially causing failure.

Rev. A | Page 13 of 20

ADD8707

OPERATING TEMPERATURE RANGE

The junction temperature is as follows:

= T

T

J

where:

T

AMB

= junction-to-ambient thermal resistance, in °C/watt.

θ

JA

P

= power dissipated in the device, in watts.

DIS

For the ADD8707, P

where:

× IDQ = nominal system power requirements.

V

DD

I

OUT X(+)

dissipation (current comes from V

−I

OU XT(-)

dissipation (current goes to GND). (V

DD

In this example, T values in Table 6.

Table 6.

V

12 14.400 8.3 0.0133

OUT

V

11 12.067 7.9 0.0311

OUT

V

10 10.512

OUT

V

9 10.051

OUT

V

8 9.878 5.6 0.0343

OUT

V

7 8.554

OUT

V

6 6.134

OUT

V

5 4.982 5.7 0.0628

OUT

V

4 4.694 3.5 0.0396

OUT

V

3 4.205 9.6 0.113

OUT

V

2 2.736 9.5 0.126

OUT

V

1 0.202

OUT

Σ(I

OUT X(+)

+ θJA × P

AMB

DIS

= ambient temperature specified on the data sheet.

can be calculated by

DIS

= VDD × IDQ + Σ(I

P

DIS

Σ(−I

OUT X(-)

× (VDD − V

× V

– V

= negative-current amplifier load power

OUT X

) × I

REG OUT

OUT X

× (VDD − V

× V

) = positive-current amplifier load power

OUT X

= regulator load power dissipation.

LOAD

= 95°C. To calculate P

AMB

(V) I

)) + Σ(−I

OUT X

× (VDD − V

OUT X(+)

) + (VDD – V

OUTX

−4.5

−4.2

−3.3

−6.9

−7.2

OUT X(-)

OUT X

REG OUT

).

DD

, assume the

DIS

(mA) P (W)

OUT X

× V

)

OUT X

)) +

) × I

LOAD

0.0473

0.0422

0.0282

0.0423

0.00145

0.582

× IDQ = 16 V × 15 mA = 0.240 W.

V

DD

– V

(V

DD

= 0.240W + 0.582W + 0.008W = 0.830W.

P

DIS

REG OUT

) × I

= (16 V – 14.4 V) × 5 mA = 0.008 W.

LOAD

Example 1

Exposed pad soldered down with via θJA = 28.3°C/W:

T

= 95°C + (28.3°C/W) × (0.830 W) = 118.5°C

J

The maximum junction temperature that is guaranteed before the part breaks down is 150°C. is The maximum process limit is 125°C. Because T

is < 150°C and < 125°C, this example

J

demonstrates a condition where the part should perform within process limits.

Example 2

Exposed pad not soldered down θJA = 47.7°C/W:

T

= 95°C + (47.7°C/W) × (0.830 W) = 134.6°C

J

In this example, T

is < 150°C but > 125°C. Although the part

J

should not exhibit any damage here, the process limits have been exceeded. The part may no longer operate as intended.

These examples show that soldering down the exposed pad is important for proper heat dissipation. Under the same powerup and loading conditions, the unsoldered part has a higher temperature than the soldered part. Therefore, it is strongly advised that the exposed pad be soldered down.

Rev. A | Page 14 of 20

ADD8707

7.31mm

SOLDER PASTE AREA

HEAT SINK

1.90mm

5.40mm

5.93mm

1.60mm

0.5mm

0.33mm DIAMETER THERMAL VIA

1.60mm

0.69mm

0.075mm

0.28mm

5.78mm

04712-020

Figure 27. 48-Lead LFCSP (CP-48) Land Pattern—Dimensions shown in millimeters

Notes:

1. Gray area represents the board metallization.

2. White area represents the solder mask and vias.

3. Hatched area is for the heat sink solder paste.

4. 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.

Rev. A | Page 15 of 20

ADD8707

TYPICAL APPLICATIONS CIRCUIT

V

OPEN

NORMALLY

V

NORMALLY OPEN

FB

700Ω*

5kΩ

+

1.2V –

VOLTAGE REGULATOR

700Ω*

11

IN

700Ω*

10

IN

700Ω*

8

IN

700Ω*

7

IN

700Ω*

6

IN

700Ω*

5

IN

700Ω*

3

IN

700Ω*

2

IN

700Ω*

1

IN

*ESD PROTECTION RESISTORS

0.1µF

V

REG OUT

55kΩ

TP12 = 500

TP11 = 419

TP10 = 365

TP9 = 349

TP8 = 343

TP7 = 297

TP6 = 213

TP5 = 173

TP4 = 163

TP3 = 146

TP2 = 95

TP1 = 7

14.4V

V

COM IN+

V

COM IN–

V

14.4V

0Ω

2.43Ω

1.62Ω

480Ω

180Ω

1.38kΩ

2.52Ω

1.20Ω

300Ω

510Ω

1.53kΩ

2.64kΩ

COM

GAMMA BUFFERS

V

OUT

V

COM OUT

12

14.4V

11

12.067V

10

10.512V

9

10.051V

8

9.878V

7

8.554V

6

6.134V

5

4.982V

4

4.694V

3

4.205V

2

2.736V

1

0.202V

210Ω

GND GND

Figure 28. Typical Applications Circuit

8.2kΩ

4.7kΩ

2kΩ

PANEL V

0.1µF

ITO

3.3µF

COM

V 16V

GAMMA 12 GAMMA 11 GAMMA 10 GAMMA 9 GAMMA 8 GAMMA 7 GAMMA 6 GAMMA 5 GAMMA 4 GAMMA 3 GAMMA 2

DD

GAMMA 1

GAMMA 12 GAMMA 11 GAMMA 10 GAMMA 9 GAMMA 8 GAMMA 7 GAMMA 6 GAMMA 5 GAMMA 4 GAMMA 3 GAMMA 2 GAMMA 1

04712-028

Rev. A | Page 16 of 20

ADD8707

V

DEVELOPMENT CIRCUIT

For development purposes, the ADD8707 is available in a generic form without the tap points (see Figure 29). The typical applications circuit for this part is shown in Figure 30. To order this version, refer to the Ordering Guide. The model listed is the development version.

V

REG OUT

FB

V

11

IN

10

IN

V

8

IN

V

7

IN

V

6

IN

V

5

IN

V

3

IN

V

2

IN

V

1

IN

700Ω*

1.2V

700Ω*

V

REG

+ –

V

COM IN–

V

COM IN+

V

GAMMA BUFFERS

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

04712-029

*ESD PROTECTION RESISTORS

Figure 29. Block Diagram for ADD8707 Development Version (with No Tap Points)

Rev. A | Page 17 of 20

ADD8707

0.1µF V

COM IN+

14.4V

8.2kΩ

4.7kΩ

5kΩ

V

IN

V

PROTECTION

FB

11

10

8

IN

7

IN

6

IN

5

IN

3

IN

2

IN

1

IN

55kΩ

ESD

RESISTOR

700Ω

+

1.2V

–

ESD

PROTECTION

RESISTORS

700Ω

V

REG OUT

VOLTAGE REGULATOR

14.4V

4.53kΩ

TP9 = 349

5.58kΩ

TP4 = 163

4.89kΩ

GND

V

COM IN–

V

GAMMA BUFFERS

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

2kΩ

PANEL V

ITO

0.1µF

3.3µF

COM

14.4V

10.051V

4.694V

V 16V

GAMMA 12 GAMMA 11 GAMMA 10 GAMMA 9 GAMMA 8 GAMMA 7 GAMMA 6 GAMMA 5 GAMMA 4 GAMMA 3 GAMMA 2

DD

GAMMA 1

GAMMA 12 GAMMA 11 GAMMA 10 GAMMA 9 GAMMA 8 GAMMA 7 GAMMA 6 GAMMA 5 GAMMA 4 GAMMA 3 GAMMA 2 GAMMA 1

04712-028

04712-030

Figure 30. Typical Applications Circuit for ADD8707 Development Version (with No Tap Points)

Rev. A | Page 18 of 20

TAP POINT AND REGULATOR VOLTAGE REQUEST FORM

REGULATOR SECTION—V

To ensure correct regulator operation VDD must exceed V

= 15.0 V.

V

DD

Parameter Value (6.9 V – 15.4 V) V

REG OUT

TAP POINT SECTION

Gamma output voltages are calculated using the following formula:

VTP

×

V

=

OUT

OUTREG

500

REG OUT

by 600 mV minimum—that is, a V

REG

= 14.4 V requires a minimum

REG

ADD8707

A Microsoft® Excel spreadsheet is available which automatically calculates the best tap point based on V voltages for each gamma output.

Output Tap Point 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

and the desired output

REG OUT

CUSTOMER INFORMATION

Name: ____________________________________________

Company: ____________________________________________

Address: ____________________________________________

____________________________________________

Date: ____________________________________________

Please return this form to your local sales office.

Rev. A | Page 19 of 20

ADD8707

OUTLINE DIMENSIONS

BSC SQ

PIN 1 INDICATOR

7.00

0.60 MAX

37

36

0.60 MAX

0.30

0.23

0.18

PIN 1

48

INDICATOR

1

1.00

12° MAX

0.85

0.80

SEATING PLANE

ORDERING GUIDE

1

Model

ADD8707WCPZ-REEL7

1

Available in reels only.

2

Z = Pb-free part.

3

Development version.

Temperature Package Package Description Package Outline

2, 3

–40°C to +105°C 48-Lead Lead Frame Chip Scale Package CP-48

(BOTTOM VIEW)

25

24

EXPOSED

TOP

VIEW

0.80 MAX

0.65 TYP

0.50 BSC

COMPLIANT TO JEDEC STANDARDS MO-220-VKKD-2

6.75

BSC SQ

0.20REF

0.50

0.40

0.30

0.05 MAX

0.02 NOM COPLANARITY

0.08

Figure 31. 48-Lead Lead Frame Chip Scale Package [LFCSP]

7 mm × 7 mm Body

(CP-48)

Dimensions shown in millimeters

PAD

5.50 REF

5.25

5.10 SQ

4.95

12

13

0.25 MIN

D04712-0-10/04(A)

Rev. A | Page 20 of 20

Datasheet ADD8707 Datasheet (Analog Devices)

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

PRODUCT OVERVIEW

FUNCTIONAL BLOCK DIAGRAM

ELECTRICAL CHARACTERISTICS

ABSOLUTE MAXIMUM RATINGS

PIN CONFIGURATION AND FUNCTION DESCRIPTION

TYPICAL PERFORMANCE CHARACTERISTICS

APPLICATION NOTES

TAP POINT SELECTION

VOLTAGE REGULATOR

LAND PATTERN

MAXIMUM POWER DISSIPATION

OPERATING TEMPERATURE RANGE

TYPICAL APPLICATIONS CIRCUIT

DEVELOPMENT CIRCUIT

TAP POINT AND REGULATOR VOLTAGE REQUEST FORM

OUTLINE DIMENSIONS

ORDERING GUIDE