ANALOG DEVICES ADA4431-1 Service Manual

Ultralow Power SD Video Filter

V

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FEATURES

Third-order, low-pass video filter

1 dB flatness out to 6 MHz

27 dB rejection at 27 MHz
Low quiescent current: 4.7 mA typical
Low power-down current: 24 μA typical
Load detection capability
SAG correction

Allows use of smaller capacitors in ac-coupled outputs
Low supply voltage: 2.5 V to 3.6 V
Charge pump

Creates a negative voltage from single positive supply

Allows capless output coupling with no dc offset
Rail-to-rail output
High input-to-output isolation in disabled state

89 dB @ 1 MHz
Small package

3 mm × 3 mm LFCSP

Low 0.55 mm package height
Wide operating temperature range: −40°C to +85°C

APPLICATIONS

Portable media players
Portable gaming consoles
Cell phones
Digital still cameras
Portable DVD players
Portable video cameras

SYSTEM

CONTRO LLER

VIDEO

DAC/

ENCODER

with Load Detection

PIN CONFIGURATION

FB1

FB2

OUT

16

15

+V

1

S

2

IN

G = 2

DIS

LDO

LPF

3

4

CHARGE PUMP

5

6

CAP3

CAP4

Figure 1.

110

4

3

2

7

+V

LDO

DIS

IN

GND

CAP4 CAP3

56891112

S

ADA4431-1

x1 x2

CAP2 CAP1

0.1µF

Figure 2. Typical Application Circuit

SAG

14

13

LOAD

DETECT

7

8

GND

CAP2

+

S

0.1µF 0.1µF

+V

S

LPF

SUBS GND

0.1µF

ADA4431-1

12

GND

SUBS

11

10

+V

S

CAP1

9

06734-001

16

FB1

15

FB2

OUT

SAG

1.0µF

VIDEO

OUT

75Ω

14

13

6734-002

GENERAL DESCRIPTION

The ADA4431-1 is a fully integrated video reconstruction filter
that combines excellent video specifications with low power
consumption, making it ideal for portable video filtering
applications. The ADA4431-1 is able to detect whether a video
load is present at the output, powering down the device when
the load is disconnected.

The ADA4431-1 operates on single supplies as low as 2.5 V
w

hile providing the dynamic range required by the most
demanding video systems. The on-board charge pump
provides a virtual negative supply, allowing the video signal to
be dc-coupled and the black level to be set to ground, while the
sync passes cleanly at 300 mV below ground.

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.

When operating with the charge pump off, the ADA4431-1

rovides a dc offset to keep the sync tip approximately 100 mV

p
above ground. In addition, the part features SAG correction,
which permits the use of smaller capacitors in applications with
ac-coupled outputs.

The ADA4431-1 is packaged in a low profile 16-lead LFCSP and

perates in the industrial temperature range of −40°C to +85°C.

o

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2007 Analog Devices, Inc. All rights reserved.

ADA4431-1

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TABLE OF CONTENTS

Features .............................................................................................. 1

Applications....................................................................................... 1

Pin Configuration............................................................................. 1

General Description......................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 5

Thermal Resistance ...................................................................... 5

Maximum Power Dissipation ..................................................... 5

ESD Caution.................................................................................. 5

REVISION HISTORY

8/07—Revision 0: Initial Version

Pin Configuration and Function Descriptions..............................6

Typical Perf or m an c e Charac t e r istics ..............................................7

Theory of Operation .........................................................................9

Overview ........................................................................................9

Charge Pump Operation..............................................................9

Load Detect....................................................................................9

Evaluation Board ............................................................................ 10

Outline Dimensions ....................................................................... 12

Ordering Guide .......................................................................... 12

Rev. 0 | Page 2 of 12

ADA4431-1

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SPECIFICATIONS

VS = 3.0 V (@ TA = 25°C, VIN = 1 V p-p, RL = 150 Ω, DIS = 3.0 V, charge pump on), unless otherwise noted.

Table 1.

Parameter Test Conditions/Comments Min Typ Max Unit

ELECTRICAL SPECIFICATIONS

Quiescent Supply Current

Normal Mode Video load present 4.7 7.2 mA
Load Searching Mode No video load 0.1 mA

Disabled Mode DIS = 0 V 24 μA
Disable Pin Current DIS = 3.0 V (enabled and charge pump on) 3 6 μA
DIS = 0 V (disabled) −17 −30 μA
Supply Voltage Range 2.5 3.6 V
Input Voltage Limited by output range 1.3 V
Input Resistance 10 MΩ
Input Capacitance 1 pF
Output Voltage Range −0.8 to +2.8 V
Output Offset Voltage −650 −600 −560 mV
Power Supply Rejection f = 100 kHz, output referred 36 42 dB
Pass-Band Gain 5.7 6.0 6.2 dB
Input-to-Output Isolation—Disabled f = 1 MHz, DIS = 0 V 89 dB

FILTER CHARACTERISTICS

−3 dB Bandwidth 7.1 7.9 9.1 MHz
1 dB Flatness 6 MHz
Out-of-Band Rejection f = 27 MHz 25 27 dB
Differential Gain Modulated 10 step ramp, sync tip at 0 V 0.7 %
Differential Phase Modulated 10 step ramp, sync tip at 0 V 0.3 Degrees
Linear Output Current 40 mA
Group Delay Variation f = 100 kHz to 5 MHz 30 ns

Rev. 0 | Page 3 of 12

ADA4431-1

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VS = 3.0 V (@ TA = 25°C, VIN = 1 V p-p, RL = 150 Ω, DIS = floating, charge pump off), unless otherwise noted.

Table 2.

Parameter Test Conditions/Comments Min Typ Max Unit

ELECTRICAL SPECIFICATIONS

Quiescent Supply Current

Normal Mode Video load present 1.6 2.2 mA
Load Searching Mode No video load 0.1 mA

Disabled Mode DIS = 0 V 24 μA
Disable Pin Current DIS = 0 V −17 −30 μA
Supply Voltage Range 2.5 3.6 V
Input Voltage Limited by output range 1.3 V
Input Resistance 10 MΩ
Input Capacitance 1 pF
Output Voltage Range 0 to 2.8 V
Output Offset Voltage 0.1 0.2 V
Power Supply Rejection f = 100 kHz, output referred 38 48 dB
Pass-Band Gain 5.8 6.0 6.2 dB
Input-to-Output Isolation—Disabled f = 1 MHz, DIS = 0 V 89 dB

FILTER CHARACTERISTICS

−3 dB Bandwidth 6.7 7.5 8.4 MHz
1 dB Flatness 6 MHz
Out-of-Band Rejection f = 27 MHz 26 29 dB
Differential Gain Modulated 10 step ramp, sync tip at 0 V 0.4 %
Differential Phase Modulated 10 step ramp, sync tip at 0 V 0.3 Degrees
Linear Output Current 40 mA
Group Delay Variation f = 100 kHz to 5 MHz 30 ns

Rev. 0 | Page 4 of 12