REV. 0

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a

AD9844A

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2000

Complete 12-Bit 20 MSPS

CCD Signal Processor

FUNCTIONAL BLOCK DIAGRAM

DATACLK

SHD

SHP

BANDGAP

REFERENCE

2:1

MUX

DOUT

AUX2IN

CLPDM

CCDIN

OFFSET

DAC

PBLK

AUX1IN

VRT

VRB

INTERNAL

TIMING

INTERNAL

BIAS

2dB~36dB

AVDD

DVDD

DVSS

AVSS

DRVDD

DRVSS

10

8

CML

DIGITAL

INTERFACE

SDATA

SCK

SL

CLPOB

12

CDS

VGA

CLP

BUF

2:1

MUX

CLP

AD9844A

4dB 6dB

INTERNAL

REGISTERS

CLP

12-BIT

ADC

6

FEATURES

20 MSPS Correlated Double Sampler (CDS)

4 dB

6 dB Variable CDS Gain with 6-Bit Resolution

2 dB to 36 dB 10-Bit Variable Gain Amplifier (VGA)

Low Noise Clamp Circuits

Analog Preblanking Function

12-Bit 20 MSPS A/D Converter

Auxiliary Inputs with VGA and Input Clamp

3-Wire Serial Digital Interface

3 V Single Supply Operation

Low Power: 65 mW @ 2.7 V Supply

48-Lead LQFP Package

APPLICATIONS

Digital Still Cameras

Digital Video Camcorders

PC Cameras

PRODUCT DESCRIPTION

The AD9844A is a complete analog signal processor for CCD

applications. It features a 20 MHz single-channel architecture

designed to sample and condition the outputs of interlaced and

progressive scan area CCD arrays. The AD9844A’s signal chain

consists of an input clamp, correlated double sampler (CDS),

digitally controlled variable gain amplifier (VGA), black level

clamp, and 12-bit A/D converter. Additional input modes are

provided for processing analog video signals.

The internal registers are programmed through a 3-wire serial

digital interface. Programmable features include gain adjustment,

black level adjustment, input configuration, and power-down

modes.

The AD9844A operates from a single 3 V power supply, typi-

cally dissipates 78 mW, and is packaged in a 48-lead LQFP.