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

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

AD9841A/AD9842A

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., 2001

Complete 20 MSPS

CCD Signal Processors

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

10/12

CDS

VGA

CLP

BUF

2:1

MUX

CLP

AD9841A/AD9842A

CONTROL

REGISTERS

CLP

ADC

4dB

6dB

COLOR

STEERING

HD

VD

PxGA

6

FEATURES

20 MSPS Correlated Double Sampler (CDS)

4 dB

6 dB 6-Bit Pixel Gain Amplifier (

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

Low Noise Clamp Circuits

Analog Preblanking Function

10-Bit (9841) or 12-Bit (9842) 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

PRODUCT DESCRIPTION

The AD9841A and AD9842A are complete analog signal proces-

sors for CCD applications. Both products feature a 20 MHz

single-channel architecture designed to sample and condition

the outputs of interlaced and progressive scan area CCD arrays.

The AD9841A/AD9842A’s signal chain consists of an input

clamp, correlated double sampler (CDS), Pixel Gain Amplifier

(PxGA), digitally controlled variable gain amplifier (VGA),

black level clamp, and A/D converter. The AD9841A offers 10-bit

ADC resolution, while the AD9842A contains a true 12-bit

ADC. 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 AD9841A and AD9842A operate from a single 3 V power

supply, typically dissipate 78 mW, and are packaged in a 48-

lead LQFP.

PxGA is a registered trademark of Analog Devices, Inc.