REV. A

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a

AD9822

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., 1999

Complete 14-Bit

CCD/CIS Signal Processor

FUNCTIONAL BLOCK DIAGRAM

9-BIT

DAC

PGA

CDS

PGA

CDS

PGA

CDS

3:1

MUX

14-BIT

ADC

14

14:8

MUX

8

BANDGAP

REFERENCE

CONFIGURATION

REGISTER

MUX

REGISTER

BLUE

GREEN

RED

BLUE

GREEN

RED

6

9

GAIN

REGISTERS

OFFSET

REGISTERS

DIGITAL

CONTROL

INTERFACE

INPUT

CLAMP

BIAS

AD9822

DRVDD

DRVSS

AVDD

AVSS

CAPT

CAPB

AVDD

AVSS

CML

OEB

DOUT

SCLK

SLOAD

SDATA

ADCCLK

CDSCLK2

CDSCLK1

OFFSET

VINB

VING

VINR

9-BIT

DAC

9-BIT

DAC

FEATURES

14-Bit 15 MSPS A/D Converter

No Missing Codes Guaranteed

3-Channel Operation Up to 15 MSPS

1-Channel Operation Up to 12.5 MSPS

Correlated Double Sampling

1–6x Programmable Gain

350 mV Programmable Offset

Input Clamp Circuitry

Internal Voltage Reference

Multiplexed Byte-Wide Output (8+6 Format)

3-Wire Serial Digital Interface

3 V/5 V Digital I/O Compatibility

28-Lead SOIC or SSOP

Low Power CMOS: 385 mW (Typ)

Power-Down Mode: <1 mW

APPLICATIONS

Flatbed Document Scanners

Film Scanners

Digital Color Copiers

Multifunction Peripherals

PRODUCT DESCRIPTION

The AD9822 is a complete analog signal processor for CCD

imaging applications. It features a 3-channel architecture

designed to sample and condition the outputs of trilinear

color CCD arrays. Each channel consists of an input clamp,

Correlated Double Sampler (CDS), offset DAC and Pro-

grammable Gain Amplifier (PGA), multiplexed to a high

performance 14-bit A/D converter.

The CDS amplifiers may be disabled for use with sensors such

as Contact Image Sensors (CIS) and CMOS active pixel sensors,

which do not require CDS.

The 14-bit digital output is multiplexed into an 8-bit output

word that is accessed using two read cycles. The internal

registers are programmed through a 3-wire serial interface, and

provide adjustment of the gain, offset, and operating mode.

The AD9822 operates from a single 5 V power supply, typically

consumes 385 mW of power, and is packaged in a 28-lead SOIC

or SSOP.