REV. 0

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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

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a

AD9807/AD9805

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

Tel: 617/329-4700

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

Fax: 617/326-8703

© Analog Devices, Inc., 1997

Complete 12-Bit/10-Bit 6 MSPS

CCD/CIS Signal Processors

FUNCTIONAL BLOCK DIAGRAM

PGA

PGA

PGA

GREEN

RED

BLUE

MUX

ADC

REF

GAIN

REGISTERS

INPUT

OFFSET

CONFIG

REGS

ODD

EVEN

8-10

12-10

12-10

MPU

PORT

CSB

RD

WR

A2

A1

A0

VREF

PIXEL

OFFSET

PIXEL

GAIN

CDSCLK1

CDSCLK2

ADCCLK

VINR

VING

VINB

DOUT

AD9807/AD9805

PGA

PGA

GAIN

REGISTERS

MUX

REF

INPUT

OFFSET

CONFIG

REGS

EVEN

ODD

MPU

PORT

X

–

CDS

CDS

CDS

PRODUCTION DESCRIPTION

The AD9807 and AD9805 are complete CCD/CIS imaging

decoders and signal processors on a single monolithic integrated

circuit. The input of the AD9807/AD9805 allows direct ac

coupling of the charge-coupled device (CCD) or contact image

sensor (CIS) output(s). The AD9807/AD9805 includes all the

circuitry to perform three-channel correlated double sampling

(CDS) and programmable gain adjustment of the CCD output;

a 12-bit or 10-bit analog-to-digital converter (ADC) quantizes

the analog signal. After digitization, the on-board digital signal

processor (DSP) circuitry allows pixel rate offset and gain correc-

tion. The DSP also corrects odd/even CCD register imbalance

errors. A parallel control bus provides a simple interface to

8-bit microcontrollers. The AD9807/AD9805 comes in a

space saving 64-pin plastic quad flatpack (PQFP) and is specified

over the commercial (0

°C to +70°C) temperature range. By

disabling the CDS, the AD9807/AD9805 are also suitable for

non-CCD applications, or applications that do not require

CDS, such as CIS signal processing.

PRODUCT HIGHLIGHTS

The AD9807/AD9805 offers a complete, single chip CCD

imaging front end in a 64-pin plastic quad flatpack (PQFP).

On-Chip PGA—The AD9807/AD9805 includes a 3-channel

analog programmable gain amplifier; it is programmable from

1

× to 4× in 16 increments.

On-Chip CDS—An integrated 3-channel correlated double

sampler allows easy ac coupling directly from the CCD sensor

outputs. Additionally, the CDS reduces low frequency noise

and reset feedthrough.

On-Chip Voltage Reference—The AD9807/AD9805 includes a

2 V bandgap reference that allows the input range of the device to

be configured for input spans up to 4 V.

6 MSPS A/D Converter—A highly linear 12-bit or 10-bit A/D

converter sequentially digitizes the red, green and blue CDS

outputs ensuring no missing code performance. The user may also

configure the AD9807/AD9805 for single channel operation.

Digital Gain & Offset Correction—Pixel rate digital gain and

offset correction blocks allow precise repeatable correction of

imaging system error sources.

Digital I/O Compatibility—The AD9807/AD9805 offers

+3.3 V/+5 V logic level compatibility.

Pin-Compatible 12-Bit and 10-Bit Versions—The AD9807 is

also offered in a pin-compatible 10-bit version, the AD9805,

allowing upgrade-ability and simplifying design issues across

different scanner models.

FEATURES

Pin Compatible 12-Bit and 10-Bit Versions

12-Bit/10-Bit 6 MSPS A/D Converter

Integrated Triple Correlated Double Sampler

3-Channel, 2 MSPS Color Mode

1

– 4

Analog Programmable Gain Amplifier

Pixel-Rate Digital Gain Adjustment

Pixel-Rate Digital Offset Adjustment

Internal Voltage Reference

No Missing Codes Guaranteed

Microprocessor-Compatible Control Interface

+3.3 V/+5 V Digital I/O Compatibility

Low Power CMOS: 500 mW

64-Pin PQFP Surface Mount Package