AD9822 Datasheet, PDF (1/15 Pages) Analog Devices – Complete 14-Bit CCD/CIS Signal Processor

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Complete 14-Bit
CCD/CIS Signal Processor
AD9822
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.
FUNCTIONAL BLOCK DIAGRAM
AVDD AVSS
CML
CAPT CAPB
AVDD AVSS
DRVDD DRVSS
VINR
VING
VINB
OFFSET
CDS
9-BIT
DAC
PGA
BANDGAP
REFERENCE
AD9822
CDS
9-BIT
DAC
CDS
9-BIT
DAC
INPUT
CLAMP
BIAS
PGA
3:1
MUX
14-BIT
ADC
14
14:8 8
MUX
PGA
6
9
CONFIGURATION
REGISTER
MUX
REGISTER
RED
GREEN
BLUE
RED
GREEN
BLUE
GAIN
REGISTERS
OFFSET
REGISTERS
DIGITAL
CONTROL
INTERFACE
CDSCLK1 CDSCLK2
ADCCLK
OEB
DOUT
SCLK
SLOAD
SDATA
REV. A
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© Analog Devices, Inc., 1999