Complete 14-Bit
CCD/CIS Signal Processor
a
AD9822
FEATURES
PRODUCT DESCRIPTION
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
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.
؎350 mV Programmable Offset
Input Clamp Circuitry
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.
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
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.
Low Power CMOS: 385 mW (Typ)
Power-Down Mode: <1 mW
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.
APPLICATIONS
Flatbed Document Scanners
Film Scanners
Digital Color Copiers
Multifunction Peripherals
FUNCTIONAL BLOCK DIAGRAM
AVDD
AVSS
CML
CAPT
CAPB
AVDD
AVSS
DRVDD DRVSS
CDS
PGA
VINR
VING
AD9822
OEB
BANDGAP
9-BIT
DAC
REFERENCE
14
8
14:8
MUX
3:1
MUX
14-BIT
ADC
DOUT
CDS
CDS
PGA
9-BIT
DAC
CONFIGURATION
REGISTER
MUX
REGISTER
SCLK
PGA
VINB
DIGITAL
CONTROL
INTERFACE
RED
GREEN
BLUE
SLOAD
SDATA
6
9-BIT
DAC
GAIN
REGISTERS
RED
GREEN
BLUE
INPUT
CLAMP
BIAS
9
OFFSET
OFFSET
REGISTERS
CDSCLK1 CDSCLK2
ADCCLK
REV. A
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.
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Tel: 781/329-4700
Fax: 781/326-8703
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© Analog Devices, Inc., 1999