Complete 20 MSPS
CCD Signal Processors
a
AD9841A/AD9842A
PRODUCT DESCRIPTION
FEATURES
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.
20 MSPS Correlated Double Sampler (CDS)
4 dB ꢀ 6 dB 6-Bit Pixel Gain Amplifier (PxGA®)
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
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.
APPLICATIONS
Digital Still Cameras
Digital Video Camcorders
The AD9841A and AD9842A operate from a single 3 V power
supply, typically dissipate 78 mW, and are packaged in a 48-
lead LQFP.
FUNCTIONAL BLOCK DIAGRAM
HD
VD
AVDD
AVSS
PBLK
CLPOB
CLP
COLOR
STEERING
DRVDD
DRVSS
4dB ꢀ 6dB
2dB–36dB
VGA
PxGA
CDS
CCDIN
10/12
2:1
MUX
ADC
DOUT
CLP
6
VRT
VRB
BANDGAP
REFERENCE
CLPDM
AUX1IN
OFFSET
DAC
10
2:1
MUX
BUF
INTERNAL
BIAS
CML
AUX2IN
8
CONTROL
REGISTERS
CLP
DVDD
DVSS
DIGITAL
INTERFACE
INTERNAL
TIMING
AD9841A/AD9842A
SHP
SHD DATACLK
SL
SCK
SDATA
PxGA is a registered trademark of Analog Devices, Inc.
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2001