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AD9945
Complete 12-Bit 40 MHz
CCD Signal Processor
FEATURES
40 MSPS Correlated Double Sampler (CDS)
6 dB to 40 dB 10-Bit Variable Gain Amplifier (VGA)
Low Noise Optical Black Clamp Circuit
Preblanking Function
12-Bit 40 MSPS A/D Converter
No Missing Codes Guaranteed
3-Wire Serial Digital Interface
3 V Single-Supply Operation
Low Power: mW @ 3 V Supply
Space-Saving 32-Lead 5 mm
ⴛ
5 mm LFCSP
APPLICATIONS
Digital Still Cameras
Digital Video Camcorders
PC Cameras
Portable CCD Imaging Devices
CCTV Cameras
FUNCTIONAL BLOCK DIAGRAM
DATACLKSHDSHP
BAND GAP
REFERENCE
DOUT
CCDIN
PBLK
REFT
REFB
INTERNAL
TIMING
6dB TO 40dB
AVDD
DVDD
DVSS
AVSS
DRVDD
DRVSS
10
DIGITAL
INTERFACE
SDATASCK
SL
CLPOB
12
AD9945
CONTROL
REGISTERS
12-BIT
ADC
CLP
VGACDS
GENERAL DESCRIPTION
The AD9945 is a complete analog signal processor for CCD
applications. It features a 40 MHz single-channel architecture
designed to sample and condition the outputs of interlaced and
progressive scan area CCD arrays. The AD9945’s signal chain
consists of a correlated double sampler (CDS), a digitally con-
trolled variable gain amplifier (VGA), a black level clamp, and a
12-bit A/D converter.
The internal registers are programmed through a 3-wire serial digital
interface. Programmable features include gain adjustment, black
level adjustment, input clock polarity, and power-down modes.
The AD9945 operates from a single 3 V power supply, typi-
cally dissipates mW, and is packaged in a space-saving
32-lead LFCSP.
REV.
160
160
C
781/461-3113
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