REV.B
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AD9845B
Complete 12-Bit 30 MSPS
CCD Signal Processor
FEATURES
Pin Compatible with AD9845A Designs
12-Bit 30 MSPS A/D Converter
30 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
Preblanking Function
Auxiliary Inputs with VGA and Input Clamp
3-Wire Serial Digital Interface
3 V Single-Supply Operation
Low Power: 153 mW @ 3 V Supply
Space-Saving 48-Lead LQFP Package
APPLICATIONS
High Performance Digital Still Cameras
Industrial/Scientific Imaging
FUNCTIONAL BLOCK DIAGRAM
DATACLK
SHDSHP
2:1
MUX
DOUT
AUX2IN
CLPDM
CCDIN
AUX1IN
INTERNAL
TIMING
2dB~36dB
AVDD
DVDD
DVSS
AVSS
DRVDD
DRVSS
10
8
DIGITAL
INTERFACE
SDATASCKSL
CDS
VGA
BUF
2:1
MUX
CLP
AD9845B
CLP
ADC
COLOR
STEERING
HD VD
PxGA
6
BAND GAP
REFERENCE
VRT VRB
CLP
12
BLK CLAMP
LEVEL
CONTROL
REGISTERS
CLPOB
PBLK
4dB 6dB
GENERAL DESCRIPTION
The AD9845B is an improved version of the AD9845A CCD
signal processor. It features a 30 MHz single-channel architec-
ture designed to sample and condition the outputs of interlaced
and progressive scan area CCD arrays. The AD9845B’s signal
chain consists of an input clamp, a correlated double sampler
(CDS), PxGA, a digitally controlled VGA, a black level clamp,
and a 12-bit A/D converter. Additional input modes are also
provided for processing analog video signals.
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.
The AD9845B operates from a single 3 V power supply, typi-
cally dissipates 153 mW, and is packaged in a 48-lead LQFP.
