Correlated Double Sampler (CDS)

AD9823


Rev. 0
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FEATURES
40 MHz correlated double sampler (CDS)
Fixed 3.5 dB CDS gain
Low noise optical black clamp circuit
3 V single-supply operation
14-lead TSSOP package

APPLICATIONS
Digital still cameras
Digital video camcorders
CCTV cameras
PC cameras
Portable CCD imaging devices




FUNCTIONAL BLOCK DIAGRAM
04538-0-001
CLP
CCDIN
3.5dB FIXED GAIN
VDD
GND
OUTPUT
REFOUT
AD9823
CDS
INTERNAL
REFERENCE
BYP3BYP1
OUTPUT
BUFFER
OUTPUT
BUFFER
CLPBYP2
SHDSHP
INTERNAL
TIMING

Figure 1. Functional Block Diagram



PRODUCT DESCRIPTION
The AD9823 is a correlated double sampler for digital camera
applications. It features a 40 MHz CDS amplifier with 3.5 dB of
fixed gain, an internal voltage reference supply, and timing
control for the SHP and SHD sampling clocks. Output buffers
are also included, providing drive strength for PCB traces and
direct connection to an image signal processor such as the
AD9821.
The AD9823 is ideal for applications that need to place the CDS
and VGA/ADC circuits on separate PC boards. The “pseudo
differential” outputs of the AD9823 provide good signal
integrity when interfaced with the differential input AD9821.
The AD9823 operates from a single 3 V power supply, typically
dissipates 50 mW, and is packaged in a 14-lead TSSOP package.