LM98501CCVBH National Semiconductor, LM98501CCVBH Datasheet - Page 13

• Manufacturer Part Number: LM98501CCVBH
• Description: IC CAMERA SIGNAL PROCESS 48-LQFP
• Manufacturer: National Semiconductor
• Type: Camera Interfacer

Specifications of LM98501CCVBH

• Applications: Digital Camera, Conferencing, Scanner
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LM98501CCVBH

Digital Output Timing
System Timing
System Overview
INTRODUCTION
The LM98501 is a 10-bit, complete analog-to-digital camera
signal processor for use with CCD imager systems operating
from a single +3V supply. The internal processing is carefully
optimized to maintain the signal-to-noise ratio and excellent
dynamic performance of most popular CCD imagers. The
system block diagram of the LM98501, shown on the cover
page of the datasheet, highlights the main features of the de-
vice: correlated double sampling (CDS), 0 dB–32 dB digitally
programmable gain amplifier (PGA), digital black level cor-
rection feedback loop, 8-bit DAC, analog clamp, bandgap
voltage reference, and a 10-bit, 27 MHz analog-to-digital
converter.
FIGURE 7. Digital Output Data Timing
FIGURE 8. System Timing
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CORRELATED DOUBLE SAMPLING
Correlated double sampling (CDS) is a key feature in CCD
image processors. The sampling process consists of two
samples being taken for each pixel. The first stores the reset
voltage of the input pixel, and the second stores the video
signal amplitude. The two samples are subtracted from one
another, effectively removing the reset error offset of each
pixel. This sampling system operates at 27 MHz, allowing
the use of imagers that have resolution at high speeds. Op-
eration at these higher clock rates generates electronic im-
ages similar to a high-speed camera, preventing blearing of
the image caused by motion during the exposure.
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