PAS6311LT Specification

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PixArt Imaging Inc.

v1.5 2007/10/02

3.

Block Diagram & Function Description

3.1. Block Diagram

Figure 3.1 Shows the PAS6311LT sensor block diagram

The PAS6311LT is a 1/6” CMOS imaging sensor with 640 ( H ) x 480 ( V ) physical pixels. The

active region of sensor array is 648 ( H ) x 488 ( V ). The sensor array is cover with Bayer pattern color

filters and µ-lens. The first pixel location ( 0,0 ) is programmable in 2 direction ( X and Y ) and the

default value is at the left-down side of sensor array.

After a programmable exposure time, the image is sampled first with CDS ( Correlated Double

Sampling ) block to improve S/N ration and reduce fixed pattern noise.

Three analog gain stages are implemented before signal transferred by the 10-bits A/D converter.

The front gain stage ( FG ) can be programmed to fit the saturation level of sensor to the full-range input

of ADC. The programmable color gain stage ( CG ) is used to balance the luminance response difference

between B/G/R. The global gain stage ( GG ) is programmed to adapt the gain to the image luminance.

The fine gained signal will be digitized by the on-chip 10-bits A/D converter. After the image data

has been digitized, further alteration to the signal can be applied before the data is output.

3.2. Defect Compensation

The defect compensation block can detect the possible defective pixels and replace it with average output

of like-colored pixels on either side of defective pixel. It’s no limitation on the capability of defective

number. This function is also enabled or disabled by user.

3.3. Companding Curves

The companding function is used to simulate the gamma curve and do non-linear transformation before

outputting data. There are 8 curves selected by setting register Compand_Sel as shown in Figure 3.2 and

this function is also enabled or disabled by user.