TC281

1036-

× 1010-PIXEL CCD IMAGE SENSOR

SOCS058D – JUNE 1996 – REVISED MARCH 2003

6

POST OFFICE BOX 655303

IAG

~1

µs

Transfer The

First Line From

SA to AR

Transfer The

Second Line

Adding to The First

Each Additional Pulse

Bins One Additional Line

Serial Line Readout

SAG

TRG

SRG

RST

Figure 5. Special Modes of Operation: Binning

detailed description

The TC281 image sensor consists of five basic functional blocks:

image-sensing area

The image-sensing area contains 1036 x 1010 pixel elements. A metal light shield covers 28 pixels on the left

edge of the sensing area, 8 pixels on the right edge, and 10 rows at the bottom of the sensing area. The dark

pixel signal is used as a black reference during the video signal processing. The dark references accumulate

the dark current at the same rate as the active photosites, thus representing the true black level signal. As light

enters the active photosites in the image area, electron hole pairs are generated and the electrons are collected

in the potential wells of the pixels. The wells have a finite charge storage capacity determined by the pixel design.

When the generated number of electrons in the illuminated pixels exceeds this limit, the electrons can spill over

into neighboring pixels and cause blooming. To prevent this, each horizontal pair of pixels in the image sensing

area shares a lateral overflow drain structure which provides up to a 1000-to-1 protection against such

undesirable phenomena.

advanced lateral overflow drain

The advanced lateral overflow drain structure is shared by two neighboring pixels and provides several unique

features in the sensor. By varying the dc bias of the drain pin, the blooming protection level can be controlled

and traded for the well capacity.