TC281 Datasheet, PDF (6/18 Pages) Texas Instruments – 1036- × 1010-pixel ccd image sensor

TC281
1036- × 1010-PIXEL CCD IMAGE SENSOR
SOCS058B – JUNE 1996 – REVISED MAY 1999
Transfer The
First Line From
SA to AR
Transfer The
Second Line
Adding to The First
IAG
SAG
~1µs
Each Additional Pulse
Bins One Additional Line
TRG
SRG
RST
Serial Line Readout
Figure 5. Special Modes of Operation: Binning
detailed description
The TC281 image sensor consists of five basic functional blocks: 1) the image-sensing area, 2) the advanced
lateral overflow drain (ALOD), 3) the storage area, 4) the serial register, and 5) the bulk charge detection (BCD)
node with the buffer output amplifier.
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 can be used as a black reference during the video signal processing. The dark references will
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 could spill over into neighboring pixels and cause blooming. To prevent this problem, 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 phenomenon.
advanced lateral overflow drain
The advanced lateral overflow drain structure is shared by two neighboring pixels and provides several unique
features thus available in the sensor. By varying the dc bias of the drain pin, it is possible to control the blooming
protection level and trade it for the well capacity.
Applying a 10-V pulse for a minimum duration of 1 us above the nominal dc bias level causes charge in the image
area to be completely cleared. This feature permits a precise control of the integration time on a frame-by-frame
basis. The single-pulse clear capability also reduces smear by eliminating accumulated charge from the pixels
before the start of the integration (single sided smear).
6
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265