TC253SPD-B0 Datasheet, PDF (6/23 Pages) Texas Instruments – 680 x 500 PIXEL IMPACTRON CCD IMAGE SENSOR

TC253SPDĆB0
680 × 500 PIXEL IMPACTRON CCD IMAGE SENSOR
JULY 2003 − SOCS084
Polysilicon Gates
n − Buried Channel
p − Substrate
X
Ø
p+
Virtual Phase
ÎÎÎÎÎÎÎÎÎ
+++++++++++++++++++++++++
Pixel Cross Section
Integrated
Charge
IAG2/SAG2
IAG1/SAG1
Channel Potential
Figure 1. Image Area and Storage Area Pixel Cross Section With Potential Diagram
advanced lateral overflow drain
The advanced lateral overflow drain structure is shared by two neighboring pixels in each line. Varying the dc
bias of the antiblooming drain controls the blooming protection level and trades it for well capacity. Applying a
pulse to the drain, approximately 7 V above the nominal level for a minimum of 1 µs, removes all charge from
the pixels. This feature permits precise control of the integration time on a frame-by-frame basis. The
single-pulse clearing capability also reduces smear by eliminating accumulated charge in pixels before the start
of the integration period (single-sided smear). The application of a negative 0.5-V pulse to the antiblooming
drain during the parallel transfer is recommended. This pulse prevents the creation of undesirable artifacts
caused by the on-chip cross talk between the image area gate clock lines and the antiblooming drain bias lines.
serial register and charge multiplier
The serial register is used for transporting charge stored in the memory pixels to the output amplifier. However,
the TC253SPD-B0 device has a serial register with twice the standard length. The first half has a conventional
design that interfaces with the memory and the clearing drain as it would in any other CCD sensor (for example
the TC237 sensor). The second half, however, is unique and includes 400 charge-multiplication stages with a
number of dummy pixels that are needed to transport charge between the active register blocks and the output
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