TC271 Datasheet, PDF (4/22 Pages) Texas Instruments – 1080 × 580-PIXEL CCD IMAGE SENSOR

TC271
1080 × 580-PIXEL CCD IMAGE SENSOR
SOCS039A – JANUARY 1994 – REVISED JUNE 1996
Terminal Functions
TERMINAL
NAME
NO.
ABG†
2
ABG†
20
I/O
DESCRIPTION
I
Antiblooming gate
I
Antiblooming gate
ADB
5
I
Supply voltage for amplifier-drain bias
AMP GND
9
Amplifier ground
CDB
10
IAG†
3
IAG†
19
I
Supply voltage for clearing-drain bias
I
Image-area gate
I
Image-area gate
OUT1
8
O Output signal 1
OUT2
7
O Output signal 2
OUT3
6
O Output signal 3
SAG1
4
I
Storage-area gate
SAG2
17
I
Storage-area gate
SRG1
14
I
Serial-register gate 1
SRG2
15
I
Serial-register gate 2
SRG3
16
SUB†
1
SUB†
11
SUB†
12
SUB†
22
I
Serial-register gate 3
Substrate and clock return
Substrate and clock return
Substrate and clock return
Substrate and clock return
TDB
21
I
Supply voltage for top-drain bias
TMG
18
I
Transfer-multiplex gate
TRG
13
I
Transfer gate
† _{All pins of the same name should be connected together externally (i.e., pin 2 to pin 20,}
pin 3 to pin 19, etc.).
detailed description
The TC271 consists of five basic functional blocks: (1) the image-sensing area, (2) the multiplexer block, (3)
the image-storage area with dual-field memories, (4) the serial-register and transfer gates, and (5) the low-noise
signal-processing amplifier block with charge-detection nodes. The location of each of these blocks is identified
in the functional block diagram.
image-sensing area
Figure 4 and Figure 5 show cross sections with potential-well diagrams and top views of image-sensing
elements. As light enters the silicon in the image-sensing area, free electrons are generated and collected in
the potential wells of the sensing elements. During this time, blooming protection is activated by applying a burst
of pulses to the antiblooming-gate inputs every horizontal-blanking interval. This prevents blooming caused by
the spilling of charge from overexposed elements into neighboring elements. Thirty-four full columns and one
half-column of elements at the right edge of the image-sensing area are shielded from incident light; these
elements provide the dark reference used in subsequent video-processing circuits to restore the video-black
level. There are also one full column and one half-column of light-shielded elements at the left edge of the
image-sensing area and four lines of light-shielded elements at the bottom of the image area immediately above
the multiplexer. The latter prevent charge leakage from the image area into the multiplexer.
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