TC217_08 Datasheet, PDF (4/21 Pages) Texas Instruments – pixel ccd image sensor

TC217
ą
1158ĆĂ×Ă488ĆPIXEL CCD IMAGE SENSOR
ą
SOCS015C − OCTOBER 1989 − 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 TC217 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 1 and Figure 2 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. There are 23 full columns and one
half-column of elements at the right edge of the image-sensing area that 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 half-column of light-shielded elements at the left edge of the image-sensing area and
two 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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