TC217

1158-

× 488-PIXEL CCD IMAGE SENSOR

SOCS015C – OCTOBER 1989 – REVISED JUNE 1996

4

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

ABG†

2

I

Antiblooming gate

ABG†

20

I

Antiblooming gate

ADB

5

I

Supply voltage for amplifier drain bias

AMP GND

9

Amplifier ground

CDB

10

I

Supply voltage for clearing drain bias

IAG†

3

I

Image-area gate

IAG†

19

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

I

Serial-register gate 3

SUB†

1

Substrate and clock return

SUB†

11

Substrate and clock return

SUB†

12

Substrate and clock return

SUB†

22

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).