TC341

780×488 PIXEL

CCD IMAGE SENSOR

SOCS083A – OCTOBER 2002

4

POST OFFICE BOX 655303

Terminal Functions

TERMINAL

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

CDB

10

I

Charge clearing drain bias

GND

1, 4, 7, 17,

18, 19, 22

Chip substrate (SUB)

IAG

3, 20

I

Image area gate

IDB

21

I

Input diode bias

NC

11, 12, 16

–

No connection

ODB

2

I

Charge overflow drain bias

RSG

13

I

Detection node reset gate

SAG

5, 6

I

Storage area gate

SRG

15

I

Serial register gate

TRG

14

I

Transfer gate

VDD

9

I

Amplifier drain bias

VOUT

8

O

Sensor output

detailed description

The TC341 sensor consists of four basic functional blocks: the image-sensing area, the image storage area,

the serial register, and the charge detection amplifier. The location of each of these blocks is identified in the

functional block diagram.

image sensing and storage areas

Figure 1 shows a cross-section with potential-well diagrams and Figure 2 shows a top view of pixels in the

image-sensing and storage areas. As light enters silicon in the image-sensing area, electrons are generated

and collected in potential wells of the pixels. Applying a suitable dc bias to the antiblooming drain provides

blooming protection. The amount of charge that exceeds a specified level, determined by the ODB bias, is

drained away from the pixels. If it is necessary to remove all previously accumulated charge from the wells, a

short positive pulse must be applied to the drain. This marks the beginning of the new integration period. After

the integration cycle is completed, charge is quickly transferred into the memory where it waits for readout. The

lines can be read out from the memory in a sequential order to implement progressive scan, or two lines can

be summed together in the serial register to implement a pseudo-interlace scan. The true interlace scan is

implemented by skipping odd or even lines, depending on the readout field, and dumping the unwanted charge

into the clearing drain that is located next to the serial register.

Twenty-six columns at the left edge of the image-sensing area are shielded from incident light. These pixels

provide the dark reference that is used in subsequent video-processing circuits to restore the video black level.

An additional four dark lines, located between the image-sensing area and the image storage area, were added

for isolation.