TH7887A Datasheet, PDF (12/21 Pages) ATMEL Corporation – Area Array CCD Image Sensor 1024 x 1024 Pixels with Antiblooming

Exposure Time
Reduction
The TH7887A allows exposure time control (electronic shutter function).
The exposure time reduction is achieved by pulsing all the Φ Pi gates to 0V to continu-
ously remove all photogenerated electrons through antiblooming drain VA.
Figure 12. Timing Diagram for Electronic Shutter
Image period
ΦA
Φ P1
1 µs
1 µs
Φ P2
Φ P3
Φ P4
Transfer
Obturation
Fall times and rise times: see figures 7 & 8
Integration
Table 2. Drive Clock Characteristics
Parameter
Symbol
Min
Image zone clocks
ΦP1, 2, 3, 4
High level
8.5
Low level
0
Memory zone clocks
ΦM1, 2, 3, 4
High level
8.5
Low level
0
Memory to register clocks
ΦM
High level
8.5
Low level
0
Antiblooming gate
ΦA
High level (integration)
5.5
Low level (transfer)
0
Value
Typ
9
0.5
9
0.5
9
0.5
5.5
0.5
Max
9.5
0.8
9.5
0.8
9.5
0.8
5.5
0.8
Unit
Remarks
Typical input capacitance
V
15 nF
V
See Figure 13
Typical input capacitance
V
15.5 nF
V
See Figure 13
Typical input capacitance
V
10 nF
V
Typical input capacitance
V
14 nF
V
See Figure 13 and Figure 15
12 TH7887A
2146A–IMAGE–05/02