LUPA-1300 Datasheet, PDF (14/48 Pages) Cypress Semiconductor – 1.3 M Pixel High Speed CMOS Image Sensor

LUPA-1300
Datasheet
3.1 Pixel architecture
The active pixels allow synchronous shutter “i.e. all pixels are illuminated during the
same integration time, starting from the same moment in time. After a certain
integration time, the pixels are readout sequentially. Readout and integration are in
parallel, which means that when the image sensor is readout, the integration time for
the next frame is ongoing. This feature requires a memory element inside the pixel,
which affects the maximum fill factor. A schematic representation of the pixel is
given in figure 4.
Vpix
reset
Row
sample
select
precharge Mem
Figure 4: schematic representation of the synchronous pixel as used in the LUPA
design
The signals mentioned in figure 4 are the internal signals, generated by the internal
drivers, required to have the synchronous shutter feature.
The photodiode is designed to obtain sensitivity as high as possible for a dynamic
range of at least 60dB. Consequently the photodiode capacitance is 10fF @ the
output, resulting in a S/N of more than 60dB as the rms noise level is within the
expectation of 45 noise electrons. The pixel was specially designed to have a very low
parasitic light sensitivity (<0.5%). The pixels are based on the high-fill factor active
pixel sensor technology of FillFactory (US patent No. 6,225,670 and others)).
Cypress Semiconductor Corporation 3901 North First Street
San Jose, CA 95134 408-943-2600
Contact [e-mail] Document # : 38-05711 Rev.**( Revision 3.1) Page 14 of 48