LUPA-1300 Datasheet, PDF (45/48 Pages) Cypress Semiconductor – 1.3 M Pixel High Speed CMOS Image Sensor

LUPA-1300
Datasheet
8 Application notes & FAQ
Q: Can the LUPA-1300 directly drive an ADC?
A: Yes, coupling the LUPA-1300 to a set of 16 ADC’s close to the chip is the
preferred way of operation. A suitable ADC must have thus
• Input range equal or larger than the 1.2 V- 0 V sensor signal swing
• In view of the LUPA-1300’s S/N 10 bits are suitable. 11 or 12 bits may be
considered too.
• Input capacitance 20 pF or lower (high output loads will limit the speed). And
no significant resistive loading.
• Sampling frequency 40 MHz (or the application specific sample rate)
• The ADC’s input bandwidth must be sufficiently higher than the sampling
frequency, in order to avoid RC contamination between successive pixels.
Q: How does the dual slope extended dynamic range mode works?
A:
Reset pulse
Read out
Double slope reset pulse
Total integration time
Reset level 1
p1
Reset level 2
p2
p3
p4
Saturation level
Double slope reset time (usually 5-10% of the total
integration time)
Figure 25: Dual slope diagram
The green lines are the analog signal on the photodiode, which decrease as a result of
exposure. The slope is determined by the amount of light at each pixel (the more light
the steeper the slope). When the pixels reach the saturation level the analog signal
will not change despite further exposure. As you can see without any double slope
pulse pixels p3 and p4 will reach saturation before the sample moment of the analog
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Contact [e-mail] Document # : 38-05711 Rev.**( Revision 3.1) Page 45 of 48