KAI-4021 datasheet(49/56 Pages) ONSEMI

49 / 56 page

KAI-4021 Image Sensor

www.truesenseimaging.com

Revision 1.1 PS-0014 Pg 49

LARGE SIGNAL OUTPUT

When the image sensor is operated in the binned or summed interlaced modes there will be more than 20,000

electrons in the output signal. The image sensor is designed with a 31 µV/e charge to voltage conversion on the

output. This means a full signal of 20,000 electrons will produce a 640 mV change on the output amplifier. The output

amplifier was designed to handle an output swing of 640 mV at a pixel rate of 40 MHz. If 40,000 electron charge

packets are generated in the binned or summed interlaced modes then the output amplifier output will have to swing

1280 mV. The output amplifier does not have enough bandwidth (slew rate) to handle 1280 mV at 40 MHz. Hence, the

pixel rate will have to be reduced to 20 MHz if the full dynamic range of 40,000 electrons is desired.

The charge handling capacity of the output amplifier is also set by the reset clock voltage levels. The reset clock driver

circuit is very simple if an amplitude of 5 V is used. But the 5 V amplitude restricts the output amplifier charge capacity

to 20,000 electrons. If the full dynamic range of 40,000 electrons is desired then the reset clock amplitude will have to

be increased to 7 V.

If you only want a maximum signal of 20,000 electrons in binned or summed interlaced modes, then a 40 MHz pixel rate

with a 5 V reset clock may be used. The output of the amplifier will be unpredictable above 20,000 electrons so be

sure to set the maximum input signal level of your analog to digital converter to the equivalent of 20,000 electrons

(640 mV).

KAI-4021 датащи(PDF) 49 Page - ON Semiconductor