A linear-logarithmic CMOS sensor with offset calibration using an injected charge signal

A combined linear and logarithmic image sensor is implemented in a 0.35 /spl mu/m 1P3M technology. The pixel is 7.5/spl times/7.5 /spl mu/m/sup 2/ with a 37% fill factor and contains only 4 transistors. Offset calibration in the logarithmic region is realized by using electrical charge injection into the photodiode. The sensor achieves 120 dB DR and the offset calibration reduces the FPN from 13 mV to 5 mV.