Design and tests of offset-compensated in-pixel amplifiers for CMOS pixel sensors

This paper presents novel in-pixel amplifiers for CMOS pixel sensors. Two kinds of offset-compensated amplifiers allow the sensors to achieve a high signal-to-noise ratio. Based on theoretical analysis, the gain of the input offset-compensated amplifier is less sensitive to threshold voltage variation than the output offset-compensated amplifier. A 12 μ m pitch CMOS pixel sensor with the input offset-compensated amplifier was therefore designed and fabricated in a 0.13 μ m CMOS technology. Measurements indicate that the implementation of this amplifier can result in a high signal-to-noise ratio for a CMOS pixel sensor.