A low noise wide dynamic range CMOS image sensor with low-noise transistors and 17b column-parallel ADC

An extremely low temporal noise and wide dynamic range CMOS image sensor is developed using low-noise transistors and high gray-scale resolution (17b) folding-integration/cyclic ADC. Two types of pixel are designed. One is a high conversion gain (HCG) pixel with removing the coupling capacitance between the transfer gate and the floating diffusion, and the other is a pixel for wide dynamic range (WDR) CMOS imager with the native transistor as a source follower amplifier. The CMOS image sensor which is in combination with the proposed pixels and the high performance column ADC has achieved a low pixel temporal noise of 1.1e^-_rms and a wide dynamic range of 87.5dB with the video rate operation (30Hz). In addition, the WDR pixel has a very small occurrence of the RTS noise because of the effect of the native transistor in the pixel. The implemented HCG CMOS imager and WDR CMOS imager using 0.18μm technology have the pixel conversion gain of 73.2-μV/e^- and 22.8-μV/e^-, respectively.