Abstract
Characteristics of a column-parallel Cyclic analog-to-converter (ADC) with 4bit fronted gain stage for low-noise wide dynamic range CMOS image sensors are investigated. The signal amplification and output range expansion are obtained by the 4bit fronted gain stage which consist of a switched capacitor (SC) amplifier, 4bit single slope ADC and 4bit digital-to-analog converter (DAC). The front-end gain stage has a function of folding, and high gain=16, a low-noise level while maintaining a wide dynamic range is realized. A prototype 1M-pixel CMOS image sensor is implemented with a 0.18-um 1P4M CMOS image sensor technology. The dynamic range and noise level are 74.2[dB] and 6[e^-], respectively.
