CMOS图像传感器中RSD A/D转换器的设计与实现

Design and realization of RSD A/D converter in CMOS image sensors

提出了CMOS图像传感器中RSD A/D转换器的设计方法。基于冗余符号数(RSD)算法,RSD A/D转换器降低了对比较器的性能要求。并且全差分的模拟信号处理用以改进抗噪声度,信噪比和系统的动态范围。RSD A/D转换器是基于90 nm CMOS工艺实现的,测试结果表明它的微分非线性误差(DNL)为±1 LSB,积分非线性误差(INL)为±1.5 LSB,总的未调整误差(TUE)为-3 LSB^1 LSB,功耗约为20 mW。

A cyclic redundant singed digit（RSD） analog to digital converter（ADC） in CMOS image sensor is presented. Based on RSD principle, RSD A/D converter reduces the requirements of comparators. Fully differential analog signal handling greatly-improves noise rejection, signal-noise-ratio（SNR） and dynamic range of the system. This ADC is fabricated in the standard 90 nm CMOS technology and achieres some good characteristics such as low power high resolution,high speed and small silicon area, The measured DNL is less than± 1 LSB,and the measured INL is less than ± 1.5 LSB. Total unadjusted error is -3 LSB-1 LSB. Power consumption is 20 mW at 5 V power supply.