Correlated Double Sampling with Adjustable Interval for Low Noise Hyperspectral Infrared Focal Plane Readout Circuits

Abstract

Low noise is a key requirement of Readout Integrated Circuits (ROIC) in hyperspectral applications for its low radiation. Correlated Double Sampling (CDS) is commonly used to suppress noise. In this paper, CDS is improved by adjusting the time interval between the clamp and sample-and-hold (SH), which can filter low-frequency noise flexibly. An ROIC input stage integrated with low-noise capacitive trans-impedance amplifiers (CTIA) and CDS with adjustable interval (AICDS) is designed in 180 n m CMOS process. A timing generator is proposed to vary the interval regulation amount from 0 μs to 15 μs . The SPECTRE simulation indicates that, by decreasing this time interval, the noise electrons are significantly decreased from 48.72 e - to 22.15 e - , and SNR is enhanced by 5 dB (20 pA injection current). The design of AICDS can improve the noise performance of hyperspectral ROIC, thus can be widely used.