Response of Correlated Double Sampling CMOS Imager Circuit to Random Telegraph Signal Noise

This paper presents analytical and experimental noise of a correlated double sampling (C.D.S) readout circuit used in CMOS active pixel image sensors. The work takes into account low frequency noise, mainly Random Telegraph Signal (R.T.S) noise, in modern MOS transistors with very small geometries. The impact of the source-follower transistor noise power spectral density through C.D.S is studied. The results allow the determination of the output r.m.s noise versus random telegraph signal noise characteristics. We shw that R.T.S noise of the source-follower is a major factor influencing the circuit output r.m.s. noise. Theoretical results are compared with experimental data.