Noise analysis of switched-capacitor circuits

Switched-capacitor (SC) circuit has been a well known analog circuit block. Since their characteristics are determined by capacitance ratio, SC circuits are suitable for on-chip implementations. Eventhough there are so many publications on the design of SC circuits, only a few of them discuss the property of noise in SC circuits. Linear noise analysis are common in continuous-time systems. However, SC circuits are operating in discrete-time domain and their noise properties are known to be a non-linear phenomenon and dificult to be analyzed by hand. This paper will show a noise analysis of an SC integrator as an example for a better understanding of the analysis method. It will be shown by simulation results that the proposed formula gives a better approximation of noise power spectral density (PSD).