Estimation of Aliasing Effects Due to Periodical Nonuniform Individual Sampling in High-Q Switched-Capacitor Filters

The periodical nonuniform individual sampling scheme has been shown suitable for capacitance spread and total capacitor area reduction in high quality (Q) factor switched-capacitor (SC) filters. However, the use of periodical nonuniform clock signals results in additional aliasing components in the output spectrum. This paper presents a simple model to analyze the generation of such alias components and gives practical expressions to estimate their power. The results are verified through circuit simulation of a 10.7-MHz second-order SC bandpass filter in a 0.35-mum CMOS technology. Implications on the use of this technique in the design of intermediate-frequency filters are discussed