ABSTRACT
The coefficients in a switched-capacitor (SC) filter are realized by ratios of capacitances. The accuracy of such ratios directly influences the locations of the filter poles and zeros. SC filter performance not only depends on the accuracy of the ratios of capacitors which determine the coefficients in the transfer function, but also on how well the op amps and switches in the filter are implemented. The coefficients in an SC filter are realized by ratios of capacitances. In CMOS technologies, a capacitor is usually implemented as two layers of conducting material sandwiching a thin layer of silicon dioxide which serves as high-quality dielectric. This chapter discusses circuit noise, power supply noise coupling, clock feedthrough, as well as circuit techniques which minimize those spurious signals. Switches in CMOS SC circuits are implemented with either single MOS transistors or pairs of NMOS–PMOS transistors. One of the basic limitations on achievable dynamic range in any electronic circuit is noise.
