Abstract
This article discusses the limitations of passive filters as they pertain to tolerances of resistors, inductors, and capacitors and how these limitations are overcome in part by eliminating inductors from the active filters. Switched-capacitor filters, in comparison, improves active filters further in part because a metal-oxide semiconductor (MOS) integrated capacitor with a few switches can easily substitute resistors. The functionality of a switched capacitor as well as its primary applications including in active filter design are introduced. Implementation issues of switched capacitors in conjunction with complementary metal-oxide semiconductor (CMOS) technology such as parasitic capacitance are discussed. Possible solutions to help minimize these issues are also addressed. Switched filters are clocked, sampled-data systems where the input signal is sampled at a high rate and is processed on a discrete-time basis.