Second-order switched capacitor building block and its application to the design of silicon efficient filters

Two types of 2nd-order switched capacitor (SC) building block are developed to facilitate the design of silicon efficient SC filters. The derivation of their z-domain equivalent admittances, based on the principle of charge conservation, is given. A 2nd-order bandpass filter and a 3rd-order Chebyshev lowpass filter using such building blocks have been successfully implemented with discrete components. In addition to a reduced number of operational amplifiers (OA), a reduction in total capacitance and the number of switches is also achieved. Experimental results are in good agreement with theory