Exact analysis and sensitivity of nonideal switched capacitor networks through op amp asymptotic modelling

Abstract

A computer-oriented method for exact frequency-domain analysis of nonideal switched-capacitor (SC) networks is presented. It is based on the utilization of an SC macromodel for the operational amplifiers (op amps) when its own clock frequency tends to infinitum. This method extends the capability of a similarly based one previously developed by the authors. Its application allows the z-domain transfer functions, the complete frequency spectrum, and response sensitivities to element changes to be obtained in a quite inexpensive way. It basically consists of closed-form manipulations over a reduced set of matrices derived by means of an adaptation of the two-graph modified nodal approach. Therefore, no additional matrices need to be obtained. Also, the need for explicit numerical integration in each phase is eliminated because it is included in the procedure. This technique not only reduces the computational cost of spectral analysis of SC networks, but also makes exact sensitivity calculation very easy when compared with previously published works