Elimination of parasitic capacitances in switched-capacitor circuits by circuit transformations

A general method is presented which allows one to eliminate all parasitic capacitances to ground in a switched-capacitor circuit. The circuit transformation is generated by transformations on the nodal admittance matrix which leaves the transfer function invariant. In almost all cases the minimal number of operational amplifiers required for stray capacitance insensitive circuits is obtained. A few examples illustrate the method and for one of them a sensitivity comparison between the original and the transformed switched-capacitor circuit is carried out.