Influence of circuit nonidealities on switched-capacitor resonators

Two different approaches exist to implement the resonators needed by a switched-capacitor (SC) bandpass modulator. Both methods use a negative feedback loop around two elements. In the first approach, these elements are SC integrators, and, in the other approach, they are implemented with SC delay cells. In this paper, the impact of nonideal circuit behavior, finite opamp gain, finite unity-gain bandwidth, and nonzero input capacitance, on the center frequency and quality factor of these resonators is analyzed and simulated when used at f_s/n.