Capacitors configured in a switched-
capacitor circuit on a
semiconductor device may comprise very accurately matched,
high capacitance density
metal-to-
metal capacitors, using top-plate-to-bottom-plate fringe-
capacitance for obtaining the desired
capacitance values. A polysilicon plate may be inserted below the bottom
metal layer as a shield, and bootstrapped to the top plate of each
capacitor in order to minimize and / or eliminate the parasitic top-plate-to-substrate
capacitance. This may free up the bottom metal layer to be used in forming additional fringe-capacitance, thereby increasing capacitance density. By forming each capacitance solely based on fringe-capacitance from the top plate to the bottom plate, no parallel-plate-capacitance is used, which may reduce
capacitor mismatch. Parasitic bottom plate capacitance to the substrate may also be eliminated, with only a small capacitance to the bootstrapped polysilicon plate remaining. The capacitors may be bootstrapped by
coupling the top plate of each capacitor to a respective one of the differential inputs of an
amplifier comprised in the switched-capacitor circuit.