LOW DISTORTION FILTERS

摘要

An integrated continuous-time active-RC filter comprises a set of opamp integrators with Operational Transconductance Amplifiers (OTAs). The filter further includes at least one assistant connected between the input and output of each of the integrators of the set to enhance the linearity and speed of the opamp integrators of the set. The assistant comprises a plurality of sets of transconductors connected in parallel to each other wherein each set of transconductors is formed by a pair of MOSFETs connected in series, with one MOSFET operating in the triode region and the other MOSFET operating in the saturation region. The assistant is configured to provide an assistant current to be injected into the source of each of the integrators in the set to enhance the linearity and speed of the opamp integrators of the set.