Integrated continuous-time balanced filters for 16-b DSP interfaces

Abstract

A fully integrated, low-distortion, balanced, continuous-time filter fabricated in 5-V, 1.6- mu m CMOS is presented. Active RC structures are used in a leapfrog topology, with time constants set by integrated passive resistors and capacitors. Accurate tuning is achieved by selection of capacitor elements under the control of a new calibrator circuit. With a 2-V/sub rms/ differential input and output, the filter achieves -94-dB THD (total harmonic distortion) and 95-dB signal-to-noise ratio. Tuning accuracy is maintained to within +or-5% of nominal over the commercial temperature range.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>