'R-lens filter': An (RC)/sup n/ current-mode lowpass filter

摘要

A continuous-time (RC)/sup n/ lowpass filter is presented that can be fully integrated with cutoff frequency down to the 0.1 MHz range. The circuit is based on a cascade of new compact RC-cells that provides current amplification and filtering with minimum power dissipation (>15 /spl mu/W/pole) using a single supply voltage (2 V). The high value resistance of the RC-cell is obtained by means of a current conveyor feedback that de-magnifies the signal current flowing in a small physical resistor. The circuit is intrinsically low-noise due to a 'cooling effect' in the equivalent resistor.