Low-power CMOS switched-capacitor lowpass filter using current conveyors

Abstract

A new approach is proposed to the design of high-order switched-capacitor LPFs of megahertz cutoff frequency for communications channel selection. It essentially uses current conveyors instead of op amps to achieve low power consumption. A fifth-order Chebyshev LPF with a 1-MHz cutoff frequency is thus synthesized and fabricated in a 0.35-μm CMOS technology. The LPF consumes less than 10 mW from a 3-V power supply and exhibits a third harmonic distortion better than −54 dB in response to a 1-V sinusoidal input at the cutoff frequency. The rms noise voltage is at most 1.9 mV in a 2-MHz bandwidth.