A compact subthreshold CMOS 2nd-order gm-C lowpass filter

This paper presents a compact transistorized lowpass filter circuit that employs global feedback to suppress the circuit's nonlinearity in the filter passband. The proposed circuit combines only 4 subthreshold-biased transistors in the filter core and 3 branches of current consumption. The proposed filter can be operated from a 1-V single supply. Circuit simulations using Cadence for 0.35-μm CMOS technology parameters are given. Comparison with relevant designs in the category of nanopower filter is also provided.