A 0.5-V, 2-nW, 55-dB DR, fourth-order bandpass filter using single branch biquads: An efficient design for FoM enhancement

A compact nano-power fourth-order bandpass filter operating from a 0.5 V supply, with an adjustable center frequency ranging from 125 Hz to 16 kHz, is presented. The filter is constituted from cascadable second-order circuit cells that are realized by a network of three transistors and two capacitors comprising only one branch of bias current. The measurement results of the filter fabricated in a 0.18-μm CMOS IC process indicate that, for a 1 kHz center frequency, a dynamic range of 55 dB is obtained from 2 nW power consumption. These results lead to best figure of merit achieved when compared to other existing designs to date.