A 1.5-V, 300-nW, continuous-time allpass filter With 67 dB dynamic range

Abstract

A compact 1st-order analog allpass filter operating from a 1.5 V DC supply is presented. The proposed circuit is formed by a handful of subthreshold pMOS transistors, two capacitors and one current source. Verified by circuit simulations using RF Spectre and the AMS 0.35-micron CMOS parameters, the proposed filter consumes 300 nW quiescent power and contributes output noise voltage of 0.03 mVrms while providing a 90-degree phase-shift frequency of 22 kHz. The differential input signal voltage swing and dynamic range are 0.1 Vp and 67.7 dB, respectively.