0.28-nW level-shifter folded flipped source follower fourth-order low-pass-filter IC design

Abstract

ABSTRACT Low-pass-filter (LPF) is strictly required to process signal in battery-operated wearable healthcare systems. However, in these battery-operated systems improving signal quality and power efficiency of LPF is a challenging task. This manuscript presents a 4th-order LPF architecture based on level-shifter and folded flipped source follower (LSFFSF) techniques which consumes power of 0.28 nW. The LSFFSF LPF is simulated in Cadence Virtuoso 180 nm technology using BSIM3V3 MOS model and is capable of delivering gain of −0.27 dB, cut-off frequency of 99.91 Hz, input referred noise of 79.9 μVrms, dynamic range (DR) of 50.47 dB, total harmonic distortion (THD) of −50.06 dB at 80.31 Hz. The figure of merit (FOM) of LSFFSF LPF is 2.11 × 10−15 J with area consumption of 0.021 mm2. Additionally, the statistical process and mismatch analysis values for gain, THD and DR with 400 iterations show coefficient of variation of 1.92, 0.21 and 0.013, respectively. Comparison of the proposed LSFFSF LPF with other LPF architectures establishes its potential advantage in terms of low-power consumption, enhanced THD, DR and least FOM. The LPF architecture presented in this work is suitable candidate for wearable EEG healthcare applications.