A 4-μW Bandwidth/Power Scalable Delta-Sigma Modulator Based on Swing-Enhanced Floating Inverter Amplifiers

Abstract

This article presents a fully dynamic scalable switched-capacitor delta-sigma modulator that achieves a 94.1-dB dynamic range (DR). Power-and- bandwidth scalability by only changing the clock frequency is achieved using a capacitively biased and swing-enhanced floating inverter operational transconductance amplifier (OTA). Fabricated in a 180-nm CMOS process, the prototype achieves an signal-to-noise-and-distortion ratio (SNDR) of >87 dB across 4× scaling from 100 to 400 kHz of the sampling frequency f_ S. At 200-kHz f_ S , it achieves an SNDR/DR of 89.3/94.1 dB while consuming 4 μ W , leading to a DR-based Schreier figure of merit (FoM) of 177.1 dB.