A4 -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 scalabil- ity 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 fS, it achieves an SNDR/DR of 89.3/94.1 dB while consuming 4 µW, leading to a DR-based Schreier figure of merit (FoM) of 177.1 dB.