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

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\times $
scaling from 100 to 400 kHz of the sampling frequency
$f_{\mathbf {S}}$
. At 200-kHz
$f_{\mathbf {S}}$
, it achieves an SNDR/DR of 89.3/94.1 dB while consuming
$4 \mu \text{W}$
, leading to a DR-based Schreier figure of merit (FoM) of 177.1 dB.