A 94.1 dB DR 4.1 nW/Hz Bandwidth/Power Scalable DTDSM for IoT Sensing Applications Based on Swing-Enhanced Floating Inverter Amplifiers
Yibo Zhao, Huajun Zhang, Yaopeng Hu, Yuanxin Bao, Le Ye, Wanyuan Qu, Menglian Zhao, Zhichao Tan
Abstract
IoT sensing applications operating from batteries or harvested energy require microwatt data converters. To accurately measure small signals, they often need to achieve a high DR (>90dB) and better linearity than the transducers themselves (>14b) with a BW in the kHz range. IoT systems also often consist of multiple sensing modalities with different BW requirements and are often heavily duty-cycled to reduce power consumption. This paper presents a fully dynamic discrete-time delta-sigma modulator (DTDSM) that supports 4x bandwidth/power scaling without any programming overhead except for changing f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> , using a capacitively biased swing-enhanced floating inverter amplifier (SEFIA). The prototype, fabricated in 180nm CMOS, consumes only 4μW at 800Hz BW and achieves >87dB SNDR over 2 octaves of f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> , between 100 kHz and 400 kHz, and a DR of 94.1 dB while operating with an OSR of 125.