A calibration-free 96.6-dB-SNDR non-bootstrapped 1.8-V 7.9-mW delta-sigma modulator with class-AB single-stage switched VMAs

Abstract

This paper presents a 96.6-dB-peak-SNDR and 50-kHz-bandwidth switched-capacitor delta-sigma modulator for ADC operating at 1.8 V and consuming 7.9 mW. This performance is achieved by the introduction of Class-AB single-stage switched variable-mirror amplifiers (VMAs) combined with an optimized architecture and a 5-phase switched-capacitor scheme. The resulting 1.8-mm2 delta-sigma modulator is integrated in a standard 0.18-μm 1P6M CMOS technology and reaches a Schreier figure of merit of 164.6 dB from experimental SNDR measurements without the need for any clock bootstrapping, analog calibration or digital compensation technique.