A 100kHz-BW 99dB-DR Continuous-Time Tracking-Zoom Incremental ADC with Residue-Gain Switching and Digital NC-FF

Abstract

This paper proposes a continuous-time (CT) tracking-zoom (TZ) incremental ADC (I - ADC) that reuses a quantizer for both the coarse SAR and fine DSM stages. The TZ I-ADC addresses the input bandwidth (BW) limitation issue with simple DAC code update. A residue-gain (RG) switching technique is proposed to mitigate the inconsistent signal transfer function (STF) in the fine CT incremental DSM (I-DSM). A digital noise-coupling-feedforward (DNC-FF) architecture is proposed to reduce the out-of-band gain (OBG). Fabricated in a 180nm CMOS process, the prototype consumes 2.52mW under a 1.8V supply, achieving 99-dB DR. 93.8-dB SNDR. and 102.5-dB SFDR.