A 2MHz-BW 96.8dB-SNDR 98dB-SNR CT-Zoom ADC With Residue Feedforward, Redundancy and Fully LMS-Based Calibration

This article describes a continuous-time (CT)-Zoom ADC utilizing a single-amplifier biquad (SAB)-based integrator to achieve fourth-order noise shaping, a residue feedforward (FF) path to mitigate both signal transfer function (STF) peaking and quantization noise leakage, as well as a fully LMS-based digital calibration to reduce R-DAC mismatch. Applying redundancy to the split R-DAC provides the ADC a large maximum stable amplitude (MSA) and robustness to RC variations. Fabricated in a 40nm CMOS, the ADC achieves 96. 8dB SNDR and 98dB SNR in a 2MHz bandwidth, and consumes 21.1mW at a 1. 2V supply. These results correspond to state-of-the-art $\mathrm{F}\mathrm{o}\mathrm{M}\mathrm{s}_{-}$SNDR of l76.6dB and $\mathrm{F}\mathrm{o}\mathrm{M}\mathrm{s}_{-}\mathrm{S}\mathrm{N}\mathrm{R}$ of l77.8dB.