OTA-Free 1-1 MASH ADC Using Fully Passive Noise-Shaping SAR VCO ADC Sanjeev Tan

Abstract

We present an OTA-free 1-1 multi-stage noise- shaping (MASH) analog-to-digital converter (ADC) utilizing a fully passive noise-shaping successive approximation register (NS-SAR) as the first stage and an open-loop ring voltage- controlled oscillator (VCO) as the second stage. The key con- tribution of this work is to address the challenge of driving large sampling capacitors for high-resolution NS-SAR. The proposed architecture allows a low-resolution NS-SAR stage and leverages residue attenuatio