Dissertation Defense

Advanced Noise-Shaping SAR ADC Techniques

Hsiang-Wen Chen
Hsiang-Wen Chen Defense Photo
Location: Lurie Engineering Center Building (LEC) 2210
   The noise-shaping (NS) SAR ADC has revolutionized analog-to-digital conversion by combining the efficiency of the SAR architecture with the resolution of the delta-sigma modulator (DSM). As a result, NS SARs deliver both record area efficiency and energy efficiency. This thesis focuses on techniques that advance NS-SAR performance.
   The first work presents a cascaded NS-SAR architecture that increases noise-shaping order to 4th and thus enables a high resolution with reduced hardware cost. The proposed architecture also includes a two-phase settling amplifier to improve the noise-power efficiency.
   The next work introduces a new hybrid architecture that utilizes a cascaded NS-SAR quantizer to boost the noise-shaping efficiency of a voltage-controlled oscillator (VCO)-based continuous-time (CT) DSM. The key innovation is an anti-aliasing filter (AAF) that bridges the VCO frontend with the NS-SAR quantizer, enabling the time-domain information to be directly sampled as voltage-domain information. The hybrid architecture provides a 3rd-order noise transfer function (NTF) while maintaining simple loop dynamics. Together with the newly-proposed DAC mismatch shaping technique, this work requires no calibration or coefficient tuning.
Chair: Michael P. Flynn