A Scaling Compatible, Synthesis Friendly VCO-based Delta-sigma ADC Design and Synthesis Methodology

Abstract

Conventional analog/mixed-signal (AMS) circuits design methodology relying heavily on the use of operational amplifiers (opamps) to process signals in voltage-domain (VD) encounters severe difficulties in advanced nanometer-scale CMOS process. We present a novel scaling compatible, synthesis friendly ring voltage-controlled oscillator (VCO) based time-domain (TD) delta-sigma analog-to-digital converter (ADC) whose performance improves as technology advances. Decomposed into digital gates (e.g. inverters) and a small set of simple customized cells (e.g. resistors), its layout is fully synthesizable by leveraging digital layout synthesis tools. Post-layout simulation results demonstrate the scaling compatibility of the proposed ADC and a drastic boost to design productivity.