A 1.2-V 108.9-dB A-Weighted DR 101.4-dB SNDR Audio $\Sigma\Delta$ ADC Using a Multi-Rate Noise-Shaping Quantizer

Abstract

Along with the trend to reduce the power consumption of mobile devices, interface circuits such as analog-to-digital converters (ADCs) should also be designed to operate reliably at low supply voltages without compromising production yield. We present a high-fidelity audio ${\Sigma \Delta }$ ADC suitable for low-voltage mobile applications, based on a new multi-bit quantizer. Its effective resolution is increased economically by augmenting an internal low-resolution quantizer with the proposed multi-rate noise-shaping technique. Fabricated in a 0.13- ${ \mu }\textbf {m}$ CMOS technology, our ADC uses 3.5 mW at 1.2 V, and achieved an A-weighted DR of 108.9 dB and a peak signal-to-noise and distortion ratio of 101.4 dB.