A second order discrete-time ΔA analog to digital converter for audio applications

Abstract

This paper aims to present the design of a second order discrete-time sigma delta analog to digital converter (ADC). This converter is intended for integration within an audio application, the input bandwidth being 25kHz. The article also provides details regarding the stability of second and third order modulators. The converter implemented in 180nm achieves a SNR of 87.25dB, for a 5V supply voltage, with a sampling rate of 12.8MHz and oversampling ratio (OSR) of 256, and consumes 3.81mW.