A sigma-delta ADC design for audio applications

Abstract

An analog-to-digital converter (ADC) that uses delta-sigma modulation technique is less restricting to analog circuit specification, consumes less circuit power, and achieves higher resolution. This chapter presents an oversampling, second-order, fully differential design for a sigma-delta ADC, which is suited to audio applications. The modulator architecture is first designed using the behavioral simulator in MATLAB and then the TSMC 0.18 μm single-poly six-metal process. Using a sampling frequency of 6.4 MHz, an oversampling rate of 128 and an input amplitude of -3 dB of the full swing, a signal-to-noise ratio (SNR) of 92 dB is achieved using behavioral simulations and a ratio of 89 dB from the circuit simulations. This is equivalent to 15-bit resolution. © 2013 Springer Science+Business Media New York.