A 1.6V ΔΣ ADC for digital electret microphone

Abstract

A switched-capacitor delta-sigma analog-to-digital converter (ADC) including preamplifier and bandgap reference for digital electret microphone is presented. It uses quantization noise coupling to achieve third-order noise shaping with only two integrators. The prototype ADC is fabricated in a 0.18μm CMOS process. The single-loop, 1-bit, third-order delta-sigma ADC operates at OSR of 64 provides 70.8dB dynamic range (DR) and 65.7dB peak signal-to-noise ratio (SNR) over a signal bandwidth of 20kHz with 1.6V supply while consuming 1mW power including preamplifier and on-chip reference.