Audio Pre-Amplifiers for Digital Electret Microphones in 0.18um CMOS Process

摘要

This paper presents CMOS audio pre-amplifiers with integrated voltage regulators for digital electret microphones. Several techniques for achieving high input impedance and proper input bias, as well as methods for implementing very low-frequency integrated high-pass filtering are presented. The amplifier with integrated high-pass filter has 14.8 dB of specified voltage gain, 200 muA of current consumption from 2.4 V-3.6 V supply, 60 dB of total harmonic distortion, and 72.8 dB signal to noise ratio at 1 Vpps and 1 kHz output.