Low Distortion Analog Front-End for Digital Electret Microphone

Abstract:

This paper presents a low distortion analog front-end (AFE) circuit to process electret microphone output signal. A source follower is employed for the input buffer to interface electret microphone directly to the IC with level shifting. A single-ended to differential converter with output common-mode control is presented to compensate the common-mode variation resulted from gate to source voltage variation in the source follower. A replica stage is adopted to control the output bias voltage of the single-ended to differential converter. The prototype AFE circuit fabricated in a 0.35μm CMOS technology achieves 68.2dB peak SNDR and 79.9dB SFDR over an audio signal bandwidth of 20kHz with 2.5V supply while consuming 1.05mW.

• Periodical: Applied Mechanics and Materials (Volumes 475-476)
• Pages: 1633-1637
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.475-476.1633
• Online since: December 2013
• Authors: Seung Yong Bae*, Jong Do Lee, Eun Ju Choe, Gil Cho Ahn
• Keywords: Analog Front-End, Electret Microphone, High Input Impedance, Single-Ended to Differential Converter

References

[1] K. -P. Walder et al: A Low Power, Wide Dynamic Range Multigain Signal Processor for the SNAP CCD, IEEE Transactions on nuclear science, Vol. 51, no. 5, pp.1936-1941, Oct. (2004).

DOI: 10.1109/tns.2004.834717