A 185 μW −105.1 dB THD 88.6 dB SNDR Negative-R Stabilized Audio Preamplifier

Abstract

This paper presents a low-power preamplifier for high fidelity audio codecs. It attains high linearity at low power by using a negative-R stabilized amplifier architecture that employs a negative-R assisted amplifier in a low-frequency path to cancel the non-idealities of a main amplifier. This shows the in-band noise attenuation of amplifiers and the drastic improvement of the linearity. Fabricated in a 65-nm CMOS process, the preamplifier achieves −105.1 dB THD, 88.6 dB SNDR, and 89.3 dB DR with 20 dB gain in 20 kHz bandwidth, while consuming only 185 μW from a 1.2 V supply. This results in the highest energy-efficiency FoMSNDR of 168.9 dB among audio preamplifiers.