0.5-V bulk-driven differential amplifier

A new 0.5-V fully differential amplifier is proposed in this article. The structure incorporates a differential bulk-driven voltage follower with conventional gate-driven amplification stages. The bulk-driven voltage follower presents differential gain equal to unity while suppressing the input common-mode voltage. The amplifier operates at a supply voltage of less than 0.5 V, performing input transconductance almost equal to a gate transconductance and relatively high voltage gain without the need for gain boosting. The circuit was designed and simulated using a standard 0.18-mu m CMOS n-well process. The low-frequency gain of the amplifier was 56dB, the unity gain bandwidth was approximately 3.2MHz, the spot noise was 100nV/Hz at 100kHz and the current consumption was 90 . Copyright (c) 2012 John Wiley & Sons, Ltd.