1 V fully balanced differential amplifiers: Implementation and experimental results

Abstract

We report a novel low voltage fully differential class AB operational amplifier and a fully balanced preamplifier, which are based on Dynamic Threshold voltage MOSFET (DTMOS) transistors. Pseudo P type DTMOS transistors are used to enhance the differential input common-mode range. The proposed circuits were fabricated using standard CMOS 0.18 μm CMOS process technology. The fully differential class AB amplifier is implemented to enhance the noise performance of low voltage high precision switched capacitor circuits, the fully balanced preamplifier is implemented to drive the differential inputs of the analog to digital converter used in the analog front-end of a near-infrared spectroreflectometry (NIRS) receiver of a multi-wavelength wireless brain oxymeter apparatus. The power consumption of the proposed preamplifier is only 80 μW. The minimum experimental supply voltage is roughly 0.8 V.