Gain improvement in operational transconductance amplifiers using Graded-Channel SOI nMOSFETS

This paper studies the performance of operational transconductance amplifiers (OTAs) fabricated with Graded-Channel (GC) Sol nMOSFETs and designed to provide high open-loop voltage gain or high gain-bandwidth characteristics. Different design targets were taken in account such as similar power dissipation, transconductance over drain current ratio and die area. Comparisons with OTAs made with conventional Sol nMOSFETs., are performed showing that the GC OTAs presents larger open-loop voltage gain without degrading the phase margin, unit gain frequency and slew rate simultaneously with a significant required die area reduction depending on L-LD/L ratio used. Circuit simulations and experimental results are used to qualify the analysis. (c) 2005 Elsevier Ltd. All rights reserved.

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