Design and Simulation of a Two Stages OPAMP Using Positive Feedback for Achieving to a High Unity Gain Bandwidth and a High DC Gain
Subject Areas : electrical and computer engineeringP. Moallem 1 , A. Shiri Sichani 2
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Keywords: Unity gain bandwidthDC gainpositive feedback,
Abstract :
The Fabrication of switch capacitor Filters and continuous time CMOS circuits, with a suitable unity gain bandwidth, a high DC gain and a high quality factor are a major challenge in integrated circuits design basically. This article is proposed a novel positive feedback topology for designing of OPAMP kernel and then a sample of OPAMP based on this method by tuning of the fabrication parameters is designed. The results of simulations which are done in frequency and time domain demonstrate that unity gain bandwidth of the designed OPAMP is greater than 1.4GHz and DC gain is greater than 108dB that in comparison with similar designs based on positive feedback can demonstrate there are plentiful increment in unity gain bandwidth and suitable increment in DC gain. The phase margin of the designed OPAMP is greater than 170 degree. Moreover, investigation of the proposed design outputs in time domain demonstrates the stability of the proposed OPAMP.
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