Modified CMOS Op-Amp with Improved Gain and Bandwidth(<Special Section>Analog Circuit and Device Technologies)

概要

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This paper presents a novel gain boosted and bandwidth enhanced CMOS Op-Amp based on the well-known folded cascode structure. In contrast with the conventional methods which increase output resistance for gain boosting, the transconductance of the circuit is increased, therefore the -3dB frequency is the same as for folded cascode structure. With negligible extra power consumption, the unity gain bandwidth is increased considerably. In this method, a new node is created in the circuit which introduces a pole to the transfer function with a frequency lower than cascode pole; feed-forward compensation is employed to reduce the effect of this pole on the frequency response. The input common mode range is limited slightly by 0.2-0.3V with respect to folded cascode which is insensible. HSPICE simulations using level 49 parameters (BSIM3v3) in a typical 0.35μm CMOS technology result in three times gain boosting and 60% enhancement in unity gain bandwidth compared to folded cascode, while the power consumption is increased by 10%.
社団法人電子情報通信学会の論文
2006-06-01