Hybrid Cascode Compensation for Two-Stage CMOS Opamps

Mohammad YAVARI

IEICE TRANSACTIONS on Electronics   Vol.E88-C    No.6    pp.1161-1165
Publication Date: 2005/06/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.6.1161
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit and Device Technologies)
Category: Building Block
operational transconductance amplifiers,  cascode compensation,  switched-capacitor circuits,  

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This paper presents the analysis of hybrid cascode compensation scheme, merged Ahuja and improved Ahuja style compensation methods, which is used in two-stage CMOS operational transconductance amplifiers (OTAs). The open loop signal transfer function is derived to allow the accurate estimation of the poles and zeros. This analytical approach shows that the non-dominant poles and zeros of the hybrid cascode compensation are about 40 percent greater than those of the conventional cascode compensation. Circuit level simulation results are provided to show the accuracy of the calculated expressions and also the usefulness of the proposed cascode compensation technique.