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Macromodeling of the A.C. Characteristics of CMOS Op-Amps

Mandal, Pradip and Visvanathan, V (1993) Macromodeling of the A.C. Characteristics of CMOS Op-Amps. In: 1993 IEEE/ACM International Conference on Computer-Aided Design, ICCAD-93. Digest of Technical Papers, 7-11 November, Santa Clara,California, 334 -340.


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An analytical-knowledge-based statistical method is developed to derive macromodels for the highly nonlinear AC response functions of CMOS op-amp circuits. Simple circuit analysis is used to motivate the use of logarithmic transformations. By this transformation, linear models are fitted over a large domain of the independent variables (typically, transistor widths) with very few circuit simulations. From circuit analysis it is deduced that poles and zeroes are appropriate for empirical modeling instead of directly modeling the response functions like unity gain frequency or phase margin. We have demonstrated the usefulness of the proposed method by using it to model the transfer function of a two-stage compensated CMOS op-amp circuit. The model is compared with SPICE3 simulations and shown to have excellent predictive capability, with a speed-up of more than 500.

Item Type: Conference Paper
Publisher: IEEE
Additional Information: Copyright 1990 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Department/Centre: Division of Interdisciplinary Sciences > Supercomputer Education & Research Centre
Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited: 22 Aug 2008
Last Modified: 19 Sep 2010 04:26
URI: http://eprints.iisc.ac.in/id/eprint/6741

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