Constant-g sub(m) rail-to-rail CMOS op-amp input stage with overlapped transition regions

Conventional techniques to achieve a constant-g sub(m) rail-to-rail complementary N-P differential input stage require complex additional circuitry. In addition, the frequency response and common-mode rejection ratio (CMRR) are degraded. An economical but efficient design technique to overcome these...

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Bibliographic Details
Published in:IEEE journal of solid-state circuits 1999-02, Vol.34 (2), p.148-156
Main Authors: Wang, M, Mayhugh, T L, Embabi, Sh H K, Sanchez-Sinencio, E
Format: Article
Language:English
Subjects:
Circuits
CMOS
Degradation
Economics
Electric circuits
Frequency response
Rejection
Transconductance
Online Access:Get full text
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Summary:Conventional techniques to achieve a constant-g sub(m) rail-to-rail complementary N-P differential input stage require complex additional circuitry. In addition, the frequency response and common-mode rejection ratio (CMRR) are degraded. An economical but efficient design technique to overcome these problems is proposed. The proposed technique strategically overlaps the transition regions of the tail currents for the n- and p-pairs to achieve constant overall transconductance. Experimental results demonstrate that g sub(m) variation can be restricted to within plus or minus 4% with improved CMRR and frequency response.
ISSN:0018-9200
DOI:10.1109/4.743758