Published in Proceedings of the 39th IEEE Midwest Symposium on Circuits and Systems: Ames, IA, Volume 2, August 18, 1996, pages 957-960.
NOTE: At the time of publication, the author Vladimir Prodanov was not yet affiliated with Cal Poly.
The definitive version is available at http://dx.doi.org/10.1109/MWSCAS.1996.588120.
A CMOS op-amp input and gain stage suitable for low voltage operation are introduced. The input stage operates in strong inversion and has common-mode range beyond rail-to-rail. It uses two complementary differential pairs connected in parallel. The common-mode dependent current biasing employs only four transistors, does not require additional voltage references, current switches and/or current mirrors and does not increase the minimum required supply voltage. The variation of the net transconductance is approximately 15% over the entire common-mode range. The gain-stage has constant output resistance. In addition it reduces the variation of the net transconductance due to variations in μn/μp ratio.
Electrical and Computer Engineering
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