An enhanced fully differential folded-cascode op amp

Author

Nakamura, Katsufumi ; Carley, L. Richard

Author_Institution

Dept. of Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA

Volume

27

Issue

4

fYear

1992

fDate

4/1/1992 12:00:00 AM

Firstpage

563

Lastpage

568

Abstract

An enhanced fully differential folded-cascode operational-amplifier topology that achieves improved DC gain and common-mode rejection without sacrificing slew rate is presented. The large-signal operation of the new topology is completely symmetric, providing equal positive and negative slew-rate behavior by making use of current mirrors rather than current sources as normally found in full differential folded-cascode op-amps. An additional advantage of the enhanced topology is that its common-mode output impedance is a factor of g_mr_o (typically 1-2 orders of magnitude) lower than the differential-mode output impedance, significantly improving the common-mode rejection ratio. The predicted performance is verified by simulations and preliminary experimental results

Keywords

CMOS integrated circuits; DC amplifiers; differential amplifiers; network topology; operational amplifiers; CMOS; CMRR; DC gain; common-mode output impedance; common-mode rejection ratio; current mirrors; differential amplifiers; differential-mode output impedance; experimental results; folded-cascode op amp; large-signal operation; operational-amplifier; performance; simulations; slew rate; Analog integrated circuits; Circuit topology; Impedance; Inverters; MOSFETs; Mirrors; Operational amplifiers; Predictive models; Voltage;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.126544

Filename

126544