A high-swing 2-V CMOS operational amplifier with replica-amp gain enhancement

Author

Yu, Paul C. ; Lee, Hae-Seung

Author_Institution

Massachusetts Inst. of Technol., Cambridge, MA, USA

Volume

28

Issue

12

fYear

1993

fDate

12/1/1993 12:00:00 AM

Firstpage

1265

Lastpage

1272

Abstract

A general gain-enhancement technique for operational amplifiers using a replica amplifier is described. Unlike conventional techniques such as cascoding, which increases the gain by increasing the output resistance, the replica-amp technique increase the gain by matching the main and the replica amps. Among the advantages of the replica-amp technique are low supply, high swing, and effectiveness with resistive loads. This technique has been demonstrated in a 1.2-μm CMOS two-stage op amp. Operating from ±1-V supplies, the op amp has an effective open-loop dc gain of greater than 10 000, while maintaining a high swing of 100 mV from either supply rails. The gain-enhancement circuit is shown to have only a small effect on the settling time experimentally, analytically, and in SPICE simulation

Keywords

CMOS integrated circuits; feedback; linear integrated circuits; operational amplifiers; replica techniques; 100 mV; 2 V; CMOS operational amplifier; CMOS two-stage op amp; SPICE simulation; effective open-loop dc gain; gain-enhancement circuit; gain-enhancement technique; high swing; high-swing; low supply; replica-amp gain enhancement; resistive loads; settling time; supply rails; Analog circuits; Analytical models; Circuit simulation; Feedback circuits; Low voltage; Operational amplifiers; Out of order; Rails; SPICE; Signal to noise ratio;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.261993

Filename

261993