An integrated low-voltage class AB CMOS OTA

Author

Harjani, Ramesh ; Heineke, Randy ; Wang, Feng

Author_Institution

Dept. of Electr. Eng., Minnesota Univ., Minneapolis, MN, USA

Volume

34

Issue

2

fYear

1999

fDate

2/1/1999 12:00:00 AM

Firstpage

134

Lastpage

142

Abstract

We present a new circuit topology for a low-voltage class AB amplifier. The circuit shows superior current efficiency in the use of the supply current to charge and discharge the output load. It uses negative feedback rather than component matching to optimize current efficiency and performance, resulting in a current boost ratio exactly equal to one. Measurement results for an example circuit fabricated in a 2-μm CMOS process are given. The circuit uses a quiescent supply current of 0.2 μA and is able to settle to a 1% error in 1.1 ms for a 0.4-V input step and a load capacitance of 35 pF. The circuit design is straightforward and modular, and the core circuit can be used to replace the differential pair of other op-amp topologies

Keywords

CMOS analogue integrated circuits; feedback amplifiers; low-power electronics; operational amplifiers; 0.2 muA; 2 micron; CMOS OTA; circuit topology; current boost ratio; current efficiency; current utilization; integrated low-voltage class AB amplifier; negative feedback; op amp design; CMOS process; Circuit synthesis; Circuit topology; Current supplies; MOS devices; Negative feedback; Operational amplifiers; Tail; Transconductance; Voltage;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.743753

Filename

743753