Design considerations for common-mode feedback circuits in fully-differential operational transconductance amplifiers with tuning

Author

Wu, Pan ; Schaumann, Rolf ; Latham, Paul

Author_Institution

Dept. of Electr. & Comput. Eng., Portland State Univ., OR, USA

fYear

1991

fDate

11-14 Jun 1991

Firstpage

1363

Abstract

Power consumption, chip area, feedback loop gain, parasitic capacitance and nonlinearity of three popular common-mode feedback (CMF) circuits used in operational amplifiers are analyzed and compared. One of them is chosen as a candidate for CMF in fully differential operational transconductance amplifiers (OTAs). Three improved versions of this circuit that can be used in an OTA without leading to DC offset caused by the always unavoidable tuning are proposed. Simulation results show that the improved circuits reduce the DC offset from 0.6 V to nearly zero for the whole tuning range

Keywords

active networks; feedback; operational amplifiers; tuning; DC offset; chip area; common-mode feedback circuits; feedback loop gain; fully-differential operational transconductance amplifiers; nonlinearity; parasitic capacitance; tuning; Circuit optimization; Circuit simulation; Differential amplifiers; Energy consumption; Feedback circuits; Feedback loop; Operational amplifiers; Parasitic capacitance; Power amplifiers; Transconductance;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 1991., IEEE International Sympoisum on

Print_ISBN

0-7803-0050-5

Type

conf

DOI

10.1109/ISCAS.1991.176624

Filename

176624