Title :
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
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;
Conference_Titel :
Circuits and Systems, 1991., IEEE International Sympoisum on
Print_ISBN :
0-7803-0050-5
DOI :
10.1109/ISCAS.1991.176624
