Effect of nonlinearity in the CMFB circuit that uses the differential-difference amplifier

Author

Zhang, Mo M. ; Hurst, Paul J.

Author_Institution

Dept. of Electr. & Comput. Eng., California Univ., Davis, CA

fYear

2006

fDate

21-24 May 2006

Lastpage

1393

Abstract

This paper considers one type of common-mode feedback (CMFB) circuit that uses two differential pairs to sense the common-mode output voltage (V_oc) of a fully differential op amp. Analysis of the circuit and simulation show that even powers of the differential-mode output voltage (V_oc) affect the common-mode control signal generated by the CMFB circuit. As a result, undesired tones appear in V _oc and V_oc due to transistor nonlinearity in the CMFB circuit. SPICE simulation results show that adding degeneration resistors to the differential pairs reduces the undesirable tones significantly

Keywords

differential amplifiers; feedback amplifiers; nonlinear network analysis; operational amplifiers; SPICE simulation; common-mode feedback circuit; degeneration resistors; differential operational amplifier; differential-difference amplifier; Analytical models; Circuit analysis; Circuit simulation; Differential amplifiers; Feedback circuits; Operational amplifiers; Output feedback; Power generation; Signal analysis; Voltage control;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2006. ISCAS 2006. Proceedings. 2006 IEEE International Symposium on

Conference_Location

Island of Kos

Print_ISBN

0-7803-9389-9

Type

conf

DOI

10.1109/ISCAS.2006.1692854

Filename

1692854