An analysis and implementation of common mode feedback in high-speed fully differential op-amp

Author

Chen, Chen ; Ge, KangKang ; HE, Lenian

Author_Institution

Zhejiang Univ., Hangzhou

fYear

2007

fDate

22-25 Oct. 2007

Firstpage

631

Lastpage

634

Abstract

A systematic analysis on the common mode (CM) component in fully differential operational amplifier is presented. It is revealed that there are two distinct CM closed loops active in a differential op-amp. After a general analysis on the stability of those two CM loops, a novel common mode feedback (CMFB) is proposed for a high-speed fully differential op-amp with a bandwidth of 350 MHz. CMFB is used for each stage of the op-amp. The chip was designed and implemented by using CSMC 0.5 mum CMOS mixed signal process. The testing results indicate that the high-speed op-amp works well and the CM loops are stable.

Keywords

CMOS integrated circuits; differential amplifiers; feedback; mixed analogue-digital integrated circuits; network analysis; operational amplifiers; CSMC CMOS mixed signal process; common mode component; common mode feedback; fully differential operational amplifier; high-speed fully differential op-amp; systematic analysis; Bandwidth; CMOS process; Delta modulation; Differential amplifiers; Feedback circuits; Feedback loop; Negative feedback; Operational amplifiers; Stability analysis; Voltage;

fLanguage

English

Publisher

ieee

Conference_Titel

ASIC, 2007. ASICON '07. 7th International Conference on

Conference_Location

Guilin

Print_ISBN

978-1-4244-1132-0

Electronic_ISBN

978-1-4244-1132-0

Type

conf

DOI

10.1109/ICASIC.2007.4415710

Filename

4415710