Los Angeles, CA
March 31, 2009 to April 2, 2009
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/CSIE.2009.173
A Constant-gm CMOS Operational amplifier with Rail-to-Rail input common-mode voltage range has been designed. The input stage is based on two pairs of single p-channel differential pairs and two identical n-channel source followers as DC level shifters, which realizes rail-to-rail input swing. To attain a constant-gm over the whole common-mode input range, the compensation circuit which is based on processing signal currents has also been designed. The technique is universal in that the constant-gm can be obtained independent of I-V characteristic and is compatible with deep submicron CMOS devices. Using BSIM3v3 model of a standard 0.6µm CMOS process, simulation result shows that the input /output swing of the op amp circuit is rail-to-rail. The op-amp achieves open-loop gain of 113.57dB, unity–gain bandwidth of 11.9MHz and phase margin of 53°.
Rail-to-Rail, class-AB, unity
Zhao Wu, Fu Rui, Zhang Zhi-Yong, Cheng Wei-Dong, "Design of a Rail-to-Rail Constant-gm CMOS Operational Amplifier", CSIE, 2009, 2009 WRI World Congress on Computer Science and Information Engineering, CSIE, 2009 WRI World Congress on Computer Science and Information Engineering, CSIE 2009, pp. 198-201, doi:10.1109/CSIE.2009.173