Title :
A 100-dB CMRR CMOS Operational Amplifier With Single-Supply Capability
Author :
Ivanov, Vadim ; Zhou, Junlin ; Filanovsky, Igor M.
Author_Institution :
Texas Instruments Inc, Tucson, AZ
fDate :
5/1/2007 12:00:00 AM
Abstract :
A CMOS operational amplifier that has a common-mode rejection ratio (CMRR), a power-supply rejection ratio (PSRR), and gain above 100 dB for each of these parameters is described. This is achieved by combining a high output-impedance tail current source with a stable drain-source voltage of the input transistors. The common-mode input signal range includes the negative rail. This is obtained by controlling the bulk bias of the input and cascoding transistors. The amplifier consists of two gain stages connected via cascoded current mirrors. The gain is improved by using gain boost in the current mirrors, and by the suppression of impact ionization current in the output stage
Keywords :
CMOS integrated circuits; impact ionisation; operational amplifiers; CMRR; PSRR; bulk bias control; common mode rejection ratio; gain boost; impact ionization control; operational amplifiers; power supply rejection ratio; CMOS technology; Circuits; Impact ionization; Mirrors; Operational amplifiers; Power amplifiers; Rails; Tail; Threshold voltage; Voltage control; Bulk bias control; common-mode rejection ratio (CMRR) and power-supply rejection ratio (PSRR) improvement; gain boost; impact ionization control; operational amplifiers (opamps);
Journal_Title :
Circuits and Systems II: Express Briefs, IEEE Transactions on
DOI :
10.1109/TCSII.2007.892403
