Title :
Constant-gm rail-to-rail CMOS op-amp input stage with overlapped transition regions
Author :
Wang, Minsheng ; Mayhugh, Terry L., Jr. ; Embabi, Sherif H K ; Sánchez-Sinencio, Edgar
Author_Institution :
Dept. of Electr. Eng., Texas A&M Univ., College Station, TX, USA
fDate :
2/1/1999 12:00:00 AM
Abstract :
Conventional techniques to achieve a constant-gm rail-to-rail complementary N-P differential input stage require complex additional circuitry. In addition, the frequency response and common-mode rejection ratio (CMRR) are degraded. An economical but efficient design technique to overcome these problems is proposed. The proposed technique strategically overlaps the transition regions of the tail currents for the n- and p-pairs to achieve constant overall transconductance. Experimental results demonstrate that gm variation can be restricted to within ±4% with improved CMRR and frequency response
Keywords :
CMOS analogue integrated circuits; operational amplifiers; CMOS opamp; circuit design; common mode rejection ratio; complementary N-P differential pair; constant-transconductance rail-to-rail input stage; frequency response; overlapped transition regions; Circuits; Degradation; Frequency response; Mirrors; Operational amplifiers; Rail to rail inputs; Signal processing; Tail; Transconductance; Voltage;
Journal_Title :
Solid-State Circuits, IEEE Journal of
