Patent ID: 7030697

Claim:
A CMOS operational transconductance amplifier, comprising: a differential input transistor pair providing an input stage for receiving a pair of input voltages; a current source, coupled to the differential input transistor pair, for providing current to the differential input transistor pair; an output transistor for conducting an output current proportional to a difference between the pair of input voltages applied to the differential input transistor pair; a cascode current mirror section, coupled to the differential input transistor pair and the output transistor, the cascode current mirror section providing a mirrored current as the output current for the output transistor, the cascode current mirror section comprising a first current mirror transistor coupled to a drain of a first transistor of the differential input transistor pair and a second current mirror transistor coupled to a drain of a second transistor of the differential input transistor pair, the second current mirror transistor being coupled to the output transistor; and a common-mode feedback section, coupled to the differential input transistor pair, wherein the common-mode feedback section absorbs a current change in the current source to maintain a constant current in the output transistor, the common-mode feedback section comprising a second current source and a common-mode feedback differential pair, a transistor of the common-mode feedback differential pair mirroring current through the first current mirror transistor.