Patent ID: 7138866

Claim:
An operational amplifier comprising: first and second power supply terminals; first and second input terminals; first and second output terminals; a first differential amplifier circuit including a first drive cascode circuit connected to said first and second output terminals and a first tail current source connected between said first drive cascode circuit and said first power supply terminal, said first differential amplifier circuit being adapted to amplify first and second input signals supplied to said first and second input terminals and transmitting said amplified first and second input signals to said second and first output terminals, respectively; a second differential amplifier circuit including a second drive cascode circuit and a second tail current source connected between said second drive cascode circuit said first power supply terminal, said second differential amplifier circuit being adapted to amplify said first and second input signals; a first circuit connected between said first output terminal and said second power supply terminal, said first circuit serving as an input-stage load and an output drive circuit; a second circuit connected between said second output terminal and said second power supply terminal, said second circuit serving as an input-stage load and an output drive circuit; a first input-stage load circuit, connected between a first terminal of said second drive cascode circuit and said second power supply terminal; and a second input-stage load circuit, connected between a second terminal of said second drive cascode circuit and said second power supply terminal.