OPERATIONAL AMPLIFIER CIRCUIT

PURPOSE:To obtain a circuit configuration of a full differential amplifier circuit capable of fixing an in-phase potential at an output terminal to a desired value, low in the sensitivity against dispersion in the elements and high in in-phase gain. CONSTITUTION:Transistors(TRs) 10, 11, 33 form a differential pair and drains are respectively connected to drains of constant current source TRs 31, 32. Furthermore, drains of TRs 19, 20 whose gates are connected respectively to output terminals 72, 73 are connected in common and to a TR 17 in cascade and connected to a mirror circuit comprising TRs 16, 12 and 16, 6, drains of the TRs 6, 12 are connected respectively to drains of the differential pair and the drains are connected to drains of TRs 9, 15 whose gates connect to a reference potential point via TRs 8, 14 in cascode connection. TRs 22, 24 form an output stage and TRs 1-5 and a constant current source 50 form a bias circuit.