Gallium-Arsenide Operational Amplifier with Class AB Push-Pull Output Cascade and Input n-JFets

The basics of circuit design of gallium-arsenide operational amplifiers (Op-Amps), implemented on the basis of combined technical processes that ensure the creation of n-JFet field-effect and PNP bipolar transistors, are considered. Such an elemental basis complicates the circuit synthesis of precision Op-Amps due to the lack of n-p-n transistors. A significant feature of the Op-Amp put forward by the authors of the article, which is protected as an object of intellectual property, is the implementation of a push-pull output cascade of class AB only on gallium-arsenide PNP bipolar transistors. In addition, the investigated Op-Amp circuit has relatively small values of the offset voltage’s systematic component (400uV), as well as a low noise level, which is ensured by the use of n-JFet. The computer simulation results of the amplitude and frequency responses of GaAs Op-Amp with load resistances greater than 2 $\mathrm{k}\Omega$ are presented.