Precision Operational Amplifier on nJFet Arsenide-Gallium Field Effect Transistors and p-n-p Bipolar Transistors

The circuitry of differential stages and operational amplifiers (Op-Amp) on their basis realized on field (nJFET) and p-n-p BJT arsenide-gallium transistors is considered. Analytical expressions allowing to determine the dependance of the systematic component of the zero bias power (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OS</inf> ) on the base current gain of bipolar transistors are obtained, which allow to explain the effect of V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OS</inf> reduction to the level of 1uV. The calculation of the Gain coefficients of individual operation amplifiers stages, which has four high-impedance nodes, is performed. Computer modeling in the design automation software (LTspice) shows that the proposed circuit solution of the operational amplifiers provides a gain of more than 120 dB, and a small level of V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OS</inf> .