Circuit Engineering of GaAs Op Amps with Class-AB Push-Pull Output Stage on n-Channel JFets and pnp Bipolar Junction Transistors

The article discusses promising circuitry solutions of the gallium-arsenide operational amplifiers (Op Amps), implemented in an elemental composition based on combined tech processes, including n-channel JFet and pnp bipolar junction transistors. The specified limited elemental composition complicates the circuitry synthesis of Op Amps due to the lack of npn bipolar junction transistors, on which Op Amp's current mirrors are made in classical circuitry. It was revealed that the suggested Op Amp circuits have increased voltage gain values (73 dB) and high linearity of the amplitude response in circuits with 100% negative feedback at load resistances of more than 2
$\mathrm{k}\Omega$
. In addition, the explored Op Amp circuit has a low noise level, which is ensured by the use of n-channel JFets.