The paper considers schematics of low-power Output Stages (OS) and class AB Buffer Amplifiers (BA) for analog microcircuits realized on arsenide gallium n-channel field-effect transistors with control p-n junction and arsenide gallium bipolar p-n transistors within combined processes. The developed output stages are characterized by a relatively small static current consumption (about 100-200 mA), provide operation at load resistances greater than 1-2 kW, and have, as a rule, an increased input resistance. The maximum values of BA output currents for the positive polarity of the output voltage (vout) are determined by the width of the JFET channel, and for the negative vout half-wave, by the base current amplification factor of the BJT. In this connection, it is recommended to use compound Darlington p-n-p transistors in BA circuits. The results of computer simulation of the amplitude characteristics of push-pull BAs in LTspice at different load resistances show that the proposed circuit solutions provide the maximum amplitudes of positive and negative output voltages, close to the supply voltages. The circuit solutions considered are recommended for use in low-power operational amplifiers, including those operating under harsh operating conditions. The novelty of the paper lies in the investigation of a family of new push-pull class AB output stages for operational amplifiers, protected by 4 Russian patents and implemented under severe circuit restrictions on the types of GaAs transistors used (nJFET and nBJT).

Over the past few decades, portable electronics have been playing a prominent role in daily life, including Micro- Electromechanical Systems (MEMS) and Nano-Electromechanical Systems (NEMS) (Lee et al., 2003; Albano et al., 2007; Muntaser et al., 2015; and Muntaser and Buaossa, 2021). These devices, among many others, require a reliable energy storage and conversion device in order to function properly, the typical device being a battery. Many batteries are available for these applications, but the most promising proves to be Lithium-Ion Batteries (LIBs), mostly due to their ability to provide high voltages and large energy storage densities (Tarascon and Armand, 2010). LIBs have a very wide range of applications, including environment-friendly electric vehicles (Muntaser et al., 2016; and Elwarfalli et al., 2019) and rechargeable phone batteries (Kitaura et al., 2011; Elwarfalli et al., 2016; and Muntaser et al., 2017). The main advantage of LIBs (Li-ion) is their high energy density. They have a long cycle of life. Li-ion does not suffer from high selfdischarge rate, and memory effect of Nickel-Cadmium (NiCd) and Nickel Metal Hydride (NiMH) batteries. Unlike Sealed Lead Acid (SLA) and NiCd, LIBs do not contain toxic heavy metals. The main disadvantage of LIBs is that they require careful attention to safety; overcharging, overheating or short-circuiting a charged LIB can result in fire or explosion (Isaacson et al., 2000).

The term "LIB" refers to a diverse family of battery chemistries. All LIBs use a process known as intercalation, in which lithium ions are incorporated into the structure of the electrode material. Lithium ions move from the positive to the negative electrode during charging and from the negative to the positive electrode as the battery is discharged (Zaghib et al., 2012; and Muntaser et al., 2017). Most types of LIBs available today differ in the composition of their positive electrode (cathode). New materials for the negative electrode are also being developed, but few of these are available on the market (Patel, 2011).