Method for Improving the Performance of Operational Amplifier with HA2700 Microchip Architecture

A circuit technique for increasing the maximum output voltage slew rate (SR) of an integrated operational amplifier (OpAmp) with the HA2700 microchip architecture based on the modernization of the input differential stage (DS) is considered. An OpAmp architecture is proposed in which the influence of parasitic capacitances of DS reference current sources and capacitances on the transistor substrate on the SR is minimized. This allows the use of micron technological processes in the fabrication of CBJT OpAmps, which are widely used to improve the radiation resistance of microchips. Computer simulation of the proposed OpAmp is performed, which shows that the SR of the new circuit differs from the SR of the well-known serial OpAmp by more than 40 times and reaches values of about 800 V/µs at the emitter current of the input transistors of the DC in the range of up to 80-100 μA. The developed OpAmp is recommended for practical use in discrete-to-analog filters on switched capacitors.