Method for Increasing the Speed of Operational Amplifier Based on “Folded” Cascode

Prospective circuits of fast-speed operational amplifiers (Op-Amps) based on a “folded” cascode implemented on silicon bipolar transistors, as well as GaAs JFET and GaAs p-$n$-$p$ BJT transistors are proposed. Computer modeling of Op-Amps in the LTspice environment showed that the Op-Amp's open-loop gain exceeds 60 dB, and their slew rate (SR) reaches hundreds of $\mathbf{V}/\boldsymbol{\mu \mathrm{s}}$. The developed operational amplifiers can be recommended for use in analog front-end, used in detectors of various physical quantities for high energy physics, space tools and medicine.

I. Introduction

In modern microelectronics, a rather important problem is the development of new circuit solutions that allow improving the main qualitative indicators of the basic functional unit of modern automation, radio engineering and communication systems — operational amplifiers (Op-Amps) [1]–[3]. Among them are open-loop voltage gain, maximum output voltage slew rate (SR), transient settling time (t_set), static current consumption, etc. [1]–[4].