Design of an improved high gain and high slew rate operational amplifier

Operational amplifiers find extensive applications in analog integrated circuits. With the advancement of technology, higher performance requirements for operational amplifiers have emerged. This paper presents an enhancement of the operational amplifier based on a folded cascode configuration, employing a recycling folded cascode structure and a comparator. By increasing the transconductance and the charge/discharge current of the Miller capacitance, both the gain and the slew rate of the circuit are improved. Utilizing a 0.18 μm CMOS process, simulations conducted with Cadence software demonstrate that the open-loop gain reaches 88.61 dB, with a phase margin of 44°, and the positive and negative slew rates achieve 23.18 MV/s and 22.12 MV/s, respectively.