A fast settling Slew Rate Enhancement technique for operational amplifiers

Abstract

This paper presents a fast settling SRE (Slew Rate Enhancement) technique for operational amplifiers. An opamp using a constant-g m biasing together with the proposed SRE circuit is designed and it is shown that stable large and small signal characteristics can be achieved across the wide range of temperature. The opamp was designed and laid out in Jazz 0.18µm process using 1.8V supply voltage. The core circuit consumes 3mA while the SRE circuit has a static power consumption of only 200uA (%6.67 of the power of the core circuitry). The slew rate of the opamp has increased from 25 V/us to 150 V/us at room temperature. The low variation of both small signal as well as large signal characteristics of the opamp across the temperature has been verified by Spectre simulation using PSP models.