Two-stage class-AB OTA with enhanced DC gain and slew rate

This article proposes a new two-stage class-AB operational trans-conductance amplifier (OTA). In this OTA, the characteristics of class-AB are applied in both of the stages. By increasing the effective trans-conductance of the first stage, DC gain is improved. Non-linear current mirror boosts the current of the second stage; therefore, slew rate (SR) is increased. In order to verify the performance of the proposed OTA, some simulations are carried out in a 0.18-μm CMOS process in which the supply voltage is 1.8 V. The simulation results indicate 21-dB enhancement in DC gain and 2.7 times improvement in SR compared to its conventional counterpart. The post-layout and Monte Carlo simulations show the proposed OTA has better performance than the state-of-the art designs.