55 dB DC gain, robust to PVT single-stage fully differential amplifier on 45 nm SOI-CMOS technology

The design of a single-stage operational transconductance amplifier is presented, which uses self-cascode transistors and current shunt stages to improve its DC gain. The proposed amplifier is implemented in a standard 45 nm silicon on insulator CMOS process. Simulation results show that the amplifier has a DC gain above 50 dB despite physical and environmental variations with a minimum gain bandwidth product of 540 MHZ and more than 55° phase margin. In addition, the simulated transient behaviour is shown to be robust, with a slew rate of 500 V/μs and a settling time of 7 ns with 1% accuracy for a C_L of 0.3 pF.