A Fully Differential Operational Amplifier with Negative Resistance Gain Enhancement

A fully differential CMOS operational amplifier with the minimized channel length of alI transistors, and the negative resistance with cascode transistor is proposed to gain enhancement. The circuit has been designed to operate with 2.5V single supply and has been simulated in 0.25 μ CMOS process. Simulation results showed an effective open-loop DC gain of 86 dB, gain bandwidth of 200MHz and phase margin of 80°.