Improved Gain Folded Cascode OpAmp Employing a Novel Positive Feedback Structure

A new topology for gain enhancement of conventional folded cascode amplifier is proposed. The new architecture enhances the DC gain by means of a positive feedback path, while the frequency response of the circuit remains unchanged. The objective is carried out by adding a single differential path to perform the feedback role and operates as a current splitter for the amplifier's output stage. Analytic expressions along with simulation results for TSMC 0.18μm standard CMOS technology are provided for justification. Our proposed amplifier enhances DC gain for 75.6 dB while GBW remains unchanged (656 MHz) comparing to conventional folded cascode amplifier.