A high DC-gain modified CMOS OTA

A new operational transconductance amplifier (OTA) based on the conventional triple folded cascode (TFC) structure is presented. Using the proposed method, the DC gain enhances by adding only three positive feedback devices to the TFC structure. The simulation results for the designed OTA in a typical 0.35μm CMOS technology show 20dB DC gain enhancement of conventional TFC while bandwidth, output voltage swing range, and the phase margin of conventional TFC are not affected. Higher linearity in the larger output voltage swings is the other advantages of proposed approach in comparison to previously reported positive feedback methods.