Transconductance enhancement method for operational transconductance amplifiers

An improved recycling structure for an operational transconductance amplifier is proposed. The proposed structure separates the AC path from the DC path, and achieves a significant boost in transconductance under the same power and area budget. A folded-cascode amplifier employing the improved recycling structure was implemented in SMIC standard 0.13 µm CMOS process. Simulation results show that the enhancement of transconductance leads to 230% improvement in gain-bandwidth product and 13 dB boost in gain compared with the conventional folded cascode.