Design and Simulation of Current Feedback Operational Amplifier in 180nm and 90nm CMOs Processes

This paper proposes a Current Feedback Operational Transconductance Amplifier (CFB OTA) with a folded cascode op-amp as input stage cascaded with class AB buffer as output stage. This gives better results on parameters such as bandwidth, slew rate, settling time and input offset voltage compared to the conventional CFOA. Hence it carries significance in high frequency applications such as A/D converters and active filters where CMOS CFOA used as an active building block. CADENCE simulation results are obtained using 180nm CMOS process (supply voltage of ±2.5V, 100μA biasing current) and 90nm CMOS process (supply voltage of ±1.2V, 50μA biasing current). Some of the performance parameters obtained are DC gain of 60.2dB, open-loop gain bandwidth product(GBW) of 307 MHz, slew rate (SR+) of +30V/μS to +90V/μS and DC input offset voltage of −0.6nV.