Abstract
In this work, design and calibrated simulation of multistage operational amplifiers (OP-AMPs) employing carbon nanotube field effect transistors (CNTFET) has been performed. The OP-AMPs designed are three stage OP-AMPs (3SOA), employing 45 nm technology node CNTFETs. Three structures of proposed CNT based 3SOAs have been designed and simulated using HSPICE and compared with the conventional CMOS-based 3SOAs. The three proposed 3SOAs include one using only CNTFETs (pure), and the other two employing a combination of CNTFETs and the conventional MOSFETs (hybrid). The comparative analysis of the proposed 3SOAs revealed that a significantly improved performance is achieved in the proposed pure CNT based 3SOA in comparison to the conventional technology based 3SOA. It has been observed that a significant increase in DC gain and slew rate of 19.14% and 274.6%, respectively, has been achieved in the proposed pure CNT3SOA in comparison to the conventional CMOS based 3SOA. Further, the output resistance and the power consumption have got reduced by 133 times and 200% respectively in the proposed pure CNT-3SOA in comparison to conventional CMOS-OP AMP. Furthermore, it has also been observed that the gain margin (GM), phase margin (PM), power supply ratio (PSRR) and common mode rejection ratio (CMRR) have increased significantly in the proposed CNT based 3SOAs in comparison to the conventional CMOS-based 3SOAs. Finally, the proposed 3SOAs have been used in designing integrators and differentiators. It is observed that the CNT-3SOA based integrators and differentiators show better performance than the CMOS-3SOA based Integrators and differentiators.