Carbon Nanotube Based Operational Transconductance Amplifier: A Simulation Study

Abstract

MOS technology is convenient for implementing OTAs because MOSFETs are inherently voltage-controlled current devices. A variety of CMOS OTAs with different topologies have been developed for different purposes. In this chapter, design and simulation of novel operational transconductance amplifiers (OTAs) based on carbon nanotubes (CNT) has been performed. Two structures of CNT based OTAs have been proposed and have been compared with a conventional CMOS based OTA. The two CNT based OTAs include the one employing CNT based NMOS and conventional PMOS transistors, named as NCNT-PMOS-OTA and the other employing CNT based PMOS and conventional NMOS transistors, named as PCNT-NMOS-OTA. The proposed structures are designed using HSPICE and are based on 45 nm technology node. The key characteristics of the proposed devices, like DC voltage gain, average power, bandwidth and output resistance have been computed. It has been observed that CNT based OTAs result in high performance in comparison to CMOS-OTA. The DC gain has increased by 44.4 % in PCNT-NMOS OTA and 69.3 % in NCNT-PMOS OTA in comparison to CMOS-OTA. The average power has decreased by 24.18 % in PCNT-NMOS OTA and 14.98 % in NCNT-PMOS OTA in comparison to CMOS-OTA.