Investigation of the Carbon NanoTube Field Effect Transistor characteristics in GM-C filter

Abstract

Carbon NanoTube Field Effect Transistor (CNTFET) is the new alternative and promising nano-scaled device for the implementation of high performance, and low power circuits. In this paper, comparison of CNTFET devices with MOSFET devices in the application of operational transconductance amplifier (OTA) in the GM-C filter is analyzed. The effect of capacitance with channel length, number of tubes, and chirality at frequency 5MHz is studied. The MOSFET filter uses 16 pF capacitors with the OTAs, whereas in the CNTFET filter only 0.8 pF capacitance is needed to achieve the same frequency response while preserving the same levels of total harmonic distortion. The proposed design of GM-C filter using CNTFET makes a reduction up to 95% of the capacitance needed over the MOSFET one, and also a reduction up to 95% in the bias current needed. Both are major benefits in the chip size, IC fabrication, and power consumption aspects.