Current-Mode Electronically Tunable Resistor-less Universal Filter in ±0.5V 32Nm CNFET

Abstract

Carbon Nanotube based transistor (CNFET) has significant potential to replace CMOS in the future for the design of high performance analog/digital circuits due to its better electrostatics and higher mobility. This paper presents a low-voltage current-mode universal filter designed employing a single CNFET-based Current Controlled Conveyor (with only Z- current outputs) as the active element along with a resistor and two grounded capacitors. The filter can be configured to obtain four functions: low-pass, high-pass, band-pass and band-reject. Tunability of all the filter outputs with respect to a bias current has been analyzed. Further, a resistor-less implementation of the universal filter is also presented. Electronic tunability of the filter parameters using a control voltage is then demonstrated. The performance of both the versions of the filter circuit has been evaluated using HSPICE. The simulation results are found to be in agreement with the theoretical predictions.