Efficient radix- r adders for nanoelectronics.

In this study, a new design method and efficient designs for radix-radders are proposed for carbon nanotube field effect transistor (CNFET) FET nanotechnology. This application also investigates the capability of the nanoscale device for designing high-performance analogue circuits. The proposed designs benefit from the unique electrical properties of CNFET, such as near-ideal current voltage characteristics, very high transconductance, high-performance switches and very high-performance and high-gain binary inverters, at nanoscale. Moreover, adjustable threshold voltage and the same mobility of electrons and holes in a CNFET facilitate the design and modification procedures. The proposed design can be considered as an instance of a general adder, capable of adding radix-rdigits with high precision. It is noteworthy that a very limited number of carbon nanotube diameters for designing the proposed adder are needed, which enhance the manufacturability. The proposed circuits are designed based on arithmetic relations and are also verified at 32 nm feature size using HSPICE and the Stanford standard SPICE model. [ABSTRACT FROM PUBLISHER]