Multi-digit Binary-to-Quaternary and Quaternary-to-Binary Converters and Their Applications in Nanoelectronics

Using the multi-valued logic causes the reduction in interconnections, thereby leading to the reduction in chip area and interconnection power dissipation. In order to take advantage of the multi-valued logic, the structure of a mixed-radix system using multi-valued and binary logic is more suitable than that of only using the multi-valued logic; so, the design of a multi-digit converter is necessary. In this paper, first, a new efficient quaternary-to-binary converter and a binary-to-quaternary converter based on multi-threshold voltage are designed using carbon nanotube field effect transistor (CNTFET). Then, multi-digit quaternary-to-binary and binary-to-quaternary algorithms are discussed and implemented. Subsequently, these converters are used in a multi-digit quaternary adder. It is shown that, if quaternary numbers are initially converted into binary numbers and then summation is performed (by using multi-digit quaternary-to-binary and binary-to-quaternary converters), the complexity is considerably reduced, as compared with using the quaternary full adders. Also, some other applications of these converters are discussed. The simulation results using the Stanford 32-nm CNTFET model in the HSPICE software at 0.9 V indicate the correct operation and the high performance of the proposed designs.