Design and Implementation of a Low Power Ternary Full Adder

Abstract

In this work, the design and implementation of a low power ternary full adder are presented in CMOS technology. In a ternary full adder design, the basic building blocks, the positive ternary inverter (PTI) and negative ternary inverter (NTI) are developed using a CMOS inverter and pass transistors. In designs of PTI and NTI, W/L ratios of transistors have been varied for their optimum performance. The ternary full adder and its building blocks have been simulated with SPICE 2G.6 using the MOSIS model parameters. The rise and fall times of PTI show an improvement by a factor of 14 and 4, respectively, and that of the NTI by a factor of nearly 4 and 17, respectively over that of earlier designs implemented in depletion-enhancement CMOS (DECMOS) technology. The noise margins improve by a factor of nearly 2 in PTI and NTI, respectively.The ternary full adder has been fabricated in MOSIS two micron n-well CMOS technology. The full adder and its building blocks, NTI and PTI have been tested experimentally for static and dynamic performance, compared with the SPICE simulated behavior, and close agreement is observed.The ternary-valued logic circuits designed in the present work which do not use depletion mode MOSFETS perform better than that implemented earlier in DECMOS technology. The present design is fully compatible with the current CMOS technology, uses fewer components and dissipates power in the microwatt range.