Ultra-Low Cost Full Adder Cell Using the nonlinear effect in Four-Input Quantum Dot Cellular Automata Majority Gate

Document Type: Research Paper


1 Department of Computer Engineering, Central Tehran Branch, Azad University (IAUCTB), Tehran, 13185-768, Iran

2 Department of Computer Engineering, Shahid Beheshti University



In this article, a new approach for the efficient design of quantum-dot cellular automata (QCA) circuits is introduced. The main advantages of the proposed idea are the reduced number of QCA cells as well as increased speed, reduced power dissipation and improved cell area. In many cases, one needs to double the effect of a particular inter median signal. State-of-the-art designs utilize a kind of fan out to achieve these resulting in increased number of cells, dissipating more power and decreasing the overall speed of the circuits. In this paper, we have presented cell alignment to multiply the effect of a certain signal by two, three or even more. This can be considered as a new vision to design any arbitrary circuit needing this property. Furthermore, a new coplanar crossover approach has been introduced which is able to make the coplanar crossover in two consecutive clocks with one rotated cell in the worst case. In order to prove the efficiency of the proposed ideas, a new Full Adder cell and a new Carry Ripple Adder (4-bit) have been designed which provides less QCA cell count as well as less power dissipation and cost.