Design of QCA based memory cell using a novel majority voter with physical validation

Abstract

Quantum Dot Cellular Automata (QCA) is a unique transistor less paradigm which effectively uses change in cell polarization to perform logical operations with high speed, low power and high intricacy. In recent years, the need of high performance memory cell is increased for improving the system performance. This paper presents the design of a QCA based memory cell with read write capabilities. In recent past, most of the QCA circuits are designed using the conventional three input majority voter. The conventional three input majority gate is not fault tolerant. Thus, we need an alternative design which can serve as the majority voter and also shows the fault tolerance. Moreover, the design of three input majority voter is not much addressed . In this paper, an alternative, simple structure of three input majority voter is presented which is better than the conventional one in terms of fault tolerance. In addition to this, the proposed three input majority voter is power aware and efficient to realize various digital circuits. The correctness of the proposed majority voter is validated through the physical proof. Moreover, the proposed gate is subjected to cell displacement defect to investigate the testability. The proposed gate is further used to implement rudimentary elements such as XOR gate, multiplexer and D latch. Finally, the design of Random Access Memory (RAM) cell with read, write, set and reset capabilities is proposed using the presented majority voter. The proposed circuits are further subjected to comprehensive analyses for estimation of cost functions and energy dissipation. The investigation of presented circuits manifests the use of proposed majority voter for next generation computing circuits.