Designing Counter Using Inherent Capability of Quantum-dot Cellular Automata Loops

Quantum-dot cellular automata presents a promising Nano-scale technology for replacement of conventional CMOS-based circuits. According to the significant role of counters in computing units, designing diverse types of counter circuits has attracted many attentions, so far. This paper presents a QCA-compatible single layer architecture for 4-bit counter circuit, however by generalizing the main idea, n-bit counter can be engendered in a similar way. The proposed circuit is designed without employing conventional flip-flops‘ structures by allotting the distinct clock cycles to each counting unit. The comparison results with the bestreported structure reveal the superiority of our design in terms of circuit complexity and required layers for accessing to input and output cells. The proper output waveforms obtained by the QCADesigner tool proves the precise functionality of the proposed counter.