New Design of a 4-Bit Ripple Carry Adder on a Nano-Scale Quantum-Dot Cellular Automata

Quantum-dot cellular automata (QCA) is a new computing paradigm based on cellular automata with appealing characteristics such as high speed, low power consumption, and high density for realizing quantum computers. On the other hand, an adder is the primary circuit in any digital processor and ripple carry adder is a basic building block of other adders. Therefore, efficient design of this type of adder may lead to the efficient design of the whole system. So, in this paper, a new design of ripple carry adder is proposed to decrease the number of cells and area as possible. Simulation results using QCA Designer verifies the correctness of the proposed circuit and validates its efficiency in terms of a number of cells and area.