A reversible ALU using HNG and Ferdkin gates in QCA nanotechnology

Quantum dot cellular automata (QCA) with the characteristics such as low energy dissipation and high density is a suitable alternative technology to CMOS technology. Arithmetic logic unit (ALU) is one of the most important critical components of a microprocessor, and it is the core component of central processing unit (CPU). In this work, a novel reversible ALU in QCA nanotechnology is proposed. The reversible ALU contains three Ferdkin gates and one HNG gate. The proposed structure needs one constant input and generates only one garbage output. The proposed circuit does not need any rotated cells and only uses one layer that improves the manufacturability of the design interestingly. This circuit can perform 20 operations such as AND, OR, XOR, XNOR, COPY, addition, and increment. Our design contains only 480 cells and 12 majority voters and requires 15 clock phases. The proposed structures are simulated using QCADesigner version 2.0.3. The reversible ALU, despite a 25% increase in operations, has a 28% improvement in cell numbers and a 6% improvement in delay.