BCD Adder Designs Based on Three-Input XOR and Majority Gates

Lots of emerging techniques can natively realize majority-of-three (MAJ) gates. Although enhanced gates such as exclusive-OR (XOR) gates can be implemented by several MAJ gates, there exists much efficient XOR design which directly derived by the physical attributes of emerging techniques. In this brief, we proposed multi-digit binary coded decimal (BCD) adder designs represented based on three-input exclusive-OR (XOR3) and MAJ gates. BCD adder is widely used in financial, commercial, and industrial computing. We implemented the designs using quantum-dot cellular automata (QCA) technology. The proposed logic representations are validated using different types of binary adders as well as QCA design strategies. The introduction of XOR3 gates is conducive to achieve compact logic representations, which positively affect both the area and delay of QCA layouts. Compared with the existing best designs, the proposed 1-digit BCD adder has 50% less area and 10% less delay, and the 8-digit BCD adder has a $3.42\times $ improvement of area-delay product.