Fault-Tolerant Single-Port Block RAM on Virtex-6 FPGA Using QCA Multiplexers and Efficient D Flip-Flops

This paper presents a Block RAM design using a fault-tolerant multiplexer and a D flip-flop based on quantum-dot cellular automata (QCA) technology. QCA is a fast, transistor-less nanotechnology that overcomes CMOS limitations, such as short-channel effects and sub-threshold leakage. A robust 2:1 multiplexer was designed with 10 quantum cells in a 0.02 µm2 area and a 0.25 clock cycle delay, offering significantly lower energy dissipation compared to existing designs. Additionally, an area-efficient D flip-flop layout was created, featuring 21 cells, a 0.01 µm² area, and one clock cycle delay. These components were integrated into a Block RAM with a memory reconfiguration block. Implemented on QCADesigner 2.0.3, the Block RAM contains 2034 quantum cells in 1.98 µm² and has a 3.5 clock cycle delay. Energy dissipation was measured at 0.412 meV using QCADesigner-E. The proposed design demonstrates superior efficiency and low-power consumption.