Concurrently testable FPGA design for molecular QCA using conservative reversible logic gate

Reversible logic is attracting the researchers attention for fault susceptible nanotechnologies including molecular QCA. In this paper, we propose concurrently testable FPGA design for molecular QCA using conservative reversible Fredkin gate. Fredkin gate is conservative reversible in nature, in which there would be an equal number of 1s in the outputs as there would be on the inputs, in addition to one-to-one mapping. Fault patterns in Fredkin gate are analyzed using HDLQ tool due to a single missing/additional cell defect in molecular QCA. Exhaustive simulation shows that if there is a fault in molecular QCA implementation of Fredkin gate, there is a parity mismatch between the inputs and the outputs; otherwise the inputs parity is same as outputs parity. Thus, any permanent and transient fault in molecular QCA that results in parity mismatch can be concurrently detected. The logic block and the routing fabric (both are programmable) are the two key components of an FPGA. Thus, we have shown the Fredkin gate based concurrently testable designs of the configurable logic block (CLB) and the routing switch of a molecular QCA-based FPGA. Analysis of power dissipation in the proposed FPGA is also shown.