Neutron Radiation Testing of Fault Tolerant RISC-V Soft Processor on Xilinx SRAM-based FPGAs

Many space applications are considering the use of commercial SRAM-based FPGAs over radiation hardened devices. When using SRAM-based FPGAs, soft processors may be required to fulfill application requirements, but the FPGA designs must overcome radiation-induced soft errors to provide a reliable system. TMR is one solution in designing a fault tolerant soft processor to mitigate the failures caused by SEUs. This paper compares the neutron soft-error reliability of an unmitigated and TMR version of a Taiga RISC-V soft processor on a Xilinx SRAM-based FPGA. The TMR RISC-V processor showed a 33× reduction in the neutron cross section and a 27% decrease in operational frequency, resulting in a 24× improvement of the mean work to failure with a cost of around 5.6× resource utilization.