SRAM FPGA Reliability Analysis for Harsh Radiation Environments

This paper investigates the viability of deploying SRAM-based FPGAs into harsh Earth-orbit environments. A reliability model is presented for estimating the of SRAM FPGA designs in specific orbits and orbit conditions. The model requires orbit-and condition-specific SEU rates and design-specific estimates of the probability of failure during a single scrubbing period. Probability of failure estimates are reported for several FPGA designs from both fault-injection and accelerator experiments. The model also includes a method for estimating composite mean time to failure (MTTF) that incorporates all orbit conditions over a solar cycle. Despite using pessimistic assumptions, the results from this model suggest that SRAM FPGA designs protected by TMR and scrubbing operate very reliably in a LEO orbit and surprisingly well in "harsh" orbits.