Mitigating single-event upsets in COTS SDRAM using an EDAC SDRAM controller

Abstract

From deep space missions to low-earth orbit satellites, the natural radiation of space proves to be a hostile environment for electronics. Memory elements in particular are highly susceptible to radiation charge that if latched can cause single-event upsets (SEU, bit-flips) which lead to data corruption and even mission critical failures. On Earth, SDRAM devices are widely used as a cost-effective, high performance storage elements in almost every computer system. However, their physical design makes them highly susceptible to SEUs. Thus, their usage in space application is limited and usually avoided, requiring the use of radiation hardened components which are generally a few generations older and often much more expensive than COTS. In this paper, an off-chip SEU/MBU mitigation mechanism is presented that aims to drastically reduce the probability of data corruption inside a commercial-off-the-shelf (COTS) synchronous dynamic random access memory (SDRAM) using a triple modular redundant (TMR) scheme for data and periodic scrubbing. The proposed mitigation technique is implemented in a novel controller that will be used by the single-event upset detector (SEUD) experiment aboard the KTH MInature STudent (MIST) satellite project.