On-Orbit Observations of Single Event Upset in Harris HM-6508 1K RAMS

The SEU and latchup rate of a satellite subsystem containing 384 Harris HM-6508 RAMs was observed over a 2 year period. The satellite was in a low polar orbit. A total of 47 single SEUs, 9 double, 1 triple and 1 quadruple events were observed; the multiple events were 19% of the total. No latchup was observed. The error rate was 7.6 × 10-2 SEUs/chip-year and an upper limit was found of the ratio of latchups/SEUs of 1.7 × 10-2. The observed SEU rate was consistent with predictions based upon laboratory test, using the Lawrence Berkeley Laboratory 88" cyclotron.