SEU characterization and design dependence of the SA3300 microprocessor

A detailed characterization is presented of the single-event upset (SEU) sensitivity of the SA3300 microprocessor focusing specifically on the internal general-purpose registers. SEU response is explored as a function of temperature and logic state of the registers. The effects of two different design variations on SEU vulnerability are outlined. Microprobe measurements using a pulsed Nd:YAG laser suggest that the observed pattern dependence for both design revisions is due to bipolar photocurrent in a vertical n/sup +/pn transistor. A slight temperature dependence was observed in both design revisions. This is consistent with the use of oversized restoring transistors to minimize SEU vulnerability rather than polysilicon feedback resistors. More recent data show threshold above 120 MeV-cm/sup 2//mg with 80-k Omega feedback resistors. >