5 SEL Results

During SEL characterization, the device was heated using forced hot air, maintaining the IC temperature at 125°C. The temperature was monitored by means of a K-type thermocouple attached as close to the IC as possible. The species used for the SEL testing was a Praseodymium (⁵⁹Pr) ion with an angle-of-incidence of 39° for an LET_EFF = 85MeV-cm²/mg. The kinetic energy in the vacuum for this ion is 2.114GeV (15-MeV/amu line). A flux of approximately 10⁵ ions/s-cm² and a fluence of approximately 10⁷ ions/cm² were used for two runs. The V_S supply voltage is supplied externally onboard at the recommended maximum voltage setting of 12V. Run duration to achieve this fluence was approximately 2 minutes. No SEL events were observed during both runs shown in Table 5-1. Figure 5-1 shows a plot of the current vs time.

No SEL events were observed, indicating that the LMP7704-SP is SEL-immune at LET_EFF = 85MeV-cm²/mg and T = 125°C. Using the MFTF method described in Appendix A and combining (or summing) the fluences of the two runs at 125°C (2 × 10⁷ ions/cm²), the upper-bound cross-section (using a 95% confidence level) is calculated in Equation 1:

Figure 5-1 Current Versus Time (I vs t) Data for V_S Current During SEL Run # 10