During the SEL testing the device was heated to 125°C by using a Closed-Loop PID controlled heat gun (MISTRAL 6 System (120V, 2400W). The temperature of the die was verified using thermal camera prior to exposure to heavy ions.

The species used for the SEL testing was Homium (¹⁶⁵Ho at 15 MeV / nucleon). For the ¹⁶⁵Ho ion an angle of incidence of 0° was used to achieve an LET_EFF = 75 MeV × cm² / mg (for more details, see Table 8-4). The kinetic energy in the vacuum for this ions is 2.474 GeV. Flux of approximately 10⁵ ions / cm²× s and a fluence of approximately 10⁷ ions / cm² per run was used. Run duration to achieve this fluence was approximately two minutes. The four devices were powered up and exposed to the heavy-ions using the maximum recommended input voltage and boot voltage of 14V. The ASW (High-Side Driver Signal Return) was set to 150V with respect to AGND (low-side driver signal return). The device was set in both PWM and IIM modes during testing. For more information see Single-Event Effects section. No SEL events were observed during all nine runs, indicating that the TPS7H60x5-SP is SEL-free up to 75 MeV × cm² / mg. Table 8-4 shows the SEL test conditions and results. Figure 7-1 shows a plot of the current versus time for run 1.

Using the MFTF method shown in Single-Event Effects (SEE) Confidence Interval Calculations and combining (or summing) the fluences of the four runs at 125°C (9 × 10⁷), the upper-bound cross-section (using a 95% confidence level) is calculated as: