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 constantly monitored during testing at TAMU through an IR camera integrated into the control loop to create closed-loop temperature control.

The species used for the SEL testing was Holmium (¹⁶⁵Ho at 15MeV/nucleon). For the ¹⁶⁵Ho ion an incidence angle of 0° was used to achieve an LET_EFF = 75 MeV×cm²/mg (For more details, see Table 5-1). The kinetic energy in the vacuum for this ions is 2.474 GeV. Flux of ≈1 × 10⁵ ions/cm²/s and a fluence of ≈10⁷ ions/cm² per run was used. Run duration to achieve this fluence was ≈2 minutes. The eight devices were powered up and exposed to the heavy-ions using the maximum recommended input voltage of 14V with the maximum recommended load of each respective device. No SEL events were observed during all eight runs, indicating that the TPS7H401x-SP is SEL-free up to 75 MeV×cm²/mg. Note that due to the performance of the TPS7H4011-SP an experiment was conducted with the TPS7H4012-SP and the TPS7H4013-SP to determine if a SW to GND Schottky diode was required for operation during SEE testing. As shown in the table below it was found that both the TPS7H4012-SP and TPS7H4013-SP pass the full SEL run conditions regardless of whether or not the Schottky is present, indicating the Schottky is not required for SEE performance.Table 8-4 shows the SEL test conditions and results. Figure 7-1 shows a plot of the current versus time for run 3.

Using the MFTF method shown in Single-Event Effects (SEE) Confidence Interval Calculations and combining (or summing) the fluences of the eight runs at 125°C (8 × 10⁷), the upper-bound cross-section (using a 95% confidence level) is calculated as: σ_SEL ≤ 4.61 × 10^-8 cm²/device for LET_EFF = 75 MeV×cm²/mg and T = 125°C.