During SEL characterization, the device was heated using a closed-loop PID controlled heat gun [MISTRAL 6 System (120V, 2400W)] to 125°C. 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 DUT temperature was monitored prior to being irradiated with a FLIR IR-camera to ensure the junction temperature at KSEE. The species used for SEL testing was ¹⁶⁵Ho and ¹⁶⁹Tm. Incident angle was used which achieved an LET_EFF of 75MeV·cm²/mg.

6 production units of the TPS7H3024-SP were tested for SEL at a flux of ≈6 × 10⁴ ions/cm²·s, a fluence of ≈ 10⁷ ions/cm², maximum recommended V_IN voltage (14V), maximum recommended V_PULL-UPX voltage (7V). For SEL testing the device was configured in 4 different operating modes.

1. U1 - MODE 0, WD SW
2. U2 - MODE 0, WD Off
3. U3 - MODE 1, WD SW
4. U4 - MODE 1, WD Off

For more configuration information please refer to Table 6-1.

Not a single functional interrupt was observed, neither a high current event on any of the power supplies of the TPS7H3024-SP. This indicates the TPS7H3024-SP is SEL-free. The results for four runs across four devices are shown in Table 8-3. A typical V_IN current versus time plot during a SEL run is shown in Figure 7-1 and Figure 7-2.

Using the MFTF method described in Single-Event Effects (SEE) Confidence Interval Calculations application report and combining (or summing) the fluence of the six runs at 125°C (6 × 10⁷) ions/cm², the upper-bound cross-section (using a 95% confidence level) is calculated as:

σ_SEL ≤ 6.15 × 10^-8 cm²/device for LET_EFF = 75MeV·cm²/mg and T = 125°C.