Dear [Manufacturer's Technical Support Team],

We are currently using the CAB425M12XM3 device in our power system and have encountered potential degradation issues during long-term power cycling tests. We would appreciate your support in reviewing our application conditions and providing any relevant degradation or lifetime data for the device.

1. Application Configuration

DC Link Voltage: 600 V

Topology: 1 leg with 2 parallel-connected CAB425M12XM3 devices

Switching Frequency: 20 kHz

Gate Resistance (Rg): 5 Ω

Cooling Method: Wieland Heatsink (CP 3012)

1. Power Cycling Test Conditions

We are running a long-term power cycling test with the following periodic profile:

Period 1: 650 A_rms 60 Hz AC current applied for 10 seconds

Period 2: 0 A_rms (idle) for 20 seconds

Total Cycles So Far: Approximately 5000 cycles

According to our PLECS simulation (including thermal model), the estimated junction temperature during Period 1 reaches approximately 130°C.

1. Observed Issue

After ~5000 cycles, we have started to see activation of the Desaturation Protection circuit, which was not triggered previously. This behavior suggests a potential degradation of the MOSFETs.

We are using a custom gate driver, and this issue was not observed in earlier cycles. No significant change has been made to the system configuration since the test started.

Request

Based on the above operating and test conditions, could you confirm if such degradation is expected for the CAB425M12XM3 device?

Do you have relevant power cycling / lifetime / degradation data or failure mechanisms for this part under similar conditions (especially high current cycling with elevated junction temperatures)?

Are there any known failure modes (e.g., bond wire fatigue, solder degradation, increased R_DS(on)) that could explain the Desat triggering?

We would greatly appreciate your insights or recommendations on this matter, including any potential improvements to the operating conditions to extend device longevity.

Please let us know if you require additional data or waveforms from our side.