We are using LM63615DQPWPRQ1 to supply two 12V axial fan. Converter input voltage is 24V. Total measured nominal output current for fan's is 600mA. Fan startup maximum current is 1000mA for short time period. Design done according WEBENCH tool. All products tested with production tester after manufacturing. Devices shipped to field over 5k. Currently failure rate is 2% and failure modes pointed to LM63615-Q1 to burned open or short. Fault distribution data shows that converter failure occured 10 to 140 days after installation. Most of devices still working without issues after 500 days.
Could you help or explain what might lead to this kind of failure?
I can provide more information if needed.