PMP30600-TH: withstand 75 V continuous input?

Hi Electronx,

Thank you for using the e2e forum.
I would not recommend to operate the PMP30600-TH design with Vin 75V continuously.
Both the FETs and several input caps are rated for 80V max, which leaves very little margin and might lead to failures at voltage spikes.
Additionally, there might be strong ripple current at the L2 inductor at switching frequency of 100kHz.

The buck controller LM5146 itself is still suitable for these specs, so I would suggest modifying the design before applying 75V input voltage continuously.
Regarding different FET and input cap choices, there is a LM5146-Q1-EVM12V PCB on the according product page, which has larger input ratings (Vin 14-85V). The max load current is lower, therefore this design should not be implemented without changes either, but it might offer additional reference.
https://www.ti.com/product/LM5146#design-tools-simulation

Please let me know if there are additional questions.

Best regards,
Niklas