TPS54326: TPS54326RGTR output shorted

Hi Joe,

About the "shorted", please check and answer below questions before the deeply analysis:

1. SW short to GND?

2. VIN short to GND?

3. other pins short to GND?

4. did your remove the "BAD" TPS54326 and soldered a good TPS54326 to test again? test results?

5. How about the input voltage of TPS54326? value? Hot plug or not? do you check the waveforms, ramp up smooth or not? do you find voltage spike?

Dear Jason,

Thank you for the reply.

The short was SW to GND each time.

The TPS54326 was replaced and the fault was removed.

The +12V input comes from a 1RU meanwell power supply (AC to DC)

The power cable from the 1RU meanwell power supply to board is about 3.5m.

The board uses a LM25066 with input protection (SMBJ14A). 

The output of the LM25066 connects to the TPS54326 devices.

I have checked all rails and they are well behaved during power on and off.

I have not seen any transients due to unplug of the 3.5m cable.

Regards Joe

Hi Joe,

All the 3 failed part are +2V5 output?

Please upload all the output SCH and PCB files.

Thanks,

Lishuang

Dear Lishuang,

Can we please take this off line then I can share files.

Regards Joe