TPS54325: Input 5V power up, sometimes TPS54325 do not output.

Part Number: TPS54325 Hi team, My customer used TPS54325 for 5V input to 1.2V output. If the 5V power up slowly up to 16ms, TPS54325 don't ouput 1.2V, like shutdown. If the 5V power up quicker up to 5ms, TPS54325 work normally and have 1.2V output. Do you know why? Below waveform show 1.2V shutdown

Eggsy, TPS54325 has latching under voltage protection. If the input voltage rises too slowly and the output is not within 70% of the set value after 1.7 X the slow start time, the device will latch off. See section 8.3.5 in the datasheet.

Hi John, DO you see the waveform blue one. We can see the FB pin voltage go up and go down. Do you know why? Thanks!

Eggsy, The scope shot is too low resolution. I cannot read anything from it. What are the voltage scales?