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

Eggsy Pang

Expert 4985 points

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

over 4 years ago

0 JohnTucker over 4 years ago

TI__Guru**** 191445 points

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.

0 Eggsy Pang over 4 years ago in reply to JohnTucker

TI__Expert 4985 points

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!

0 JohnTucker over 4 years ago in reply to Eggsy Pang

TI__Guru**** 191445 points

Eggsy,

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

Power management

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