TPS54394: TPS54394 supplied chips will be damaged to short during power up.

Hi, liu yu 

Which pin is damaged?

Just SW1 is shorted to GND? 

The extra large Cout will not cause IC damaged, i think it is not related with Cout.  

I suspect the damage is caused by poor layout. 

Could you send me the schematic and layout? 

TPS54394 is not damaged.

The chip which get power feed from TPS54394 is damaged.(shorted.)

Hi, 

Could you send me the schematic and layout? 

TPS54394's output is stable? 

Is there over voltage on TPS54394's output? 

Do you have any waveforms? 

TPS54394's output is stable? -------->Yes

Is there over voltage on-------> No.ic-mc-power.pdfpower pcb.docx TPS54394's output? ------>No

Hi, liuyu 

I have reviewed schematic and layout, it looks okay. 

And from your feedback, i think it is not caused by TPS54394. 

Hi,

We found that it will only happened during power on, before  FPGA & MCU application load is programed to flash.

Which meas the load is very very light. We try to indcrease the inductor & reduce Cout, the failure rate wll be decreased a lot.

We thought maybe something related with TPS54394 Eco-mode.

We measured the waveform of SW node, which supply to 1.0V@very light load.

Please help to check.

The waveform above is abnormal?

Is it in eco-mode?

If it is always woring in eco-mode, what is the Fsw?

Hi, liuyu 

The waveforms are normal. 

In Eco-mode, the Fsw is related with loading. 

BTW, are you in China? 

You can send email to me, zhao-ma@ti.com 

Yes，  I am in China.

So we can send email to you in Chinese?

Hi, liuyu 

Sure, we can talk in Chinese.