TPS54418 / Start-up failure

How often does the board fail to start up?  Can you look at the PH node on a failure to start event?  If there are just a few very high frequency pulses, it may indicate a known issue.  This issue is fixed on teh latest production silicon, but there may be some older devices still in circulation.  Can you provide the lot code of the failing part?

Hi John-san,

This fail is happened approximately one time per ten time on the same board. And also they are using three TPS54418 to regulate +1.8V, +1.2V and +0.9V and then this fail  is confirmed at +1.2V and+0.9V. They have not confirmed at +1.8V portion. I added the schematic for all portions for your information.

Please see attached which is included the waveform of PH node and more.

Regarding lot code, I will get back to you when I will be able to confirm it.

Finally, please let me know who knows this issue well in TIJ? I would like to ask about detailed information about this issue.

Best Regards,

Sonoki

Hi John-san,

I checked that the marking information of their device is C3CE.

Can you let us know the date code which is fixed the known problem?

Please see the waveform in attached. They confirmed that the start-up failure at +5V to +1.2V, but never seen at +5V to +1.8V. Actually there is difference at waveform of PH node.

Best Regards,

Sonoki

Hi John-san,

I need to comment for following items, so please give your advice.

1, The waveform from customer is the same issue with known issue on previous silicon?

2, Is there any problem in their design of external components?

    ---> We checked it by using Webench then no problem was found.

3, Do you have the way to reject the problematic devices in customer's product line?

4, Will the following method be effective to reject it?

    - Continue on/off of input voltage for 40times under high temperature

5, Please let us know what was the problem in previous silicon.

6, Is this issue happened or not depend on the design?

   * They confirmed the normal power-up with 1.8V output voltage setting as attached.

Please give your comments via TIJ person if you can not comment on this post.

Best Regards,

Sonoki

Hello - 

I work with the product line currently supporting TPS54418. I will help find the proper contact for this issue. 

Matt Schurmann

One thing I might recommend is to submit a failing part for FA.  They can verify if this is in fact the known issue or something else.

I agree with John - the best thing to do would be to contact your local Field/Applications office, to submit the parts for Failure Analysis (FA). From there, TI's quality engineers will work to identify/verify the issue, and provide the information asked for above.