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TPS84A20: Pin 7 Package/Solder Pad Failures

James Susong
Prodigy 30 points
Part Number: TPS84A20

Tool/software:

Several TPS84A20RVQT devices have failed in the field with low output voltage. We have found some devices have hairline cracks between the pin 7 metalization and the package (see images below) and others have at a failed solder joint at pin 7. Is TI aware of any cause for these types of failures?

  • 0
    TI__Expert 5990 points

    Hi James

    can you help me understand at what conditions that this occur on your application, is there any stress on the part , pictures you show is near a corner pin . so need more information from you to better understand and address .

    This looks like a reflow stress and modules are more sensitive than ICs while reflow

    Thank you

    Savith

  • 0 in reply to Savith Kumar Rayakanti
    Prodigy 30 points

    Hi Savith,

    We are investigating possible mechanical impact and deflection near this location of the PCB. Please provide more information regarding possible reflow issues.  Note: The PCA is assembled per MSL 3.

    Sincerely,

    James Susong

  • 0 in reply to James Susong
    TI__Expert 5990 points

    Checking with internal team will get back once I get the information

    Thank you

    savith

  • 0 in reply to Savith Kumar Rayakanti
    TI__Expert 5990 points

    Hi James
    Make sure you are following the EVM layout guidance and are not doing something that might add extra stress on the device pins.

     

    what is the use case. Is the PCB potentially flexing in the application? How long have the parts worked in the field until this issue came up?

     

    If you are using the standard MSL3 guidelines it is probably fine but I would verify their reflow temp does not go above 245C. Even though the reflow profile is MSL3, we specify 245C due to the package height.

    Thank you

    Savith