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TPS62869: TPS62869 work abnormally after SMT patch

Hale Tan
Expert 3770 points
Part Number: TPS62869

Tool/software:

Hi team,

The customer found that TPS62869 work abnormally after SMT patch. They found that 1 pcs can't read the I2C address and no output. And another 1 pcs can read I2C address but also no output. So they want to know whether we can provide some judgment about which function in the devices works abnormally. They have tested Impedance of all of pin. And the abnormal devices PIN Impedance are the same as the normal PINs Impedance. If you have any suggestion about how to avoid such issue, please help share your comments.

  • 0
    TI__Guru**** 150930 points

    Hi Hale,

    What is SMT patch?

    They can try resoldering the IC, in case one of the pins is not making good contact.  They can also try soldering it on an EVM and seeing if it works there.

    They can also measure Vin, Vout, SW, and VSET at power up to see if there is any difference between a good board and bad board.

    Chris

  • 0 in reply to Chris Glaser
    TI__Expert 3770 points

    Chris,

    They have verified that the issue devices are working abnormally and did test such as ABA.  Just want to make sure, what function do you think are wrong with the issue devices? Are there any suggestions to avoid such problems? 

    Chris Glaser said:
    What is SMT patch?

    SMT means PCBA process.

  • +1 in reply to Hale Tan
    TI__Guru**** 150930 points

    Hi Hale,

    It is still not clear to me.  Do they not work after the initial reflow and assembly onto the PCB?  If so, these sorts of issues are usually debugged by the company doing the SMT--they may need to change their reflow process somehow.

    Do the devices still not work on an EVM?  And does a good device work on the failing system?

    I would still like to see waveforms of those signals to compare them.

    In any case, I'm not sure if it matters which function of the IC is damaged--the IC sounds like it is damaged and they must prevent such damage in the future.

    Chris

  • +1 in reply to Chris Glaser
    TI__Expert 3770 points

    Chris,

    Chris Glaser said:
    If so, these sorts of issues are usually debugged by the company doing the SMT--they may need to change their reflow process somehow.

    Understood. Thanks.