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TPS40170: Device damaged

Josep Colominas
Prodigy 10 points
Part Number: TPS40170

Hi,

TPS40170 generally performs well in our design, delivering over 200W to the load. Vin is 48V and Vout variable.
But sometimes our customer return us burned PCBs with the device damaged for no reason, always with similar behavior. 
We attach image. We also attach part of the schematic. Anyone have any idea why this happens?

Thanks

  • 0
    TI__Mastermind 26520 points

    Hello Jospeh,

    Typically when a device fails in this catastrophic manner its likely due to electrical over stress (EOS).  Do you have a condition where there is a VIN transient that is greater than the VIN maximum capability for this device?  Do you have an input filter that is well damped?  Input transient and or an under damped input filter can lead to EOS.  Other possibilities that contribute to EOS is poor layout, another condition is if the load is inductive.  Please provide details on the above points.

    I have assigned this thread to Tim who will assist from here.  Thanks in advance.

  • 0
    TI__Mastermind 49597 points

    Hi Josep,

    Just looking at the schematic, the input capacitance is very low (only 220nF). It should be at least a few uF to manage the switching current, especially at the low switching frequency.

    If further analysis is required here, please complete the TPS40170 quickstart calculator and send the applicable switching waveforms (SW, HDRV, LDRV).

    Regards,

    Tim