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Original question:

PTH05050W: PTH05050W module internal schematic

PTH05050W: Frequent failures observed at negative voltages during ESS

KARTHIK ARADHYA
Prodigy 30 points
Part Number: PTH05050W

In proven design,PTH05050WAH is used.This component is failing frequently at negative temperatures when we subject the assembled PCB to thermal cycling[-30 to 55 degrees]. This IC is not recovering when PCB is brought back to room temperature.It generates 0v in failed condition and sometimes  more than the desired voltages.kindly guide to sort out the issue.ceramic capacitors are used in the design.

  • 0
    TI__Guru*** 145930 points

    Hi Karthik,

    Can you share some more details about the thermal stress test?  Is the PCB/IC powered and on during the temperature change or is it unbiased?  Is there any humidity present, which might condense during temperature changes, or has the environment been dried out before the test?

    Does the module work normally if power is removed and then re-applied or does it appear permanently damaged?

    Has this behavior occurred on multiple modules or has only 1 been tested?

    Can you send your schematic and any waveforms before, during, after the thermal stress?  You can post them here or send them to me in a 'conversation'.

  • 0 in reply to Chris Glaser
    Prodigy 30 points

    3 ICs are used in the card to generate 1.5,2.5 and 3.3v to provide supply FPGA and cpld.(I cannot share schematic due to restrictions)

    During ESS (Thermal cycling)(-30 to 55 degrees),PCB is powered on through out the cycle.Card draws 1.3 A.when it fails at negative temperatures(-10 to -30),current drawn reduces to 0.2 to 0.6A.

    components are failing permanently in random fashion.It is observed in 3 cards.the batch details of IC are 831197v and 2c1202v.

    Note:

    1. 3 cards were subjected to ESS and All 3 cards failed due to this component.

    After replacing components,card became functional.

    2.As per procedure,the Thermal chamber will be dried out fully before ESS.

  • 0 in reply to KARTHIK ARADHYA
    TI__Guru*** 145930 points

    Thank you for the details of your setup Karthik.

    Does it work fine when held at the same low temperature?  i.e. is it the temperature level or temperature change that causes an issue?

    You can share anything with me, by private message, by clicking on the conversation bubble at the very top right of the page.  Is this allowed for you?

    If you can, you can just share the schematic around the 3x PTH modules and list all the output cap part numbers on the output bus.  The total capacitance is important, not just what is near the PTH modules.