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Random Failures in Latest Build

Category: Hardware
Product Number: ADM7171

We have been using the ADM7171 for couple of years now, all low volume runs <60 pcs per run, and have never had any issues.  On our most recent run we are now seeing, as far as we can tell, random failures of the ADM7150ACPZ-3.3.  We have six of these supplies per board and the failures are random within and between boards.  There is no systematic failure we have been able to identify and as mentioned we have been using this part with these components for a couple of years and have never once seen a failure.

All failures have been observed off of the assembly line.  Occasionally we have seen a failure after rework when using a part from the same batch, currently these parts are on order at all suppliers so we have not been able to purchase more.

The failure is generally been observed as an output voltage of ~1.3 V to 1.4 V instead of the fixed 3.3 V.

We have had a change in manufacturers on the most recent run switching to a vapor phase process instead of conventional reflow.  No other parts on the board have experienced failures, off of the assembly line.

The parts purchased this run were from a recommended distributer, Arrow.

Parents
  • Thanks for confirming you're using the ADM7150.
    Given that this design has been in place for a couple of years and the device was ordered through an ADI-authorized distributor, Arrow; suggests the issue might be related to one of the following:

    • Changes in the Bill of Materials (BOM)
    • Board assembly process
    • Manufacturing variations

     

    Here are few things I would recommend:

    1. Check and confirm no change in BOM for circuitry associated to ADM7150
    2. For soldering please refer to JEDEC standard J-STD-020 :

        https://www.jedec.org/

      For LFCSP packages please see our guide at this link:

       https://www.analog.com/en/resources/app-notes/an-772.html

      For SOIC-EP packages please see attached guide 

       PDF

    3. You can also X-ray your device to confirm you have enough coverage

       

      4. Check if the IC is getting correct input voltage at Vin, are you measuring correct voltage on Vreg

        

     

Reply
  • Thanks for confirming you're using the ADM7150.
    Given that this design has been in place for a couple of years and the device was ordered through an ADI-authorized distributor, Arrow; suggests the issue might be related to one of the following:

    • Changes in the Bill of Materials (BOM)
    • Board assembly process
    • Manufacturing variations

     

    Here are few things I would recommend:

    1. Check and confirm no change in BOM for circuitry associated to ADM7150
    2. For soldering please refer to JEDEC standard J-STD-020 :

        https://www.jedec.org/

      For LFCSP packages please see our guide at this link:

       https://www.analog.com/en/resources/app-notes/an-772.html

      For SOIC-EP packages please see attached guide 

       PDF

    3. You can also X-ray your device to confirm you have enough coverage

       

      4. Check if the IC is getting correct input voltage at Vin, are you measuring correct voltage on Vreg

        

     

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