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TLK110: AVDD3.3(Pin 22)and PFBIN2(Pin37) are both short to GND

Intellectual 2655 points

Replies: 7

Views: 70

Part Number: TLK110

Hi team

My customer developed 50 units demo products with TLK110 as the Ethernet PHY. But after a period of operation, we found that 4pcs TLK110 are malfunctional out of the 50 units demo products. When we removed the failure TLK110 from the board and tested it, we found that AVDD3.3(Pin 22)is short to GND and PFBIN2(Pin37) is short to GND. And all the 4pcs failure parts have the same phenomenon. 

So I just want to check with you is there any possible reason to damage Pin22 and Pin37 at the same time? Thanks.

Best regards,

Wayne

7 Replies

  • Hi team,

    Add one more question. Could you please provide the internal structure of PFBIN2, PFBIN1 and PFBOUT? I just want to understand how the internal circuit is so I can find some clue why PFBIN2 is short to GND. Thanks.

    Best regards,

    Wayne

  • In reply to Wayne Wang20:

    Hi Wayne,

    Thank you for sharing this information. I will have to ask our design team about the internal structure and how this phenomenon occurred. 

    I will try to get back to you in the next couple of days with their response.

    Thanks,

  • In reply to Cecilia Reyes:

    Hi Wayne,

    I have a couple more questions:

    1. Can you please share your schematic?

    2. When you removed the device, were the decoupling capacitors on these pins damaged? 

    3. What type of design is this? Is this used for POE? 

    4. Is there a reason you are using the TLK110 and not one of our newer devices in our portfolio?

    Thanks,

    Cecilia

  • In reply to Cecilia Reyes:

    Hi Cecilia,

    Please see the schematic as  below.

    Echo to your question:

    1. When you removed the device, were the decoupling capacitors on these pins damaged? 

    The caps are all OK. And when customer removed failure device from the board and then solder new device onto the board, the new device works normally

    2. What type of design is this? Is this used for POE? 

    Not for POE, just basic Ethernet communication. It is used to update software to the main  controller.

    3. Is there a reason you are using the TLK110 and not one of our newer devices in our portfolio?

    No specific reason. This is a old previous design and it is just SOP recently.

    Best regards,

    Wayne

  • In reply to Wayne Wang20:

    Hi Wayne,

    Thanks for the update. For future designs I believe it is best to push the customers to the new products in our portfolio.

    Can you explain more on what you mean by the board had malfunctioned? 

    For the decoupling capacitor question I find it interesting that the capacitors on PFBIN1/2 and PFBOUT were OK when those pins shorted to ground. How did you check that the pins on the failed devices were shorted?

    Thanks,

    Cecilia

  • In reply to Cecilia Reyes:

    Hi Cecilia

    The board had malfunctioned means when customer plug in a RJ45 cable, they found the Ethernet communication cannot work.

    For the failed device, we removed it from the board and use a digital multimeter to test the resistance from its each pin to its GND pin. And we found those 2 pins are both shorted to GND pin.

    So is there any feedback from design team about the internal structure? Thanks.

    Best regards,

    Wayne

  • In reply to Wayne Wang20:

    Hi Wayne

    Unfortunately according to our design team we cannot share the internal structure of the pins. 

    Best,

    Cecilia

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