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AM1806: AM1806 internal electrical connection block on the USB0_VDDA33 pin side

Anthony Yoo68
Expert 1320 points
Part Number: AM1806
Hello
My customer is using the AM1806.
However, the AM1806 is being damaged during the manufacture of the customer's board, which has recently applied the AM1806.
More specifically, I received a report on TI bad analysis that told me that the USB0_VDDA33 pin was damaged by EOS.
Currently my customers are suspected of ESD or Surge, but the USB0_VDDA33 pin is not directly connected to the external power line.
Therefore, I suspect that I received Damage due to ESD or Surge coming through USB Vbus 5V power supply.
Can you check the internal electrical connection block of the AM1806? Or can you check the internal electrical connection block on the USB0_VDDA33 pin side?

Please check!
  • 0
    TI__Mastermind 29210 points
    Hi Anthony,

    Was the schematic checked by TI?
    Is the USB electrically configured as device only or does it also support being a host?
    Can you confirm all voltages are within spec and any power sequencing requirements are satisfied?

    Has the customer implemented the recommended load switch to prevent 5V from reaching VBUS whenever the USB 3V3 rails are not supplied?

    There is a known leakage path from VBUS to the 3.3V supply rail, but I would not have expected a sudden EOS to occur during board assembly/test. Is the customer able to root cause the test or assembly event that leads to this failure (ie supplying external power to VBUS)?

    Refer to processors.wiki.ti.com/.../_AM1x_Schematic_Review_Checklist

    "When USB PHY is powered off while still connected to a powered-on host, the customer would notice leakage voltage on the 3.3V supply. This is due to the fact there is a path between VBUS and 3.3V supply rail, that when 3.3V is not applied to the power rail, allow voltage to be leaked from powered VBUS to the 3.3V supply rail. If USB PHY remains to be powered off for an indefinite time, then there is a risk of long-term fatigue on the PHY internal circuitry."

    For debugging tips, refer to processors.wiki.ti.com/.../AM1808_Hardware_Debugging_Guide

    With more information and preferably a copy of the schematics, we can investigate this issue further.

    Regards,
    Mark
  • 0 in reply to Mark Mckeown
    Expert 1320 points

    Hi Mark

    Thank you for your reply.

    We have confirmed your answer and will check with your customer for the information you mention.

    Is it possible to see the electrical connection block diagram inside the AM1806 for the IC internal block separately?

    If you need any procedure to get it, please let me know.

    Thank you 

    Best regards

    From Anthony

  • 0 in reply to Anthony Yoo68
    TI__Mastermind 29210 points
    Hi Anthony,

    No, we do not have any block diagram showing the electrical connections inside the AM1806.
    This information is conveyed with tables in the datasheet.
    See the POWER GROUP(3) column in the Terminal Functions Tables.
    And their mapping to the Supply and Ground Terminal Functions Table.

    I have a slide about the USB leakage paths, but it is marked as TI Proprietary - NDA Restrictions. I would have to either find out if it has been released publicly in another format or scrub it of NDA information and seek approval for general release.

    Is there any further question about this issue?

    Regards,
    Mark