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TPD4S012: TPD4S012 enumeration issues with USB2.0

Part Number: TPD4S012

I am using this part for ESD protection of a USB2.0 interface.  The part has been used in production for years with no issue but over the last couple weeks we are running into issues where the USB I/F will not enumerate.  We remove this device and it works fine (but we obviously don't want to run this I/F without ESD protection).

It's a pretty straightforward part but is there possibly a short/open condition with soldering that may cause the issue we see where the USB 2.0 I/F will not enumerate (acts like it doesn't see the device) with this part inserted?

  • Hello Howard,

    I'm sorry you're experiencing this issue. This does sound like the diode is shorting the signal to ground since the system works after removing it. This usually happens when the diode experiences a transient ESD voltage that is higher than its IEC 61000-4-2 rating (in this case 9-10 kV), or it experiences a constant DC voltage (> 20 us pulse) that is higher than its Vrwm (in this case 5.5 V for D+/- and ID pins and 15 V for Vbus). I have a couple of follow up questions for this:

    1. Was there any sort of stress testing done before these diodes started to fail?

    2. Are the normal operating voltages across the protected lines still at or below the device Vrwm?

    3. Is there any chance of an additional induced current across these lines? (refer to page 3 of this document for details)

    Let me know if you need clarification on any of these questions. 


    Matt Smith 

  • Hi Matt,

    Thanks for the response!  In answer to your questions:

    1. No, there was no ESD testing performed on these specific units nor any "stress" testing pertaining to source voltage/temperature/vibe.

    2. This part is protecting a USB2.0 I/F and therefore the reverse working max voltage (Vrwm) should not be violated.

    3. The part is right next to the USB2.0 connector and the path only goes to the USB interface on a TI TM4C129NCZAD processor which is farther away from the connector.

    Some additional information since I put this issue in:  It seems that putting the part back onto the board brings back full functionality.  In other word the USB interface will not enumerate, we take this part off and it works fine, we put the part back on an it still works fine.  

    We have a couple people looking at this issue, would you be open to meeting over the phone with us to discuss this issue?  It may save some time going back and forth on the E2E site.

  • BTW, Matt, is there a number I can call you at? Or can you call me?  (408) 761-3724.  Thanks very much, Howard.

  • Matt Smith was instrumental in pulling together representatives of the product line to allow us to come up with an action plan to analyze a root cause of the issue.  I really appreciate how he "went the extra mile" to assist us with an urgent issue.  With the TI team input we are working toward resolution.

  • Howard,

    Glad that we were able to work through this issue together. Feel free to mark this issue as resolved and reach out if you have any more questions on this or other ESD/TVS related issues.