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TPS22948: TPS22948

John DeCesare
Intellectual 310 points
Part Number: TPS22948

Tool/software:

Hi,

I am using a MIC2091 to provide power to an HDMI port. It is failing quite often and I would like to replace it with the TPS22948.  I have hot-wired a TPS22948 in my circuit and tested it. Plugging sinks and sources to it.  So far so good.  But I would like for the circuit reviewed as my customer wants to have a ferrite bead for EMI in the path.   

Also, I was looking at the forum and found this thread.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/926520/tps22948-reverse-protection?tisearch=e2e-sitesearch&keymatch=TPS22948#

This describes what I am seeing with the MIC2091 part and it seems as if the TPS22948 can fail if something "hot" is plugged into the HDMI port if the enable is low. The thread is locked so I cannot see the conclusion which is fairly concerning.  Is it possible to see what the end result of that particular thread is?

Thanks!

John

  • 0
    Intellectual 310 points

    Will anyone be looking at this question?

  • 0 in reply to John DeCesare
    TI__Mastermind 38985 points

    Hi John,

    Due to lot of lab testing, I wasn't able to get back on this. 

    The schematic looks fine. Do you have any waveforms during the test which is resulting in the device failing. Hot plugging can cause high transients. 

    Unfortunately, this thread is over 4 years old so I am not sure if I can access the discussion which they had. 

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    Intellectual 310 points

    Hi Arush,

    No problem on the delay. We are all busy!!  The failure on the Microchip was very infrequent but enough to raise eyebrows and unfortunately, I could never catch a scope shot of when it failed as it never did in my testing.

    The TPS22948 had the same pinout so I was able to solder it into a board and test that as well.  It never seemed to fail but again I couldn't sit there for days on end plugging and unplugging my monitor.

    If I did NOT see that thread regarding your chip failing in what is seems to be a very similar situation, I would have designed the part in but the thread concerns me as I don't want to design in another part that will fail.  So if there is any way to see the conclusion of that thread that would be great.

    If not, then I don't think I should design this part in since it has some history of failures.  Do you have another similar part that will fit the application?

    Thanks!

    John

  • 0 in reply to John DeCesare
    TI__Mastermind 38985 points

    Hi John,

    I understand your decision. It is not possible to check on the discussion from the previous thread as the previous applications engineer is no longer in this team. 

    Let me try to answer this question from my understanding. Most likely you already thought this, but I am just mentioning just in case. 

    Hot-plugging the output with 5V can result in transients, which can exceed the abs maximum of the device (6V). I know, you weren't able to capture the fault but you should be able to check the transients maximum. Also if you try to connect the plug faster, you should be able to get higher transients.

    Connecting some decoupling cap near the device out pin should help if it is these transients which is causing the fail.

    Best Regards,
    Arush

  • 0 in reply to Arush Gupta
    Intellectual 310 points

    Hey Arush,

    Not shown in the schematic (sorry!) is a RCLAMP0524PATCT TVS diode very close to the pin of the HDMI connector.  I would think that would help, if not eliminate the transients.  If I decide to use the TPS part, I can put some caps near the device.  What do you think about the TVS part?

    Thanks!

    John

  • 0 in reply to John DeCesare
    TI__Mastermind 38985 points

    Hi John,

    I don't think TVS part will help much as the abs maximum of the device is 6V and the clamping voltage of this device is 15V. On evaluation, if it is reducing the transients then that is good.

    Best Regards,
    Arush