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TPD12S520: HDMI 1.4b compliance testing

Raja Ashutosh Kedia
Intellectual 430 points
Part Number: TPD12S520
Other Parts Discussed in Thread: TPD1E05U06

Hi,

We are planning to use the TPD12S520 device for ESD protection and/or Level shifting of HDMI TMDS/Control signals. I see that its datasheet mentions "Supports All HDMI 1.3 and HDMI 1.4b Data Rates". However, has the device HDMI 1.4b compliance testing been performed on the device and is it HDMI 1.4b compliant?

Further, we have also used TPD1E05U06 part for ESD protection to +5V signal from HDMI connector. Please let us know about HDMI compliance of this part as well.

Also, please let us know if we need to follow any guidelines apart from those mentioned in the datasheet to be HDMI 1.4b compliant.

Regards

Raja

  • 0
    TI__Genius 9230 points

    Hi Raja,

    TPD12S520 & TPD1E05U06 would not be subject to HDMI compliance testing; however the added capacitance of the TVS diodes can lengthen the rise and fall times of the data signals, thus reducing the controller's ability to support the switching speeds necessary for HDMI 1.4b.

    Luckily, since the TVS diode capacitance of these ESD devices are very low (0.8-pF & ~0.5 pF, respectively) they should have an insignificant effect on these rise and fall times.

    As long as the combination of your HDMI controller & the ESD device can support the needed switching speed with a consistent signal, you should be compliant from a physical layer point of view. Keep in mind that HDMI compliance is also firmware/software driven, so your controller should be your main focus for whether your system is HDMI 1.4b compliant or not.

    Let me know if this answer your questions.


    Thanks,
    Thomas A.

  • 0 in reply to Thomas Amlee
    Intellectual 430 points

    Dear Thomas,

    Thanks for the detailed response.

    Are you aware of these devices being used in a system, in which HDMI compliance testing is done and verified?

    Regards

    Raja

  • 0 in reply to Raja Ashutosh Kedia
    TI__Genius 9230 points
    Hi Raja,

    Can you rephrase the question? I'm a little confused by the wording.

    My understanding is that you send your system to an HDMI certifying authority, they test the HDMI functionality of your product (mainly software driven tests) and tell you whether your whole system is compliant. The way that the ESD device would have any influence on this is if the capacitance of the ESD diodes interferes with the eye diagram of the data or control signal resulting in dropped bits which would cause variation in the data sent or received by the controller.

    Regards,
    Thomas A.