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SN65DP159: DP159 used with fixed TX Termination in HDMI1.4b and HDMI2.0

Kawai
Guru 19785 points
Part Number: SN65DP159

Hi Team,

Can we support (guarantee the operation) customer using TX termination fixed to "75-150 [Ohm]" for HDMI2.0 and HDMI1.4b ?

The recommendation should be the following setting.

They want to minimize the I2C communication, however, the problem is that since they use in I2C mode, they cannot set to automatic select mode.

What would be the side effect by using in fixed termination with 75-150 Ohm ?

It seems to be passing the Compliance Test.

Best Regards,

Kawai

  • 0
    TI__Expert 5455 points
    Hello Kawai

    The range from 75 to 150 Ohms, is the termination that the device should have and they shouldn't have any problem with this one.
    HDMI2.0 standard requires the transmitter termination impedance should be between 75 to 150-Ω. Older versions of the HDMI standard required no source termination. For HDMI1.4b when data rate over 2 Gbps, the output performance could be better if the termination value between 150 to 300-Ω which was allowed. The SNx5DP159 supports three different source termination impedances for HDMI1.4b and HDMI2.0. Pin 36, TX_TERM_CTL, offers a selection option to choose the output termination impedance value. This can be adjusted by I2C; reg0Bh[4:3] TX_TERM_CTL.
    In this case, the We recommend selecting the "automatically selects the impedance option" because this one is not configured only by I2C. If you only want to use strapping mode, you can also configure this option if you let floating the TX_TERM_CTL.

    Regards
    Francisco
  • 0 in reply to Francisco Javier Zamudio
    Guru 19785 points
    Hi Francisco-san,

    I apologize for the late reply. I would like to clarify your comments above.

    Do you mean that customer could use this way without problem, since HDMI 1.4b or older versions does not have requirements for source termination ?

    One problem for this device is that if customer chooses to use I2C control, there is no way to select "Automatically selects the impedance option". It was better to have the same function through I2C configuration.

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Expert 5455 points
    Hello Kawai

    Yes, I do. Do you know the data rate that they will use?

    Regards
    Francisco
  • 0 in reply to Francisco Javier Zamudio
    Guru 19785 points

    Hi Francisco-san,

    They will use for both HDMI1.4b and HDMI2.0.

    Best Regards,

    Kawai

  • 0 in reply to Kawai
    TI__Expert 5455 points
    Hello Kawai

    I recommend you to use the 75 - 150 Ohms termination impedance. The other options are if you want to have the best performance by the chip, but for the application, the best option is 75 - 150 Ohms.

    Regards
    Francisco
  • 0 in reply to Francisco Javier Zamudio
    Guru 19785 points
    Hi Francisco-san,

    I will tell them that they could use 75-150 Ohms TX termination for both HDMI2.0 and 1.4b.
    Thanks for your support.

    Best Regards,
    Kawai