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DS64BR401, DS80PCI800/402 - Using as a Display Port repeater

Guru 19775 points
Other Parts Discussed in Thread: DS80PCI800, DS64BR401, SN75DP130, TMDS141

Hi Team,

Please let me ask you about the display port repeater.

[Question]
Our customer is considering to use DS64BR401 for Display Port / HDMI input. Would there be any problem using this device ? How about DS80PCI800 for Display port / HDMI application ?
I believe the it has enough bandwidth.

.

I know that there is a dedicated repeater (redriver) for each interfaces. If you cannot replace with these devices, I would appreciate it if you could tell me the reason why.

Best Regards,
Kawai

  • Hi Kawai,

     

    There are several reasons for using dedicated technology redriver.  The devices you show support PCIE and SATA/SAS type of applications.  These technologies have their own methods for link training and detection.  DiplayPort has its own link training methods that adjusts output swing and pre-emphasis levels that the above would not support and could cause issues in a box to box link.  DisplayPort also has other signaling that is important to understand like the AUX and Hot plug Detect signal.  Look at the SN75DP130 to understand the difference. 

    As for HDMI, the above devices have the wrong interface.  HDMI is based upon TMDS physical layer which is DC coupled 3.3V common mode.  To see the difference see the TMDS141 which is an older version but still shows the difference.  HDMI like DisplayPort has other signals to take into account, DDC and HPD.

    Regards

    Richard Hubbard

  • Hi Kawai-san,

    I agree with Richard's comments. The DS80PCI800 and DS64BR401 were not designed for Display Port/HDMI applications. As a result, the repeaters are not tested or validated for the Display Port/HDMI protocol specifications and signaling requirements. This also means that our repeaters are not ensured to work properly in applications than the ones supported in accordance with the front page of the datasheet, even if they can theoretically work at the operating data rate for Display Port/HDMI. Users who choose to use the DS80PCI800 and DS64BR401 for applications outside of the original design scope do so at their own risk.

    Because of this situation, we recommend using other repeaters or retimers that have been designed with intent for use with Display Port/HDMI applications.

    Regards,

    Michael

  • Hi Richard-san, Michael-san,

    Thank you for the explanation. I understood.

     We will answer and ask our customer to use the dedicated DisplayPort or HDMI devices.

    Best Regards,
    Kawai