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SN65DP149: Using SN65DP149 as DVI input stage

Part Number: SN65DP149
Other Parts Discussed in Thread: TMDS181, TMDS171, TMDS261B, TMDS361B

We are currently designing a video processing product and chose the SN65DP149 as a DVI input stage in front of an FPGA. The signal path is designed to be:

PC DVI/HDMI output -> cable -> connector -> SN65DP149 -> 100 ohms PCB traces -> FPGA I/Os.

The application example in SLLSEL2C (figure 28) shows the case of using the IC as an output stage. Unfortunately the other use case ("dongle application") is not shown, as figure 29 is a duplicate of figure 28.

Can you tell me if the IC can be used for our planned application, as described above? Do you have access to the correct schematic for the "dongle application"?

Thank you in advance.

Best regards
Lukas

  • Lukas

    The DP149 input is intended to be used with a AC-coupled HDMI. For PC DVI/HDMI output, most likely it will be DC-coupled HDMI. So DP149 is not the right device for this design. Please take a look at the TMDS171 or TMDS181 for this design.

    Thanks

    David 

  • Hi David,

    thank you for the response. We previously planned to use the TMDS181 in our design but it became unavailable so we changed it to TMDS171 which now is sold out too. Is there another device you can recommend for my use case?

    Best regards

  • Hi,

    How about the TMDS261B or TMDS361B? They are two or three port DVI or HDMI switch that allows up to two DVI or HDMI ports to be switched to a single display terminal.

    You can use DP149 for your design, but you also have to AC coupling the DP149 input and also add 50ohm termination to 3.3V. When you add external 50ohm termination network, you are creating a double termination network and the input signal amplitude will be cut in half. So you may need to adjust the PC amplitude to compensate for this reduction in amplitude.

    Thanks

    David

  • Thank you David. We will evaluate your suggestion!

    Best regards
    Lukas