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SN65DP159: Use SN65DP159 at the HDMI 2.0 RX Side ,substitute TMDS181.

chiu wesley
Prodigy 40 points
Part Number: SN65DP159
Other Parts Discussed in Thread: TMDS181

HI Ti TEAM:

We want to use SN65DP159 at the HDMI 2.0 RX side to replace TMDS181.(We want to remove TMDS181)

HDMI CONN(HDMI 2.0 RX) ---> SN65DP159--> Xilinx FPGA --> (XILINX HDMI IP)

Please confirm the feasibility of this solution.

Is there any other concerns?

Please let me know!

Thank you a lot^^

  • 0
    TI__Genius 13290 points

    Hello, 

    What is the intended input into the device DP++ or TMDS?

    The DP159 is AC coupled input and intend to be used with a AC-coupled HDMI or DP++ source. The TMDS181 is a DC-coupled input and intend to be used with a DC-couple HDMI source. 

    You can replace the DP159 with the TMDS181 but make sure that you are using the device with an AC coupled input and not a DC coupled input.

    Thanks,

    Zach

  • 0 in reply to Zach Dryer
    TI__Guru**** 150185 points

    Hi

    The DP159 is expected to work with a DP++ or an AC-coupled source as Zach pointed out in his response.

    But DP159 can also work with a DC-coupled input. When interfacing to a DC-coupled input, the DC-coupled or HDMI source expects to see a common mode voltage of 3.3V. An external termination network (Rterm) to 3.3V is therefore needed to restore this common mode voltage as shown below.

    However this effectively creates a double termination network. A Rterm of 50ohm can be used but it will cut the output swing in half. This means to use the Dp159 as a sink side application, the source need to be tuned to compensate for the drop in output swing.

    A larger Rterm will minimize the impact of double termination. The maximum value used for Rterm will depend on the HDMI TX capabilities. HDMI TX vendor needs to be consulted to find out the maximum allowed Rterm.

    Thanks

    David

  • 0
    Prodigy 40 points

    HI Zach:

    What is the intended input into the device DP++ or TMDS?-->We FPGA IP is TMDS format of input!

  • 0 in reply to chiu wesley
    TI__Genius 15055 points

    Hey Wesley, 

    David's response should cover what you need to be aware of when using the DP159 in a sink application. As long as the issues of double termination and proper biasing are handled correctly the DP159 can work in a sink application.

  • +1 in reply to Vishesh Pithadiya
    Prodigy 40 points

    Hey Vishesh & David:

    We know that from HDMI connectors --->50ohm termination to 3.3V ---> AC coupling cap ---> DP159 input side.

    We want to know, the circuit output from DP159 to FPGA MGT Bank.
    Can this related circuit be provided?

    Thank you a lot^^

  • 0 in reply to chiu wesley
    TI__Guru**** 150185 points

    Hi,

    Since the FPGA input typically requires to be AC coupled, you would have AC coupling capacitors between the DP159 and the FPGA. But the DP159 output would require the 3.3V termination voltage. So you will have 50ohm to 3.3V termination. So the entire structure will be

    DP159 ---> 50ohm termination to 3.3V ---> AC coupling capacitors ---> FPGA

    You can adjust DP159 VSADJ to compensate for the drop in the output signal amplitude.

    Thanks

    David