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Original question:

TDP158: Looking for a redriver for HDMI2.0

TDP158: TDP158 work as HDMI redriver for 4K60p application

Gary Teng
Genius 5830 points
Part Number: TDP158
Other Parts Discussed in Thread: TMDS181

Hi sir,

 My customer use TDP158 as HDMI redriver on intel Elkhart lake platform and they have question about HDMI level shifter configuration on bios setting: If they set the level is 450mV (as default), the max output resolution is 1080p. But if they adjust it to 850mV, they can get 4K video signal. We see they have ac couple capacitor on board. Do they still need external termination to 3.3V between the HDMI source and AC cap as the previous post suggestion? And any suggestion for the pull up resistor? Thanks for your kindly help.

e2e.ti.com/.../3388969

Best regards,

Gary Teng

  • 0
    TI__Guru**** 176721 points

    Gary

    Does the source support AC-coupled (DP++) or DC-coupled HDMI? If the source supports AC-coupled HDMI, then you just need to have AC coupling caps between the source and the TDP158. But if the source only supports DC-coupled HDMI, then you will need the external termination and the AC coupling caps or switch to TMDS181. A larger termination resistor (Rterm) will minimize the impact of double termination. The maximum value used for Rterm will depend on the HDMI TX capabilities. Typical Rterm is 50ohm, but it will cut the signal amplitude in half.

    Thanks

    David