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HDMI to CVBS conversion


I found a way to convert HDMI to CVBS with two chips: HDMI->ADV7611->ADV7393->CVBS

Is this the easiest and cheapest solution?

Parents Reply Children in reply to Mihalich

1) Use 22 or 33 Ohm resistors instead of 75 Ohm series resistors.  Normally PCBs are designed for 50 Ohm and you try to match line impedance to the PCB designed impedance.  Need 50 Ohm PCBs for HDMI traces

2) Check out for a simple tools to specify PCB trace impedances

3) 1V8_PVDD and 1V8_PVDD_DAC need to be very clean rails.  I don't see the decoupling caps here.  Usually a LC type filter on the rails

4) 7393 DAC output needs a 75 Ohm series resistor with a 75 Ohm load resistor at the end of the cable and the video_out trace designed for 75 Ohm PCB trace.

5) You caught exposed ground pads on both parts.  GOOD.  You don't know how many people miss that.

  • Thanks.

    I will consider all the comments.

    All power rails have filtration like in DS.

    About 7393 DAC output. DAC FULL DRIVE OPTION not recomended 75 Ohm series resistor, see picture:

  • FormerMember
    0 FormerMember in reply to Mihalich

    You are correct.  Sorry, I looked at too many schematics that day.