Hi ADI Expert,
My customer refer the CFTL CN0422 HDMI-isolation reference design to made their owe PCB, but failed at HDMI compliance testing and some monitor can't turn-on too.
The device configuration all the same as CN0422 720P/60Hz.
Blow as capture of HDMI compliance test report.
Item 2~4 source eye diagram fail, data jitter was out of spec.
Item 18~25 source low amplitude fail, out of spec 2.700V~ 2.900V
So I checked PCB layout again, Pls refer to PCB placement as blow, as you can see Skylake-U chips output TMDS signal as TMDS-1 trace first, which length around 3000mil than pass through a connector to isolation daughter board. TMDS-2 trace length around 2500mil passed through to ADN4654, than couple out iso-TMDS trace length around 1000mil.
Each of TMDS data0~2 and clk pairs are length equally.
I doubt of trace length and connector attenuation effect, may I have your comment of this issue, thanks.
[edited by: RayW at 9:36 AM (GMT -4) on 15 Sep 2020]