Do they have any special routing requirements?
These lines should be routed just like the HDMI differential pairs: Routed as a differential pair with 100 ohms impedance and length matched.
I have an additional question regarding the HEAC lines. The user guide indicate AC coupling and 50ohm termination to 1.8V. The online reference design has both the 1.8V option and it has a different option for terminating the HEAC lines to GND. It appears that the reference design has the ground resistors stuffed and not the 1.8V resistors. I can't find any commom mode requirements for the HEAC input signals. What is the correct implementation?
I think the reference schematic (ADV7511_ADV7343_Eval_Sch_revE.pdf) includes component options to use or not use the HEAC functionality. The option to not use HEAC is what is populated by default.
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