Any one knows how to do ADV7441A ADC calibration for CVBS and VGA source ?
I can't find any documents about that.
Any comments is welcomed.
According to our ADV7441A support team, all ADCs are optimized at test. There is no need for these to be calibrated by customers.
Thanks for your reply..
Besides to that calibration problem, I have a new question about VGA input layout after reviewing EVB design file.
As recommand, input should provide 75-ohm impedance for VGA traces but I don't see that implemented on EVB.
Do you have idea why?
I see in the ADV7441A schematic that "Trace impedance of analog inputs to be 75 ohms". Why do you think the trace impedance of VGA signals on the evaluation board is not 75 ohms? How can you determine this?
You are right that there's description about 75 ohm impedance for VGA input on schematic file.
But if you check "layout.pdf" especially Layer 1 and Layer 2 for VGA traces, the trace width is similar to HDMI trace.
In my opinion, the impedance control for VGA trace is calculated reference to Layter 2 GND.
It should be thinner to achieve 75 ohm.
Sorry that i just noticed there have different trace width if I enlarge the pdf file..
I think your EVB did achieve that...
Besides that I noticed that in layout guide it mentioned better to have GND between traces, but it was totally removed in EVB..
Thanks for reply Matt!!
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