ADV7611 at resolution 1920 1080 60Hz has some noise

I got it.

I saw that for pixel clock frequencies above 110Mhz, the magnitude of LLC signal rapidly decreased, from 3v3 to something near to 1V, so started to think that this degradation could have cause some misalignment between clock and data lines going to the DAC ADV7125. 

When i came to this thread: https://ez.analog.com/video/f/q-a/9697/adv7611-video-quality-issue, i thought it was my same problem, and the proposed solution worked also for me.

Adjusting the DLL PHASE did the trick.

Kind Regards

emazed

Hi,

  Thanks for letting us know.

Thanks,

Poornima

One other issue to watch for is the bandwidth of the scope you are using to measure the clock frequency with.  If it is only a 200MHz scope then it will start attenuating the signal and turn it into a sinewave.

The DLL adjustment needs to be done a the fastest format and will often fix noise issues that don't appear at slower formats.  Each design might need different adjustments however once found it should be baked into the configuration and good for the entire product's production run.