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Multi Chip ADV7619 output flicker issue

Question asked by paul.shi@analog.com Employee on Jul 1, 2015
Latest reply on Jul 1, 2015 by mattp

    My customer finds when they use multi chips ADV7619 (8pcs ADV7619 at most) on one board to process 8 channel UHD video input signal, some ADV7619 output display flicker.

 

    By checking the schematic, the serial resistor of Clock and resistor is 22ohm, (internal synchronization mode and default drive current). The schematic below shows the suggested resistor value is 75ohm, but another reference manual suggest 33~220ohm.

 

     we try these value resistor from 22ohm to 100ohm or add a small capacitor, no improvement at all, But if reduce the TMDS clock such as down to 148MHz, the problem seems improve a little.

 

     They hope to know the consideration of the resistor value selection, they usually to use 22ohm. And hope to know if they use multi ADV7619 on one board, the smaller resistor such as 22ohm will increase the EMI and cross talk issue?

 

 

     

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