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[ADV7181D] Which is better single GND plane or analog / digital separated GND?

Question asked by Tamu on May 23, 2014
Latest reply on Jun 18, 2014 by GuenterL

Hello.

 

I have some questions about GND layout of ADV7181D.
My customer is going to draw layout of their board.

 

Question 1:
In "ADV7181D_Evaluation_Board_Rev0_Layout.pdf", the GND layout is a big single GND plane.
It is not separated analog and digital.
In HW manual Figure 78: PCB Ground Layout, the GND layout is separated analog section and digital section.
Which is better?
We think big single GND plane is better because HW manual Figure 78 seems to cause larger current under ADV7181D than big single GND plane. We think it may cause higher temperature of ADV7181D package.
What do you think?

 

Question 2:
If GND layout which is separated analog section and digital section is better, which GND pin of ADV7181D should be connected to analog GND?
(If big single GND plane is better, you don't need to answer this question.)

 

Question 3:
Is the exposed pad connected to the GND pin in ADV7181D internally?

 

Thank you!
Best regards.

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