ADM2587 layout to pass EMI/EMC tests

Document created by analog-archivist Employee on Feb 23, 2016Last modified by analog-archivist Employee on Feb 23, 2016
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I'm designing a 4 layer board and I'm using your ADM2587 in our design. Our PCB
must pass EMI/EMC tests and I'm implementing on my board all the techniques
that I readed on the AN-0971 AppNote.

I'm using a board stack-up like this one:
 
Signal/GND fill
Power
GND
Signal/GND fill
 
But I'm having trouble implementing a board's edge guard ring in my design
because the AppNote does not say if I should connect my guard ring with my Top
and bottom ground fill.
 
Also, the Figure 27 on page 17 seems confusing, because at the right side you
can see that the ground guard ring and the top power fill are short-circuited.

In Figure 28, when implementing the guard ring, it does connect to the internal
GND planes, but not with the the top and bottom GND fills.

To summarize: Can I connect the guard ring with the my Top and Bottom GND fill
planes?

 

I’ve attached gerber files for our 4-layer board for the ADM2587E
(EVAL-ADM2587EEB1Z).(See attached file: ADM2582E_C4.zip)

We typically tie the edge guard to the ground fill on the top/bottom layers on
our boards.

AN-0971 does suggest a separate edge guard on the top/bottom layers, I don’t
know if this has extra benefit (though frequent vias are advised between the
top/bottom ground fill and the internal ground reference plane).

Figure 27 appears to have an error, the power plane should not be connected to
the edge guard and should be the same on the right side as on the left of the
diagram where it is shown not connected.

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