[SI-LIST] Ground Fill Question

From: "Vishram Pandit" <vishrampandit@xxxxxxxxxxx>
To: si-list@xxxxxxxxxxxxx
Date: Thu, 05 Sep 2002 12:09:02 +0000


I have a question about the ground fill. Typically, for our designs, after 
signal and plane routing is done, the ground fill is used on the remaining 
space. After laying the ground fill, the CAD engineers see whether they can 
find ground vias from the ground fill to the ground plane. If there is no 
via, they remove the patch. It turns out that the ground patches are present 
even if there is only one via on the entire patch. To give an example, say 
there is a ground patch on the sides of a rectangle 2cmx2cm shape. It is 
grounded only at one corner to the ground plane.

Theoretically, we should have as many as ground vias as possible from the 
ground fill (patch) to the ground plane. However, because of the complexity 
of the board, we found only one possible ground via. In this case, will the 
given ground patch be helpful or harmful? What should be the criterion? Is 
there any such design rule stating that there should be a ground via within 
xx cm of distance. Obviously, it is going to be a function of frequency. If 
so, should I use the maximum frequency on the board? If there is no 
grounding via within xx cm of the distance should we reduce the size of the 
ground fill??

Thanks in advance,
Vishram


_________________________________________________________________
Chat with friends online, try MSN Messenger: http://messenger.msn.com

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                //www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

[SI-LIST] Ground Fill Question

Other related posts: