About where to connect ground planes...

Technically, it depends on the design. But don't be concerned, unless you are on the bleeding edge of the performance envelope (i.e. approaching GHz), this usually won't be something that will make make a difference. Generally speaking, the more vias the better.

Dave.

What would be the point of that? The whole point of vais is to provide the shortest route to ground and also to make it easier to route. If you use a star ground like method I would imagine the ground plane would be somewhat useles? I'm sure its better than nothing but I'm guessing that its effectiveness is drastically weakend.

I have no idea. I imagine its not that big a deal because high performance PCB's have many vias. Chances are you solve more problems than you create if you use many vias rather than trying to minimize them.

What type of application will this board be used in? Will it be exposed to heat, moisture, etc... If so, think carefully about flooding top and bottom layers with ground plane. Dendretic growth could kill an otherwise good product.

Gerb

The vias are already connected to the ground panel which is an internal layer. That is the point indeed. I don t want to "reconnect" them to a "redundant" ground panel, placed at the top of the board (many little ground loops).

Unless you're doing something specific like coplanar waveguide, additional topside ground pours probably have no effect.

If two points are already connected by a sheet of copper, more copper won't do much. "Ground loops" is a pretty fuzzy concept in this context.

If you're trying to reduce the sheet resistance of the internal ground plane for some reason, use lots of vias.

John

It should do no harm - just FYI, that's not where "ground loops" come from.

Cheers! Rich

Thanks for the quotation.

Cheers...

Franco.