Jack;
We use 4.2 if was closer to the stuff we were using
-
Lou Dallara   Techno Visionary
"We have it in our power to begin the world again."
       -Thomas Paine, Common Sense (1776)
http://www.waterw.com/~ldallara/pcb_index.html

Olson, Jack C wrote:
>
> WARNING: this is a very unexciting question...
>
> My software does some basic signal integrity analysis,
> and I just noticed it defaults the dielectric constant for
> regular FR4 to 4.7
>
> I was under the impression that most FR4 is at 4.2-4.3
> these days (more resin? thinner cores? can't remember...)
>
> Even a brief response will be appreciated!
>                                                                 Jack
>
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-

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