FreeLists / si-list / [SI-LIST] Re: FR4

["Greim, Michael" <mgreim@xxxxxxxxxxxx>]

Here are a couple of links to papers that 
may be useful for you.....

http://www.speedingedge.com/docs/tutorial.doc

http://www.amp.com/products/simulation/files/papers/dc99cmdh.pdf

Best Regards,

Michael C. Greim                 Sonus Networks
mgreim@xxxxxxxxxxxx        978-589-8336

Making the world safe for digital signals everywhere

And all this science I don't understand
It's just my job six days a week

The time is gone. The email's over
Thought I'd something more to say......


-----Original Message-----
From: Martyn Gaudion [mailto:martyn.gaudion@xxxxxxxxxxxxxxxxxxxx]
Sent: Tuesday, July 10, 2001 4:57 PM
To: si-list@xxxxxxxxxxxxx
Cc: Rich Peyton
Subject: [SI-LIST] Re: FR4



Rich,

Its well worth taking a look at the laminate vendors web sites.

It is also worth noting that FR4 is a resin glass
composite based on Glass with Er of around 6 and
resin with Er of around 3.

If you are designing differential traces on fine
spacings you need to take this into account.

Typically most fabricators use 4.3 or 4.2 for single
ended designs, but for close spaced differential traces
they use 3.6 to 3.8

An explanation of this effect is here:

www.polarinstruments.com/support/cits/AP139.html

Kind regards
Martyn Gaudion



At 13:57 10/07/01 -0400, you wrote:

>Hi
>
>what is the dielectric constant for FR4?  Or a web site with listing of
>typical materials and there constants?
>
>Thanks,
>Rich
>
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