The Dk listed in IPC-4101 slash sheets is maximum allowed, not nominal.
Typical FR-4 is in the 4.2-4.6 range. Getek/Megtron is lower, in the 3.8-4.0
range.
A lot of PWB prints call out "Getek or equivalent" when they do specify it.
It is a polyphenylene oxide/epoxy mixture.

Tim Reeves

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Marsico, James
Sent: Wednesday, February 25, 2004 7:42 AM
Subject: IPC-4101 Material


Good day...
Our designers want to use an FR-4 material which is designated as
IPC-4101/25.  The /25 material has a permittivity of 4.4, while the other
FR-4 materials (/21and /24) are listed as 5.4.  I found out that GETEK is
classified as /25, and was wondering if this is the only /25 material
available.  Is there a generic (or product) name for the /25 material?  The
slash sheets in 4101 have a maximum permittivity at 1 Mhz, do the graphs
exist that show the Dk at various frequencies?

Jim Marsico
Senior Engineer
Production Engineering
EDO Electronics Systems Group
[log in to unmask] <mailto:[log in to unmask]>
631-595-5879

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