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March 1998

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Subject:
From:
TOSTEVIN_BC <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 17 Mar 1998 19:03:26 -0500
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     Jan,

     One place where Alloy-42 is routinely used, is in components which
     require some significant degree of hand assembly. Alloy-42's stiffness
     apparently tolerates this process better than the softer copper leads.
     Parts in this category include many of the SMT telecommunications
     impedance matching networks, hybrids, filters, 10 Base-T modules, etc.
     They usually contain toroid core transformers, whose windings must be
     hand soldered to the leadframe.

     Without a sufficient solder dip coating, and a warmer profile than
     normal, Alloy-42 parts can be quite difficult to solder.

     Bruce Tostevin
     Benchmark Electronics Inc.
     Hudson, NH


______________________________ Reply Separator _________________________________
Subject: [TN] leadframe materials
Author:  Jan Vercammen <[log in to unmask]> at 0UTG0ING
Date:    3/16/98 3:15 PM


hello,

I have a few questions concerning package leadframe materials of integrated
circuit packages. I have subscrided only recently to ChipNet and I will
submit the same questions there. However, some of the subscribers on TechNet
may have valuable info on the subject.

-1- are non-copper materials (e.g.Invar, Kovar or Alloy-42 which are Fe-Ni
    alloys) still used alot for leadframe design of surface mount devices?
    What is the percentage of copper leadframes on the market today?
-2- is there a finish used for copper leadframes and, if so, what materials
    are used and what is the covered thickness?
-3- who has information on or can list references or literature on the complex
    permeability of non-copper leadframe materials ( (e.g.Invar, Kovar or
    Alloy-42)

All help, however small is appreciated.


regards,

Jan Vercammen

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