Seamon, James A (GEL,MSX) wrote:
> 
> HELLO TECHNETTERS,
> 
>         DOES ANYONE HAVE ANY ADVICE ON FINDING DERATING CURVES FOR BOARD
> MATERIALS FR4, Chem1,Chem2 or Chem3? I AM RUNNING THERMAL TESTS ON P.C.
> BOARDS FOR UL QUALIFICATION AND I AM SEEING TEMPERATURES AROUND 140'c.
> ANY INFORMATION WOULD BE APPRECIATED GREATLY.
> 
>                 THANK YOU FOR YOUR TIME AND CONSIDERATION.
> 
>                                 J.A.S.
> James A. Seamon
> 
> James A. Seamon
> 
> 
James

The thermal rise above ambient charts in the IPC's-D-275 and the newer
222x series of specifications are based primarily on convective air flow
heat transfer with some thermal spreading resistance of the base
material to provide some additional heat source area.  I don't have any
personal experience with the Chem 1, 2 or 3 laminated materials.  I
suspect the thermal conductivity properties of the base materials are
very similar to the GE and GF (FR4) materials used to develop the
charts.

Ralph

Ralph Hersey & Associates
PHN:  510.454.9805
FAX:  510.454.9805
e-mail:  [log in to unmask]

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