I have some FETs soldered to exposed surfaces on my board (D-squared
package).  Under some conditions, they may get up around 120C (the part is
rated up to 175C).  I'm not worried about the FET, but I may be playing with
fire on the board.  I want to know how much fire I'm playing with . . .
The IPC maximum temperature spec for FR-4 is 120C (if I'm reading things
correctly).  What type of things start to happen at this temperature?  Is
this where the board starts to discolor over time, or are there physical and
electrical changes that occur in this range.  Do I need to worry about long
term reliability?

Thanks,
Carl

Carl Van Wormer
Cipher Systems
1815 NW 169th Place, Suite 5010
Beaverton, OR  97006
Phone (503)-617-7447    Fax (503)-617-6550

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