Dan Michaels wrote:
>
> ........
> >
> >Now that we can get heat rise on a trace, which I had some data on before, what
> >is a safe operating temperature?  If board browning or mask discoloration
> is the
> >primary limitation for your design, at what absolute temperature does the mask
> >begin to be damaged?  If we know the absolute temperature, then we know the
> >ambient+rise.
> >
>
> The general bent of this thread seems a little strange to me.
>
> As a general rule of thumb in electronics, it seems reasonable to
> allow 2-3x safety margin on most critical design decisions - especially
> those concerning power dissipation levels. It would seem that even so
> much as thinking about driving traces to the point where they are
> heating up or glowing or discoloring the pcb might be like flying
> too close to the sun on waxed wings.


Obviously, visable signs of damage to the PCB are not wht you use for a
good design goal. So, what *would* you use as the limiting factor(s) for
temperature and power dissipation of the trace?

-- Rich