Re: P&H Injector Interface

[garwillis@msn.com (Garfield Willis)]

On Fri, 19 May 2000 16:40:26 -0400, "Swayze" <kswayze@bellsouth.net>
wrote:

>I checked one of my handbooks for some charts on heat transfer and..
>surface area wise
>in free air at 25degC an enclosure would dissipate about  3 W/cm**2 surface
>area
>
>the figures for dissipation using a metal plate kick up to almost 16W/cm**3
>up to about 80W/cm**3
>
>no real hard equations here, just rough graphs.

Oh yah, tanks. Got it covered. They teach you all that stuff in EE charm
school. :) BTW, the problem in this case (no pun intended) isn't so much
the amount of heat, it's the underhood worst-case ambient you have to
deal with to design in the right safety margin. Plus, failure rate in
semiconductors is directly related to depth and frequency of thermal
cycle, so even if you make everything keep the junction temps just below
max worst case, you're still stressing the device. That's why you want
plenty of margin.

Gar


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