I'm not sure this is the correct forum for this topic, but here is my two 
cents worth.  As I understand it, there is a trend in much of the military 
industry to use parts which have not been screened to military standards and 
which may not even necessarily meet the required military temperature range. 
 This requires two things: 1) the supplier of the parts must be certified by 
you or someone you trust to supply commercial parts which will "survive" the 
environment for your product, and 2) you "may" need to relax some of the 
specified parameters to compensate for the expanded temperature range over 
which the part must operate.

A group who has done extensive work in this area is the CALCE Electronic 
Packaging Research Center at the University of Maryland.  They claim that 
many parts are designed to operate over a wider temperature range than 
specified and they may be willing to tell you what their internal design 
temperature rule are.  They will probably not be willing to guarantee these 
parameters, however, because they are not tested over temperature.  The 
CALCE Electronic Packaging Research Center  cites a test case of a Motorola 
MC68332 32-bit microprocessor in a 132 lead PQFP package specified to run 
from -40 to 85 degrees C.  10 of 10 devices tested passed parametric testing 
to -70 degrees.  One device stopped operating properly at -90 degrees until 
its temperature was raised.  20 out of 25 devices passed functional testing 
at -150 degrees.  Later qualification tests to -65 degrees found 0 out of 
720 devices tested!  They also commented that even though the parts were 
rated for 16MHz (suggesting that they were the units that failed to pass as 
20MHz parts), the devices tested at the high end temperatures operated at 
16MHz all the way up to 170 degrees C!

A web location you might want to look at is:   http://www.calce.umd.edu

John

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