Chip operating temperatures

[Mike Fahrion]

> To paraphrase Stephen Dubovsky's comment:
> 
> >   In a nutshell:  If you derate the comercial parts they often work well
> > outside their spec temp range.  
> 
> The chips (usually) are physically the same.  If there is are several
> sets of parameters in the databook (comm, ind/auto, military) you can
> usually just use the other set of numbers.
> 

An additional factor to ease your mind.  The parts will only have to 
operate in that extreme cold condition for a *very* short time.  The 
power consumption of the parts will heat them very quickly relative 
to that low of an ambient temp.  Obviously later the heat of the 
cabin will bring them up to a comfortable temp.

To take it one step further, it isn't terribly difficult to add a 
heater circuit that will turn on power to a several watt resistor 
when the ambient is below a certain threshold temp.  Almost always, 
this is the most practical way to extend operation of a circuit into 
frigid temps due to the (sometimes) availability problems of wide 
temp parts.

-mike
mfahrion at bb-elec.com