I was just wondering what the issues with "too much cooling" might be.  I
seem to recall that most integrated circuits have lower temp ratings but I
always assumed that this was just a packaging constraint since you don't
want to freeze the plastic encapsulation material or it might become
brittle and crack due to the thermal stress between the "hot" chip and the
cold outside.  Mil-Spec chips with ceramic encapsulation have much wider
temp ranges.  I've always assumed the lower low end was due to the better
thermal stress characteristics of ceramic (lower coefficient of thermal
expansion) and the higher high end was due to higher thermal conductivity
of the particular encapsulation ceramic when compared to the epoxy plastics
normally used.  I thought all the microprocessors these days were in
ceramic packages so that the low temperature rating would be virtually
non-existant.

My question is, are thermal stress limitations the only reason for low end
temperature requirements with IC's (obviously with display devices like
LCD's freezing can wreak havoc, but I'm interested in microprocessors).  I
suppose issues like condensation could be a problem (I know for a fact that
computers operate very poorly when cooled with coffee, even if it is cold)
but I'm wondering about inherent temperature limitations  not ancillary
problems like condensation or thermal stress.  Anybody know of this type of
problem with current microprocessor technology?

Max

>On 23 Sep 98 at 17:08, Roberto Safora wrote:
>> Talking about cooling. Is there any special thing when we are dealing
with
>> amd k6 266 or 300 mhz?
>> do the cooling fans I was using with P166 mmx fit them(amd)?
>  They will fit, but they may not be sufficient.  The fans that I use
>on most of my machines ("AOC CPU Cooler") are 25mm "thick", but
>there's a 35mm version that I'm using on my Cyrix MX-PR233+, which I
>intend to replace soon with a K6-2/300.
 > The older K6s may be okay with the slightly smaller fans.  [You
>*can* put too much cooling on a CPU, but only with a Peltier
>device....]
>David G

                                  -----
       **Need help with PCBUILD mailing list? Send an Email to:**
        Bob Wright<[log in to unmask]> or Drew Dunn<[log in to unmask]>