Automotive electronics vs Minnesota winters


Electronic goodies are rated for service over specific ranges of temperature. I recently came across some temperature range tabulations as shown in Figure 1.

Figure 1 Temperature ranges and commonalities.

Nomenclature alone isn’t enough of a guide due to the name commonalities, but there is one aspect of the temperature limits that merits the telling of a tale.

Back around 1986, I was talking with a semiconductor company’s tech rep about plastic packaged semiconductor temperature ranges. I could understand such devices not being rated to high temperatures of 125°C as in military rated devices, but why were they limited at cold to only -40°C instead of -55°C?

The fellow told me that the epoxy material of the “plastic package” was the problem. His anecdote to me was that there was no epoxy that could be used at colder than -40°C. I’ve never seen this documented, but that was the tale.

Thirty-plus years later, it this still so? Please see the following from Google (Figure 2).

Figure 2 A generalized comment on the weather.

I have heard of some places that have only two yearly seasons—winter and Wednesday. Minnesota might be one of them. In any case though, winter temperatures can dip below that -40°C number which raises a question.

Figure 3 An automotive rated semiconductor.

If I have electronic components like this (Figure 3) incorporated into my automobile and I wake up in the morning to a record low temperature in the northern Midwest United States (or Canada), can I be assured that my automobile will actually function?

Comments?

John Dunn is an electronics consultant, and a graduate of The Polytechnic Institute of Brooklyn (BSEE) and of New York University (MSEE).

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