Industrial vs. commercial grade parts

[jmaja]

What is the actual difference between these? When should industrial ones be used?

E.g. I have used LTC2415-1 and my next design may be used outside 0-70 C, thus I was going to choose the industrial grade version of it. But then I saw the review of Fluke 28 Series II with a photo, which shows LTC2435-1 (20 bit sister to 24 bit 2415-1) without mark "I". Thus the most industrial Fluke multimeter does not use the industrial grade version. Why should I? http://www.eevblog.com/images/Fluke28pcbbottom2.jpg

Joakim

[Simon]

extended or military range parts are a minimum of -40 to +125C, you have to remember that the temperature inside boxes etc can be well over ambient. there are also ranges of -55 to +150C for some parts

[poorchava]

It's possible that you can get i.e. 75*C inside some control device, but rather unlikely that a multimeter's internals would be exposed to such conditions.

[jmaja]

The example part LTC2415/35 has the only difference in the absolute maximum values, 0-70 C vs -40-85 C. Fluke is using the 0-70 C part, but still allowing use down to -15 C and  even to -40 C for 20 minutes.

[Neilm]

Quite often a manufacturer will use a commercial part if it is one that they use else where, either because the designers haven't realised that this part is the lesser temperature spec, or that they have decided to take a risk with the lesser spec - "it'll probably work well enough"

Neil