On Fri, 21 Dec 2007 14:32:36 +0100 "Rikard Bosnjakovic" wrote: > I'm having a couple of LM317:s which I'm about to use in a hockey > arena (with ambient temperature around -10 degrees Celcius). In the > datasheet - maximum ratings section - for the 317, I find "T_op > Operating junction temperature: 0-125". It'll most probably work well. Manufacturers test their products and if they are within specs -55 - 125, or so they're put in the mil-spec box, etc. What's left, if they still work, is sold as commercial range. So, taking into account probability, your ICs are likely to work till -20C, could work till -40, but unlikely below that, 'cause they be sold as automotive (more expensive) parts. Even then, it's highly unlikely they'd present some irreversible damage - they'd probably just be outside the specs. Of course probability is just that. John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist