Hi Guys,
We currently have a circuit that has been in production for a number of years now, and are having issues with both older and newer units failing at different temperature ranges(mainly the hotter side). I wouldn't have been too concerned if it was a particular batch, that had failed but different units across a number of different production runs is a bit worrying.
There are a number of different IC's (5 in total) in this circuit which populate an area 72mm (~3") x 72mm , there are two that are rated between 0-70C, one that is -40 to 85C and the rest -40 to 125C.
The suspect units are failing from about 37C to 60C, but the majority are at 50C.