How is device operating temperature range determined? I supposed that for a specified temperature range all the built in components have to support it. I am in doubt because I saw some commercial product with specified the lowest temperature of -30°C, but implements some IC that has 0 - 70°C operating temperature range (see EDIT). And that is crucial part of the device. How is that possible? Is that certification violation? Is it reliable to use in range that is not covered by all the components?
EDIT: I must add that maybe I made bad assumption. Sometimes, device manufacturers have option to order specific IC variants from the IC manufacturers (like variants with industrial, mil/space grades), that are not initially available. In my particular case, the IC I am mentioned is LM380N that has specified operating temperature range 0 - 70°C in the corresponding datasheet. This IC (audio power amplifier) I found in service manual schematic (not by inspecting hardware) for the device I am referring. However, not sure if some other than commercial variant is available and implemented in the hardware. Anyway, I appreciate each answer.