DP83640: Clarification on Temperature Spec

Thank you David,

Just to make sure I understand, if the chip is on a board and the surrounding air temperature is below 85C then we are within recommended operating range.  This takes into account the temperature rise to the junction temperature of the die, which will be higher.

Seems that these parameters are often misunderstood.   For FPGAs I am used to seeing a max Junction Temperature but perhaps that's because they can be high power device that could require thermal management like heat sinks, blowing air, etc?

Thank you for your response!

Hi,

This is a really good app note on the IC Package Thermal Metrics and thermal calculation. The critical factor affecting device reliability and functionality is the junction temperature, not the ambient temperature. The device will function at ambient temperatures between –40C and 85C when proper care is taken to ensure that the absolute maximum operating temperatures are not exceeded.

Thanks

David

David (ASIC) Liu said:

The critical factor affecting device reliability and functionality is the junction temperature, not the ambient temperature. The device will function at ambient temperatures between –40C and 85C when proper care is taken to ensure that the absolute maximum operating temperatures are not exceeded.

Hi David,

I think I've come complete circle on this as we were trying to calculate the junction temperature.   Is the absolute max operating temperature the same as the Absolute Max Rating (i.e., I thought the latter were stress ratings and not operational?).   Perhaps this is where my confusion comes from.

Thank You