The generic equation to compute T_{J} is the following:

*T _{J} = T_{A} + R_{J-A} x P_{TOT}*

where:

- T
_{J}is the junction temperature, - T
_{A}is the ambient air temperature, - R
_{J-A}is the junction-to-air thermal resistance (see Junction-to-Air Thermal Resistance for details) and - P
_{TOT}is the total power consumed in the product.

The data sheet limit on T_{J} (T_{J_Limit}) induces a limit on T_{A}, as
shown in the following equation:

*T _{A_MAX} = T_{J_Limit} - R_{J-A} x P_{TOT}*

The maximum ambient temperature (T_{A_MAX}) an application can support is
a function of T_{J_Limit}, the total power dissipation and the
junction-to-air thermal resistance.