What is Junction Temperature?
In the field of electronics, the junction temperature and the operating temperature can be the same; for example, the semiconductor in use in the device. However, the junction temperature is directly affected by the ambient temperature as well, and for integrated circuits, the following equation depicts this relationship between the two measurement parameters.
TJ = Ta + (PD x Rja)
Whereas in this equation:
TJ represents the Junction Temperature in Celsius
Ta represents the Ambient Temperature in Celsius
PD represents the power dissipation of the integrated circuit in Watts
Rja represents the Junction to Ambient thermal resistance in Celsius/Watts.
Furthermore, the junction temperature, which is short for transistor junction temperature (semiconductor), is the maximum operating temperature of the actual semiconductor in use in the electronic device. During operation, it is higher than the temperature of the part's exterior and the case temperature. Also, the difference is equivalent to the amount of heat transferring from the junction to the case multiplied by the junction-to-case thermal resistance.
Moreover, numerous physical properties can affect the temperature of semiconductor materials. This includes the thermal production of charge carriers, the diffusion rate of dopant elements, and carrier mobilities.
