Is it possible to predict the actual IC junction temperature in application using an alternative technique to a full blown detailed model representation of the package in a CFD simulation?  The short answer is yes.  The mathematical tools to do this are Theta-JB and Psi-JB and in this cooling ZONE library article, we explain how you do this.  Click to this link which brings you to the article in the coolingZONE Library, “Two New Friends, Theta-JB and Psi-JB“.