[BillA]

understanding one's goal is ever a good starting point
this thread was about the relationship of Tc and Tj
Tc, where measured and how measured, is just exactly that

since we all agree that Tj is itself a convenient fiction, useful for approximations, virtually any criticism could be made
Tj as used is a silicon design parameter;
take it from there

EDIT
I would add that with a 'large' die the thermal mapping is neither known or constant;
the initial assumptions will perforce carry through all subsequent calcs
GIGO at work if not reasonable
yes bobo, I want to see what you come up with
I somehow sense that there is a shifting target in progress, please do be clear on the intended goal
- BUT, if the basis is a collection of assumptions - what can the results be ?

much better Inco's approach, use data to back into the question