We don't typically put thetaJC values in the data sheets of PowerPAD-packaged devices as this number is not very useful. The key number is the dissipation factor, which is also thetaJA, junction-to-ambient. This number encompasses ALL the thermal resistances in a typical system and is the best number to use in most cases for thermal calculations.
However, we DO publish thetaJC (although it's listed thetaJB) in our app note, SLMA002D: PowerPAD Thermally Enhanced Package Application Report (Rev. D
If you're looking for a quick guide on how to use PowerPAD, look at PowerPAD Layout Guidelines written by my colleague YBQ.
-d2