Hi, That number sounds a reasonable Theta-Junction-Ambient. I've also have information from our PowerStep01 App support contact that from experimental test data the Theta-Junction-Case Rj-c = 0.222 K/W

I am using FloTherm thermal simulation software to check component temperatures. For expected 3.3W power dissipation of the PowerStep01 in this application I need the thermal impedance to to get an idea of the package temperature rise.