Calculate temperature-rise for DC/DC converter

[Spike101]

Hi,

I need a DC/DC converter that converts 12V to 24V with an output current of about 1.5A. I was thinking about using this one:

S24SP24002PDFA - http://www.deltaww.com/fileCenter/products/download/01/0102/datasheet/DS_S24SP24002.pdf

But I can't figure out how hot it's going to be at 1.5A output current. From the graph on the top right side on P3 of the datasheet I assume that the power dissipation will be about 3.5W. But I can't find a ThetaJ-A value or something else in °C/W (maybe i'm just overlooking it somehow). Or is there some other way to calculate the temperature rise?

Thanks,
Sebastian

[Spike101]

Good idea (i would have never found that way of calculating it.. )!
Thanks!