# schottky diode power rating

I am trying to calculate the power rating of a schottky diode. The diode in question is the 1N5822U from ST Micro (a rad hard schottky diode). The datasheet is - Diode datasheet

Now, I am using in a circut that has about 2Amps. Now, the power dissipated throgh this diode is given by the equation below . It is given in the page 2 of the datasheet.

Now, i am assuming If(av) = 2Amps. What would If(rms) be ? This is a dc system so the RMS can be assumed to be just a dc level current ?

Also, now from this value I get the power dissipated by my circuit and not the max rated power of this diode. For, this I am making use of the Thermal resistance value = 7degree Celcius/Watt. The max operating or junction temp possible is 150degrees celcius. So, taking this into pic the difference from normal operating room temp and the max (150-25 = 125). So, the max is 125degrees celcius rise. This means that 125/7 = 17W. Approx 17W is the max power rating of trhis schottky. Is my assuption correct ?