heatsink calculate
Maximum Power Dissipation which can be handled by any device at a given ambient temperature is given by following formula
Pdallowed = (Tjmax - Ta)/Rthj-a
Where,
Pd - Power Dissipation allowed
Tjmax - Maximum junction temperature (from datasheet) = 175C max
Ta - Ambient temperature (system specification) - you will have to specify
Rthj-a - Thermal resistance from junction of IC to air This normally is submiison of various thermal resistances in the path of flow of heat from junction to ambient)
Rthj-a = (Rtj-c + Rtc-s + Rts-a) parallel Rtj-a(datasheet)
Rtj-c, Rtc-s, Rtj-a specified in datasheet
Rts-a is the radiation thermal resistance which I guess is difficult to calculate so we normally do by experimentation or define the maximum operating temperature at the sink itself rather than ambient temperature
If this allowed power dissipation is less then your caluclated power dissipation then you will need to use a heatsink and if you search on google you will find a lot of heat sink suppliers with applications notes on how to choose a heat sink
This is the detail calulation which we do
But if u just want a rough idea then you can check the datasheet for
Linear derating factor For power with temperature
so at particular case temperature how much power can be dissipated you can know
200W is for case temperature of 25C