so, i have a bunch of to-220 L4006L5TP triacs laying around and i have to design an AC phase control pcb, reading the datasheet i saw that the Rθ(J-A) is 50°C/W, the Rθ(J-C) is 3.3°C/W and the voltage drop is 1.6V, since the max current of the design is 1A i have to dissipate 1.6W to the pcb itself. according to this question i need a heatsink with thermal resistance less than 36.7°C/W to 16.7°C/W to keep the triac in the 80°C to 60°C range considering that the air inside the case is 45°C is it possible to achieve this with only using the pcb as heatsink with horizontal mounted triac and some CPU thermal paste? if yes, how?
tl;dr: is it possible to use the pcb as a heatsink and achieve less than 36.7°C/W using some thermal paste?if yes, how?