The temp. rise of SM resistors depends largely on heat conduction through the end terminations, which can vary significantly depending on PCB material and layout (i.e. pad size, trace area, copper thickness, air convection, etc). Typical temperature rise at full rated power is 100C for MPF1,2,3 and 150C for MPF2S & 3S (based on DIN44050 PCB material with 500 sq. mil circuit traces MPF1, 2, 2S and 1000 sq. mil MPF3,3S). It is recommended to evaluate product in actual use conditions to ensure the proper component and PCB layout is utilized.