This tool is designed to calculate the heat dissipation and the heatsink thermal resistance required given four parameters: Maximum ambient temperature, Maximum case temperature, Power output of your RF amplifier. TA , Ambient Temperature: ℃ TC , Maximum Case Temperature: ℃ POUT , Power Output: W Ef , Efficiency (enter whole number, I.e. 80): % Reset PD , Power Dissipated = 45 W JSA , Heat Sink Thermal Resistance Required = 0.222222222222 ℃/W