Selected "Tiny Cooling Fan" radiator select volume to meet the requirements of several radiator. Using the selected data sink (preferably data under the harshest ambient temperature Ta), the thermal resistance of the heat sink available natural convection time. In "Tiny Cooling Fan" installation space and cost conditions allowed, should use the lowest heat sink thermal resistance. It should be remembered that the substrate temperature is slightly lower, mean time between failures (MTBF) will be significantly improved. If you choose "Tiny Cooling Fan" is greater than the thermal resistance of the heat sink according to paragraph (2) of the calculated thermal resistance, should be used in a larger volume of the radiator, or use other cooling methods (such as forced convection cooling, etc.).