The light-emitting diode of an LED package radiates light and heat according to the input power. However, the surface area of an LED package is quite small,and the package itself is expected to release little heat into the atmosphere.An external radiator such as a heat sink is thus required.The heat dissipation structure up to the connection portion of the external radiator uses mainly heat conduction.
This document describes the detailed heat dissipation structure of the Citizen CLL050 series LED packages. It explains that while the package itself releases little heat to the atmosphere due to its small surface area, an external radiator such as a heat sink is required for efficient cooling via heat conduction.
The datasheet provides specific thermal design formulas and charts to help engineers calculate junction temperature (Tj) based on input power, ambient temperature, and thermal resistance. It includes simulation data for the CLLO50-1825A1 model to guide the selection of external heat dissipation parts like grease and heat sinks.
The absolute maximum junction temperature (Tj) rating in the specifications is 150°C.
The outline dimensions of the heat sink are W 64mm x H 40mm.
The thermal conductive grease has a value of 4.5W/m.K.