Heatsink Design and Selection

LS-85

Design factors which influence the thermal performance of a heat sink

When selecting or designing a heatsink the following factors must be considered:

 

What is a heatsink?

In electronic systems, a heatsink is a passive component that cools a device by dissipating heat into the surrounding air. Heatsinks are used to cool electronic components such as high-power semiconductor devices, and optoelectronic devices such as higher-power lasers and light emitting diodes (LEDs). Heatsinks are heat exchangers such as those used in refrigeration and air conditioning systems, or the radiator in an automobile.

How does a heatsink work?

A heatsink is designed to increase the surface area in contact with the cooling fluid surrounding it, such as the air. Approach air velocity, choice of material, fin (or other protrusion) design and surface treatment are some of the factors which affect the thermal performance of a heatsink.

Where are heatsinks used and how are they attached?

Heatsinks are used to cool computer central processing units (CPUs) or graphics processors. Heatsink attachment methods and thermal interface materials also affect the eventual die temperature of the integrated circuit. Thermal adhesive or thermal grease fills the air gap between the heatsink and device to improve its thermal performance. Theoretical, experimental and numerical methods can be used to determine a heatsink's thermal performance.