Understanding Heatsinks

Posted Feb 11th 2011
Heat Sink Diagram

In many electronic applications, temperature becomes an important factor when designing a system. Switching and conduction losses can heat up the silicon of the device above its maximum Junction Temperature (Tjmax) and cause performance failure, breakdown and worst case, fire. Therefore the temperature of the device must be calculated not to exceed the Tjmax. To design a good Thermal Management solution, the Tj should always be kept at the lowest operating temperature.

Maximization of Thermal Management

Thermal management should be determined at the board layout design stage, not later. It is feasible and less costly to determine the thermal load at your design process of the pcb board. The ability to design in optimal solutions, more flexibility, more choices, and also to save possible device failures after the design has been finalized. Most of the problems occurring at the end of the design cycle are due to thermal management considerations.

Heat Transfer Basics

Heat transfer occurs when two surfaces have different temperatures, thus causing heat energy to transfer from the hotter surface to the colder surface. For example, voltage is the driving force that causes current to flow. By analogy, temperature is the force that causes heat to flow. If the temperature difference is increased, the amount of heat flow will be increased.

Download PDF: heatsink-basics.pdf

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