What Size Heat Sink Do I Need?

In early-stage project design, thermal management often becomes a critical discussion point, especially when power density or total power exceeds the capabilities of off-the-shelf solutions. A common early question is, “Have we left enough room for the heat sink?”

To quickly estimate the required heat sink volume, engineers can use a simple equation based on volumetric thermal resistance:

V = (Q × Rv) / Required ΔT

Where:

  • V = Heat Sink Volume
  • Q = Power (in watts)
  • Rv = Volumetric thermal resistance (refer to the table below)
  • Required ΔT = Maximum allowable temperature rise (thermal budget)

Volumetric Thermal Resistance (Rv) Associated with Different Airflow Levels

The table below provides volumetric thermal resistance (Rv) values for different airflow levels. These values are essential for accurately estimating the heat sink volume.

While this equation offers a volume estimate, it doesn’t account for factors like material selection, fin spacing, or thermal interface materials (TIM). However, it’s proven to be a valuable starting point for directional analysis.

Here are the links to an online calculator and a usage guide that gives you a few needed tips.

Related Link

Heat Sink Performance Calculator

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Posted on

September 26, 2024