How to Do Thermal Simulation of PCB: Step-by-Step Guide

To do a thermal simulation of a PCB, use specialized software like ANSYS or Altium Designer with thermal analysis features. Model the PCB layers, components, and heat sources, then run the simulation to visualize temperature distribution and identify hotspots.

Syntax

Thermal simulation involves setting up a model with these key parts:

• Geometry: Define PCB layers and component shapes.
• Material Properties: Assign thermal conductivity and heat capacity.
• Heat Sources: Specify power dissipation of components.
• Boundary Conditions: Set ambient temperature and cooling methods.
• Solver Settings: Choose steady-state or transient analysis.

These inputs are entered into the simulation software interface or script.

plaintext

Model PCB {
  Layers: [Copper, Dielectric, Copper]
  Components: [IC1, Resistor1]
  Materials: {
    Copper: thermal_conductivity=400 W/mK
    Dielectric: thermal_conductivity=0.3 W/mK
  }
  HeatSources: {
    IC1: power=2 W
    Resistor1: power=0.5 W
  }
  BoundaryConditions: {
    AmbientTemperature: 25 C
    ConvectionCoefficient: 10 W/m2K
  }
  Solver: SteadyState
}

Example

This example shows how to set up a simple thermal simulation in a PCB thermal analysis tool using a script-like input.

plaintext

PCB_Thermal_Simulation {
  Layers: [TopCopper, Dielectric, BottomCopper]
  Materials: {
    TopCopper: thermal_conductivity=385
    Dielectric: thermal_conductivity=0.25
    BottomCopper: thermal_conductivity=385
  }
  Components: {
    U1: power=1.5
    R1: power=0.3
  }
  BoundaryConditions: {
    AmbientTemp=30
    Convection=15
  }
  AnalysisType=SteadyState
  RunSimulation()
  Output: TemperatureMap
}

Output

Simulation completed.
Max temperature: 75°C at U1
Temperature distribution map generated.

Common Pitfalls

Common mistakes when doing PCB thermal simulation include:

• Ignoring accurate material properties, which leads to wrong temperature results.
• Not modeling all heat sources or underestimating power dissipation.
• Skipping boundary conditions like convection or radiation, causing unrealistic cooling effects.
• Using steady-state analysis when transient effects matter, or vice versa.
• Over-simplifying geometry, missing critical heat paths.

Always validate your model with real measurements if possible.

plaintext

/* Wrong: Missing convection boundary condition */
BoundaryConditions: {
  AmbientTemperature: 25 C
}

/* Right: Include convection for realistic cooling */
BoundaryConditions: {
  AmbientTemperature: 25 C
  ConvectionCoefficient: 10 W/m2K
}

Quick Reference

Step	Description
1. Define Geometry	Model PCB layers and components accurately.
2. Assign Materials	Set thermal properties for each material.
3. Specify Heat Sources	Input power dissipation for components.
4. Set Boundary Conditions	Include ambient temperature and cooling.
5. Choose Solver	Select steady-state or transient analysis.
6. Run Simulation	Execute and review temperature results.
7. Validate	Compare with measurements or expected results.

Key Takeaways

Use accurate material properties and power values for reliable thermal simulation.

Include realistic boundary conditions like convection to model cooling properly.

Choose the right analysis type: steady-state for constant heat, transient for changing heat.

Model PCB geometry and components carefully to capture heat flow paths.

Validate simulation results with real-world data when possible.