Thermal vias are plated through-holes used to transfer heat from one side of a PCB to the other, typically from a component's thermal pad to a heat-spreading copper plane or external heatsink. Proper thermal via design is critical for power electronics, LED lighting, and high-performance computing applications.

When to Use Thermal Vias

Via Design Parameters

Via Fill Options

Best Practices

• Via in Pad: For best thermal performance, place vias directly within the thermal pad. Use filled and capped vias to prevent solder voiding.
• Copper Planes: Connect vias to large internal or external copper planes to spread heat effectively. Use heavy copper (2oz+) for power applications.
• Thermal Relief: Remove thermal reliefs from via connections in thermal zones to maximize heat transfer.
• Grid Patterns: Use regular via arrays (3×3, 4×4, 5×5) for uniform heat distribution and easier design rules.
• Calculate Margins: Add 20-30% more vias than calculated minimum to account for manufacturing variations and non-ideal thermal paths.

Thermal Calculation Reference