Calculate PCB via current carrying capacity based on size and plating thickness.
Finished hole diameter
Typical: 0.8-1.0 mil
Via barrel length
| Via Type | Drill | Finish Ø | Current (1 via) |
|---|---|---|---|
| Microvia | 4 mil | ~6 mil | ~0.3 A |
| Small | 8 mil | ~10 mil | ~0.5 A |
| Standard | 12 mil | ~14 mil | ~0.7 A |
| Power | 20 mil | ~22 mil | ~1.0 A |
| Large | 30 mil | ~32 mil | ~1.4 A |
PCB vias are plated holes that connect traces between layers. The current capacity depends on:
For a standard 12 mil via with 1 mil plating, you'd need approximately 7-8 vias for 5A with a 10°C temperature rise. Always add margin and distribute vias across the current path.
Filled vias (with copper or conductive epoxy) provide better current capacity and thermal performance. However, they add cost. For most applications, standard plated vias with proper sizing work well.
Standard PCB fabs support 8-10 mil drill minimum. HDI boards can go down to 4 mil laser-drilled microvias. Smaller vias cost more and have lower current capacity.