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Thermal Via Array Calculator

Calculate thermal resistance of a PCB thermal via array for heat spreading from SMD packages to inner copper planes or heatsinks.

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Formula

θvia=Lk⋅A,θarray=θviaN\theta_{via} = \frac{L}{k \cdot A}, \quad \theta_{array} = \frac{\theta_{via}}{N}
θ — Thermal resistance (°C/W)
L — PCB thickness (via length) (m)
k — Thermal conductivity (W/m·K)
A — Via cross-sectional area (m²)
N — Number of vias

How It Works

Thermal vias are critical components in electronic thermal management, serving as conductive pathways to transfer heat away from high-power components. The thermal resistance of a via is calculated by considering its physical characteristics: length, cross-sectional area, and material conductivity. In printed circuit board (PCB) design, multiple vias can be strategically arranged to enhance heat dissipation efficiency.

Worked Example

Problem: Calculate thermal via array resistance for a 1.6mm thick PCB with 4 parallel copper vias of 0.3mm diameter Solution: 1. Single via thermal resistance: R_via = 1.6mm / (385 W/m·K * π*(0.15mm)²) 2. Parallel via array reduction: R_array = R_via / 4 3. R_via ≈ 0.92 K/W 4. R_array ≈ 0.23 K/W

Practical Tips

  • ✓Use solid copper fill for maximum thermal performance
  • ✓Consider via diameter and spacing carefully
  • ✓Verify thermal simulation results with physical testing

Common Mistakes

  • ✗Neglecting via aspect ratio
  • ✗Assuming uniform thermal conductivity
  • ✗Overlooking via placement precision

Frequently Asked Questions

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