1. What is Via Thermal Resistance?

The thermal resistance of a via (R_via) measures how effectively heat is conducted through a plated through-hole in a printed circuit board (PCB). It's a crucial parameter in thermal management of electronic devices.

2. How Does the Calculator Work?

The calculator uses the via thermal resistance equation:

Where:

• \( R_{via} \) — Thermal resistance (K/W)
• \( L \) — Length of the via (m)
• \( k \) — Thermal conductivity of the via material (W/m·K)
• \( r \) — Radius of the via (m)

Explanation: The equation shows that thermal resistance increases with longer vias and decreases with larger cross-sectional area or higher conductivity materials.

3. Importance of Via Thermal Resistance

Details: Accurate thermal resistance calculation is essential for PCB thermal design, ensuring components stay within safe operating temperatures and optimizing heat dissipation paths.

4. Using the Calculator

Tips: Enter length in meters, thermal conductivity in W/m·K, and radius in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical thermal conductivity for PCB vias?
A: Copper vias typically have k ≈ 400 W/m·K, but this can vary based on plating thickness and quality.

Q2: How does via diameter affect thermal resistance?
A: Since resistance is inversely proportional to radius squared, doubling the radius reduces resistance by a factor of 4.

Q3: What are typical via thermal resistance values?
A: For a 1.6mm thick PCB with 0.3mm diameter copper via, R_via ≈ 5-10 K/W.

Q4: Does this account for thermal interface materials?
A: No, this calculates only the via resistance. Additional resistances from solder, TIMs, etc. must be considered separately.

Q5: How accurate is this simple model?
A: It provides a good first approximation but doesn't account for thermal spreading resistance or non-uniform plating.