1. What is Via Thermal Resistance?

Definition: Thermal resistance measures how much a via (vertical interconnect access) in a PCB resists heat flow.

Purpose: This calculation helps engineers design proper thermal management in electronic circuits by understanding heat dissipation through vias.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \theta \) — Thermal resistance (K/W)
• \( L \) — Length of the via (m)
• \( k \) — Thermal conductivity of the via material (W/m·K)
• \( A \) — Cross-sectional area of the via (m²)

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

3. Importance of Via Thermal Resistance

Details: Proper thermal resistance calculation ensures effective heat dissipation in PCBs, preventing overheating and improving reliability.

4. Using the Calculator

Tips: Enter the via length in meters, thermal conductivity (default 400 W/m·K for copper), and cross-sectional area in m². All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical thermal conductivity for vias?
A: Copper vias typically have 400 W/m·K, while other materials vary (aluminum ~200, FR4 ~0.3).

Q2: How do I calculate cross-sectional area?
A: For circular vias, use \( A = \pi r² \) where r is the radius.

Q3: Why is thermal resistance important in PCBs?
A: It helps determine if vias can adequately transfer heat from components to heat sinks or other cooling mechanisms.

Q4: How does via plating affect thermal resistance?
A: Thicker plating reduces resistance by increasing effective cross-sectional area.

Q5: Can I use this for multiple parallel vias?
A: For N identical parallel vias, divide the single via resistance by N.