1. What is the PCB Via Current Equation?

The PCB via current equation estimates the current carrying capacity of a via based on its diameter and the allowable temperature rise. It's essential for designing reliable printed circuit boards that won't overheat.

2. How Does the Calculator Work?

The calculator uses the PCB via current equation:

Where:

• \( I \) — Current capacity (Amperes)
• \( k \) — Material constant (0.048 for outer layers, 0.024 for inner)
• \( T \) — Temperature rise (°C)
• \( d \) — Via diameter (mm)

Explanation: The equation accounts for the relationship between via size, temperature rise, and current carrying capacity in PCB design.

3. Importance of Via Current Calculation

Details: Proper via sizing is crucial for preventing overheating, ensuring signal integrity, and maintaining PCB reliability. Undersized vias can lead to thermal failure.

4. Using the Calculator

Tips: Enter the constant (k), desired temperature rise in °C, and via diameter in mm. Typical values are pre-filled as examples.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between outer and inner layer constants?
A: Outer layers (k=0.048) can carry more current due to better heat dissipation to the environment compared to inner layers (k=0.024).

Q2: What's a typical temperature rise limit?
A: Common limits are 10°C for general designs, up to 20°C for high-current applications, depending on reliability requirements.

Q3: Does via plating thickness affect current capacity?
A: Yes, this calculation assumes standard 1 oz (35μm) copper plating. Thicker plating increases current capacity.

Q4: How does via aspect ratio affect this calculation?
A: The equation assumes reasonable aspect ratios (typically < 10:1). Extreme aspect ratios may require derating.

Q5: Can this be used for high-frequency applications?
A: For high-frequency designs, consider both current capacity and impedance requirements.