1. What is a PCB Trace Width Calculator?

Definition: This calculator determines the minimum width of a PCB trace needed to carry a specified current while keeping the temperature rise within acceptable limits.

Purpose: It helps PCB designers ensure proper current-carrying capacity and prevent overheating in electronic circuits.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

• \( Width \) — Trace width (mils)
• \( I \) — Current (amps)
• \( \Delta T \) — Temperature rise (°C)
• \( thickness \) — Copper thickness (oz/ft²)
• \( k \) — Constant (0.048 for external, 0.024 for internal traces)

Explanation: The formula calculates the minimum trace width needed to safely conduct the specified current without exceeding the allowed temperature rise.

3. Importance of Proper Trace Width

Details: Correct trace width prevents overheating, ensures reliable operation, and maintains signal integrity in PCB designs.

4. Using the Calculator

Tips: Enter the current in amps, desired temperature rise (default 10°C), copper thickness (default 1 oz/ft²), and select trace location (external/internal).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between external and internal traces?
A: External traces are on outer layers with better heat dissipation (k=0.048), while internal traces are in inner layers with poorer heat dissipation (k=0.024).

Q2: What's a typical temperature rise limit?
A: 10°C is common, but higher values (20-30°C) may be acceptable depending on application.

Q3: How does copper thickness affect trace width?
A: Thicker copper allows narrower traces for the same current, as shown by the thickness exponent in the formula.

Q4: What if my calculated width is too narrow?
A: Consider increasing copper thickness, allowing higher temperature rise, or using multiple parallel traces.

Q5: Does this account for high-frequency effects?
A: No, this is for DC/low-frequency current. High-frequency designs require additional considerations for impedance and skin effect.