1. What is a PCB Trace Width Calculator?

Definition: This calculator determines the appropriate trace width for PCB conductors based on current, temperature rise, copper thickness, and layer type.

Purpose: It helps PCB designers ensure proper current carrying capacity while maintaining acceptable temperature rise in traces.

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 layers)

Explanation: The formula calculates the minimum trace width needed to carry a given current while keeping temperature rise within specified limits.

3. Importance of Proper Trace Width

Details: Correct trace width prevents overheating, ensures reliable current capacity, 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 layer type. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between internal and external layers?
A: External traces can dissipate heat better, hence the different constant (k) values in the formula.

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

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

Q4: What if my calculated width is too narrow for manufacturing?
A: Use the minimum manufacturable width and consider increasing copper thickness or adding parallel traces.

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