1. What is a PCB Track Width Calculator?

Definition: This calculator determines the minimum width of a PCB trace needed to carry a specified current without exceeding a given temperature rise.

Purpose: It helps PCB designers ensure proper current carrying capacity and prevent overheating of 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 external/0.024 internal)

Explanation: The formula accounts for current, allowable temperature rise, copper thickness, and whether the trace is on an external or internal layer.

3. Importance of Proper Track Width

Details: Correct trace width prevents overheating, voltage drops, and ensures reliable PCB operation. Too narrow traces can overheat and fail.

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.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between internal and external layers?
A: External layers can dissipate heat better, hence the different k constants (0.048 vs 0.024).

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 width?
A: Thicker copper allows narrower traces for the same current, as shown by the thickness exponent.

Q4: What units are used?
A: Width in mils (1 mil = 0.001 inch), current in amps, thickness in oz/ft² (1 oz = 1.37 mils).

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