1. What is PCB Trace Width Calculator?

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

Purpose: Helps PCB designers ensure proper current carrying capacity and prevent overheating in circuit board traces.

2. How Does the Calculator Work?

The calculator uses the IPC-2221 formula:

Where:

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

Explanation: The formula calculates width based on current, allowable temperature rise, copper thickness, and trace location.

3. Importance of Proper Trace Width

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

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between internal and external traces?
A: External traces dissipate heat better (k=0.048), while internal traces (k=0.024) need to be wider for the same current.

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

Q3: How does copper thickness affect width?
A: Thicker copper (2oz/ft²) allows narrower traces for the same current.

Q4: What's the minimum practical trace width?
A: Typically 5-10 mils for most PCB manufacturers, though some can do 3-4 mils.

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