thermal-disppation-dat
⚙️ Key Factors
The current-carrying capacity of a 2.54mm (0.1 inch) wide PCB trace depends on:
- Copper thickness (measured in oz/ft²)
- Temperature rise allowed
- Trace location (internal vs. external)
📊 General Guidelines (Based on IPC-2221)
| Copper Thickness | Trace Type | Temp Rise | Approx. Max Current |
|---|---|---|---|
| 1 oz (35µm) | External trace | 10°C | ~2.6 A |
| 1 oz (35µm) | External trace | 20°C | ~3.8 A |
| 2 oz (70µm) | External trace | 20°C | ~5.0–6.0 A |
| 1 oz (35µm) | Internal trace | 20°C | ~2.0–2.5 A |
📏 Rule of thumb: For 1 oz copper, every 1mm width can safely carry ~1 A (for external traces and ~10–20°C temp rise).
🧠 Tips
- Use wider traces or thicker copper if higher current is needed.
- Consider thermal relief, via stitching, or multiple layers for better performance.
- For high currents (>5 A), use solid copper pours or bus bars.
🛠️ Example
For a 2.54mm wide, 1 oz copper external trace with 20°C rise:
- Safe current = ~3.5–4.0 A