Calculation Notes
To ensure a trace can carry a given current capacity (I), this tool calculates the trace width required. Internal trace values are the results for a trace within a multilayer, although outer traces that are potted or insulated should also use internal values. Outer trace values are the results for a trace that is exposed to the air, normally on the top or bottom layers of a circuit.
Factors that influence the trace width calculation include:-
- Max current (i)
- Trace thickness (t)
- Max desired temperature rise (ΔT)
a_{ext} = \left( \frac{i}{0.048\times {\Delta T}^{0.44}} \right) ^\frac{1}{0.725}\; (external trace area)
w_{ext} = \frac{a_{ext}}{1.378 \times t}\; (external trace width)
a_{int} = \left( \frac{i}{0.024\times {\Delta T}^{0.44}} \right) ^\frac{1}{0.725}\; (internal trace area)
w_{int} = \frac{a_{int}}{1.378 \times t}\; (internal trace width)
References:
- Electrical Circuit Theory and Technology (ISBN 978-1-85617-770-2)
- Douglas Brooks, "Temperature Rise in PCB Traces", 1998
Disclaimer: The information and this tool are provided with no liability of any kind whatsoever, use at your own risk.