From Current Budget to a Copper Design Rule
A power path should begin with a load budget, not a convenient routing width. Identify continuous current, startup current and fault current separately. The trace-width equation is useful for the continuous case, while startup and fault behavior need time-dependent reasoning.
A practical review sequence
First choose the local ambient temperature and allowed rise. Obtain minimum finished copper from the fabricator, then enter the path current and length in the trace-width calculator. Record both the minimum and the chosen rounded-up width. Inspect pad exits, thermal spokes and vias for smaller cross-sections. Next, compare voltage drop with the load supply budget and include the return path and connectors. Finally, validate the assembled prototype under realistic enclosure conditions. A calculation register should capture the board revision, copper specification, input set and measurement result.
Explore the calculator →