Current (I)
A
Thickness (t)
Temperature Rise (TRise)
Ambient Temperature
Trace Length
Formula
First, calculate the Area:
Then, calculate the Width:
For IPC-2221 internal layers: k = 0.024, b = 0.44, c = 0.725
For IPC-2221 external layers: k = 0.048, b = 0.44, c = 0.725
where k, b, and c are constants resulting from curve fitting to the IPC-2221 curves.
Common values:
Thickness: 1 oz
Ambient: 25 C
Temp rise: 10 C
Minimum Trace Width
mil
Internal Layers
Required Trace Width (W)
Resistance
Ω
Voltage Drop
V
Power Loss
W
Minimum Trace Width
mil
External Layers in Air
Required Trace Width (W)
Resistance
Ω
Voltage Drop
V
Power Loss
W
