P C B line width and current relationship
The current capacity of copper foil with different thickness and different width is shown in the following table:
Copper skin thickness 35um Copper skin thickness 50um Copper skin thickness 70um
Copper t=10 Copper t=10 Copper t=10
Current A Width mm Current A Width mm Current A Width mm
6.00 2.50 5.10 2.50 4.50 2.50
5.10 2.00 4.30 2.00 4.00 2.00
4.20 1.50 3.50 1.50 3.20 1.50
3.60 1.20 3.00 1.20 2.70 1.20
3.20 1.00 2.60 1.00 2.30 1.00
2.80 0.80 2.40 0.80 2.00 0.80
2.30 0.60 1.90 0.60 1.60 0.60
2.00 0.50 1.70 0.50 1.35 0.50
1.70 0.40 1.35 0.40 1.10 0.40
1.30 0.30 1.10 0.30 0.80 0.30
0.90 0.20 0.70 0.20 0.55 0.20
0.70 0.15 0.50 0.15 0.20 0.15
NOTE 1 The current-carrying capacity of the copper foil width when copper foil is used as a conductor to pass high currents should be determined by reference to the numerical derating of 50% in the table. "Because of the limited thickness of the copper-clad copper foil, the current-carrying capacity of the copper foil should be considered in the strip copper foil that needs to flow a large current. Still taking the typical 0.03mm thickness as an example, if the copper foil is used as the width W (mm), length of L (mm) of the strip wire, the resistance is 0.0005 * L / W ohms. In addition, the copper foil's current carrying capacity is also related to the type of printed circuit board components, the number and heat dissipation conditions. In consideration of safety, the current carrying capacity of copper foil can generally be calculated according to the empirical formula 0.15*W(A).
Generally, the thickness of the copper foil on the PCB is 35um, and the width of the line is 1mm. Then, the cross-sectional area of the line is 0.035mm2, and the current density is usually taken as 30A/mm2. Therefore, 1A current can flow per millimeter of line width.
IPC275-A has a calculation formula on the standard. It is related to temperature rise, copper foil thickness, A.
I = 0.0150 (DT 0.5453) (A 0.7349) for IPC-D-275 Internal Traces
I = 0.0647 (DT 0.4281) (A 0.6732) for IPC-D-275 External Traces
The IPC275-A standard was not found.
If conditions permit, the wider and the better, the wider the better. Try out the general parameters only to ensure safety, too thin ground line noise will be very large
In terms of 1 Oz plates
Width 10°C 20°C 30°C 45°C
0.127mm (.005”) 200mA 225mA 250mA 275mA
0.254mm (.010”) 400mA 450mA 600mA 750mA
0.381mm (.015") 550mA 600mA 750mA 1A
0.508mm (.020”) 650mA 700mA 800mA 1.2A
0.635mm (0.25”) 750mA 1A 1.2A 1.7A
1.270mm (.050”) 1.5A 1.7A 2.2A 2.8A
2.540mm (.100”) 2.2A 3.1A 3.7A 4.5A
3.810mm (.150”) 3.0A 4.0A 5.2A 6.1A
Copper skin thickness 35um Copper skin thickness 50um Copper skin thickness 70um
Copper t=10 Copper t=10 Copper t=10
Current A Width mm Current A Width mm Current A Width mm
6.00 2.50 5.10 2.50 4.50 2.50
5.10 2.00 4.30 2.00 4.00 2.00
4.20 1.50 3.50 1.50 3.20 1.50
3.60 1.20 3.00 1.20 2.70 1.20
3.20 1.00 2.60 1.00 2.30 1.00
2.80 0.80 2.40 0.80 2.00 0.80
2.30 0.60 1.90 0.60 1.60 0.60
2.00 0.50 1.70 0.50 1.35 0.50
1.70 0.40 1.35 0.40 1.10 0.40
1.30 0.30 1.10 0.30 0.80 0.30
0.90 0.20 0.70 0.20 0.55 0.20
0.70 0.15 0.50 0.15 0.20 0.15
NOTE 1 The current-carrying capacity of the copper foil width when copper foil is used as a conductor to pass high currents should be determined by reference to the numerical derating of 50% in the table. "Because of the limited thickness of the copper-clad copper foil, the current-carrying capacity of the copper foil should be considered in the strip copper foil that needs to flow a large current. Still taking the typical 0.03mm thickness as an example, if the copper foil is used as the width W (mm), length of L (mm) of the strip wire, the resistance is 0.0005 * L / W ohms. In addition, the copper foil's current carrying capacity is also related to the type of printed circuit board components, the number and heat dissipation conditions. In consideration of safety, the current carrying capacity of copper foil can generally be calculated according to the empirical formula 0.15*W(A).
Generally, the thickness of the copper foil on the PCB is 35um, and the width of the line is 1mm. Then, the cross-sectional area of the line is 0.035mm2, and the current density is usually taken as 30A/mm2. Therefore, 1A current can flow per millimeter of line width.
IPC275-A has a calculation formula on the standard. It is related to temperature rise, copper foil thickness, A.
I = 0.0150 (DT 0.5453) (A 0.7349) for IPC-D-275 Internal Traces
I = 0.0647 (DT 0.4281) (A 0.6732) for IPC-D-275 External Traces
The IPC275-A standard was not found.
If conditions permit, the wider and the better, the wider the better. Try out the general parameters only to ensure safety, too thin ground line noise will be very large
In terms of 1 Oz plates
Width 10°C 20°C 30°C 45°C
0.127mm (.005”) 200mA 225mA 250mA 275mA
0.254mm (.010”) 400mA 450mA 600mA 750mA
0.381mm (.015") 550mA 600mA 750mA 1A
0.508mm (.020”) 650mA 700mA 800mA 1.2A
0.635mm (0.25”) 750mA 1A 1.2A 1.7A
1.270mm (.050”) 1.5A 1.7A 2.2A 2.8A
2.540mm (.100”) 2.2A 3.1A 3.7A 4.5A
3.810mm (.150”) 3.0A 4.0A 5.2A 6.1A