PCB Current and Line Width
The calculation of PCB current-carrying capacity has always lacked authoritative technical methods and formulas. Experienced CAD engineers can make more accurate judgments by relying on personal experience.
The current carrying capacity of a PCB depends on the following factors: line width, line thickness (copper foil thickness), and allowable temperature rise.
The Relationship between Copper and Platinum Thickness, Line Width and Current In PCB Design
Before understanding the relationship between copper and platinum thickness, line width and current in PCB design, let us first understand the conversion between the units of ounces, inches and millimeters of PCB copper thickness: “In many data sheets, the copper thickness of PCB is often expressed in ounces. Do units, it is converted to inches and millimeters as follows:
1 ounce = 0.0014 inches = 0.0356 millimeters (mm)
2 ounces = 0.0028 inches = 0.0712 millimeters (mm)
Ounce is a unit of weight, the reason why it can be converted to millimeters is because the copper thickness of the pcb is ounces per square inch”
PCB design copper-platinum thickness, line width and current relationship table
It can also be calculated using the empirical formula: 0.15×line width (W)=A
The above data are all line current carrying values at a temperature of 25°C.
Conductor impedance: 0.0005×L/W (line length/line width)
The Relationship between Copper Foil Thickness, Trace Width and Current in PCB Design
The current strength of the signal. When the average current of the signal is large, the current that the trace width can carry should be considered.
The relationship between copper foil thickness, trace width and current in PCB design
When using copper foil as a wire to pass a large current, the current carrying capacity of the copper foil width should be derated by 50% with reference to the value in the table.
In PCB design and processing, OZ (ounce) is often used as the unit of copper thickness. The definition of 1OZ copper thickness is that the weight of copper foil in 1 square foot area is one ounce, and the corresponding physical thickness is 35um; 2OZ copper thickness is 70um.
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