How to Calculate PCB Trace WidthBefore we move further and discuss how to calculate PCB trace width, let’s first define what PCB traces are, and why they are used.
Copper TracesThe base of the PCB is made of a substrate which is fiberglass. And most common fiberglass is composed of FR4 material. This substrate material is non-conductive and provides the core strength and rigidity to the board. On top of the substrate is the copper trace. These traces are conductive and electrically connect different electrical components on the board. They come with varying thickness depending on the applications they are used in. The capacity of the current passing through the copper traces mainly defines the width of the copper trace. More width of copper trace allows more amount of current to flow. If the PCB is a one-layer PCB, then the copper traces are laminated on one side of the board. If it is a two-layer PCB then copper traces are laminated on both sides of the board. Multiple-layer PCB can support up to 16 layers of copper traces on board.
Formula to Calculate Trace WidthThe equation to calculate the width of the trace is given below.
Width [mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz])… where 1.378 is related to standard 1 ounce pour thickness. So, before calculating the width we must know the trace area which can be calculated by the following equation. Trace area can be calculated by the following equation:
Area [mils²] = (Current[Amps] / (k*( Temp_Rise[°C] )^b) )^(1/c)… where for external layer, k = 0.048, b = 0.44, c = 0.725. … and for internal layers value of ‘k’ will change and it will become 0.024 while both value of ‘b’ and ‘c’ remains same. This equation to calculate area tells us how wider the trace needs to be to conduct current without any potential issues. It is important to note that the required widths of traces for inner layers are commonly higher compared to the width of traces on the outer layers. You can use any width depending on the application. -- Know that… after designing the PCB on any software, you need to fabricate the board which you can fabricate yourself. If you don’t want to involve yourself in the hassle of fabrication of PCB right from the scratch, you can outsource the manufacturing of your boards. PCBWay is one of the renowned service providers. Just go to their website, connect with them, and order an online quote for your required board before making your decision for the final circuit board. We have always worked with them, when it comes to PCB designing and they have always provided best job. That’s all for today. I hope you’ve enjoyed reading this article. If you’re unsure or have any questions, you can approach me in the section below, I’d love to help you the best way I can. Feel free to share your valuable feedback and suggestions around the content we share so we keep coming back with quality content customized to your exact needs and requirements. Thank you for reading the article.