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Subject: Request for Assistance: Determining Track Width for Unknown Circuit

Parth , 10-14-2023, 09:10 AM
I am in the process of working on a design that involves designing a printed circuit board (PCB), but I lack specific information about the electronic components and requirements for the circuit. As a result, I am facing some challenges in determining the appropriate track width for the PCB.

I am reaching out to seek your expertise and guidance on how to decide on the track width without detailed knowledge of the circuit's specifications. Any general rules of thumb or best practices that can be shared would be greatly appreciated.

If you have any resources, guidelines, or recommendations for selecting a safe and reasonable track width for a PCB that could work for a wide range of electronic applications, it would be immensely helpful.
QDrives , 10-14-2023, 09:13 PM
Generally power tracks are wider (say 0.5mm) than signal (0.2mm).
There is a minimum track width (and spacing) that is determined by the fabricator of the bare board and is driven by the copper thickness. So thicker copper will require wider tracks and spacing.
Then there is the temperature rise due to the current flowing through the tracks. IPC-2221 has details on this, but I would suggest using PCB toolkit and see the maximum current for a given temperature rise.
The rest is up to you.
Robert Feranec , 10-15-2023, 05:27 AM
Usually I start routing signal tracks by width between 0.1 - 0.3mm and by the end of the layout I simply select all these tracks and make them narrower to meet impedance requirements based on specific stackup (use impedance calculator of your PCB manufacturer and for example for 50 ohm tracks it will tell you what your track width should be - if you dont know what impedance you should use, 50 ohm is often used value for digital signals). As @QDrives pointed out, you may want to route power tracks wider than signal tracks.
Here is an example of Impedance calculator: https://cart.jlcpcb.com/impedanceCalculation
Here are some examples of different stackups: https://jlcpcb.com/impedance
Here are examples of PCB Manufacturer capabilities: https://jlcpcb.com/capabilities/pcb-capabilities
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