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fleakour , 09-29-2025, 08:35 AM

Hello everyone, I'm trying to complete my first two-layer PCB layout and have a few basic questions about routing and grounding:

Trace Width: For standard signal traces carrying low current (e.g., tens of milliamperes), what is the default minimum trace width? Is there a rule of thumb that ensures reliability while not taking up too much routing space?

Ground Plane Connection: I've added many ground points for decoupling capacitors to the GND plane. When connecting component ground pads to the ground plane, is it always better to use a solid connection rather than a thermal relief pad? When is thermal relief necessary?

Robert Feranec , 09-29-2025, 10:17 AM

maybe this can help: https://youtu.be/VGY1qFE-kC0

Robert Feranec , 09-29-2025, 10:21 AM

but for two layer PCB it's not going to be so easy as you can't really follow impedance recommendations, so it may not be very important what signal width to use. In that case you can use a little bit wider tracks as is limitation of your PCB manufacturer, e.g. often I route for example with 10mil tracks .. but often I change it by the oend of the design based on recomended impedance, for example to 6 mils. For power usually minimum track width is 20mil, when connecting small pins, maybe down to 13mils.

Robert Feranec , 09-29-2025, 10:22 AM

for longer power paths i can go wider e.g. 40mils or I draw power planes.

QDrives , 09-29-2025, 09:56 PM

A thermal relief is needed when the connection is to a large copper area.