For a 1oz FR-4 PCB, is there an ideal PCB trace width for data lines? For power supplies, I realize wider is usually better, and power planes are preferred. But what about data lines? Is narrower better? Should I simply just use as narrow as the PCB fabricator supports reliably?
I've heard some advantages of using narrower PCB traces, but want to verify:
- Narrower lines results in higher resistance, which lowers the likelihood that series resistors are needed, and reduces EMI compared to wider lines.
- Narrower lines allow for easier routing, i.e. between other tracks and pads.
Are there uses for different widths for different frequencies -- i.e. SPI/i2c frequencies versus MIPI/USB frequencies?
I have been using the default of 10 mils...that seems kind of too large. Any width to use as a starting point/default? Perhaps 5mils or 6mils? If I use 6 mils, should I also use 6mils minimum trace to trace design rule?