Hi Scott,
In dealing with trace width, here are a couple of things to consider. 1) Temperature rise, current, voltage drop, arc resistance (for higher voltages), and impedance (for transmission lines); and 2) Fab capabilities.


For the first one, you likely know the current going through the traces, so you only need to decide what is an acceptable temperature rise for the trace. This rise is the temperature of the trace above ambient temp. 10-20 degrees C would be a lot of temperature rise unless you are building a high power circuit.
http://circuitcalculator.com/wordpress/category/calculators/pcb/
look down the list. There are other handy calcs for power dissipation as well.

For the second one, Check with your PCB Fab house and see what they are capable of doing. I generally add a little insurance by *not* going all the way down to the minimum trace/space dimensions that they are capable of. Instead, make your minimum a couple of mils bigger than theirs. For low power signals, it's not uncommon to see 0.007" traces. Also, remember that a low frequency (slow rise/fall time, or analog) trace can be 'necked down' (reduced in width) just where you need it for some applications, but don't try that with fast signals.



Quoting Scott Schuehle <scott.schue...@gmail.com>:

Hi all,
I'm working on the the APS board and I was just wondering what the min.
trace width should be.  One of the ICs I'm using is a 3mm x 3mm MSOP-10
(TPS2490 hotswap controller) and the lands are narrow and close together
meaning if I use the default 0.016'' trace width, I get a keepout error.
Are 0.01'' traces wide enough?  Thanks!

Scott






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