PCB trace width for buttons/LEDs/pots

Rather quick question - is 10mil width trace enough for switches+LEDs connected in matrix and 10k linear pots? Should I expect any issues? My matrix has 220ohm resistors so max current should be around 23mA, I think 10mil should be enough but better safe than sorry.

10 mil is fine.

Thank you!

kustom:
Rather quick question - is 10mil width trace enough for switches+LEDs connected in matrix and 10k linear pots? Should I expect any issues? My matrix has 220ohm resistors so max current should be around 23mA, I think 10mil should be enough but better safe than sorry.

For 23mA 0.25 mil would be fine! Heat dissipation goes with the square of current, so a ten fold difference in current
means a hundred-fold difference in wire size... (very very roughly)

The more important consideration is whether the trace is a power or ground line - in which case
it should be wider when between a load and its decoupling capacitor, since the series inductance
is important in this circumstance (not really a worry here).

can you explain the series inductance?

I think the more important consideration is ensuring your boards are manufactured with unbroken traces. I usually build with 24 mil traces by default.

db2db:
can you explain the series inductance?

Any length of wire or PCB track can be considerd to be an inductor. However at these frequencies it is very small so is not a consideration.

At what point does one begin to worry about inductance?

A designer I know uses 50mil traces for power on small boards. That's complete overkill for current, so why is inductance such a worry here?

The 50mil traces are used to keep the temperature down, not to prevent inductance. I usually don't go below 32mil for my VIN traces (usually around 12V), especially for boards with motor drivers, etc. that draw lots of current!

db2db:
At what point does one begin to worry about inductance?

It is a bit of a continuum but about when the wavelength of the frequency you are dealing with is ten times or less than the size of the track. Then you get into transmission line considerations where line inductance matters as well.
Remember sharp edges have a lot of harmonics if you want to keep them sharp.

db2db:
At what point does one begin to worry about inductance?

When ever using fast logic chips - these days that means any chip!

Typical switching speeds are measured in billions of volts per second, high frequency decoupling
is essential to reliable operation.

zapterra:
The 50mil traces are used to keep the temperature down, not to prevent inductance. I usually don't go below 32mil for my VIN traces (usually around 12V), especially for boards with motor drivers, etc. that draw lots of current!

If temperature was the only factor then 10mil traces would be fine upto about 0.3A (less than 1 degree rise),
but its not the issue, the issue is series impedance to the supply, both resistance and inductance.

For logic chips the inductance dominates by orders of magnitude - a decoupling capacitor at the end
of 5 inches of 6mil traces won't do much useful, but placed 5mm away on 50mil trace and a ground plane
will be very effective.

For high current devices then obviously resistance matters, and for very high currents on PCBs you will start to
worry about traces overheating, but that's in the multiple amps domain, and you'd go to 2oz or thicker copper
to help with that (which won't have any effect at ns timescales due to the skin effect)

MarkT:

db2db:
At what point does one begin to worry about inductance?

When ever using fast logic chips - these days that means any chip!

Not hard to know a trace size based on current, but when laying out a board, how does one know what size trace to select to reduce inductance?