Changing trace width

I set the grid to 0.0125 (IIRC) but the smallest option for trace size that I see is 8mil. I set this, but all the traces remain the same size. This means that traces to two adjacent pins on a SOIC-24 package almost touch–literally, it looks like at best a hairline (literally, .003") is all the spacing between them. To get a planar layout, I need to run traces between the pins. I’m outsourcing the fab, so I don’t have the limits of my mill to contend with. I’m driving some (14 total, arranged 2x7) LEDs, and a trace calculator tells me that I need at least 0.066mil from output pin to LED. For each bank of seven LEDs the 140ma current requires a 1-mil trace, and the Vcc-to-split requires 2.5 mils (Vcc to first LED hot bus, 2.5 mils; the trace that drops from the upper hot bus to the lower hot bus need only be 1 mil). The processor is an SOIC-8 form factor. So how do I reduce the trace width to something smaller than the default size, which is massive? I’d like to get it down to the width of an SOIC pin pad. And I want to set it so that all new manual traces get created at that size.

A searchable online help would be, well, a big help.

FZ was designed to be a beginners tool, hence the breadboard view, so maybe in the future.

Maybe make parts with special narrow pads.

While I rarely make boards, a quick search for trace width in this forum turned up this one from Steelgoose and Old_Grey which implies while you can’t change trackwidth globally you can change it via inspector on a by trace basis. That said you may be better off with one of the more advanced packages

(edit) I just tried a soic 18 package (don’t know if that is the same spacing you are using) and ran a wire from a resistor to a pin then selected the trace and changed the track size in inspector to 8 mil and it goes between the pins fine (after I reduced the grid size to .01) not ideal but it seems to work as long as the 8mm trace is fine enough for what you need to do.


I think it was on EEVblog that Dave said that not all production houses can go below 4mil.