Zone Minimum Fill Width

Layout
1

If you do a DRC check on the attached board you will see an error which points to the failure to connect the ground plane to the small pins of the LTC2499. If you look at the zone properties you will see a limit of 10mils (KiCAD 6.0). If I change this to 1 mill all works fine. (see attached)
However-am I taking a risk here-seems like a lot of the KiCAD defaults work and make sense. Also I think the pins are about 25 mils so not sure why I needed to reduce this value.

Fritz

PD_reader_REV0.zip (1.4 MB)

zone_properties
zone_properties1029×387 58.2 KB

2

remark: your attached project doesn’t contains a GND-zone on TOP copper, so the project doesn’t represent your last edited version.

Nevertheless I have looked into the prject (and created a TOP-GND-plane for tests). I think you have to reduce minimum width because:

  • you have set the zone pad connections to thermal relief
  • the pads of the LTC2499 are 0.25x0.875mm (== 9x34mil)
  • I suppose that the thermal spokes for the thermal relief are restricted to be smaller than the pad-width
  • so the zone must have a minimum width <= 0.25mm (9mil), the 10mil standard-value is a fraction to big
3

Thanks.—I goofed on the 0.25–that was MM so yes- we are looking at 9mil and I am under the 10mil setting. SO–I guess it is to the board manufacturer at that point-I am sure they can handle that.

And sorry on losing the GND plane–happened again–probably some problem on my end.

thanks!
fritz

4

I do not know where the boards are being made, but JLCPCB has no problem with 8 mil (almost all my boards have that minimum) and 5mil is their limit.

5

Thanks
I have used JLCPCB before–I think most vendors can handle this
fs

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