How is the clearance calculated?

[crgarcia]

I want to set 1.5 mm clearance for a net class:

But when I set it into my net, it get’s 0.25mm ckearance:

Is that because it says (diff pair)? I have not routed it as diff pair

Thanks!

[Jonathan_Haas]

Diff pairs are created by ending you net names in N and P. Maybe KiCad sees L-IN as the negative part of a diffpair L_IN and L_IP. What version are you using?

[crgarcia]

You’re right!
I’m using the latest version, I renamed it to L_INPUT and it stopped doing that.
My (beginner and questionable) opinion is that Kicad should use something else, like _N, -N but not just N. Just in English, there are tons of words ending with N

Thanks @Jonathan_Haas!!

[pedro]

Differential pair net names can end with “+” and “-” too, not only P and N.

[Jonathan_Haas]

That’s why I’m asking which KiCad version you use. I believe diff pair handling has been improved with 6.0.x, so it will display the correct clearance and only use the diff pair clearance if you actually create and use a L_IP net near it. But maybe this exact issue has not been fixed. So your version would be helpful.

[crgarcia]

Thanks Jonathan!
I’m using 6.0.4:

Application: KiCad (64-bit)

Version: (6.0.4), release build

Libraries:
	wxWidgets 3.1.5
	libcurl/7.78.0-DEV Schannel zlib/1.2.11

Platform: Windows 10 (build 22000), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Mar 18 2022 03:04:44
	wxWidgets: 3.1.5 (wchar_t,wx containers)
	Boost: 1.76.0
	OCC: 7.6.0
	Curl: 7.78.0-DEV
	ngspice: 36
	Compiler: Visual C++ 1928 without C++ ABI

Build settings:
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON

[craftyjon]

This should only happen if you also have a net called L-IP – do you?

If not, this is a bug that maybe @JeffYoung can take a look at

[JeffYoung]

This looks like False isolation shown in pcbnew (#11314) · Issues · KiCad / KiCad Source Code / kicad · GitLab.