Design rules editor?


#1

Dear Kicad Member,

I have a question related with “Diff Pair Width” and “Diff Pair Gap”
What’s it related with ?
What’s the value for it ?

Any practical links explain it ?

Thanks


#2

The latest version of kicad i have used is 4.0.6, so it may be different on .7 or the nightlies.

On my version, it related to the openGL differential pair router, the width was the width of each of the tracks, the gap was the space between them, e.g. for USB traces on my last 4 layer board, was 0.3mm trace widths, seperated by a 0.2mm gap


#3

How to mark it in the schematic ?

For example

USBP+

USBP-

?


#4

#5

The rules as of 4.0.6 where both USBP_P / USBP_N and USBP+ / USBP- are valid for describing a differential pair, You label those traces with those names, and the differential routing will pick up on it.

I’m not sure if its been improved, but most of my use of the router required some followup tweaking to make it connect to the pads like how i desired. (mainly did not like the pitch of the QFP being thinner than the pair gap.

For clarity, the device in the middle is an ESD protection chip.