Hello,
I would like to add a rule while creating my differential pair but I don’t know how to do it. I would like that the space between 2 different pairs is 0.76mm but I don’t know how to set that up.
If you have any idea on how I could do it, it would be more than welcome ^^
Best regards
Thomas
Dimensions ->Differential pair dimensions
Hello,
What I would like to do is to add a rule for inter-pair keep out. I have several SATA, so it is two differential pairs for each and the space between each pair should be at least 0.76mm but I don’t know if it is possible to add this rule.
The width of my pair is ok and the space between each lane of one pair is also good but I now need to fix the space between 2 different pairs if it is possible ^^
Best regards
Thomas
Hello,
I found this figure :
With “Differential pair dimensions” I can set my width to 6mil and my trace gap to 8, but is there a way to fix the inter-pair keep_out to 30mil or I have to do it approximately ?
I am not really familiar with it and maybe it is not a big deal to have those 30mil between 2 pairs but I heard it has to be as “clean” as possible ^^
Best regards and thanks in advance
Thomas
I had the same issue with a layout over a year ago. Differential pair bus, equal length, with a gap requirement. As I recall, I set the differential routing spacing, but then used the main DRC settings to set the gap. I think I then had to change the DRC setting back to the pair spacing to get it to pass DRC. Be warned, this was pre-4.x stable release so I don’t know the behavior is still the same.
I would like to see these feature updates related to the Design Rules:
Most of the time the fine-pitched BGA region will have different constraints than the rest of the board.
There is also a USB 3.0 interface on this board. In case it’s not known, if you have high-speed controlled impedance traces on your board, you also need to let the board fab house know. Just because you specify 6 mil traces with a gap of 8 mil, they may not come out to the calculated 90 Ohms due to variations on fab process, prepeg thickness used, etc. On my Fab layer, I have a notes sections that calls out the following:
The board house will generally then come back and tell me they are adjusting the 6/8mil pairs to 5.8/7.5 or something to match their particular process for those traces.
Aaron
And how do you indicate to them the net names?
I replied directly to the post above mine but for some reason the site doesn’t show that.
Best in that case is to mark the part you want to address and hit the ‘Quote’ button that appears.
That way the one being quoted also get’s a message - depending on his personal settings.
Another way to get the attention of someone is to start writing an @ , a list will pop up and you can select or keep writing the name of the person - this also will send him a message.
Yes, I often do that, but sometimes I click the “Reply” button in the individual post as you just did. Sometimes it works, sometimes it doesn’t.
@1.21Gigawatts, I export the IPC-D-356 Netlist File from File -> Fabrication Outputs, and include it in the fab package. In the past, I have had a NOTES section that stated something like:
But this is more of a pain to keep track of, and if a trace jumps layers it is a pain.
Aaron
Hello Group,
I guess this topic has suddenly stopped, but I’m also curious about the issue with differential pair design rules.
sometimes i want to shove the differential pair, but the gap will only follow the rules set for other traces.
