I like that Mechanical Layer idea... How would this affect bareboard testing, I wonder.
Damon Kelly Hardware Engineer > -----Original Message----- > From: Ian Wilson [mailto:[EMAIL PROTECTED]] > Sent: Thursday, 21 February 2002 12:10 > To: Protel EDA Forum > Subject: [PEDA] Tie compoents(Ex: RF footprints) > > > On 11:50 AM 21/02/2002 +1000, Damon Kelly said: > >Yes, I would really like a "Tie Net" entity! > > > >Particularly (or most commonly) for the "analog ground" and > "digital ground" > >situation. I set different nets in the schematic, but when > it comes time to > >layout the PCB, the DRC spits the dummy when I tie the two > grounds together > >at the star point. > > > >Does anyone have a work-around for this? > >i.e. keep the two grounds (AGND and DGND) separate, EXCEPT > for the nominated > >tie point > > > >Damon Kelly > >Hardware Engineer > > > There are a few workarounds. The one that I think is most > documentable but > sometimes subject to Gerbering issues is the Lomax Virtual Short. > > Basic method: make a really small gap between two small pads > (0.1 mil), > give each pad a name and then create a special clearance > design rule to > allow such a small gap between these pads. Issues to watch > for are gerber > rounding and aperture matching. So set a tight apt matching > tolerance and > set gerber to include more than the standard 3 decimal figures. > > Tell your board house that what the really small (0.1 mil) > clearance is for > and let them know that you do not want it resolved - you want them to > manufacture this as a short. > > I like this workaround, for now, mostly as it is possible to > document the > rule (with the rule comment) and the Gerbering requirements > pretty easily. > > There are other methods as well: > Use a mech layer to tie the nets and then include that mech > layer on the > particular layer plot. > Use the allow short circuits design rule (but this does not > allow you to > control where and in how many places the short should be). > > There is a FAQ and this item is in there but the FAQ is not > well known and > there has been further discussion on the best way forward > since the FAQ > entry (I think). Search the archive for previous discussions on this. > > Ian Wilson > * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://firstname.lastname@example.org * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *