Hello Austin, If you add a Diffp_min_space property = 4.5 mil it will clear the DRC. This is a new constraint that was added in V15.2. -Stephen -----Original Message----- From: Austin Franklin [mailto:austin@xxxxxxxxxxxx] Sent: Monday, March 21, 2005 2:23 PM To: PCB Forum Mailing List Subject: [PCB_FORUM] differential spacing clearance specification problem... Hi, I have set-up the following in Allegro 15.2: Using the Constraint Manager spreadsheet, differential signals are paired. Line spacing and gap etc. are NOT specified in the spreadsheet, only phase tolerance and uncoupled length. In Constraints/Physical rule set I setup a Constraint Set Name "100_OHM_DE" and have set DiffPair primary gap to 4.5 mils. In Constraints/Spacing rule set I setup a Constraint Set Name "DIFF_SPACING" and give a Line to Line spacing of 9 mils. What my goal is here, is to have a differential gap of 4.5 mils, and a differential pair to any other signal clearance of 9 mils. I then set-up via the assignment table and constraint manager so that these rules apply to the differential pair signals under General Properties/Physical, using Constraint Sets-Physical & Spacing. What I get are trace to trace DRC errors within a differential pair, saying the target clearance is 9 mils, and there is only 4.5. There should only be 4.5, and it should not be checking trace to trace within the differential pair. What am I doing wrong? It *works* right, in that I get a differential gap of 4.5, and I get a pair to other signal spacing of 9, but I get the LL DRC errors. Regards, Austin ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list please login at //www.freelists.org. Our list name is icu-pcb-forum or go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx Want to post a job listing ? DON'T DO IT HERE! Better yet, join our jobs listing forum. SUBSCRIBE: icu-jobs-forum-subscribe@xxxxxxxxxx POST: icu-jobs-forum@xxxxxxxxxx ----------------------------------------------------------- ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list please login at //www.freelists.org. Our list name is icu-pcb-forum or go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx Want to post a job listing ? DON'T DO IT HERE! Better yet, join our jobs listing forum. SUBSCRIBE: icu-jobs-forum-subscribe@xxxxxxxxxx POST: icu-jobs-forum@xxxxxxxxxx -----------------------------------------------------------