I don't think you can setup an exact difference for a diff pair.
We use the uncoupled length, Gather control = ignore and then setup max mm and
phase tolerance.
On our chips the the general rule is that the trace should be equal lenght from
the BGA edge.
Another ways is to include the first peace of trace in the connector/chip
symbol.
Finally you can make a clength report including delay and import it into excel
to check the lengths
Hi
Peter Sxrensen
MTS Engineer
Ethernet Product Group
Vitesse Semiconductor Corporation
Location: Hxrkfr 16, 2730 Denmark
Tlf +45 4485-5996
Cell +45 4050-7098
Fax. +45 4485-5939
-----Original Message-----
From: Musetti, Carl [mailto:cmusetti@xxxxxxxxxxxxxxxx]
Sent: 8. december 2004 15:48
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [BULK] - [PCB_FORUM] Differential Pairs on 15.2
Hi All,
Has anyone had to deal with differential pairs in 15.2 that are not
balanced out of the IC. The Mellanox
InfiniHost_III_MT25208 spec that the PCIX bus diff pairs are not balanced out
the chip and give the skews and states that the skew must be accounted for on
the PC layout to balance the pair completely end to end. How would I configure
this rule in allegro? For instance is there a way to tell the tool to route the
+ end 50 mils longer than - end?
Thanks for all replies in advance
Carl
************************************************************
* Carl T. Musetti Infinicon Systems *
* Tel: 610-233-4828 680 American Ave, Suite 100 *
* Fax: 610-233-4777 King of Prussia, PA 19406 *
* cmusetti@xxxxxxxxxxxxx *
************************************************************
-----------------------------------------------------------
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
-----------------------------------------------------------
