Bear in mind that placing a track under a 0805 or bigger causes a bump
(teeter-totter (spelling ???) affect) which will cause the resistor to
teeter on this bump.
Solder Mask can easily add 0.003" to 0.004" of height. (Placement of SM
onto a PCB does not yield that accurate a thickness). This causes 1 of
either 2 pads to be slightly in the air, resulting in it wetting slower
than the other pad, which then pulls the resistor in the direction of
the pad which wets first ( the proper term escapes me - someone please
enlighten me).
Results in opens, extra work, drop in quality, etc, etc.
Regards
TDK
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
George Patrick
Sent: Friday, July 07, 2006 9:33 AM
To: [log in to unmask]
Subject: Re: [DC] Routing under vias
Only thing we don't route between is 0402's.
--
George Patrick
Tektronix, Inc.
Central Engineering, EDS Applications Support
P.O. Box 500, M/S 39-512
Beaverton, OR 97077-0001
* 503-627-5272 (voice) * 503-627-5587 (fax)
http://www.tektronix.com http://www.pcb-designer.com
"Off-Grid and Proud of it!"
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Adam
Smith
Sent: Thursday, July 06, 2006 07:07
To: [log in to unmask]
Subject: Re: [DC] Routing under vias
Has anyone tried routing under 0603s?
Adam Smith, CID
IR Halifax
7020 Mumford Rd
Halifax NS B3L 4S9
902.431.1644 x262
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of
Matthew Lamkin
Sent: July 6, 2006 4:51 AM
To: [log in to unmask]
Subject: Re: [DC] Routing under vias
Sometimes there is no choice but to either take a trace under a
component (where it will not affect or be affected by that component) or
put in awkward via's and break planes underneath etc which can often
look and perform worse.
Although we may well try not to route through/under a component
sometimes we have to see sense & ignore the whinges of the repairers
(who should only be doing this very rarely).
We can always just tell the Whinger that it was not done using a via for
EMC reasons, and because they don't know anything about it usually just
wander away grumbling :-)
Although I won't go underneath anything 0805 and below anyway.
Matthew.
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of Adam
Smith
Sent: Tuesday, July 04, 2006 3:26 PM
To: [log in to unmask]
Subject: [DC] Routing under vias
I'm just wondering what the general consensus is with routing under
components? In general my company has always frowned upon routing under
resistors and capacitors. I am working on a small 2 layer board and
would like to use the components as jumpers to limit the number of layer
changes for a few signals. Any thoughts?
Adam Smith, CID
IR Halifax
7020 Mumford Rd
Halifax NS B3L 4S9
902.431.1644 x262
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