On the face of it, no, never had to.
However, compare to the fanout of a 0.5mm BGA inner rows. Running a 75um track in the ~250um gap between the pads, and still
under the solder mask. There are a heck of a lot of volume designs incorporating such practices.
A 0402 will typically have 0.6mm between the pads. The solder mask is much thinner than the solder past and finished joint
thickness. Should be possible, but I would have a concern about tombstoning although this depends very much on the assemblers
capability. All of my 0402 footprints are without mask between pads for this reason, and to facilitate cleaning.
Best Regards
David Greig
______________________________
GigaDyne Ltd
5 Albany Business Centre
Gardeners Street
Dunfermline KY12 0RN
United Kingdom
t: +44 (0)1383 624 975
www.gigadyne.co.uk
______________________________
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Tempea, Ioan
Sent: 16 February 2007 14:35
To: [log in to unmask]
Subject: Re: [DC] Traces between 0402 pads
Rodney,
it is unfortunately supposed to be a high-runner, on FR4 and on top of it is going to be lead-free.
Ioan
-----Original Message-----
From: Brand, Rodney [mailto:[log in to unmask]]
Sent: Friday, February 16, 2007 9:32 AM
To: (Designers Council Forum); Tempea, Ioan
Subject: RE: [DC] Traces between 0402 pads
Ioan,
It is application that is the real issue. Is this a high volume circuit board, a low volume circuit board or a one-time no-rules
lab/bench board? Is this a standard board, module board or a substrate? Each carry a different assembly technique and have
different design rules. Start there looking for design guidelines from your venders.
IMHO
Rodney
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