Dave,

I've used the IPC-7351 land pattern generator for around 5 years and
never had a assembly house complain about component placement issues.  I
do highly recommend it for both saving time and for minimizing headaches
at the assembly house.

Typically I use the nominal settings for the components and the
courtyards(spacing around the part).  Using the courtyards as the
placement boundary, I can place them with the boundaries touching (i.e.
spacing set to 0).  This leaves about 20-25 mils between the physical
bodies of the components which is more than enough space for typical
parts for pick and place machines.

On denser designs or design that have to fit a very small form factor, I
occasionally use the "least" setting which still permits enough space
between the parts for most pick and place machines.

Hope this helps,

-Jeffrey

________________________________

JEFFREY A. JENKINS
SR. PCB/CAD Designer CID+
L-3 COMMUNICATIONS LINKABIT DIVSION
3033 Science Park Rd. 
San Diego, CA 92121
Tel:  (858) 552-9832
Fax:  (858) 552-9487
[log in to unmask]


-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Dave
Pollum
Sent: Wednesday, October 14, 2009 9:06 AM
To: [log in to unmask]
Subject: Re: [DC] clearance between SMD devices


 >Dave,
 >
 >Check for IPC-7351, the courtyard is what you need. Download the free
landpattern calculator or 
 >viewer from www.pcbmatrix.com and look for this info.
 >
 >Regards,
 >
 >Ioan Tempea, ing.

Ioan;
So does this mean that If select a medium courtyard that I can have one
courtyard touch another 
courtyard and I'll be OK, or do I need a gap between courtyards?
-Dave Pollum

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