The main point of the spec is that you have to maintain spacing.  If the
non-functional land is out in the middle of nowhere, breaking out of it is
not an issue.  If there is a trace running near it, you still have to
insure that the drilled hole does not violate the minimum design spacing
between the hole and the trace.  My concern is that the non-functional land
was made smaller to make room to run an extra trace.  Also if you have a
fine pitch connector withe reduced land sizes, you need to insure that the
hole that breaks out of the pad does not violate spacing to an adjacent pad
in the connector.

Joe Schmidt
Raytheon Product Development Engineering
P. O. Box 11337 Bldg. 807 MS J6
Tucson, Arizona 85734
Tel (520) 794-4229
Pgr (520) 489-9286
Email [log in to unmask]


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  |"Reed, Randy" <[log in to unmask]>                                                                                                         |
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  [log in to unmask]                                                                                                                              |
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  |08/17/2010 01:33 PM                                                                                                                               |
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  |[IPC-600-6012] Non-Functional Land Registration and Annular Inspection                                                                            |
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  |IPC-600-6012 <[log in to unmask]>                                                                                                               |
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IPC-6012 has no guidance on the management of non-functional lands (that
I can find) concerning registration and annular ring limits.



The scenario causing problems is designs where the non-functional pad
size is smaller than the functional pad size.  I am not trying to debate
whether this is a good design practice.



What is the intent of IPC-6012?  Should boards with registration and/or
annular ring failures on non-functional lands, with the smaller pad
size, be considered non compliant?



Randy



Randy Reed, CQE

Reliability Lab

Viasystems Group Inc.

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503.992.4421-direct  l   503.545.0150-cell




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