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1 mm Pitch BGA Courtyard - Nominal Density Level

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5not4 View Drop Down
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    Posted: 24 Aug 2015 at 5:55am
Hi Tom.
 
Is any history available for the courtyard clearance when using the old LP Calculator? For 1mm pitch BGA's it is creating a 2mm clearance for courtyards and everything that I can find within IPC7351B is stating 1mm is needed for nominal patterns. I have a feeling it is protecting for the component fiducials.
 
I apologize in advance if this is off-limits. LP Calc is still our main tool with the Library Expert as a second opinion/reference tool.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 24 Aug 2015 at 7:40am
The IPC-7351 standard has been downgraded to a Guideline.
 
 
You can use whatever Courtyard Excess you want based on if you ever "Rework" bad BGA's. If you do then you need extra clearance. How much clearance depends on the assembly shop's need for rework space.
 
If you don't rework, the courtyard can be 0.50 mm, but in Library Expert it's a User Preference for every Ball Size.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 5not4 Quote  Post ReplyReply Direct Link To This Post Posted: 27 Aug 2015 at 5:22am
Thanks, Tom.
 
We had found one of your previous (MG) Blogs and you had stated this similar thing in reference to rework/no rework clearances.
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