1 mm Pitch BGA Courtyard - Nominal Density Level

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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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5not4 Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 09 Jul 2013 Status: Offline Points: 40	Post Options Post Reply Quote 5not4 Report Post Thanks(1) Quote Reply Topic: 1 mm Pitch BGA Courtyard - Nominal Density Level 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.



Tom H Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5718	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply 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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5not4 Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 09 Jul 2013 Status: Offline Points: 40	Post Options Post Reply Quote 5not4 Report Post Thanks(0) Quote Reply 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.