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Chip Array Solder Joint Goals

Printed From: PCB Libraries Forum
Category: Libraries
Forum Name: Footprints / Land Patterns
Forum Description: [General or a CAD specific issues / discussions]
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=483
Printed Date: 28 Nov 2024 at 9:20pm


Topic: Chip Array Solder Joint Goals
Posted By: rickdehart
Subject: Chip Array Solder Joint Goals
Date Posted: 26 Jul 2012 at 2:08pm
I noticed a difference between IPC chip array solder joint goals of Toe= 0.35, Heel= -0.10, Side= -0.10 and PCB Libraries solder joint goals of Toe=0.20, Heel= 0.00, Side= 0.00.  Can you correct me if I'm wrong and if not can you please explain?
Thanks,
Rick


Replies:
Posted By: Tom H
Date Posted: 31 Jul 2012 at 7:42am
It depends on the size of the Chip Array.
 
Body Length 2 mm or greater Toe= 0.35, Heel= -0.10, Side= -0.10
 
Body Length less than 2 mm Toe=0.20, Heel= 0.00, Side= 0.00
 
Same theory standard Chip Resistors & Capacitors.
 
The are solder joint goals for micro-miniature components must be reduced to avoid excess solder to prevent solder balls and tombstoning.
  

Posted By: rickdehart
Date Posted: 01 Aug 2012 at 9:45am
I see the difference, but now I'm looking at Solder Joint Goals for > 1.6mm at Least.  (Not micro-miniature)
 
IPC (Least) Toe = 0.35, Heel = -0.10, Side = -0.10
Footprint Expert (Least) Toe = 0.15, Heel = 0, Side = -0.05
 
Do I have outdated numbers for IPC?  Am I okay using the Footprint Expert (Least) numbers?

Posted By: Tom H
Date Posted: 01 Aug 2012 at 9:59am
You are OK using PCB Footprint Expert "Least" environment.
 
The PCB Footprint Expert uses advanced technology for the unreleased version IPC-7351C.
 
If you want to know the differences between IPC-7351B and IPC-7351C download the Power Point presentation here -
http://www.pcblibraries.com/forum/pcb-library-optimization-presentation-free_topic468.html" rel="nofollow - http://www.pcblibraries.com/forum/pcb-library-optimization-presentation-free_topic468.html
 
The < 1.6 mm is being updated to < 2.0 mm to define mico-miniature component packages. The < 1.6 mm was originally defined as any component body length less than an 0603 (metric 1608) package, when in fact, the 0603 needs to be included in the mico-miniature component package category.
 


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