Generic Footprints for CAPC and RESC

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   I would like to create generic footprints for standard component sizes.  
For instance from EIA 0201 to 1210 for capacitors and EIA 0201 to 1210 for resistors.  

Having only a few verified footprints will help keep our library maintenance down to a manageable number.
Are variations between manufacturers consistent enough to do this?  
Do I just pick a representative manufacturer and go with that?

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bfrantz04 Members Profile Send Private Message Find Members Posts Add to Buddy List New User Joined: 07 May 2020 Status: Offline Points: 3	Post Options Post Reply Quote bfrantz04 Report Post Thanks(0) Quote Reply Topic: Generic Footprints for CAPC and RESC Posted: 07 May 2020 at 12:42pm
	I would like to create generic footprints for standard component sizes. For instance from EIA 0201 to 1210 for capacitors and EIA 0201 to 1210 for resistors. Having only a few verified footprints will help keep our library maintenance down to a manageable number. Are variations between manufacturers consistent enough to do this? Do I just pick a representative manufacturer and go with that?



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: 5716	Post Options Post Reply Quote Tom H Report Post Thanks(1) Quote Reply Posted: 07 May 2020 at 12:50pm
	The package sizes are fairly stable. It's the tolerances that are all over the map. Build your discrete library using the same package dimensions and tolerances. Different mfr.'s with have different package and terminal lead tolerances and these tolerances are used to create the pad stack length and width. Use reasonable tolerances that the majority of your suppliers use. Find common tolerances.
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bfrantz04 Members Profile Send Private Message Find Members Posts Add to Buddy List New User Joined: 07 May 2020 Status: Offline Points: 3	Post Options Post Reply Quote bfrantz04 Report Post Thanks(0) Quote Reply Posted: 07 May 2020 at 5:47pm
	Ok, once I have all of these tolerances put together how do I use these with the Solder Joint Goal Tables to calculate dimensions? Do we use maximal or least material or some combination of both? Also it looks like the rules are the same for capacitors and resistors now?

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: 5716	Post Options Post Reply Quote Tom H Report Post Thanks(1) Quote Reply Posted: 07 May 2020 at 6:27pm
	There are 3-tiers for the Rectangular End Cap packages. The solder Joint Goal values are all user definable. IPC-7351 is now a Guideline and has a basic starting point. The smaller the package the slighter the solder joint goal variance. Here are the current Solder Joint Goal tables - uploads/3/Library_Expert_Solder_Joint_Goal_Tables.zip Note: there are different solder joint goals for every Chip Package size.
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