PCB Libraries Forum : Chip Component Land Pattern https://www.PCBLibraries.com/forum/ Wed, 15 Apr 2026 02:15:40 +0000 Mon, 17 Sep 2012 02:31:13 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.07 360 https://www.PCBLibraries.com/forum/RSS_post_feed.asp?TID=551 <![CDATA[PCB Libraries Forum]]> https://www.PCBLibraries.com/forum/forum_images/PCBLForumLogo.gif https://www.PCBLibraries.com/forum/ <![CDATA[Chip Component Land Pattern : For those who want to customize...]]> https://www.PCBLibraries.com/forum/chip-component-land-pattern_topic551_post1772.html#1772 Author: Nick B
Subject: 551
Posted: 17 Sep 2012 at 2:31am

For those who want to customize library rules to meet manufacturer’s requirements and want to see how it works to create customized Footprint Expert DAT files (personal rules).

 
IPC-7351C Reference Calculator  (forum login is required to download)
]]> Mon, 17 Sep 2012 02:31:13 +0000 https://www.PCBLibraries.com/forum/chip-component-land-pattern_topic551_post1772.html#1772 <![CDATA[Chip Component Land Pattern : Hi all,How can I calculate...]]> https://www.PCBLibraries.com/forum/chip-component-land-pattern_topic551_post1715.html#1715 Author: bakhmat
Subject: 551
Posted: 13 Sep 2012 at 7:38am

Hi all,
 
How can I calculate Gmin for chip component (IPC-7351B)? 
I can't get the PCB Footprint Expert result.  Confused

Gmin=Smax-2*JH-SQRT(Cs^2+P^2+F^2), where 
Smax=Smin+Stol(RMS);
Smin=Lmin-2*Tmax;
Cs=Stol(RMS);
Stol(RMS)=SQRT[(Lmax-Lmin)^2+(Tmax-Tmin)^2]
JH=0 (Nominal Density for 0603 chip component)
P - placement tol.; F - fabrication tol.

Is that right?

Thanks in advance
]]> Thu, 13 Sep 2012 07:38:02 +0000 https://www.PCBLibraries.com/forum/chip-component-land-pattern_topic551_post1715.html#1715