PQFN Pad Size

IPC-7351 which was created in 2003 - 2004 is 14 years old and many things have improved in the electronics industry and IPC-7351 has not kept up with the latest technology. 

IPC-7351 has been downgraded from a Land Pattern Standard to a Guideline. 

All the Toe, Heel and Side solder joint goals are 100% user editable in Library Expert "Preferences" to allow the end user to achieve the results that are best for them. If you don't like the solder joint values, change them. Do not rely 100% on IPC-7351 as you will be disappointed if you do. 

Select the IPC tab on this page - http://www.pcblibraries.com/Products/FPX/Librarian.asp ;

The Periphery is zero "0" but there are Fabrication and Assembly Tolerances that are still being applied to the mathematical model. Turn them off and you'll get better results. In 2017, there is absolutely no need for these tolerances as fabrication and assembly manufacturing is very accurate today. 

PCB Libraries, Inc. cannot wait for the IPC-7351C Land Pattern Committee to make up their minds on what they want to do or not do. We offer guidance to the 7351C committee that is mostly provided by our customers. 

Now that the 7351 creator (Dieter Bergman) has passed away 3 years ago and the vice chairman Gary Ferrari has been MIA for the past 3 years, the Land Pattern committee seems slightly lost in their mission to keep the 7351 standard current and up-to-date.