Dimensional Principles of IPC-7351B

 

 

 

This lead style has a different calculation then the normal Gull Wing lead style:

 

 

 

All values and dimensional assignments are displayed. 

 

You can change the calculation values and observe the resulting land pattern results.

 

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Amax = the Lead Span

 

 

3D model created by Library Expert.

 

I realize this thread is 10 years old, but we are just now looking at this from the IPC standard perspective and were trying to understand Amax and what it means.  

After reading this thread, we are still confused.  Are you still saying that Amax is the maximum lead expansion that IPC calls out in their calculations?  

It seems contrary to what we are see in the IPC formulas.  How does your Amax have anything to do with whether the leads are bent inward?  drj-bbe made a good point that it would seem to be related to what they showed, which you insisted it is not the case, given your second-to-last image.  

If the calculations are only about lead expansion and minimum lead length, it would seem that any calculation would always follow the exception in note 1.