Component zero Orientation A or B?

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   We're building a lot of 4-pin DFN footprints for PCBPOD, and Pin 1 is all over the place. 
Pin 1 in lower left, upper left, upper right, lower right. 

There is no standard pin out for the 4-pin DFN package and therefore there is no standard Pin 1 Zero Orientation. Never will be. The component manufacturer's are doing whatever they want. 

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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: 6029	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Topic: Component zero Orientation A or B? Posted: 30 Mar 2020 at 11:46am
	We're building a lot of 4-pin DFN footprints for PCBPOD, and Pin 1 is all over the place. Pin 1 in lower left, upper left, upper right, lower right. There is no standard pin out for the 4-pin DFN package and therefore there is no standard Pin 1 Zero Orientation. Never will be. The component manufacturer's are doing whatever they want.
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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: 6029	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 27 Feb 2020 at 2:18pm
	Right now we're getting ready to release our V2020 Library Expert Beta in 2 weeks. The programmers are not going to update anything until after the official release in mid-April. The main reason is that V2020 is a total rewrite that started a year ago and nothing is going to distract them from meeting release deadlines. This is not an easy fix and may take a week, but the most important thing is 100,000 users with existing libraries created by Library Expert do not like changes. Even though you can control the Zero Orientation in Preferences.
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ransonjd Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 15 Nov 2016 Status: Offline Points: 142	Post Options Post Reply Quote ransonjd Report Post Thanks(0) Quote Reply Posted: 27 Feb 2020 at 1:48pm
	Hi Tom, Thanks for the info. Since there's no DFN specific reason to favor the current orientation, could the orientation be updated to match the orientation of similar 3&4-pin components? I feel like one of the major benefits of PCB libraries is the consistency of the footprints generated, and DFNs seem like an odd exception.

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: 6029	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 27 Feb 2020 at 1:17pm
	I forgot to mention the main reason. Unlike most component families, the 4-pin DFN has multiple pin configurations and Pin 1 can be in different locations. So there really is no Zero Orientation for the 4-pin DFN.
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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: 6029	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 27 Feb 2020 at 1:15pm
	It's because the "D" dimension is normally larger than the "E" dimension. Our software programmer didn't read our documentation. Not sure if IPC-7351C will ever adopt the Orientation B concept to align with the IEC 61188-7 Standard which lists both A & B orientations. I'm not sure if IPC-7351C will ever be released. The chairman Karen McConnell just stepped down after 20 years and the subcommittee is losing interest.
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ransonjd Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 15 Nov 2016 Status: Offline Points: 142	Post Options Post Reply Quote ransonjd Report Post Thanks(0) Quote Reply Posted: 27 Feb 2020 at 1:00pm
	Hi, I'm noting that 4-pin DFNs still follow "A" orientation and not "B" orientation. What's the motivation for this difference from other 4-pin components? Thanks!

AB_Regin Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 14 Mar 2018 Status: Offline Points: 24	Post Options Post Reply Quote AB_Regin Report Post Thanks(0) Quote Reply Posted: 04 Oct 2018 at 10:37pm
	Thanx Tom! I can help you by telling that I discovered this issue after POD download of this one: http://www.pcblibraries.com/POD/?M=KINGBRIGHT&PN=APHF1608SEEQBDZGKC

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: 6029	Post Options Post Reply Quote Tom H Report Post Thanks(1) Quote Reply Posted: 04 Oct 2018 at 8:23am
	I see now what you are referring to. I created the documentation, so now I have to find some 4-pin DFN parts and see what the typical pin numbering scheme is for Antenna, Capacitor, Crystal, Diode, Filter, Inductor, IC, Oscillator (the most used family for this package), Resistor & Transistor. Thank you for reporting this issue.
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AB_Regin Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 14 Mar 2018 Status: Offline Points: 24	Post Options Post Reply Quote AB_Regin Report Post Thanks(0) Quote Reply Posted: 04 Oct 2018 at 1:17am
	And more... I found this document, in which the DFN-4 is described as an oscillator (this is just a matter of a different 3D Body i guess): https://www.pcblibraries.com/Products/FPX/UserGuide/download/Library%20Expert%20Surface%20Mount%20Families.pdf Here in this document it shows the correct rotation for level B, but your library expert outputs it as level A!

AB_Regin Members Profile Send Private Message Find Members Posts Add to Buddy List Active User Joined: 14 Mar 2018 Status: Offline Points: 24	Post Options Post Reply Quote AB_Regin Report Post Thanks(1) Quote Reply Posted: 04 Oct 2018 at 12:58am
	I can add some more information after some searching.. I found this old topic: https://www.pcblibraries.com/forum/ipc7351c_topic732.html At that time you Tom said that the Library Expert follows the IPC 7315C and Level B zero rotation, but that does not seem to be the case with the DFN-4?