DFN and PSON footprint differences

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   Hi Tom and Team,
When I am creating footprints I have as a rule of thumb, to use rounded rectangle pads except for DFN, LGA, PQFN and Thermal pads. For this footprints I use rectangle pads

What about PSON? I think that this footprint has the pads underneath the body as a DFN and It should use a rectangle pad, as well.

What is the default recommendation for this footprint type?

Regards,
david

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dramos Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 18 Feb 2021 Status: Offline Points: 67	Post Options Post Reply Quote dramos Report Post Thanks(0) Quote Reply Topic: DFN and PSON footprint differences Posted: 16 Jun 2025 at 11:10pm
	Hi Tom and Team, When I am creating footprints I have as a rule of thumb, to use rounded rectangle pads except for DFN, LGA, PQFN and Thermal pads. For this footprints I use rectangle pads What about PSON? I think that this footprint has the pads underneath the body as a DFN and It should use a rectangle pad, as well. What is the default recommendation for this footprint type? Regards, david



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: 5796	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 16 hours 54 minutes ago at 7:13am
	PSON is the same as PQFN as both have Pull-Back leads under the package body. PSON/PQFN terminal leads come is 2 shapes. Rectangular Lead = Rectangular Pad D-Shaped Lead = Rounded Rectangle Pad LGAs have 2 terminal lead shapes. Square Lead - Square Pad Round Lead = Round Pad DFNs have rectangular leads Thermal Terminal Leads come in 2 shapes. Rectangular Rounded Rectangular
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dramos Members Profile Send Private Message Find Members Posts Add to Buddy List Advanced User Joined: 18 Feb 2021 Status: Offline Points: 67	Post Options Post Reply Quote dramos Report Post Thanks(0) Quote Reply Posted: 1 hour 34 minutes ago at 10:33pm
	Hi, Many thanks for the explanation! I am working on the Calculator Option File, and I would like to share with you one idea. When we are configuring the default Pin1 orientation, Pad shape... In the Components-Surface Mount , Would be very crazy - no sense idea - to separate into two different options the QFN and PQFN. SON and PSON is another example. The reason is the next, if we have a PQFN component with rectangular leads of course we will use a rectangular pad, but if we have a QFN footprint with a rectangular lead perhaps would be interesting to use a rounded rectangle pad. uploads/15739/example1_2025-06-17_22-32-35.png Thanks for your comments. Best regards, david