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April 2018

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Subject:
From:
Frank Kimmey <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Frank Kimmey <[log in to unmask]>
Date:
Fri, 6 Apr 2018 14:40:58 +0000
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Victor,
As much as I hate Librarying, I generally look for ~10% side, toe and ~20% heel .
So for a 20 mil wide lead I would use 24 mils for minimum width and increase length by 6 mils (2 in front and 4 in back).
If you want to dive deeper into the geometry of a solderjoint you can calculate some tighter numbers (lead height = pad expansion for side fillets to be 45 degree filled)
The IPC calculator for land patterns will give you better numbers but for a quickie check I use the above as minimums
Good luck,
FNK

Frank N Kimmey CID+
Electrical Engineer/PCB Design

Verifone
1400 W Stanford Ranch Road
Rocklin, CA 95765
T: 916-625-1818
M: 916-833-9877

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Friday, April 06, 2018 7:23 AM
To: [log in to unmask]
Subject: [EXT] [TN] FW: IPC Guideline for Gull Wing lead PWB pad to component lead ratio

Fellow TechNetters:

   I don't have a part number nor spec, I only have the sample PCIe LF connector, 164 gull wing pins soldered  onto a test board.   I there a simple Rule Of Thumb for selecting a suitable PWB pad side which will yield an acceptable toe, heel and side negative solder wetting angle?

Victor,

From: Hernandez, Victor G
Sent: Tuesday, April 3, 2018 10:00 AM
To: TechNet E-Mail Forum <[log in to unmask]>
Cc: Hernandez, Victor G <[log in to unmask]>
Subject: IPC Guideline for Gull Wing lead PWB pad to component lead ratio

Fellow TechNetters:

   Can someone point me in the right direction for PWB SMT pad dimensions for gull wing devices?   Heel LF solder fillet formation concern.

Victor,

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