Certain small Surface Mountcomponents, such as some SOD’s and SOTs for example, with terminal leads thatcan be in the form of either Gullwing or Outward flat ‘L’depending on their dimensions.  

It’simportant to distinguish between the two to assign the correct protrusion goals(toe, heel and side) to obtain the most reliable footprint mounting. 

This ishow the PCBL Footprint Expert does it.

Gullwing terminalsare generally for parts with relatively larger terminals and provide more heel fillet.

Gullwing goals should be applied when:

S min > D1 max

Or

(L max – L min) >= 0.50 mm

Outward Flat Lterminals are generally for smaller parts and do not provide as much heel fillet.

Outward Flat L goals shouldbe applied when:

S min <= D1 max

AND

(L max – L min)  < 0.50 mm

When a Gullwingchange to Outward L occurs, this message will be displayed: