LED footprint with a third pin

[eeheba]

hi all,

two days ago i have designed a LED footprint, and i wondered from the component view. so i start searching about it.
while i was searching i have noticed that there are LEDs with third pin but i did not understand exactly the purpose of it.
in some forums they connect the existence of this pin with the heat dissipation!
so please if any one can help me with understanding the purpose of this pin and how the pads dimensions were calculated in the attached photo, i'll be grateful.
thanks in advance.

https://media.digikey.com/pdf/Data%20Sheets/Avago%20PDFs/HSMz-Czzz.pdf

[robertferanec]

Is it the LED which you are using in your design? If not, you can just ignore it.

If you still would like to know, maybe try to ask the manufacturer. I had a quick look at the datasheet and it really looks like they do not put there much details about the additional pin - so you would need to keep digging.

[eeheba]

thanks a lot, yes it is not in my design but i need to know how to design it, so i think as u suggested i'll contact the manufacturer.