LED pinout question

Looking at an LED on JLCPCB, and it's not clear how they go about determining if pin 1 is the anode or cathode. This is from the datasheet:

https://i.imgur.com/nCvD7zD.png


And their drawing from EasyEDA has the cathode on pin 1:

https://i.imgur.com/GK696px.png


Did they just assume the pin on the left is pin 1?

Cause I'm not seeing any indication how they determined that. This is the link to the part, also has link to datasheet and EasyEDA CAD model:

https://jlcpcb.com/partdetail/Tuozha...S2_12T/C688879

I think I might have figured it out. It looks like that polarity drawing assumes the pinout is left-to-right, with cathode being pin 1.

Both images have number 1 on the left pad, so I assume you are right.

Ioannis

Well, turns out JLCPCB probably made that EasyCAD drawing. There's no pinout in the datasheet. So they most likely just looked at how the LED is packaged on the reels and made an arbitrary decision as to which pin is what.

If you want to follow some drama on LED pinouts, you can read my thread over here (this is the other place I go to get balanced information on general electronics material):

https://forum.allaboutcircuits.com/t...an-led.201924/

The absolutely necessary notation is the A and K in a diode. Numers are arbitrary and no one forces you to identify A as 1 or 2.

So the design of the part by JLCPCB seems OK to me and I would not bother more on this.

Ioannis