Half round pads


#1

Hi,

this afternoon i am working on a VSON-12 footprint. This footprint has half rounded pins :confused:
I tried a little, but I did not get a good result. This is the result:

Iam not very happy with it. It is a rectangle pad with a round pad on top.

The there a better way to make this kind of pads ? To make 12 pins like this and align these is a pain in the a**…

Thx for the suggestions…

Zh4ng


#2

you could use a python script:

Or use the array function of the opengl canvas.
(You would need to edit the pin number of each of these pins afterwards.)

Maybe a future version of kicad will have an option to create such a pad without using two overlapping pads.


#3

Got a screenshot of the land pattern from the datasheet or a link to the datasheet?
If the round part is under the body you can use it outside as well, or what is stopping you?

Also each pad has numerical input options… the circular pads diameter and rectangular pad short are not the same in your screenshot.
Also the center of the circluar pad doesn’t seem to sit right on the edge of the rectangular one.
That’s all doable with numerical input.

And once you got that for one pad you can copy&arrange the remainder via the array function.
Pretty simple really.


#4

Or by using the correct user grid settings. (might be faster.)


#5

Hm its a bq27441-G1.

next problem are the 0.05 mm solder mask clearance. I think that will be a problem at a cheap boardhouse… maybe…

I thought there is a better way than mine but i am not far off

thx


#6

so,now is all in the right place.

Only the small area of the solder mask of the rectangular pad clearance are a bit annoying.
I can’t change that, either.

I think i use only rectangular pad. I don’t see any advantages in this half round pads :slight_smile:


#7

Unfortunately there will be no better way until we have support for arbitrary pad shapes. This is being developed, but it will take a while before it is ready.


#8

a solution atm is an oval pad and a rectangular pad


#9

UUuuuu, that’s it. I did not think about that.

thx


#10

I want to show the result of my work. For the next PCB Order i put the footprint in one free space on the board and give it a try :slight smile: Anyone who has helped a great thanks!


#11

Would you mind to share also kicad_mod and 3D model? It would be nice to add those to kicad lib :slight_smile:


#12

If @Zh4ng wants to do that, his footprint would need a reference and a pin 1 marker on the fab layer.
Otherwise it really looks good.
The main question would be which library.
See the future Kicad library convention:


#13

@maui & @Rene_Poschl Sure can i share the footprint and 3D models. In a silent moment i have to read the convention.

The other thing: I want to check the footprint in real. Nothing is more annoying than a wrong Footprint … that ruins your project and gets you :rage:


#14

It may be worth having a new library for footprints such as these - SON are significantly different from e.g. standard DFN. And they can be quite bespoke.

e.g. http://www.infineon.com/dgdl/Infineon+-+Additional+Product+Information+-+SON+-+Soldering+Guidelines+-+Recommendations+for+Printed+Circuit+Board+Assembly+of+Infineon+SON+Packages.pdf?fileId=db3a30433e82b1cf013e82faab2000e5


#15

Did this footprint ever end up in a library?
I’d be happy to test it.

Cheers, Doug


#16

Yes, it is in Housings_SON.pretty


#17

Excellent!
Thanks, Doug


#18

Hmm. I’m not seeing VSON12 in the library? I’m seeing 8 and 10. Any ideas?


#19

Hi Doug,
it is the Texas_S-PDSO-N12. It is a Footprint from TI for the Fuel Gauge bq27441-G1. The KiCad Library Convention wants to be an exact name, so VSON12 -> Texas_S-PDSO-N12.

:slight_smile:


#20

As per KLC 6:

Manufacturer specific footprints that deviate from the above naming convention should be named as follows: Manufacturer_FootprintName e.g. Texas_S-PVQFN-N48