AK8963 Footprint


#1

Hi,
I’ve looked for breakout boards for a magnetometer (Compass) module) I need, AK8963 but they are expensive $25 each.

I thought perhaps I could buy the chip (surface mount) and make a board, but find they’re a challenging small size. The N is app 2x2mm and has edge connectors 4 by 4, that I may with care be able to solder and check $5ea.

I bought the C type but these have dots for connections on the bottom (14) and later I found they are app 1.6x1.6mm. $0.70each Almost too small to see (Amazing) (IPHONE compass)

Is there any way I will be able to use them?

Cheers, Camerart.


#2

A rework station would do it. But it’s possible that you would need a microscope in any case, for placement. I have done 0.5mm pitch QFN with microscope and a proper soldering iron, but it’s not easy. You would need to make longer pads and plenty of space around it.


#3

Looks like a BGA package with a few balls missing.
https://www.radio-electronics.com/info/data/smt/smd-bga-ball-grid-array-package.php

Might be quite hard to hand solder these if it is even possible.


Maybe use the qfn variant also shown in your screenshot. This would be a lot easier to solder.


#4

Hand soldering bga’s is pretty much impossible. You need the whole thing up to temp for the balls to drop correctly.

Hand soldering qfn’s is possible. But you need broken out pads you can push heat into. And in such a case I would avoid soldering the center pad if possible. As he will lead to torn pads 9/10 times withiut hot air.


#5

Do you mean the thermal pad? It might be possible to make a large through-hole pad (in this case e.g. 1.4mm hole) and solder it manually from the bottom side.


#6

Its a magnetometer, If its running hot enough to need the center pad for cooling, you have done something very wrong.

Even in such a case, Its not easy to juggle your hands to heat that hole from the bottom while perfectly aligning and ensuring its flat on the top, as such for a beginner I would normally not attempt soldering it, and to just focus on tacking pads then doing the rest.


#7

This pad might just be there for better EMC results as it allows much better GND connections


#8

Hi,
I’ve edited my first post to illustrate the three different prices, so you can see why I have ordered the C type and not the N type. (Penny pinching :grinning: )

I have a rework station, and a microscope.

Only the DOT with an entry through the perimeter is connected.

I don’t see reference to the centre connection in the D/S I’m using C not N.

The options appear to be tack wires on. I would probably lay out the wires cleaned and fixed around first in a matrix pattern, then lay the chip on them, then hot air till soldered.

Or find a BGA PCB with tracks to solder onto. Will Kicad draw a suitable BGA footprint? If so, then perhaps I could etch them.

C.


#9

KiCad it self will not make one. However you can create a suiting footprint using KiCad. (See the Package_BGA lib for examples :wink: )
There even is a BGA footprint generator wizard (not sure how good it is)
And we have BGA scripts here: https://github.com/pointhi/kicad-footprint-generator/tree/master/scripts/Package_BGA

The script and wizard will create a footprint with all pads. So you would need to manually delete the ones you do not need for this part.


#10

Datasheed solves the problem, there’s no thermal pad in the recommended footprint.


#11

So they have used a standard package and not connected that centre pad


#12

Hi R,
Thanks for the scripts, but what do I do with them? The first one has been erased!

I tried the wizard, and I could make the PINs ok, but the package disappears below 4MM. I suppose I can ignore the package actually?
C


#13

When i click the link i see this:


Meaning it is still there (in the master branch. Make sure you download this branch).

You would add your package dimensions do the bga.yml file (or make your own yml file) and call the generator with python3 bga.py bga.yml (or isntead of bga.yml use your own yml description file)
look at the current yml files for clues how to communicate your requirements to the script.


#14

Hi R,
I’m afraid this path is just too difficult for me, thanks.

However, I have been able to make a footprint in the generator, but I can’t save it in the library as it is read only.

I’ve tried making a new library, but then the PCB ‘add footprints’ can’t find it.
C.


#15

You need to add your new lib to kicad via the library manager found under the preferences menu. If you intend it to be a project specific lib then put the lib into the project directory and add it to the local table. If you want this to be the beginnings of your personal centralized library then put it somewhere where it makes sense to you and add it to the global lib table.


#16

Hi R,
I think I may have stumbled around and done almost what you suggest.
The footprint is in it’s own library at the project. (It’s only a test to see what it looks like when when printed out)

Does this look ok to proceed?
C


#17

You might have deleted the wrong pads from it. In the picture above the A1 till A4 are all present. You are missing A2.

look at page 37 of the datasheet for a better clue of how the footprint should look like: https://www.akm.com/akm/en/file/datasheet/AK8963C.pdf


#18

Hi R,
Yes, mine’s upside down! C3 is also missing, it should be B2. I’ll need to mirror image it later.

I’m not using Kicad rules, just drawing it in PCB.

It made me laugh when I printed it on an A4 sheet,so small. I used an inject printer, but make my PCBs using an old Laser, that may not be good enough resolution. I’ll see what happens later.
Thanks, C.


#19

Hand soldering ever shrinking parts is a growing problem in the electronics world.

On youtube there are a bunch of channels of people who repair phones & laptops for a living and watching some of those video’s will give you a good idea of what’s needed to solder such parts.

Some hints:

  • Tweezers.
  • Stereo microscope.
  • Plenty of flux.
  • Hot air station.
  • High Quality tools. No room for bad equipment here.

#20

Hi P,
I found an excellent video as you suggest, In the vid I could see his patience and touch sensitivity, which will need to be practiced.
Thanks.
C