LGA 14 Chip holder

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Andrew Cowan

Senior Member
I have ordered a free sample of an accelarometer, and it comes with an LGA14 layout.

Have you any ideas on how I could attach this to a PCB? I assume it is too small to solder wires to the pads connecting it to a PCB.

I want to solder it to a PCB, and then any connections that need making can be made from that PCB.

One idea I had was to make a PCB for it, add solder to the pads, heat it up with a heat gun, then place the chip onto the molten solder with tweezers.

The second picture is of it drawn in circuit wizard, compared to a normal DIP. (A 555).

Thanks for any input,

Andrew
 

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eclectic

Moderator

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Dippy

Moderator
Good spotting you 2. You probably spent more time looking than Andrew did haha.

LIS302ALB adapter board £15 from Digikey but none available.

Oh dear, should have looked before you blagged a freebie :)

Buy some CAD and make your own.
 
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westaust55

Moderator
Spent all of 5 minutes looking to find that link. Simple search for "LGA14 adapter" turned that up.

Still, might have been 5 mins more than . . . .
 
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Andrew Cowan

Senior Member
Hey! I spent 20 minutes looking for adaptors (although I got sidetracked)...

Freebies are alaways good, even if they are just an oppertunity to learn that 'there is no way I can solder an LGA socket'

Many thanks for finding lots of stuff for me to add to my wishlist (although no solderless LGA sockets),

Andrew
 
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Dippy

Moderator
'there is no way I can solder an LGA socket'

??? You give in too easily.

Part with the cash, get yourself some CAD, film, photo-resist board, create the component / outline/footprint. Etch a board, get some solder paste, have a stiff G&T, blob the solder paste on the pads (oversized of course), place the ic in position, plop the end of a 1mm soldering iron tip into the solder paste next to the ic, the heat will conduct, the solder will melt and Bob will be your Uncle.

No doubt you can get freebie CAD, the solder paste will cost as will the board and chemicals - but at least you've saved some money on the component.
It's a hard life isn't it :)

I guess that little freebie chip will end up in the back of the drawer now?
 
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Mycroft2152

Senior Member
Andrew,

You've got a real challenge on your hands, in making an adapter for that package.

Normally a smt package is normally easily doable, but that very small leadless package is another story.

The clearance between pads is minimal. Homebrewed photo process has a chance but toner transfer will probably "bleed"

You'll be fighting surface tension, not only in the etching bath but also in soldering.

A commercially made board with solder mask is the only way to go.

If you really want to give it a try, here's a link to s good technique:

http://www.zianet.com/erg/SMT_Soldering.html

For a photo solder resist and solder mask film:

http://www.pcbhobbyist.com/

If you do want to give it a try, let me know and I'll draw up the adapter in DIPTRACE for you.

Myc
 
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Charliem

Senior Member
the heat will conduct, the solder will melt and Bob will be your Uncle
Click to expand...
HEHE.

Hello Andrew,

For a good free CAD package you should look at Diptrace.They offer a free 250 pin version and its easy to work with.
 
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Andrew Cowan

Senior Member
Thanks, I'll do that. I have pretty good quality PCB making equipment available at school including photoresist boards - I can use that.

And Dippy - the only time that the chip will end up at the back of a grawer is if I try and burn it out. I will try, but who knows if I will succeed...
 
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alband

Senior Member
Did you get it working in the end.
I'm thinking of getting one to measure orientation.
Can you reply in the "pulsin then serout" post given the current discussions in "forum etiquette" about keeping threads relevant to their names (I'l planing on re-naming it once is burnt out). :)
 
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Winston Smith

New Member
I wanted to mess around with the capable and extremely inexpensive Freescale accelerometers in LGA-14 packages, so I created the artwork I could use to etch LGA-14 to DIP-14 adapters via the toner transfer method. For the toner transfer, I print on glossy magazine covers and transfer the toner using a hot laminator. After etching, the adapter array was tinned using expired solder paste in an old skillet with the excess solder being removed from traces using solder wick. For the SMT soldering, I used expired Kester Easy Profile 256 paste and the skillet method. The paste was applied through a stencil made from a small piece of transparent report cover with slots cut for the two side pad arrays. This was made by positioning the clear cover plastic over a page containing the printed artwork and using a razor blade to cut the slots in the appropriate positions. A credit card was used to wipe the paste across the stencil and a toothpick used under a magnifier to apply a tiny dab of paste to each of the end pads. The device was then picked and placed using tweezers. Even though there was no solder mask on the board, there wasn't the slightest hint of bridged joints when inspected from the bottom through the translucent circuit board and the MMA7361 functions perfectly.

600dpi artwork for a 3" x 4" board:

http://i142.photobucket.com/albums/r100/EGoldstein1984/LGA-14toDIP-14AdapterPCBartworkarra.png

Photo of etched board:

http://i142.photobucket.com/albums/r100/EGoldstein1984/LGA-14toDIP-14adaptersecthedon3x4in.jpg

Completed adapter with .1" pitch male headers:

http://i142.photobucket.com/albums/r100/EGoldstein1984/MMA7361onadapter.jpg

The white specs on the final board are tiny amounts of flux I missed when I used 91% isopropyl alcohol to clean the board after SMT soldering.
 
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Andrew Cowan

Senior Member
That looks great. I also made an adaptor board for mine in the end. Also, the first two of your links don't work - the last one does.

Andrew
 
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Winston Smith

New Member
Thanks. I fixed the links. These little gems were just too capable and far too inexpensive to let an inconvenient package type prevent me from playing with them.
 
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