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I'm expecting some interesting comments and answers on this one, mainly because I'm probably just insane for even considering / asking this.

One component I want to prototype with is the MCP73123 LiFePO4 battery management IC. The problem is that it doesn't come in anything but the DFN package, which is insanely small and has very small contacts.

IC pic

I couldn't find any posts here, and I only found one almost-useful link online that talks about prototyping with DFN components. The problem is, it assumes that it's an option to design a PCB for prototyping.

Now I realize that it's expected that someone would create a PCB, but I just wanted to test out the IC first to see how it works. So I figured, why not try to fly some 30AWG wires off of the chip and test it that way! Well, even though I seem to be able to solder the wires down, they just pop right off with the slightest tug.

It looks like my first Eagle project is going to be a PCB for this particular chip (and then I still have to deal with soldering it properly, so any tips or DFN-specific PCB layout tips here are welcome), but if anyone out there has done this successfully, please provide an answer that outlines ways to do it properly. And if it's just downright impossible, I can accept that as well. :)

EDIT -- so far, I have ruined two ICs trying to solder them to a PCB. :) I received my adapters from Proto-Advantage today... would everyone recommend Chip Quik and a hot air rework station to attach the IC?

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    \$\begingroup\$ I haven't done this but perhaps an easy way would be able to purchase an adapter and then use a hot air gun to solder the component. You will need some solder paste for this, though. After applying the solder paste, place the component and apply hot air. With some luck, the component will align itself on the pads and you should have nice joints. You can then solder wires onto the adapter and connect to your breadboard. \$\endgroup\$
    – Saad
    Commented Oct 7, 2012 at 18:04
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    \$\begingroup\$ The adapter link below is great, you can also dead bug it. Super glue it to something flat upside down, then hand solder some 30 gauge solid wire to it. In addition to the suggestions below a pin or a dental pick will be useful for breaking up all the solder shorts you're going to cause :) \$\endgroup\$
    – Some Hardware Guy
    Commented Oct 7, 2012 at 18:42
  • \$\begingroup\$ super glue... why didn't I think of that when I was soldering to the chip today? :) The good news with the MCP73123 is that they double up on the pins and put them next to each other, so solder bridging is only an issue in one or two places. :) \$\endgroup\$
    – Dave
    Commented Oct 8, 2012 at 3:21
  • \$\begingroup\$ First choice (again) is a proto-advantage adapter, with proto advantage mounting the chip!! Next choice would be jury-rigged toaster oven or skillet with solder paste and a solder paste stencil (proto-advantage will sell you a stencil for each adapter). Third choice is toaster oven or skillet without a stencil. After that I'd move to hot air. \$\endgroup\$
    – Scott Seidman
    Commented Oct 12, 2012 at 21:54
  • \$\begingroup\$ ah, wish I knew about the stencil, oh well. I've got solder paste coming and will just apply it under the microscope as carefully as I can. :) Haven't tried the oven / skillet approach before, but have read about it. Maybe I'll try it if I can find an old pan that I'm not going to cook on anymore. Do you put anything under the PCB adapter? A little olive oil, maybe? :) just kidding. \$\endgroup\$
    – Dave
    Commented Oct 12, 2012 at 22:29

5 Answers 5

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I've done this a couple of times, with a bit of practice it gets fairly easy.

enter image description here

http://ms3c.wordpress.com/2012/07/17/prototyping-the-max9814-automatic-gain-control-microphone-amplifier-ic/

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    \$\begingroup\$ For a limited range of values of easy :-) \$\endgroup\$
    – Russell McMahon ♦
    Commented Oct 7, 2012 at 22:34
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    \$\begingroup\$ Very neatly done! \$\endgroup\$
    – Johan.A
    Commented Sep 12, 2013 at 11:17
  • \$\begingroup\$ +1 "Dead Bug", although fun and expressive, is too limiting to name such works of craftmanship! DFN are EVIL :-) \$\endgroup\$
    – LorenzoDonati4Ukraine-OnStrike
    Commented Jan 5, 2016 at 12:08
  • \$\begingroup\$ Looks good. Can you help me what tools I should use to do it? \$\endgroup\$
    – MaNyYaCk
    Commented Jan 12, 2018 at 17:13
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I have done what you're describing a few times with µDFN and QFN packages.

Of course the thin wires snap off very easily, but you can prevent that if you solder the tiny package onto some very rudimentary PCB, maybe a universal one. You will of course have to position your chip upside-down on the board. You can stick it to the board using chewing gum, or you can use a small hand drill to create a concave space for the chip to rest in while you're soldering. Just make it stay there and not move.

You can also try to solder everything very quickly and use a glue gun to hold everything in place once you're done soldering.

This whole process may take time. My first successful attempt took about 30 minutes to solder a QFN16 package upside-down onto a pcb with the concave space for the chip. Practice makes perfect.

All you need to succeed:

  1. Good eyesight and eye protection (or a microscope if you have one)
  2. Very fine solder. For precision soldering this is far more important than a thin soldering iron tip. I use 0.5mm solder.
  3. Precision tweezers
  4. Good lighting
  5. A steady desk to rest your shaky hands on!
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  • \$\begingroup\$ Great tips, thanks! I'm glad I'm not the only one thinking about doing this, or having done it before! \$\endgroup\$
    – Dave
    Commented Oct 8, 2012 at 3:23
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    \$\begingroup\$ I guess I would also add -- 6. multimeter to check for shorts after soldering! \$\endgroup\$
    – Dave
    Commented Oct 8, 2012 at 3:25
  • \$\begingroup\$ Ah, indeed! Too bad it's too hard to check for bad joints. \$\endgroup\$
    – Christoph B
    Commented Oct 8, 2012 at 4:47
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    \$\begingroup\$ That's called the dead-bug-technique. As for solder, I use 0.3mm for SMD work. \$\endgroup\$
    – starblue
    Commented Oct 8, 2012 at 5:19
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    \$\begingroup\$ flux flux flux flux.... \$\endgroup\$
    – Scott Seidman
    Commented Oct 8, 2012 at 20:32
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If you can't hand solder you can always use one of these adaptors and here is another.

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  • \$\begingroup\$ Nice adapter link I didn't know you could get them so cheap! \$\endgroup\$
    – Some Hardware Guy
    Commented Oct 7, 2012 at 18:40
  • \$\begingroup\$ original question updated regarding proper usage of these adapters... \$\endgroup\$
    – Dave
    Commented Oct 11, 2012 at 23:05
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A Hot Glue gun is handy to tack down those loose wires to make sure they don't rip off the board. Locktite makes some special stuff for that, but hot glue works well, and it easier to find.

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Proto-advantage, mentioned above, will actually BUY YOUR IC from Digikey and mount it on their adapter for you at a very reasonable price!! If you have a week, this is how I would go about doing this sort of task. If this is going to become a regular thing, you might consider setting up a reflow station of sorts yourself, maybe just a hot air blower.

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  • \$\begingroup\$ Yeah, I saw this option when I ordered the adapters last night. I was tempted, but want the challenge (at least this one time) :) \$\endgroup\$
    – Dave
    Commented Oct 8, 2012 at 20:05

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