Tips: SMD Prototyping
We are starting up a new division called Re-Package.Com for people that cannot easily work with some of these ridiculous small SMD packages. But many times you have to do it yourself.
So how do you solder surface mount components on prototype board?
Simple. Turn the board upside down.
I have found that 0805 and 1206 (better) size resistors and capacitors easily fit between the tracks of Veroboard. The tracks and holes are spaced at 2.54mm (100mil) that will accept 99% of all DIP components.
To cut a track use a 3mm drill bit. DON'T use it in a drill machine. You will drill right through and probably hurt yourself. Just use your fingers and lightly rotate it until the connection is broken.
So what about those nasty little SMD ICs?
We you cannot solder those directly onto the board (unless you have microscope, steady hand and solder thin wires to the component and board). For that I use little carrier board (soon to be sold at www.re-package.com as well). The one I used is a 16 pin SO-16 footprint expanded to 100mil/2.54mm spacing. We plan to provide just the PCB and the PCB with connectors. On this design I bridged the pads to the Veroboard with a short piece of wire. BTW, we are planning SO-8, SO-16, QFP100 and QFP144 carriers. For other sizes please let me know.
What about small transistors in SOT23 packages?
Well, that just sucks. They are so cheap that you cannot really put them on a carrier board. If you really need to use them solder the 2 (in line -normally the base/gate and emitter/source) pins on 2 tracks and leave the single pin (collector/drain) in the air. Solder a thin wire to that one. Here I would really suggest to use the through hole versions if possible -unless you are testing power capability in situation.
Why do SMD?
Many times you just have SMD components available (like the ICs). Maybe your final PCB will be all SMD and you need to make sure that the heat generated by the components won't damage them.
What does the future hold in for all you experimenters?
SMD, SMD, SMD..... I went to a electronics distributor recently (well in fact several of them) and guess what? All the newer components are only available in SMD. The manufacturers are now more worried about their RoHS (particularly lead-free) rating that I don't see that they will bring out newer technology in DIP form anymore. And many manufacturers are listing their older components as "obsolete", "last shipment","not for new designs" etc... And designing custom PCBs for each project idea is proving very expensive for some people.
Each technology has its advantages and disadvantages. Through hole components let you prototype faster, you can put expensive ICs in sockets, but the maximum frequencies are lower and it costs a lot more in production. SMD components prototypes take a lot more effort, expensive chips are soldered into location, but they are much cheaper to mount in production and can achieve higher frequencies (shorter track lengths).
In the next few years you will either adapt to SMD or you need to get another hobby...like baking cookies or collecting stamps :-)
Feel free to email any other questions to firstname.lastname@example.org
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