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Questions relating to designing PCBs
By kacper
#130409
I've been experimenting with soldering of SMD inductors. So for the experience has been less then gratifying. I'm using a hot air tool but the solder underneath doesn't want to melt. :x Raping up the temperature too much will most likely melt the isolation between the windings, the question is how much the choke can tolerate (the datasheet has no guidelines for this). Does anyone how some good tips? Should I just bite the apple and go with the soldering paste approche, it seems a bit to expensive just for a prototype.
Datasheet: http://www.farnell.com/datasheets/69599.pdf
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By jthompso
#130412
For starters let me say that I use these quite a bit and there are two main ways I mount them. They reflow nicely with solder-paste and some kind of hot-plate or skillet; or alternatively you can hand solder them. The component lead generally wraps around the body enough to get a soldering iron tip onto, and typically the land pattern extends out far enough to make good contact.

That being said, I'm not sure what you mean in your post. You say that you're using a hot-air tool, but then ask if you should use the soldering paste approach. You are using solder paste in conjunction with your hot-air tool right???
By kacper
#130414
jthompso wrote:That being said, I'm not sure what you mean in your post. You say that you're using a hot-air tool, but then ask if you should use the soldering paste approach. You are using solder paste in conjunction with your hot-air tool right???
I'm using regular solder. I first apply solder to the pad. Then I flux it, place the component and use the hot-air tool.
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By leon_heller
#130416
I don't have any problems hand-soldering them with my Metcal system.
By jthompso
#130420
No idea, using 720 Fahrenheit for several seconds I've never seen a measurable change in inductance, they're a pretty tough construction.

I would definitely do them by hand, there's just too much thermal mass for the way you're doing them currently. I would strongly recommend getting a syringe of solder paste too; the way you're mounting components right now is rife for cold-joints and unsoldered contacts, the problems will really become apparent as you go down in component size.
By waltr
#130421
For temperatures, look at the manufacture's reflow guide lines. This is commonly in a separate document if the information is not in the data sheet.
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By leon_heller
#130422
The data sheet should have soldering details including maximum temperature.
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By phalanx
#130423
Reflowing with a skillet or using a soldering iron are the easiest ways to mount these. When I lay out SMD pads for devices like these which have a large thermal mass, I always size them so I have room to touch my iron directly to the pad. Any half decent soldering iron station will have no problem with those coils.

Hot air guns are not ideal for devices like that since the heat is coming from above and they have a large thermal mass.

-Bill
By NleahciM
#130428
phalanx wrote:Hot air guns are not ideal for devices like that since the heat is coming from above and they have a large thermal mass.
Exactly. It is entirely the wrong tool for the job.