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I have come across a chip which is only available in LGA. I wouldn't touch BGA, but what about LGA? How possible is it to design for one with little experience? Are there any gotchas? I'm planning to reflow solder these using a hot plate.

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3 Answers 3

up vote 6 down vote accepted

LGA is similar to BGA, but without the solder balls, so you have to apply solder paste to the pads with a stencil. I don't think you will find them any easier to use than BGA.

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Is it any comparison to QFN? –  Thomas O Feb 4 '11 at 13:23
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Quite different. I can solder QFN parts with a soldering station, quite easily. –  Leon Heller Feb 4 '11 at 13:59
    
It's LGA pads/balls/whatever around the edges only though, which makes me draw a comparison to QFN. It's an LSM303 accelerometer / magnetometer. –  Thomas O Feb 4 '11 at 17:15
    
that package looks like a cross between a QFN and a LGA. Basically its a QFN with leads that don't wrap around and are pushed in from the package edge just slightly. You won't be soldering that with an iron but i don't think it would be too difficult with a board heater and a hot air soldering unit. Or paste and a hot plate / baker. You shouldn't have the settling issues that would normally occur with a 'regular' LGA. –  Mark Feb 4 '11 at 18:55

I've done LGA on a hot plate before, but only with a stencil. I wouldn't try it without a stencil. If this is a one-off, why not try the LSM303 breakout from Sparkfun?

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Where do you get (or how do you make) your stencils? I imagine that you're not doing huge quantities if you're using a hot plate. –  Kevin Vermeer Feb 4 '11 at 20:00
    
I etch my own stencils at home with a kit from Rena Electronics. –  krapht Feb 6 '11 at 0:53

I've done an LGA without a stencil. But that was a small low pad count part (BMA180). I had to tin the pads with flux and solder, then placed the chip on top, then used hot air reflow to solder it.

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