Surface Mount Chips

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dmascare
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Surface Mount Chips

Post by dmascare » Fri Jul 01, 2005 9:01 am

I am trying to start doing some work with surface mount chips. I would like to find some kind of socket/adaptor for the chips so I can mount them to a breadboard with no soldering what so ever. I have seen some adaptor boards for protoyping, but it still appears that you need to solder the chip to the board. This would not be a big deal, but soldering to the board looks like it might require some heroics. Does anyone have any suggestions of how this type of protoypiong is typically done? Thanks for any help

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philba
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Re: Surface Mount Chips

Post by philba » Fri Jul 01, 2005 9:26 am

Surface mount is beyond easy. It's only hard until you do it, once. There are lots of tutorials on web, google is your friend.<p>The trick with ICs is to use liquid flux and tin one of the corner pads. Hold the IC in place and heat up the leg over the tinned pad to tack it in place. A steady hand helps but mine aren't that steady and I do OK. Once the IC is tacked in place you can solder the other pads. It takes about 1 IC to become competent and 2 ICs to become an expert...<p>It helps to have a decent soldering iron. You don't need a particularly small tip, either.<p>I can mount and solder SMDs much faster than through-hole stuff. I'd rather do SMDs than TH parts.

mnboy
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Re: Surface Mount Chips

Post by mnboy » Fri Jul 01, 2005 9:40 am

You could look at http://www.emulation.com They are not the least expensive, but they make prototyping adapters for a variety of surface mount components.

Gorgon
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Re: Surface Mount Chips

Post by Gorgon » Fri Jul 01, 2005 11:58 am

Hi,
If you are going to do a lot of breadboarding, the easiest thing to do is to make yourself a library of the different ic-types your use. You can buy blank SMD-to-DIP pcbs, and solder up the different circuits on them. You now have a DIP collection of the SMD circuits to prototype with.<p>It is also possible to use these adapters if you are building permanent circuits, like on veroboard/ stripboard. Or, you can make your own pcbs with real SMD layout. It's no problem to solder normal SO-xx packages, TSSOP needs a better eyesight, but is possible like Philba wrote.<p>TOK ;)<p>[ July 01, 2005: Message edited by: Gorgon ]</p>
Gorgon the Caretaker - Character in a childrens TV-show from 1968. ;)

rstofer
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Re: Surface Mount Chips

Post by rstofer » Fri Jul 01, 2005 12:12 pm

See the 3d video on this page: http://www.howardelectronics.com/naviga ... clips.html It actually works!<p>I haven't tried it with 0.5 mm spacing but it works well with 0.65. Plus the flux works well for everything else. I will never allow myself to run out!<p>The flux is NC-559-V2. Unfortunately, these is also a solder with the same number so be careful which you order.

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philba
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Re: Surface Mount Chips

Post by philba » Fri Jul 01, 2005 12:40 pm

I've seen those videos before. It really is pretty easy but you don't really need a special drag solder tip. Just about any will work. One thing they don't show is how the chip gets tacked down. I also think they overuse flux. I used to lay it down thick but now I apply just a tiny, thin coating. It doesn't take very much. Cleanup is easier. <p>By the way, avoid breathing the flux smoke - its nasty stuff.

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haklesup
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Re: Surface Mount Chips

Post by haklesup » Fri Jul 01, 2005 1:27 pm

What SMT package(s) are you trying to use?<p>Sockets are available for just about every package. Most have thru hole pins on the bottom but others just mimic the SMT footprint of the same device. I buy sockets from an extensive list of vendors but need to know what you want before recommending one. I also have an extensive inventory of PCBs used to convert these socket footprints into PGA or DIP footprints which you could wire wrap or point to point whichever way you need.<p>Unless you plan to socket many devices, you will want a production grade (as opposed to burn in grade) socket as it will be cheaper. For SOIC and PLCC you should be pretty well off. QFP sockets are probably the most expensive type followed by BGA. Other types of SO package sockets vary widely.<p>Just about anything except BGA and LGA can be soldered by hand if you use flux and some magnification with a pointy iron.

rstofer
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Re: Surface Mount Chips

Post by rstofer » Fri Jul 01, 2005 1:33 pm

Can I get a socket for a QFP 208? If so, where...<p>Thanks!

Newz2000
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Re: Surface Mount Chips

Post by Newz2000 » Fri Jul 01, 2005 2:00 pm

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by rstofer:
Can I get a socket for a QFP 208?<hr></blockquote><p>Zif socket, TH $439 (save 13% if you buy 10 or more!) :p

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philba
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Re: Surface Mount Chips

Post by philba » Fri Jul 01, 2005 2:20 pm

Other than PLCC sockets, most surface mount sockets (not adaptors) that I've seen are pretty expensive. Well more than the cost of most chips. <p>Given the ease of soldering even the fine pitch stuff, I don't see the point of spending $20 or $30 or more on a socket that I might only use a couple of times. And you'll need a collection to cover the more common chip forms. I usually just get an extra chip to prototype with. Just one man's point of view.

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haklesup
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Re: Surface Mount Chips

Post by haklesup » Fri Jul 01, 2005 2:39 pm

Ugly! The QFP-208 is a bear to socket. The tip to tip distance, lead length and package thickness must be accounted for for a correct fit in a clam shell socket (lid closes over the top) like Yamaichi and 3M. Some of the open top sockets are more compliant for fit but a little more expensive.<p>This was one of the first QFP packages available and the industry didn't quite get it standardized as well as some of the others.<p>Here is a good list of manufacturers, you may need to contact distributors to get price and delivery.
Socket manufacturer directory<p>You would be better off with a prototyping board which has the pattern for the QFP-208 on top and holes for pons around the periphery which you can populate with pins to plug into a 100mil header instead, the cost is lower and you have more vendors to choose from. Look for an ad from www.beldynsys.com which advertizes in N&V for an example.<p>Emulation tech proto board $52

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