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surface mount stuff in a hobby environment — Parallax Forums

surface mount stuff in a hobby environment

Keith MKeith M Posts: 102
edited 2005-09-12 20:47 in General Discussion
I'm·in a situation where I'll be working with a surface mount component in a prototype hobby environment.· I've never played with such small pieces before, but I'm going to try to learn.

It's an 8-pin SOIC device --- so thank god that there are only 8 pins.

I've found adapters online that adapt from SOIC to DIP.· Has anyone used them?· Which ones do you use and how well do they work?·What specs do I have to match up between my device and an adapter to make them compatible?· Are decent ones affordable?

I'm trying to interface to a solderless breadboard.

I did read some of the posts from Bean's thread·regarding his latest project.

I don't currently own a "good" soldering iron, or any tips that would come close to the size I would need.· I'll take recommendations here too if the solution requires it! [noparse]:)[/noparse]

Thanks,

Keith
·

Comments

  • bobledouxbobledoux Posts: 187
    edited 2005-08-28 22:22
    I've used Surfboards and they work well.

    My projects are moving to SMD. I make my own boards using Pulsar Toner Transfer and etching solution and a sponge. A 15 watt soldering iron is plenty big.. I use a $24 Antex in 12 watts with a small tip--$5 more. For SMD, a small diameter solder, a flux pen meet my needs. I use a headband magnifier for solder work.

    I started by buying a 100 bypass 1208 caps in .1uf and a mix of resistors in the same size. I use through hole components that I already have and mix in the SMD where they work. For example, all my DIP bypass caps are SMD between the DIP pins.

    The shift can take place slowly. I am moving to SMD because some parts are no longer packaged in through hole packages. I really like not having to drill holes.
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-08-29 02:04
    SparkFun has little boards you can use that are not too expensive.

    Look here:

    http://www.sparkfun.com/shop/index.php?shop=1&cart=372938&cat=66&

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    I wonder if this wire is hot...
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-08-29 13:29
    Keith M said...


    I've found adapters online that adapt from SOIC to DIP.· Has anyone used them?· yes Which ones do you use and how well do they work?·sparkfun, quite well What specs do I have to match up between my device and an adapter to make them compatible?· SOIC is a standard package, if you have more than one 8-SOIC to mount in a project you can get a larger size adapter and place more than one on the same adapter Are decent ones affordable? sparkfun's are < $3 for the 8-SOIC

    I don't currently own a "good" soldering iron, or any tips that would come close to the size I would need.· I'll take recommendations here too if the solution requires it! [noparse]:)[/noparse] if you want a very good quality soldering iron for a good price I suggest getting a Xytronic ESD-136 or ESD-137, availible at http://www.howardelectronics.com·for $90 and $100 respectively, they also sell tradeshow models (slightly used) for $55 and $75 repectively. And purchase the 1.6mm mini-wave tip which is designed for surface mount soldering. I own the 137 model and·2 (3?)·other members have purchased the 137 tradeshow version. All of us enjoy the quality and dependability of the soldering station. Howard Electronics has helpful and friendly staff and will promptly answer any questions or concerns you have.

    Thanks,

    Keith
    Paul

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    ·1+1=10
  • Dave PatonDave Paton Posts: 285
    edited 2005-08-29 13:47
    Keith M said...

    I don't currently own a "good" soldering iron, or any tips that would come close to the size I would need. I'll take recommendations here too if the solution requires it! [noparse]:)[/noparse]

    Keith, I've mentioned it before, but I swear by the two Weller WESD51s I have on my desk here at work. Not to slight the Xytronic units, as they are quite decent, but I've found the availability of Weller tips, parts, and accessories to be superior over the years. The convenience factor is just too high for me to switch. wink.gif

    Hints:
    -In theory, you don't need more than a few watts to solder SMT parts quickly and accurately. In practice, I've found that a slimline 20W+ iron makes it easier.
    -I like a tip temperature around 650F. That's derrived from experience and literally millions of fresh and reworked solder joints.
    -I use the tiniest tips available.0.8mm seems to stick in my head.
    -63/37 (eutectic) rosin core solder from a good manufcaturer (Kester or Multicore IMHO) is a requirement.
    -A Kester or similar flux pen wiped across the PCB pads before you put down the part helps out a lot.
    -DO NOT handle the leads or the PCB pads you plan to solder. Use tweezers or a vacuum pen. The oils in your skin will make it harder to solder parts. I know there's folks who will counter me on this, but 3 years as a solder joint metallurgist and QA inspector in a fortune 100 manuf research lab taught me more than I ever wanted to know about good and bad solder joints.

    My $0.02

    -dave

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  • Keith MKeith M Posts: 102
    edited 2005-08-30 02:32
    Thanks for the posts and the very specific information. Exactly what I needed to know.

    How do you keep the component on the header PCB when you solder it? I'm assuming the first pin soldered should hold it in place, but what about before that? I'm guessing this is especially crucial because the darn leads are so small, a slight offset can screw up everything.

    Keith
  • bobledouxbobledoux Posts: 187
    edited 2005-08-30 13:22
    I just put a wee bit of solder on a pad, set the chip in position and heat to tack it.

    One trick is to take a piece of wire, one end stuck into plywood. The other end bends in an inverted "U". The circuit board is placed under the open end and the wire tip presses the component into position.
  • knightofoldcodeknightofoldcode Posts: 233
    edited 2005-09-01 21:08
    For some of the surface mount components that aren't the smallest pitch, I just use a piece of tape to hold it in place. It's cheap, and if you put the chip on correctly and carefully lay the tape over the component, (leaveing the first pin to be soldered, exposed of course) then onto the board, it seems to hold really well, and stay accurate, assuming you're carefull, until you get the first pin soldered.

    Knight.
  • BeanBean Posts: 8,129
    edited 2005-09-01 22:58
    For two lead SMT componets and small ICs, I put solder on one pad first then put the componet down and heat the joint. Then solder the other end.

    For larger package SMT ICs I put solder on the tip of the iron, hold IC down with one finger and solder as many leads as I can before I run out of solder. If I can't hold my finger on the chip, then it's getting too hot so I quit soldering immediately to let it cool down.

    Of course I use a flux pen on all the pads first.
    I have gotten pretty good at soldering the SX48 (0.5mm pitch). Someday I want to make a video of it to show ya'll.
    Bean.

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    http://www.parallax.com/detail.asp?product_id=30012

    Product web site: www.sxvm.com

    "One experiment is worth a thousand theories"
    ·
  • Keith MKeith M Posts: 102
    edited 2005-09-02 00:16
    What size solder should I be using?

    .015, .020, .031 ??

    Paul mentioned Howard Electronics. Is there any other one-stop shopping place that deals in SMT equipment, pieces, parts for the hobbyist ??

    Keith
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-09-02 03:15
    I feel like such a brute.

    I soldered an SX20 onto a sparkfun board by clamping it in place with a needlenose vise-grip.
    Then I heated one whole side of pins at the same time with a 45W soldering wedge and dragged a swath of 60/40 solder accross it. The next step was to press solder wick against the pins with the iron to clean up all the bridging.

    It seems to have worked though...

    Keith, another good place to look for bulk components is here:

    http://www.futurlec.com/

    They have very good prices on basic components and don't brutalize you with shipping rates.

    You might also want to look at

    www.mouser.com/

    They have an amazing variety, but are a little pricier than futurlec.

    Here is one of my favorites from them:

    ]www.mouser.com/index.cfm?&handler=data.listcategory&D=*l78s05cv*&terms=l78s05cv&Ntt=*l78s05cv*&Dk=1&Ns=SField&N=0&crc=true]

    The L78S05CV voltage regulator puts out 5V of smooth current at up to 2 amps for only 46 cents each.
    These are perfect for powering up an SX project.

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    I wonder if this wire is hot...

    Post Edited (Electronegativity) : 9/2/2005 3:18:35 AM GMT
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2005-09-08 01:30
    Regarding a SOIC-to-DIP adapter: you can't beat a "Surf Board".· While they don't present a DIP footprint, the traces run out to pins on 0.1 inch pitch which you can plug into a·SIP or·modified DIP socket. ·They are available from many distributors (the usual suspects.)· You'll find a wide selection.
  • bobledouxbobledoux Posts: 187
    edited 2005-09-08 13:13
    I prefer .015 or .020 solder for SMT amd .032 for through hole. SMT takes little solder so I buy the little 1 ounce or so tubes.
  • nick bernardnick bernard Posts: 329
    edited 2005-09-08 15:40
    Bean (Hitt Consulting) said...

    Of course I use a flux pen on all the pads first.
    Bean.

    what if a flux pen, and where are they?
    a remember watching a "how to drag solder" video that someone posted some time ago and they mentioned reflow flux.
    i've been looking but cannot find any. any help?

    also if you use a hot plate to reflow solder on smt components what tools do you need? i think someone mentioned a syringe once to apply solder to pads.

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    engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
  • NewzedNewzed Posts: 2,503
    edited 2005-09-08 16:26
    I hve been soldering SMD chips for a long time.· Please, please - do not use a hot plate or a toaster oven to reflow solder.· All you are doing is subjecting a lot of components to unnecessary heat.· Most chips are designed to withstand soldering temperature for 10 seconds max on each pin.· I use solder paste applied with a syringe and a Weller EC1002-2 temp controlled solder station, with a .015 chisel tip.· I have been using the same tip for two years and it is still in excellent shape.· The EC1002-2 is no longer available but there are many suitable stations available.· Use a 20W temp-controlled station.· If you are going to solder SMDs, which are increasingly replacing DIPs, then you owe it to yourself to have the best tools available.· If you are just starting out I would recommend getting an SMD Starter Kit from Soldering Technology.· That's how you learn to solder SMDs.

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    Sid Weaver
    Do you have a Stamp Tester yet?
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    ·
  • NewzedNewzed Posts: 2,503
    edited 2005-09-08 17:42
    One thing I forgot to mention - SMD pads invariably have a bit of raised or "rounded" solder on each pad.· I always remove the excess solder with solder wick so the SMD is sitting on a perfectly flat surface.· Makes positioning so much easier.

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    Sid Weaver
    Do you have a Stamp Tester yet?
    http://hometown.aol.com/newzed/index.html

    ·
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-09-08 18:07
    Hi Newzed, thanks for the tips.

    If there's already solder on the pads then why can't I just use that to attach it to the board?

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    I wonder if this wire is hot...
  • NewzedNewzed Posts: 2,503
    edited 2005-09-08 18:24
    First, if there is solder on the SMD pads, it is difficult to hold the chip in place.· The pads need to be perfectly flat.· Second, I ALWAYS use fresh solder paste to attach the SMD to the board.· I apply a bit of paste to one of the corner pins with the chip in place, solder it, then check the aligment of the remaining pins.· With only one pin soldered, I can twist the chip a tad to improve alignment.

    Sid
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-09-08 18:33
    Thanks Sid, I can use all the help I can get.

    What is the best solder to use for SMD?

    I have been using 60/40 because I can't seem to get the lead free stuff to melt right.
    Its like I have to apply way too much heat.

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    I wonder if this wire is hot...
  • NewzedNewzed Posts: 2,503
    edited 2005-09-08 18:43
    60/40 melts at 368F.· 63/37 melts at 361 F.· Eutectic solder. 95 tin 5 silver melts at 430 F.· I always use 60/40 paste that already contains the proper amount of flux.· Solder paste is available from Digikey or Soldering Technology.

    Sid
  • BeanBean Posts: 8,129
    edited 2005-09-09 00:52
    As I mentioned in another thread, I use a hot air wand to reflow solder paste and it works great.
    I dispense the paste with a syringe. But the componets on it. Then reflow it with the wand.
    The wand I use is a SUNKO 850A I bought from sparkfun.
    Bean.

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    "SX-Video·Module" Now available from Parallax for only $28.95

    http://www.parallax.com/detail.asp?product_id=30012
    Product web site: www.sxvm.com
    Available soon!! Video overlay(OSD) module...

    "I'm a man, but I can change, if I have to, I guess"
    Red Green
    ·
  • bobledouxbobledoux Posts: 187
    edited 2005-09-09 13:06
    For someone starting out, some of thes ideas can get quite expensive. To start out don't use solder paste. Its expensive, requires refrigeration and has a short shelf life. Hot air wands aren't cheap.

    Begin with a small soldering iron, 15 watts or less and a small tip. Get a tube of liquid flux and some .015 or .020 solder. A small size Soderwick completes the materials. A headband magnifier and tweezers complete the package.

    All this stuff can be purchased for about $40. I have good luck with this simple system. You can always spend more if you find this process falls short in any way.
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-09-09 17:29
    Where is a good place to find a headband magnifier?

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    I wonder if this wire is hot...
  • NewzedNewzed Posts: 2,503
    edited 2005-09-09 18:19
    You could try Home Depot, or if you have a graphics arts store near you, try them.· Get a 5X headband.

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    Sid Weaver
    Do you have a Stamp Tester yet?
    http://hometown.aol.com/newzed/index.html

    ·
  • bobledouxbobledoux Posts: 187
    edited 2005-09-10 12:24
    Even Harbor Freight or Allelectronics.com carry headband magnifiers for about $7
  • ElectronegativityElectronegativity Posts: 311
    edited 2005-09-12 16:45
    Thanks, I ordered the one from allelectronics.

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    I wonder if this wire is hot...
  • John R.John R. Posts: 1,376
    edited 2005-09-12 17:00
    Back on the soldering iron part, and speaking of The Home Depot, does anyone have any comments (good or bad) on the "Cold Heat" thing?

    http://www.coldheat.com/

    The Home Depot carries the original unit. I know this isn't a professional grade soldering unit, but the concept is intriguing. If not for SMD, how does this work for "conventional" electronics soldering?

    John R.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2005-09-12 19:24
    Somebody bought me a 'ColdHeat'·eyes.gif.· It's pretty crude, but it has a white LED·smilewinkgrin.gif.· I wouldn't use it for anything on a PC board.· It just lets current run hog-wild which makes the heat to melt the solder.· In my opinion, the only appropriate application would be to solder a wire splice together, if you do field repair or something.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-09-12 19:26
    I bought one several years ago when they first came out (saw it on thinkgeek b4 they started their ad blitz). It is not well suited for SMD work. SMD requires a slightly different methodology that traditional work. The way I first learned, you heat the joint, then bring the solder to the joint until it flows arround the joint. SMD components are more temperature sensitive so it isn't advised to heat the joint first, but have heated solder melt flux on the joint and heat the joint until flow. (in hand work the flux is applied in a seperate step, in reflow work the flux is mixed into the solder paste). Cold heat shouldn't be used with flux, as such it is only suited for the traditional method of heating the joint first then applying solder. Since I won't use it on SMD work, it just sits on the bench because I can use the iron I use on SMD for traditional work as well.

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    ·1+1=10
  • John R.John R. Posts: 1,376
    edited 2005-09-12 20:47
    But the ads say, it's great for fine work....

    Thanks for the money saving advice.

    John R.
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