How to of prototype with surface mount chips

rmeldo

Senior Member
Hi forum,

as a newby to 21st century electronics I have a burning question:

How does an hobbyist deal with surface mounted chips?

Quite a few ICs nowaday come only in the surface mount package and are therefore difficult to handle.

I have soldered a small 8 pins surface mount chip onto an adapting board to go achieve a DIP configuration. The soldering in iself was do-able, although I haven't finished building the circuit yet, so I don't know whether I damaged the chip.

Using adaptor boards is however is inconvenient as you have to hase the right size for each chip, etc. and I was wandering whether there are stripboards/veroboards/breadboards/anyboards which can take surface mounted chips.

How do people handle such devices?
What is the best way to go about prototyping?

I looked at previous threads for a while, but not found an answer, so....


thanks

Riccardo
 

moxhamj

New Member
I used the same solution you did. Got some adaptor boards (a batch of 10 and they were very reasonably priced) and soldered them up to turn them into standard DIP parts.

I've also tried really hard to avoid surface mount, at least for prototyping.
 

kevrus

New Member
A very good video, makes it look easy(ish)...must try it sometime as ive been avoiding surface mount as well
 

westaust55

Moderator
Using SMD devices

I too have used a few 8 pin SOIC (surface mount) chips and gone the way of adapter boards. Others have become more proficient at SMD technology which would be worthwhile if you are doing more than a few chips.

Here are a couple of links to the two methods:

http://www.picaxeforum.co.uk/showthread.php?t=9611

http://www.picaxeforum.co.uk/showthread.php?t=8953

While the SOIC8 adapters are quite cheap (around AUD$0.50ea), I did a search a few weeks back for SOIC28 adapters and found them to be less readily available and expensive (up to US$100 for one) but did find a source at a better price . . . US$5 / AUD$8ea

http://cgi.ebay.com.au/SOIC28-SOIC-28-to-DIP28-PCB-adapter-for-CS8414-CS8414CS_W0QQitemZ360103844457QQcmdZViewItemQQptZBI_Electronic_Components?hash=item360103844457&_trksid=p3286.m63.l1177
 
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InvaderZim

Senior Member
I notice that Sparkfun has some protoboards with SMD in mind (models are Bandicoot, Diprotodon, and Kangaroo). I haven't used them; look like a pain in the rear, but better than trying to solder wires onto tiny pins. I'd use a breakout board for prototyping. Or if you are confident, go for a PCB: with the right design, you can make a few small boards that have the common footprints you use in a convenient package, and you can dremel out the ones you need. That might actually be the most economical, if you are clever.
 

fernando_g

Senior Member
No doubt about it, SMT has made this hobby a further challenge and the tools more expensive. But it can be done.

Semiconductors in SOIC and SOT packages are usually OK. So are caps and resistors in cases 0603 and larger.
The other packages I usually steer clear of them.

A few key things in succesfuly soldering SMT devices:

1) A temperature controlled soldering iron with replaceable fine tips
2) Hot air gun for desoldering things
3) Very fine solder, and liquid flux
4) Tweezers
5) Even though you may have a 20/20 vision, get yourself an illuminated magnifying glass.
6) Needle-pointed test leads for your multimeter

I'm sure other memeber may add to the list.
 

womai

Senior Member
I'd add one more thing, and that's solder wick (i.e. a band of braided copper ribbon) to clean up excess solder. Much easier than trying to do that with a hot air gun or a solder pump. Put it onto the excessive solder. heat it up with the soldering iron (in this case a wider tip and a bit stronger iron is helpful), and it will nicely soak up the excess. That's useful for two situations:

(1) no more need to worry about accidentally shorting two device pins together with a big blob of solder - now you can easily clean it off. Great for fine-pitch (1mm and below) soldering jobs. In fact, just make it a habit to first solder all the pins (disregarding any solder bridges between them) and then clean all of them (which will also remove the solder bridges) - makes for a pretty professional look, almost as good as reflow.

(2) great for cleaning SMT landing pads to an almost-new condition so you can have another go at soldering the part onto the board.


It's pretty hard to get multi-pin SMT chips off the board without a hot-air gun ans suitable adapters (of the size of the chip you want to desolder).

Wolfgang
 

boriz

Senior Member
“I'm sure other memeber may add to the list.”

And a steady hand!

I have a tremor and find normal through-hole soldering a challenge. It takes maybe two or three times longer than it should, and the results can be untidy. SMT is almost completely out of the question for me. Fortunately though, there are enough ‘standard’ components for just about anything I’m likely to build.
 

MBrej

Member
If you want to solder SOIC-8, you dont need to bother with an adapter, just blu-tak the IC to a turned pin IC holder, get some single cored wire/cut off resistor leads, put them into the holder, bend them towards the device and cut off the excess. When it comes to soldering, cover the joints in flux, put a small amount of solder on the iron and touch the joint and it should instantly join. As for other devices i make my own adapters as pictured.
 

Attachments

fernando_g

Senior Member
“I'm sure other memeber may add to the list.”

And a steady hand!
.
Amen!

My first projects used vacuum tubes (valves to you). Back then, the steady hand was only required to avoid touching anything that would either shock you or burn you!
 

Andrew Cowan

Senior Member
I just make a SOIC to DIP adaptor in a PCB program and solder up the chips. (You sometimes have to bend the legs a little).

Andrew
 

rmeldo

Senior Member
I found the Sparkfun adaptor boards at http://www.coolcomponents.co.uk

They seem to have a good selection. The prices are similar to Sparkfun itself and the delivery charges are "human".

www.futurlec.com seem to have good adaptor range, and much cheaper.

I guess the solution then is to buy from Futurlec and then I will be back on track with through holes boards, sockets, etc.


The protoboard "bandicoot" sounds appealing too, but I can't firm up on the best way to use it.

Any Suggestion?

Also there is the question of which pins to use. The square pins 0.64 mm size are common, but aren't they too big to put into a DIP socket? I tried to push one into a socket and they deformed it permanently. Are they good for breadboard or direct through hole soldering only?

There are round pins which go down to 0.46mm diameter, same width as a standard DIP chips, but I haven't found a vendor yet in the UK. Futurlec seem to be out of stock and don't have a picture of them. RS sell them, but you need to by £23 worth of them (a lots of pins). Has anyone found a vendor for smaller quantities and lower prices?

Would the pins be soldered on the board before or after the chip?


Thanks

Riccardo
 

westaust55

Moderator
SMD chips and adapter boards

The SOIC8 to DIP8 adapter from Futurelec is well priced but physically about 3 time the size of those I bought. Size can be a consideration when for example adding an SOIC8 F-RAM chip onto an AXE111 memory expansion board and there are other Dip sockets at very close spacing.

The typical square type header pins will fit into a DIP socket but do ocver work the spring contacts in DIP sockets. A couple of insertions and removals will be okay so try to leave the adapter in the same socket.
You certainly will not get good contact for standard DIP format IC’s into that socket thereafter.
While testing I insert the adapter into a spare DIP8 socket and plug that into the DIP socket on my board until all is sorted and I am ready to go permanent.
 

ylp88

Senior Member
I've had great success with the SMD adaptor boards from Futurlec plus they are quite cheap.

Using their adaptor boards, I've successfully been prototyping a MP3/WMA player using a PIC24FJ256GB106 chip in a TQFP64 package:

IMG_4793.JPG

(Those who are keen eyed might also notice that pin 1 doesn't align with the chamfer on the adaptor PCB, thus why I had to apply making tape pin numbers to replace those screened on the board... Took me a good hour to work that error out!)

I soldered it by flooding one side of pins (16 pins) and then using wick to draw away the excess. This was all done using generic 0.8mm solder and a normal iron with a ~2mm chisel tip. I hope to try out their TQFP80 adaptors when I make my next order.

I've also had similar success with the SMD versions of the FTDI USB chips using the same method:

IMG_0531.JPG

ylp88
 

stocky

Senior Member
Solder paste and a frypan works well for me!
Havent had to touch up a board yet!
Of course it helps to have a board with a solder mask :)
 
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