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Everything Else » Soldering (I'm freakin' out!)

December 29, 2010
by Hexorg
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Aaah! Just got an IC that I really really need... But it's in SSOP package! >_< it's so tiny!...

Ok, Stanley, calm down lol.

I'm just lost as to where to start, I have basic connections of all the parts figured out in my head but I really like to assemble everything on the breadboard before I can move everything to PCB. But now that I got this tiny person_who_has_no_father, I'm lost as to what to do.

The chip is a network controller. 28 pins.

I need some advice as to what should I do with this?

I found SSOP-28 to DIP pcb, but it's like 6 bucks! And I'll have to wait another week or two to get it.

Also I may get access to a laser printer, can toner transfer method of PCB etching give me good enough PCB for SSOP? This way I can mount RJ-45 jack on the same PCB and use the two easily.

I bet I need a smaller soldering tip too. Anyway, if any of you have a good tip or advice on what should I do, I'd gladly appreciate it.

December 30, 2010
by Hexorg
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Well, just in case anyone get SSOP package too, I found a cheap ssop to dip pcb for only a dollar. Making pcb yourself for ssop is hard, because without solder mask it is very easy to short out the pins. Besides that I found a really nice package that already has the ssop chip I have, + ethernet jack, ethernet transformer, and data resistors, it gives you a nice header for SPI and stuff :)

A good night sleep helped :)

December 30, 2010
by rajabalu21
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Could you share with us the source of this PCB? It would be nice to know where to shop around when we are in a fix.

-Raja

December 30, 2010
by Hexorg
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Oh yea, it's quite an interesting store, they have a bunch of neat stuff!

http://iteadstudio.com/store/index.php

December 31, 2010
by mongo
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SSOP's are notoriously difficult to work with manually. They were designed to be installed by machines in large quantities and the soldering techniques are also automated.

Manually, it can be done but you have to be very careful. First off, since you have to attach it to something to be able to use it, a little drop of superglue does the trick. Glue that tiny little sucker in place before trying anything else.

Once it is set in place, there are two methods to solder it into the circuit. One is the cold method, which actually uses conductive ink, where you actually paint the connections into place. Some times, it needs two or three applications but as long as the pins and the substrate make good contact, they should do nicely.

The other is actually soldering it in. For that, you need a tiny tip on a good soldering iron. Because the little things are harder to heat up, simply because there is so little contact area, you need to be very patient. Solder has a tendency to bridge between these little traces and pins, so if that happens, clean the soldering iron tip and re-melt the solder. Drag the iron along the trace and pick up the excess on the tip. Some times, actually touching up the connection with a tiny amount of fresh solder also helps, once the excess is removed.

Excess solder can also be removed with a suction type tool called a solder sucker, but you need to be fairly coordinated to do it right and not damage things. The other way is to use solder wick, which uses capillary action to wick away the excess. That takes a little practice too but it was the fery first method I used back in the early days.

December 31, 2010
by Hexorg
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Mongo, thanks a lot :) I found quite a few lodering ssop videos on youtube. it seems that flood soldering was actually the easiest - that's when you solder all pins with bridges on purpose and then using a solder sucker clean the bridges.

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