SSOP28 soldering first timer needs help

[Nordic]

So I got too brave and ordered samples of some pcm2702 and another one.

First one I want to try is the pcm2702, but OMW, it is soooooooo tiny. I feel realy intimidated by it, all butterflies in the stomach.

I found one or 2 diy posts on soldering methods for these, but nothing that inspired me with confidence yet.

Can you point me to a page or 2 where you learned or teach how to solder these maybe? pictures are good yes!!!

SSOP28 should stand for SO SMALL ONLY POSSIBLE 2 out of 8 times.

P.S. would I need tinned boards....?

[jackinnj]

have a couple cups of expresso before you try

I use Kester solder paste for my surface mount. I use a very fine needle to place a small dab on each pad. if you can tack one pin down the rest is easy.

there have been a couple of good articles on DIY reflow ovens -- most recently in Elektor this past summer. probably a winter project on this side of the shpere.

[metalman]

I recently entered into the realm of SMD soldering, and I have had reasonable success using the "Flood & Suck" method.

Basically, wipe a thin layer of liquid flux onto the pads, and while it is still tacky place the chip on the board and align the pins onto the pads. Then let the flux dry so that the chip is lightly stuck in place. Next, get a drop of solder on the iron tip and touch it gently to pins at one end of a line of pins. The drop of solder will connect together several pins, but that's OK and will be corrected later. Then repeat placing a drop of solder onto pins on the other side of the chip. Now pins on both sides of the chip soldered (bonded) in place. Next, add more solder to each row of pins until the entire row is one big solder joint. At this point the pins are "Flooded". Now, with a solder sucker or other similar desoldering tool ready, touch your iron tip to a row of pins and when you see the solder melt suck up the excess solder. This process leaves behind a solder joint underneath each pin. It may take two or three tries at "sucking" to get all the pins clear within a row, so take your time and give the chip plenty of time to cool down before try again or you will risk overheating and ruining the chip.

It is not the easiest way, certainly not the cleanest way, and it is somewhat wasteful of solder, but I have used it successfully several times now.

Cheers, Terry

[dswiston]

You can do it!

SMD is really easy if you ask me. I like it more than having to deal with wire leads everywhere. I've successfully soldered two 36 pin QFN .5mm pitch packages for a project of mine last year. Now thats SMALL. Just go for it. I prefer to load up the package with flux, tack down one pin, the swipe across the pins with solder (or you can tin the leads first, the works better in most cases) on the iron's head. If you're doing two lead components like caps etc, tin the pad, use an exacto-knife to hold the package down, and apply heat to the pad.

[BrianL]

I have used two different methods.

The first is to use a Metcal iron with really tiny tip, really fine solder, and a microscope. Have the solder wick handy just in case.

The second method is the DIY reflow oven using a toaster oven and solder paste. There is a good write-up on the Seattle Robotics Society web site.

[flg]

Yep, You can do it. The Metcal iron has no equal for this bis but, you need speed and experience. Flux first. Keep your tip clean and ready to go. I ussually hold the device in place with my left hand and a tooth pick or sharpened q-tip. Then I dab the fineist metcal tip onto .010" or .005" solder and tac down an end pin. Go to the oppositte corner and tack the opposite end pin. Then I just dab the solder on each pin a fraction of a second before the iron and do each pin. You kinda watch for the bubble of solder to flow and get outta there. You need steady hands, at least a 5X glass or microscope and small diameter solder. I must admit, I'm not sure I really see what I'm doing, the solder tip is bigger than the pins, I just know it's just like something bigger. Each pin should take less than 2 seconds (With a 700 degree Metcal). Sure you might get a few bridges but thats where the solder wick comes in. You can't hang out longer than about 3 seconds without causing problems... good luck

[gbyleveldt]

Originally posted by metalman
I recently entered into the realm of SMD soldering, and I have had reasonable success using the "Flood & Suck" method.

Basically, wipe a thin layer of liquid flux onto the pads, and while it is still tacky place the chip on the board and align the pins onto the pads. Then let the flux dry so that the chip is lightly stuck in place. Next, get a drop of solder on the iron tip and touch it gently to pins at one end of a line of pins. The drop of solder will connect together several pins, but that's OK and will be corrected later. Then repeat placing a drop of solder onto pins on the other side of the chip. Now pins on both sides of the chip soldered (bonded) in place. Next, add more solder to each row of pins until the entire row is one big solder joint. At this point the pins are "Flooded". Now, with a solder sucker or other similar desoldering tool ready, touch your iron tip to a row of pins and when you see the solder melt suck up the excess solder. This process leaves behind a solder joint underneath each pin. It may take two or three tries at "sucking" to get all the pins clear within a row, so take your time and give the chip plenty of time to cool down before try again or you will risk overheating and ruining the chip.

It is not the easiest way, certainly not the cleanest way, and it is somewhat wasteful of solder, but I have used it successfully several times now.

Cheers, Terry

I use a similar way, as in having a lot of solder all over the pins, but then I use desoldering braid to clean up the mess. It then leaves perfect looking joints. Just watch out so that you don't overheat the chip...

[ezkcdude]

I agree, although my method is slightly different:

1) Use flux pen (I use Kester "magic marker" style) to coat the pads with flux.

2) Apply solder (I use 63/37 15 mil) to pad 1 (pad corresponding to pin 1).

3) Align chip onto pads and heat up the trace leading to pin 1. Make sure the chip is firmly "stuck" in position and aligned. This is the most difficult part for me.

4) Apply flux to the entire row of pins on the opposite side of pin 1.

5) Apply bead of solder to that side and "wipe across" with tip of iron. This is the "flooding" step.

6) Typically, a few pins will be bridged together. Just use soldering braid to remove bridges.

7) Repeat steps 4-6 for other side of chip.

[Russ White]

Hi guys,

Here is how I do it,

First You will need a couple things.

1) A good flat electric griddle, or hot plate. (You can get them for about $20 at Wal Mart or Target here in the US).

2) Get some good solder paste (synthetic types work very well and require no special cleaning). Here is a good source, no connection to me at all. http://www.stencilsunlimited.com/solder_products.php I use the Syntech, and Syntech-LF which both work very very well.

3) Get a good flux pen (or some other easy way to apply good flux), They cost about $5-8.

Now here are the steps:


1) Apply a thin layer of flux on the PCB pads for the SMD parts.
2) Apply a thin line of solder paste to the all SMD pads on the PCB.
3) Apply some flux to the SMD parts on both side of the pins.
4) Carefully place the parts (it ok if they are a little askew as long as they are sitting on the correct pads).
5) Heat up the hot plate. 280-300C or so is generally fine, use a surface thermometer if you have one, if not just guess.
6) Carefully place the PCB on the hotplate.
7) Watch the solder start to melt and flow onto the pins of the SMD parts. The parts will actually try to align them,selves with the pads because of surface tension as the solder melts.
8) When all the solder is melted and shiny remove the PCB from the plate. This can be tricky, I usually do it be tying some cotton string around both ends of the PCB in such a way that I can lift it from both ends at once to keep it level.
9) Place the PCB on a cool surface and blow on it, or cool it in some other way.
10) Have a beverage of your choosing.
11) Look for any solder bridges (there will not be any once you have a bit of practice) and correct them using flood and suck, or just by heating the solder with a soldering iron and breaking the surface tension with a fine probe or tweezer. Also look for any dry pins that might need a touch with the soldering iron (this is very rare).

Works for me without fail, and it is very fast.

Cheers!
Russ

[Russ White]

If you have access to a hot air rework station (search for it on ebay, you can get them for less than $75US). You can easily use solder paste to mount SMD devices too.

That is actually my preferred method if there are just a few SMD parts on a PCB.

You will find in the long run if you pursue the hobby for a while that a hot air rework station is well worth the cost.

Cheers!
Russ