SOT23-6 package, Any experience for DIY reflow soldering

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incal
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Posted by incal: Sun. Feb 9, 2014 - 10:43 AM
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I noticed that the new package that the manufactorer insists is sot23-6 (6 pins) rather than sot 23 (3pins) 2 back 1 front.

As sot23 has 2 back and 1 front the effective distance between pads will be sufficient (2mm)

But this damn sot23-6 has all the pins togethar and the pad spacing is much lower than SOIC (0.6mm free space between pads). It has only 0.4mm free space between pads.

It is in the design phase. I use self made time/pressure controlled solder dispenser and self made PID multi step reflow oven.

Anyone experience with sot23-6 with similar equipment.

________________________________ We dream of a world where current does not need the voltage to flow.

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Learning and Information, General Electronics
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Kartman
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Posted by Kartman: Sun. Feb 9, 2014 - 11:05 AM
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Easy enough to solder by hand.

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incal
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Posted by incal: Sun. Feb 9, 2014 - 11:09 AM
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thank you for th tip

________________________________ We dream of a world where current does not need the voltage to flow.

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Kartman
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Posted by Kartman: Sun. Feb 9, 2014 - 11:56 AM
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A fine tip helps, as does some flux.

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incal
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Posted by incal: Sun. Feb 9, 2014 - 12:54 PM
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I am trying to avoid the solder tip and use only a self made dispenser just as below (i tried to link to 9min40s, if it does not works link to 9min40s)

[url]
https://www.youtube.com/watch?v=...
[/url]

And I built something like that

[url]
https://www.youtube.com/watch?v=...
[/url]

Do you think that the method without stencils will have problems for parts such as sot23-6?. Should I solder 0.4mm pad parts seperatly?

________________________________ We dream of a world where current does not need the voltage to flow.

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KitCarlson
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Posted by KitCarlson: Sun. Feb 9, 2014 - 01:54 PM
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Too much paste will make a blob. Too little, not enough for a good connection.

Follow Kartman, hand solder. Use fine solder, plate one pad with solder, move part in with tweezers and tack down. Carefully solder each pin. Use lighted magnifier if you have visual trouble.

It all starts with a mental vision.

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steve17
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Posted by steve17: Mon. Feb 10, 2014 - 12:27 AM
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I hand solder the QFN package often. I sometimes use an iron and sometimes use hot air. The gap between pads is around 0.25 mm. I use lots of flux.

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ka7ehk
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Posted by ka7ehk: Mon. Feb 10, 2014 - 06:19 AM
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I've done a number of SOT23 hand solders. It is actually one of the easier IC packages. Here is what I do, very much like KitCarson:

1. Tin one corner pad. Do not use very much solder, so that the bump of solder is not very thick.

2. Hold the package by tweezers. I find the kind with tips bend at around 45 degrees makes it much easier.

3. Position the IC over the pads and melt the solder on the one corner. While the solder is still soft, position it so that the diagonally opposite corner pin is well centered over that pad. Let the solder harden. If it is SOT23-3, use either of the other two pins for positioning.

4. Solder that opposite corner pin.

5. If the package needs adjustment, do it now, before proceeding. Soften only one corner at a time.

6. Solder the remaining pins.

It is generally easier if you can find relatively fine (small diameter) solder. Likewise, a relatively fine pitch solder point is helpful. It does not have to be ultra-fine. One like a moderately used lead pencil point is fine.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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DocJC
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Posted by DocJC: Mon. Feb 10, 2014 - 01:43 PM
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Know also that one can take a length of solder, wrap in their hands, and stretch it to make it a finer gauge.

JC

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nachus001
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Posted by nachus001: Mon. Feb 10, 2014 - 02:04 PM
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I usually solder this way:

SOT23-X : flux the component PCB area, and the component itself with a brush, with the help of tweezers. Get a solder drop on the iron's tip. Position the component over it's PCB footprint. Dispense the solder with the tip.

TSSOP's/SOIC's/X-QFP-X and similar: flux the component PCB area, and the component itself with a brush, with the help of tweezers. Position the component over it's PCB footprint. Tack the package over it's footprint. Get a solder drop on the iron's tip. Dispense the solder with the tip starting with the pins opposed to the tacks.

QFN's: Put solder paste over the center pad. Carefully position the component. Apply hot air on the component to solder the center pad. Let the component cool. Flux the component and PCB with a brush. Get a solder drop on the iron's tip. Dispense the solder with the tip. Reheat with air, to reposition the package over it's footprint (most of the time the package will reposition itself)

That's for tha packages that can be soldered by hand.

regards
Nachus

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Torby
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Posted by Torby: Mon. Feb 10, 2014 - 02:59 PM
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They're easy. I do them with the frypan or with a soldering iron.

The largest known prime number: 282589933-1

Without adult supervision.

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KitCarlson
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Posted by KitCarlson: Wed. Feb 12, 2014 - 02:05 AM
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I am curious about the fry pan method.

It all starts with a mental vision.

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DocJC
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Posted by DocJC: Wed. Feb 12, 2014 - 02:45 AM
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Quote:
I am curious about the fry pan method.

I think this was my first attempt at frying up some chips. I used a bit much solder paste, but some solder wick touch up afterwards cleaned up the solder bridges.

The thermal regulation was exquisitely controlled, as you can tell.

JC

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chartman
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Posted by chartman: Wed. Feb 12, 2014 - 12:14 PM
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Did you just lay on the paste with a syringe or something ?

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Torby
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Posted by Torby: Wed. Feb 12, 2014 - 02:40 PM
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The solder paste is almost completely solder pad repellant and will stick to your tool, not the board.

I use a toothpick. You have to kindof smash it onto the solder pads, leave it lay for a moment, then wipe away any excess.

There's a knack to getting the right amount. Not enough leaves pins unsoldered. Too much makes shorts. Neither is hard to fix and there is a pretty wide range for the amount of paste to apply.

The largest known prime number: 282589933-1

Without adult supervision.

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DocJC
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Posted by DocJC: Wed. Feb 12, 2014 - 04:10 PM
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The paste, at least the stuff I have, is pretty thick.

I cramp some into a syringe, and use a needle with most of the length of the shaft cut off.

The paste comes out in a thick ribbon, it doesn't flow well.

I use the end of the needle to cut the extruded bead of paste.

As Torby said, it doesn't want to stick to the pads, so you have to cut the ribbon with the needle or it just clings onto the needle.

Once you do a few pads its easy to get the hang of it.

I now prefer surface mount to through hole, and I prefer frying up my chips rather than hand soldering them.

I don't do enough work to justify a real reflow oven.

JC

Sorry if we've gone to far OT.

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krazatchu
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Posted by krazatchu: Wed. Feb 12, 2014 - 05:28 PM
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For reflow on the cheap...
My oven is a $17 Wallmart special, the toaster kind with the glowing quartz tubes.

No temperature control, I just set a timer, turn it on high, leave the door open for about a minute and then close it for 3 minutes.

It's seen close to 400 boards now.

Edit: And there is a tin foil shield on the top rack so the IR from the heaters doesn't over cook the dark bits.

Michael
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http://krazatchu.ca/

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steve17
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Posted by steve17: Wed. Feb 12, 2014 - 06:31 PM
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I avoid solder paste. It seems too much bother. I tin the pads with my iron, slobber on the flux, and place the components.

P.S. I like my water washable no-clean paste flux. It is a bit sticky and keeps the parts from moving around if I move the board. I also like cleaning the board afterward under the faucet. Of course those of you who like the smell of flux remover won't like it. ;)

Actually after cleaning under the faucet, you could still sniff the flux remover or isopropyl alcohol bottle. ;)

Last Edited: Wed. Feb 12, 2014 - 06:35 PM
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steve17
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Posted by steve17: Wed. Feb 12, 2014 - 06:33 PM
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Why don't I get captchad any more. Is that broken too! ;)

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KitCarlson
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Posted by KitCarlson: Thu. Feb 13, 2014 - 12:05 AM
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Quiet..... broke is good for that.

It all starts with a mental vision.

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smkipus
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Posted by smkipus: Thu. Feb 13, 2014 - 08:15 PM
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I love soldering threads!

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microguy
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Posted by microguy: Sun. Apr 20, 2014 - 05:48 AM
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Don't the threads just burn up?

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gdhospers
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Posted by gdhospers: Tue. Apr 22, 2014 - 02:02 PM
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KitCarlson wrote:
I am curious about the fry pan method.

To repair a delicate board I used this mounted upside down:
The temperature control guarantees safe preheating at max temperature <150°C. Then a short time heating with hot air does the rest.

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Torby
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Posted by Torby: Tue. Apr 22, 2014 - 05:26 PM
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I hadn't thought of that before seeing this soldering thread. I think my frypan is handier, but if no frypan is available, I don't see why an iron won't suffice.

Perhaps an iron would be most useful if the thread you're slobbering is wool?

The largest known prime number: 282589933-1

Without adult supervision.

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Torby
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Posted by Torby: Tue. Apr 22, 2014 - 05:32 PM
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KitCarlson wrote:
Quiet..... broke is good for that.

I don't think I've ever before been glad that they don't fix things 'round here.

I once made a big posting here at the freaks on how I fabricate, but I can't make the search seeker find it today.

The largest known prime number: 282589933-1

Without adult supervision.

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gchapman
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Posted by gchapman: Tue. Apr 22, 2014 - 07:20 PM
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gdhospers wrote:
To repair a delicate board I used this mounted upside down: ...
You must be more mindful than me for I'd forget a safety step and have parts and tools flying. :)

"Dare to be naïve." - Buckminster Fuller

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