Best way to solder SOIC
Feb 26, 2006 at 1:27 PM Thread Starter Post #1 of 23

FritzS

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Hi,
whats the best way to solder SOIC? I must solder AD8065 OP's on a little PCB (kit from WNA David White) for my WNA MKII.

I have only a 0,8 - 1 mm thin Weller Magnetostat solder-iron.
 
Feb 26, 2006 at 1:54 PM Post #2 of 23

PinkFloyd

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Quote:

Originally Posted by FritzS
Hi,
whats the best way to solder SOIC? I must solder AD8065 OP's on a little PCB (kit from WNA David White) for my WNA MKII.

I have only a 0,8 - 1 mm thin Weller Magnetostat solder-iron.



OK, if you're new to soldering SMD chips then the easiest way is as follows.

Get some of that double sided sellotape. fix a very small piece onto the bottom of the AD8065 and fix the 8065 onto the adaptor with the very small piece of double sided sellotape. You now have the chip in position on the adaptor. (note: if using the WNA adaptor solder the chip into position on the PCB "before" soldering the legs onto the board)

OK, now all you do (wear a pair of glasses) is carefully heat each leg / pad of the opamp whilst at the same time feeding a small amount of solder onto the pads (you dont need a lot of solder just enough to flow under the leg and onto the pad) don't hold the iron on too long the process for each leg / pad should take under 1 second. Repeat for the other 7 legs / pads and you're ready to go!

4.jpg


PS: I find it easier with a HUGE soldering iron
wink.gif
 
Feb 26, 2006 at 2:17 PM Post #3 of 23

DaKi][er

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Put solder onto one corner of the PCB pad
With tweezers holding the chip in one hand, heat up the solder you put on the pcb with your other hand
Position chip on the board with the pin in the solder and keep the heat until you get the chip sitting square or just about, don’t worry too much about low long this takes, you got a good 10 sec before you even start worrying about doing damage
You can then twist the chip a little to have it sit perfectly square and now solder the opposite corner pin
Now all you have to do is fill in the remaining pins and maybe touchup the original pin to have it looking good
 
Feb 26, 2006 at 2:30 PM Post #5 of 23

PinkFloyd

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[QUOTE='DaKi you got a good 10 sec before you even start worrying about doing damage.
[/QUOTE]

"10" seconds? that's one hell of a long time to apply heat when you can do the job in well under a second.
 
Feb 26, 2006 at 4:59 PM Post #6 of 23

kin0kin

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easiest is to do 1 pin like darkkiller said, then "flood and suck" the others. clean fast and simple.just make sure u apply enough pressure on the parts and that the parts don't get sucked in as well
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Feb 26, 2006 at 5:00 PM Post #7 of 23

69CamaroSS396

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As one relatively inexperienced with soldering, I assembled my first MINT and had little difficulty with the SOIC pieces. Maybe I was lucky, but my second MINT was just as trouble free in that regard. Whether right or wrong, I placed a very small amount of flux on the pcb on each of the 8 pads and likewise on the legs of the chip. With my soldering iron cleaned and tinned properly, I merely held a slight pressure down on the chip with tweezers to prevent it from moving, quickly touched the iron to one of the corner legs on the chip. Making sure that the chip was positioned properly, I then did the same on another corner to secure the chip's position. I cleaned and tinned my iron before soldering each leg on the chips. After all soldering was complete, I inspected closely under a microscope to be certain connections were good with no bridging.
 
Feb 26, 2006 at 11:52 PM Post #8 of 23

ericj

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lay down a layer of rosin flux on the pads, let it dry a bit. it'll get sticky. Sticky enough to keep smd components more or less in place.

Plop down the ic, line up the pins, get a dab of solder on the end of a fine tip, and start tacking down pins. Start with pin 1, and then the pin on the opposing corner from pin 1.

After those two pins it's cake. The ic isn't going anywhere. Double check alignment on both sides, and tack down each pin. You won't need to heat each leg for more than a second or so.

The flux really does help a lot. I don't care if your solder is rosin core, so is mine. Additional flux helps. A lot. I recommend it in pen form.

After you're done, just wash off the excess flux with some alcohol.
 
Feb 27, 2006 at 12:22 AM Post #9 of 23

Garbz

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method number 235:

Put the chip down, gob massive ammounts of solder across all pins, run some solder braid across them to suck up remainder. Works every time
biggrin.gif
 
Feb 27, 2006 at 12:29 AM Post #10 of 23

DaKi][er

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Quote:

Originally Posted by PinkFloyd
"10" seconds? that's one hell of a long time to apply heat when you can do the job in well under a second.


I know, just making the point that you have plenty of time, 10 sec would seem like an eternity when doing this

The flood and suck method really isn’t needed for SOIC, the pins are well spaced to easily solder them individually
 
Feb 28, 2006 at 2:06 AM Post #12 of 23

aerius

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Rube Goldberg method: Use solderpaste. Trace the pad pattern onto a thin sheet of aluminum, use a fine Dremel bit to cut out the holes. Place aluminum sheet on top of PCB such that the holes line up with the pads. Put some solderpaste on top of the aluminum. Use a credit card or other such plastic card to squeegee the paste through the holes and onto the pads. Carefully lift the aluminum sheet off the PCB. Place the chip on top of the solderpasted pads. Place the PCB into a cold toaster oven. Set the temperature to 375°F and bake for about 5-7 minutes. Turn toaster oven off, open door, allow to cool to room temperature before removing. Presto! One soldered SOIC!
biggrin.gif
 
Mar 1, 2006 at 12:01 AM Post #13 of 23

PinkFloyd

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Quote:

Originally Posted by Garbz
method number 235:

Put the chip down, gob massive ammounts of solder across all pins, run some solder braid across them to suck up remainder. Works every time
biggrin.gif



That's the way I do it but without the desolder braid
wink.gif
Remember, Fritz is new to this so advanced "power soldering" is possibly not the best way for him to start, it takes a while to be able to solder SMD blindfolded
wink.gif


<awaits method 236>
 
Mar 1, 2006 at 10:08 PM Post #14 of 23

Polaris111688

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I had to surface solder a SOIC-8 AD8620 for the first time in my PIMETA amp. The original premounted AD8620 from Brown Dog was defective for some odd reason, and I didn't feel like waiting for the replacement to come in, so I soldered on a spare AD8620 I had lying around onto the bottom of the board. The easiest way, for me, is to flow a little solder onto one of the pads first. After that, push the opamp down with one finger (I know, it sounds risky) to hold it in place, and melt the solder again to bond one pin onto the board. The rest is trivial from there.
 

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