Soldering TSSOP10

[RolfSte]

Hi Dave,

thank you for your soldering tutorials, I learned a lot.
But with this TSSOP10 I stuck ( PCA9615 ).
This is a 0.5mm beast and it has some sort of gull wings,
where the solder creeps in and creates solder bridges
between plastic body and IC leg. It is very difficult
to remove this bridge. Bridges on solders pads of
pcb are of no problem for me. I used a swipe over the pads
as you have shown.

Would you suggest another soldering technique?
Maybe to affix some solder to the pads before
and shuffle this solder to the legs of the chip?

Regards Rolf

[jmw]

Try: get the solder tip clean (don't need to be adding more solder) and apply flux generously to pins, then run the iron over the pins, close to the chip body. Gravity should do the work and pull the solder down to the pads. If you've still got bridges, get some solder wick and use the finest tip you have, and poke it between the legs, applying flux again if needed.

[jmelson]

I do 0.5mm chips all the time, and even 0.4mm, which starts to get difficult.  The chip must be well aligned to the solder pads, and the solder pads should not be more than a TINY bit wider than the component leads.  Use a MINIMUM amount of solder.  If using wire solder, you want the thinnest possible.  I have some .010" (.25mm) solder that is ideal for this purpose.  I apply liquid flux with a wire dipped in the liquid and then wiped along the pins.  Water-soluble flux is a lot easier to clean up after the soldering.

But, I am usually doing 128 - 144 lead packages in these small lead pitches.  Not sure I'd go to all this trouble with a 10-pin package.  But, you do need good magnifiers, a steady hand and fine solder and soldering iron tip.

If you attach a picture, maybe I can be more specific.

Jon

[phil from seattle]

tssops are a challenge.  I have pretty good luck with my technique.  Use a flux pen on the pads, put a blob of solder on one pad and slide the chip in place while holding the iron's tip next to the pad.  Once the solder cools, I verify the chip is aligned. Touch the flux pen to the leads being careful not to move the chip.  Now for the tricky part.  I put a very small blob of solder on the tip of the iron and stroke it along the top of a tssop lead (not the one holding the chip in place) - pulling away from the chip.  That will lay down just enough solder and it tends not to get in between the leads.  Repeat for each lead. As you get better, you will be able to do 3 or more leads with one blob of solder. I never touch the solder wire to the tssop leads while soldering - that just makes a mess.

[KL27x]

Once a big enough blob gets sucked up into the shoulder, it's pretty much over. You done messed up, already, and you might as well bring out the solderwick.

The trick is to not get that much solder on the iron/pad/pin to begin with. Large bevel tips are forgiving of the amount of solder on there. You do all the work with the flat cut face in this type of application, and gravity holds the solder on this cut face. You can get a large area of the tip in contact with the board (and hence the flux, which after it melts is very "shallow") in order to keep things working, properly. And when the tip is running lean on solder, the bevel tip is excellent at sucking out small bridges. The bridges in the toes, what sometimes can otherwise get left behind between the last two or 3 pins of a drag solder operation, not the big blobs that suck up into the shoulders.

Liquid or paste flux applied to the board is a must.

There are some SMD parts that are more sensitive than others. Yeah, sometimes you need some super fine solder wire. And sometimes, you might even look around the board for a reliable source of just a tiny bit of solder. Touching the iron to a nearby other pad on the fluxed area of board might do the trick.