vacuum tweezer thingie

We use some 2512 low-ohm resistors. But it turns out that most all sizes of surface-mount resistors can dissipate the same power (about half a watt) of they are soldered to big copper pours.

I forgot some of them (4x two in parallel) as current sense resistors on a big current mode boost supply.

Once you start down the road it only gets easier. Of course the Mantis helps. ;-)

DOn't think I have any SC79s but SC70 (in all its various leggedness) is one of my favorite packages.

I don't lose nearly that many but often we don't have all the values that are on the board, in stock. We ship everything out to be built and usually don't keep parts back for rework.

Looks ackward, but it would help some people. :)

SMD resistors. RK73H3ATTE75R0F for example.

SOD-323 is about as small as I care to go. Not really because of the size, it's about 0603 or whatever, but because the laser-scribed cathode line is damned near invisible. Accidentally get flux on it and you might as well get a new one!

Tim

Definatly agree on foot operated control, much easier to work with.

?-)

You really need a Mantis.

Start with bare pads, and solder only one side at a time in a single swipe/stroke event. A flux wetted pad, BTW.

Or use actual solder paste... a very tiny amount on each pad, and again, only solder one side at a time. For that a freshly wetted but wiped solder tip will complete each attachment. The tip of only a single tine of a good stiff tweezers, like the Excelta OODSA will apply enough pressure to perform the operation. the second connection is even easier. Total dwell time on the part? Less than 1 second per termination.

NEVER solder parts that small on pads that already have "solder bumps" on them. Bigger form factors, sure... but not these tiny buggers. You'll fracture the termination connections for sure, or the part itself. also, if you are "tiddlywinking" parts, you are grabbing them too tightly, and once in place, you don''t "hold it" with the tweezers, you use the tip of them to "pin it down" while you reflow the first end.

If you are going to reflow the whole assembly at one time, then once placed, you do not need to revisit the part. My spiel was about hand soldering technique.

And it is spelled DEFINITELY.

Don't lecture me on soldering. I've been doing it since I was three years old.

I'll bet you do NOT have a NASA cert.

Hell, Ill bet that you do not have ANY soldering certifications.

This was a fiddly one

I'll bet you don't have an engineering degree. Hell, I'll bet you don't have any college degree.

old.

any

Scatology, perhaps?

old.

any

From Poo U.

That doesn't look too bad (0603s, right?), but I would have used an X-acto knife to cut some of those into the copper.

I've done one of those before -- 'twas a TI full diff amp which came in two sizes of DFN, and naturally, I got the wrong footprint. So, flip it over, tack bits of wire on the pins, add bypass caps, and voila!

Tim

Yikes. Looks tricky.

How did you do the SPI interface?

I wonder if anyone makes little adapter boards for leadless parts.

Yup, here's one:

Next time I do one of those kitchen-sink engineering PC boards, I should include some csp adapters.