Re: soldering problem


"mnrsiat" <mnrsiat@xxxxxxxxx> wrote in message
news:1156533856.970941.57510@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi everyone,

I hope this counts as electronics as it's definitely a problem I'm
having with an electronic circuit, but more with getting it put
together on a PCB board (the circuit works fine). I'm pretty much a
newbie with very little knowledge so I may be using terms wrong & such.

I'm making a project using several dozen of a touch-sensitive circuit
which lights up an LED. Because of HIGH pricing on the DIP package,
I'm using a SOIC version of the chip, and I found a PCB adaptor that I
thought I could probably solder the chips onto easily enough.

Here's the adaptor (first item, 20 pin SOIC adaptor):
http://www.futurlec.com/SMD_Adapters.shtml

I couldn't find a picture of the chip but it's an 8-pin SOIC package.
I figured I would just ignore the extra pads and put the chip at one
end and the 3 other components at the other end wherever they fit, and
I wouldn't even need an additional board. This much is true, the 3
components fit fine and can be connected by the extra length of their
leads.

Here's the problem. My SOIC chip is skinnier than the 20 pin chip the
board was designed for. The legs don't bridge the gap. I can solder
one side down onto the pads, but I'm left with about 2-3mm of space
between the other side's legs and the other pads on the board.

I've tried a couple things, soldering tiny pieces of wire to the legs &
soldering those to the pads, as well as attempting a kind of solder
bridge on one or both sides (both is a bit easier b/c the bridge is
much shorter). But none of these work very well and they all take a
really long time.

Am I just screwed? Is there any kind of trick I might be able to use?
Does anyone know of a part that might fit my chip better?

Any suggestions much appreciated!

Rachel


IIRC, SOIC packages come in two widths: wide and narrow. The 20SOIC (and 24
and 28) is available only in wide, and the 8SOIC in narrow. I think 14 &
16SOIC come in both widths.

Sounds like you're stuck soldering small wires (28 or 30 AWG) from the pin
to the pad.

....jerry


.

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