> From:         Ben Hencke[SMTP:simap2000@YAHOO.COM]
> Sent:         Wednesday, March 17, 2004 5:00 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      [PIC:] Programming SOIC chips before soldering

> Hi all,
> I am in the process of switching to SMT parts to save
> on endless drilling for a run of devices (100+) and to
> further reduce the size of the device. I am working
> with 12f629s, so its only a 8 pin SOIC, but I need a
> way to program the buggers before I solder them in the
> circuit. ICSP is not really an option because of the
> size and compactness of the device (even bare board).
> There is definitly no room for headers.

> Is there any kind of socket or clip or something I can
> use to connect to the bare SOICs long enough to
> program and verify them? The only thing I have found
> is for DIPs.

> Any experiences with this is apreciated :-)

> TIA,
>  Ben Hencke

If you are willing to make your own, consider this:
The pitch on an 8 pin SOIC is 0.050" (spacing
between adjacent pins). This is also the spacing
of conductors in mass-termination cable (Ansley,
3M, etc.) With only 8 pins to connect, you could
take two pieces with 4 wires each, and strip back
the insulation 1/16" on each conductor. Fasten
each group of 4 wires to the edge of an insulated
support and press each support against the chip
leads from opposite sides.
1. Tin each exposed wire end to reduce problems
   from stray whiskers (strands)
2. If the leads are gull-wing type (usual on SOIC)
  arrange the plane of the leads parallel to the
  top of the chip package and press the leads
  down onto the horizontal part of the pins.
3. With J-type leads (rare), mount the supports
  perpendicular to the top of the chip and press
  them in from the sides.

With more than 8 leads, this might be more trouble
than it is worth, but only 8 should be easy.

John Power

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