On Wed, 8 Jul 1998 12:13:00 +0000, you wrote:

>I'm working on a design that uses a surface mounted PIC.  As far as I
>know, the only UV eraseable parts available are DIP packages.  I've
>tried to cobble together an adapter that allows a DIP socket to be
>soldered onto the surface mount pads, with little luck.
>
>Surely you folks have run into this problem before.  How do you go
>about testing, debugging and prototyping a surface mount design?
>
>
>
>Best Regards,
>
>Lawrence Lile
This is probably the cheapest way of doing it, but still versatile and
durable....
I made up 2 identical leads, each consisting of a 0.05" pitch
single-row socket connected to a 0.1" pitch single-row turned-pin IC
socket strip, 14 ways. Use short (<4") very flexible ribbon (The
multi-colour IDC stuff is great).

You then just solder two 0.05" pitch pin strips (e.g. Samtec) to the
SO pads (vertically) - you can eather butt-joint them, or for a
stronger joint, bend over the last 1mm of the pin to form an L, the
base of which lays along the length of the SO pad.
If durability is important, cover the joint rows with plenty of epoxy.
 Plug one of the ribbon leads onto each pinstrip. and the DIL chip
into the turned-pin sockets. Using 2 seperate cables means you only
need one pair for 20 and 28 pin chips & different pitch DILs, and the
spacing of the SO pinstrips isn't crucial. 

Once you've made up the tricky part (the cables), subsequent use on
other designs is easy and very cheap - just a couple of expendable
pinstrips.

I made up a small PCB to break the 0.05" ribbon out to 0.1", but you
could do it manually and cover with hot-melt for strain-relief. 
This method can also be used for PLCCs, but you really need to put the
4 socket strips on a PCB for alignment, and put the pinstrips in the
sockets to align them for soldering. Another small PCB to break the
ribbon out to the 40 pin DIL is also useful. 

If you need further details, EMAIL me and I'll put a couple of photos
on a webpage & dig out the Samtec partnos for the connectors.
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