Hello all,

I need to design a board with a 18F458 in the 44-pin TQFP case that now
should also accommodate a transition socket for the ICE 2000 (that's the
XLT44PT). I don't have the time to wait until I actually have the
transition socket in my hands, so I need to go by the drawings.

I had a look at the drawings in
http://ww1.microchip.com/downloads/en/DeviceDoc/51194h.pdf pages 34/35. But
I don't understand a crucial part of it. I need to know how much space
around the pads I need to leave basically free for the transition socket
leads. On page 35, it is not clear whether dimension D (550 mil) or
dimension C (650 mil) is necessary. Does this socket have two rows of
leads?

On page 32, they say to leave 25 mil between the footprint and any vias. (I
take it that doesn't apply to vias inside the pads, right?) But if
dimension C is correct, that looks more like 50 mil were necessary. They
also talk only about vias, but in the drawing it looks like the leads would
lay flat on the board, going outwards from the pads. What about traces in
that area around the footprint? It seems like there couldn't really be
anything at all (no traces) in that square C or D.

Has anybody used this socket and can help me out please with the actual
space requirements?

Thanks a lot,
Gerhard

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body