of possible interest here is that these ones i mentioned (mill max
940-99-068-24-000000) are a real bear when yanking out the chips, 
we have a proper extraction tool but the force required is so great that
it seems like half the time the chip gets lunched as the tool exits and
skims across the nearby leads turning the 68 pin part into effectively a
58 or 60 pin part

it does intuitively seem that the hi pro could offer more contact
pressure
i wonder if that is spec'd ?

Dennis Saputelli

Dennis Saputelli wrote:
> 
> i can't comment on the reliability issue (millmax makes pretty good
> stuff i think)
> but the high profile ones are sometimes larger around the perimeter even
> though the lands are the same 'footprint'
> 
> i've seen significant differences in that dimension
> 
> we are using the 68p PLCC full profile thru hole
> maybe 1000 pcs over the last 2 years and (knock on wood) have not seen
> reliability issues
> 
> also you do have to be sure that your people push them down hard into
> the socket, same with DIPs
> 
> the thermal cycling can make them walk out of their sockets
> 
> does pushing down fix the problems?
> 
> Dennis Saputelli
> 
> Lloyd Johnson wrote:
> >
> > This may be slightly off topic, but we are beginning to have occasional
> > problems with the reliability of the connections between a 68 pin low
> > profile PLCC socket and a 68 pin IC package.
> >
> > Are low profile sockets (Millmax 540-99-068-17-400200) less reliable than
> > full height PLCC sockets? Or are PLCC sockets for larger parts just
> > inherently a bad idea?
> >
> > This socket uses the same footprint as the PLCC part, so we can change to
> > direct soldering the part in place if this is needed.
> >
> > Any thoughts would be appreciated.
> >
> > Lloyd Johnson, DSS
> > Vista CA.
> >
> 
>
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