From different supplier datasheets I unfortunately get conflicting information about the compatibility of different chips and sockets.
Can I use a Ceramic Leadless Chip Carrier (LCC) in a PLCC socket? Most suppliers list the JEDEC MO-47 standard as a compatible chip which has J-shaped leads, some claim that a leadless chip carrier also works. Is this true in general or do I need a special socket (there seem to be very few leadless chip carriers available)?
Generally speaking, sockets for PLCC chips (J-lead) are not compatible with leadless chip carriers, since their contacts are typically recessed between fingers that align and grip the PLCC package itself. The chip is held into the socket by friction. Contact is primarily made on the sides of the package, not the bottom, in order to take advantage of the wiping action.
Sockets for leadless chips typically have a clamping mechanism of some sort that applies pressure to the chip package so that its pads are pushed against the contacts in the socket. Contact is primarily made on the bottom face of the package, even if the contacts wrap around to the sides.
A socket advertised as being compatible with both would have been specifically designed for that. I've never seen one, but that doesn't mean they don't exist.
