Processor Types and Specifications - Upgrading and Repairing PCs - page 89

Socket LGA775
Socket LGA775 (also called Socket T) is used by the Core 2 Duo/Quad processors, the
latest versions of the Intel Pentium 4 Prescott processor and the Pentium D and Pentium
Extreme Edition processors. Some versions of the Celeron and Celeron D also use Socket
LGA775. Socket LGA775, unlike earlier Intel processor sockets, uses a land grid array
format, so the pins are on the socket, rather than the processor.
LGA uses gold pads (called lands ) on the bottom of the processor to replace the pins used
in PGA packages. It allows for much greater clamping forces via a load plate with a lock-
ing lever, with greater stability and improved thermal transfer (better cooling). The first
LGA processors were the Pentium II and Celeron processors in 1997; in those processors,
an LGA chip was soldered on the Slot-1 cartridge. LGA is a recycled version of what was
previously called leadless chip carrier (LCC) packaging. This was used way back on the
286 processor in 1984, and it had gold lands around the edge only. (There were far few-
er pins back then.) In other ways, LGA is simply a modified version of ball grid array
(BGA), with gold lands replacing the solder balls, making it more suitable for socketed
(rather than soldered) applications. Socket LGA775 is shown in Figure 3.10 .
Figure 3.10 Socket LGA775 (Socket T). The release lever on the left raises the load plate out of the way to
permit the processor to be placed over the contacts.