Land grid array

The land grid array (LGA) is a type of surface-mount packaging for integrated circuits (ICs) that is notable for having the pins on the socket (when a socket is used) rather than the integrated circuit. An LGA can be electrically connected to a printed circuit board (PCB) either by the use of a socket or by soldering directly to the board.

The land grid array is a packaging technology with a rectangular grid of contacts on the underside of a package. The contacts are to be connected to a grid of contacts on the PCB. Not all rows and columns of the grid need to be used. The contacts can either be made by using an LGA socket, or by using solder paste.

LGA packaging is related to ball grid array (BGA) and pin grid array (PGA) packaging. Unlike pin grid arrays, land grid array packages are designed to fit either in a socket, or be soldered down using surface mount technology. PGA packages cannot be soldered down using surface mount technology. In contrast with a BGA, land grid array packages in non socketed configurations have no balls, and use flat contacts which are soldered directly to the PCB. BGA packages, however have balls as their contacts in between the IC and the PCBs. The balls are normally attached to the underside of the IC.

LGA is used as a physical interface for microprocessors of the Intel Pentium 4 (Prescott), Intel Xeon, Intel Core 2, Intel Core (Bloomfield and Lynnfield) and AMD Opteron families. Unlike the pin grid array (PGA) interface found on most AMD and older Intel processors, there are no pins on the chip; in place of the pins are pads of bare gold-plated copper that touch protruding pins on the microprocessor's connector on the motherboard.

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