Pin grid array
A pin grid array, often abbreviated PGA, is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the underside of the package. The pins are commonly spaced 2.54 mm (0.1") apart, and may or may not cover the entire underside of the package.
PGAs are often mounted on printed circuit boards using the through hole method or inserted into a socket. PGAs allow for more pins per integrated circuit than older packages such as dual in-line package (DIP).
PGA variants
Plastic
Plastic pin grid array (PPGA) packaging was used by Intel for late model Mendocino core Celeron processors based on Socket 370. Some pre-Socket 8 processors also used a similar form factor, although they were not officially referred to as PPGA.
Flip chip
A flip-chip pin grid array (FC-PGA or FCPGA) is a form of pin grid array in which the die faces downwards on the top of the substrate with the back of the die exposed. This allows the die to have a more direct contact with the heatsink or other cooling mechanism.