What Does Staggered Pin Grid Array (SPGA) Mean?
A staggered pin grid array (SPGA) is an integrated circuit socket style or pin-out having a staggered grid of pins surrounding the socket's edge, placed as several squares, one within the other. The structure is also known as intersecting squares.
SPGA is generally used on motherboards for processors based on the Socket 5, Socket 7 and Socket 8 platforms.
Techopedia Explains Staggered Pin Grid Array (SPGA)
In a staggered pin grid array (SPGA), the pins are arranged in diagonal rows. SPGA includes two square arrays of pins, balanced in both directions. In other words, the pins are arranged to form a diagonal square lattice inside the square boundary. SPGA includes an area in the center of the package in which no pins are arranged. SPGA packages are ideal for those devices that demand a higher pin density compares to what a standard pin grid array (PGA) can offer.
The initial integrated circuits had pins arranged using the PGA, which sets pins in a grid-like structure. The advancement in processor design and the demand for more pins made the PGA inappropriate and outdated. The key objective of SPGA was to reduce the size of the microprocessor when more pins are required. The SPGA structure is used by processors centered on Socket 5, Socket 7 and Socket 8 technology.
The advantage of using an SPGA formation as opposed to the earlier versions is that it consists of closer pins, thereby allowing more pins for a specific surface area. This allows for the decrease in the microchip size or, in other words, offers better transfer capacity in a similar-sized chip.