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Integrated circuits can be found in many forms on a printed circuit board (PCB). Both through-hole mount and surface mount packages are available, although surface mount packaging is becoming more prevalent in the 21st century. Global standards have been established for the different types of semiconductor packaging, including those by the Joint Electron Device Engineering Council (JEDEC) and the Japan Electronics and Information Technology Industries Association (JEITA). Some of the most common package types include grid array, plastic Quad Flat Package (QFP), Single Inline Package (SIP), Dual Inline Package (DIP), J-lead, Small Outline (SO) package, and Land Grid Array (LGA).
Grid array semiconductor packaging is available in Pin Grid Array (PGA) format, which is a through-hole mount package. A plastic PGA is square-shaped and the pins are arranged on the bottom side in this configuration. It is commonly used for microprocessors, but perhaps one of the most common formats is the ceramic Ball Grid Array (BGA), a package that is surface-mounted to the PCB via the solder balls on its underside. The BGA format can support thousands of balls, or connections; meets high input-output (I/O) requirements; and is designed for effective heat dissipation and electrical performance, since the distance between the array, die, and board is short.
A similar type of semiconductor packaging is the plastic QFP, except lead pins extend from the sides in an L-shape. Rectangular and square versions of the QFP are available, with up to a couple of hundred leads, as well as packages classified for fine pitch, heat sink, metric, and thin configurations. There is also a rectangular surface mount package called a small outline J-lead package. The J-shaped leads are bent backward onto the body of the package, which is often used for memory chips.
Like the QFP, SO semiconductor packaging has pins that extend in an L shape from the sides, and is sold in a wide range of minor classifications based on width and pin pitch. The SIP, incorporating up to a few dozen pins, has through-hole pins on one side and stands upright on a PCB. This package is commonly used within a network of resistors on a board. On a DIP, the lead pins are located on both sides. Standard, ceramic, and versions encased in glass are available.
The LGA package is another type of configuration. Neither lead pins nor solder balls are used. Metal pads are arranged in a grid over the bottom surface, and can number to over 1,600. Like the BGA semiconductor packaging, the LGA is also suitable for use in high I/O applications.
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