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LQFP
A quad flat package (QFP) is a surface-mounted integrated circuit package with "gull wing" leads extending from each of the four sides. Socketing such packages is rare and through-hole mounting is not possible. Versions ranging from 32 to 304 pins with a pitch ranging from 0.4 to 1.0 mm are common. Other special variants include low-profile QFP (LQFP) and thin QFP (TQFP). The QFP component package type became common in Europe and United States during the early nineties, even though it has been used in Japanese consumer electronics since the seventies. It is often mixed with hole mounted, and sometimes socketed, components on the same printed circuit board (PCB). A package related to QFP is plastic leaded chip carrier (PLCC) which is similar but has pins with larger pitch, 1.27 mm (or 1/20 inch), curved up underneath a thicker body to simplify socketing (soldering is also possible). It is commonly used for NOR flash memories and other programmable components. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solder Bridge
Solder mask, solder stop mask or solder resist is a thin lacquer-like layer of polymer that is usually applied to the copper traces of a printed circuit board (PCB) for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads. A solder bridge is an unintended electrical connection between two conductors by means of a small blob of solder. PCBs use solder masks to prevent this from happening. Solder mask is not always used for hand soldered assemblies, but is essential for mass-produced boards that are soldered automatically using reflow or wave soldering techniques. Once applied, openings must be made in the solder mask wherever components are soldered, which is accomplished using photolithography. Solder mask is traditionally green, but is also available in many other colors. Solder mask comes in different media depending upon the demands of the application. The lowest-cost solder mask is epoxy liquid that is silkscreened th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual In-line Package
In microelectronics, a dual in-line package (DIP or DIL), is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads (as observed in Rent's rule); eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density chip carriers. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages. A DIP is usually referred to as a DIP''n'', where ''n'' is the total number of pins. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pin Grid Array
A pin grid array (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 allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chip Carrier
In electronics, a chip carrier is one of several kinds of surface-mount technology packages for integrated circuits (commonly called "chips"). Connections are made on all four edges of a square package; compared to the internal cavity for mounting the integrated circuit, the package overall size is large.Kenneth Jackson, Wolfgang Schroter, (ed), ''Handbook of Semiconductor Technology Volume 2'',Wiley VCH, 2000, ,page 627 Types Chip carriers may have either J-shaped metal leads for connections by solder or by a socket, or may be lead-less with metal pads for connections. If the leads extend beyond the package, the preferred description is " flat pack". Chip carriers can be smaller than dual in-line packages and since they use all four edges of the package they can have a larger pin count. Chip carriers may be made of ceramic or plastic. Some forms of chip carrier package are standardized in dimensions and registered with trade industry associations such as JEDEC. Other forms ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposed Pad
Expose, exposé, or exposed may refer to: News sources * Exposé (journalism), a form of investigative journalism * '' The Exposé'', a British conspiracist website Film and TV Film * ''Exposé'' (film), a 1976 thriller film * ''Exposed'' (1932 film), a 1932 film starring Barbara Kent * ''Exposed'' (1938 film), a 1938 film starring Glenda Farrell * ''Exposed'' (1947 film), a 1947 film starring Adele Mara * ''Exposed'' (1983 film), a 1983 film starring Nastassja Kinski * ''Exposed'' (2003 film), a 2003 American independent comedy film * ''Exposed'' (2011 film), a 2011 film starring Jodi Lyn O'Keefe * ''Exposed'' (2016 film), a 2016 film starring Keanu Reeves Television * "Exposé" (''Lost''), a 2007 episode of ''Lost'' * '' Exposé: America's Investigative Reports'', a PBS news/documentary series * ''eXposed'', the pilot of the American television show ''The Gifted'' * ''Exposed'' (U.S. game show), a 2007 American dating game show that aired on MTV * ''Exposed'' (Canadia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Spreader
A heat spreader transfers energy as heat from a hotter source to a colder heat sink or heat exchanger. There are two thermodynamic types, passive and active. The most common sort of passive heat spreader is a plate or block of material having high thermal conductivity, such as copper, aluminum, or diamond. An active heat spreader speeds up heat transfer with expenditure of energy as work supplied by an external source. A heat pipe uses fluids inside a sealed case. The fluids circulate either passively, by spontaneous convection, triggered when a threshold temperature difference occurs; or actively, because of an impeller driven by an external source of work. Without sealed circulation, energy can be carried by transfer of fluid matter, for example externally supplied colder air, driven by an external source of work, from a hotter body to another external body, though this is not exactly heat transfer as defined in physics. Exemplifying increase of entropy according to the secon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Mount
Surface-mount technology (SMT), originally called planar mounting, is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). An electrical component mounted in this manner is referred to as a surface-mount device (SMD). In industry, this approach has largely replaced the through-hole technology construction method of fitting components, in large part because SMT allows for increased manufacturing automation which reduces cost and improves quality. It also allows for more components to fit on a given area of substrate. Both technologies can be used on the same board, with the through-hole technology often used for components not suitable for surface mounting such as large transformers and heat-sinked power semiconductors. An SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quad Flat No-leads Package
Flat no-leads packages such as quad-flat no-leads (QFN) and dual-flat no-leads (DFN) physically and electrically connect integrated circuits to printed circuit boards. Flat no-leads, also known as micro leadframe (MLF) and SON (small-outline no leads), is a surface-mount technology, one of several package technologies that connect ICs to the ''surfaces'' of PCBs without through-holes. Flat no-lead is a near chip scale plastic encapsulated package made with a planar copper lead frame substrate. Perimeter lands on the package bottom provide electrical connections to the PCB. Flat no-lead packages include an exposed thermally conductive pad to improve heat transfer out of the IC (into the PCB). Heat transfer can be further facilitated by metal vias in the thermal pad. The QFN package is similar to the quad-flat package (QFP), and a ball grid array (BGA). Flat no-lead cross-section The figure shows the cross section of a flat no-lead package with a lead frame and wire bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrix Cx486SLC
The Cyrix Cx486SLC is a x86 microprocessor that was developed by Cyrix. It was one of Cyrix's first CPU offerings, released after years of selling math coprocessors that competed with Intel's units and offered better performance at a comparable or lower price. It was announced in March of 1992, and released 2 months later in May, with a price of $119. It was priced competitively against the Intel 486SX, causing Intel to lower the price of their chip from $286 to $119 in just days. Specifications The 486SLC is based on the i386SX bus, and was intended as an entry-level chip to compete with the Intel 386SX and 486SX. SGS-Thomson and Texas Instruments manufactured the 486SLC for Cyrix. Texas Instruments also sold it under its own name as TX486SLC. Later, Texas Instruments also released their own version of the chip, the TI486SXLC which featured 8KB internal cache vs 1KB in the original Cyrix design. These chips went under the name Potomac, and Cyrix would receive full royalties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermally Conductive Pad
In computing and electronics, thermal pads (also called thermally conductive pad or thermal interface pad) are pre-formed rectangles of solid material (often paraffin wax or silicone based) commonly found on the underside of heatsinks to aid the conduction of heat away from the component being cooled (such as a CPU or another chip) and into the heatsink (usually made from aluminium or copper). Thermal pads and thermal compound are used to fill air gaps caused by imperfectly flat or smooth surfaces which should be in thermal contact;AMD - Thermal Interface Material Comparison: Thermal Pads vs. Thermal Grease Accessed 23 February 2014 they would not be needed between perfectly flat and smooth surfaces. Thermal pads are relatively firm at room temperature, but become so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball Grid Array
A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The traces connecting the package's leads to the wires or balls which connect the die to package are also on average shorter than with a perimeter-only type, leading to better performance at high speeds. BGAs were introduced in the 1990s and became popular by 2001. Soldering of BGA devices requires precise control and is usually done by automated processes such as in computer-controlled automatic reflow ovens. Description The BGA is descended from the pin grid array (PGA), which is a package with one face covered (or partly covered) with pins in a grid pattern which, in operation, conduct electrical signals between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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