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| In electronics, a '''chip carrier''' is one of several kinds of packages for ]s. Connections are made on all four edges of a square package. 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. Chip carriers are smaller than ]s and since they use all four edges of the package can have a larger pin count. Chip carriers may be made of ceramic or plastic. | In ], a '''chip carrier''' is one of several kinds of ] packages for ]s. Connections are made on all four edges of a square package. 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. Chip carriers are smaller than ]s and since they use all four edges of the package 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 ]. Other forms are proprietary to one or two manufacturers. | ||
| ==Plastic leaded chip carrier== | |||
| ] Motorola MC68HC711E9CFN3 in QFJ52 / PLCC52]] | |||
| ], an application of the PLCC68 package, in a ].]] | |||
| ] DualBIOS in QFJ32 / PLCC32]] | |||
| A ''plastic leaded chip carrier'' ('''PLCC''') has a rectangular plastic housing. It is a reduced cost evolution of the ceramic leadless chip carrier (CLCC). | |||
| A premolded PLCC was originally released in 1976, but did not see much market adoption. Texas Instruments later released a postmolded variant that was soon adopted by most major semiconductor companies. The ] trade group started a task force in 1981 to categorize PLCCs, with the MO-047 standard released in 1984 for square packages and the MO-052 standard released in 1985 for rectangular packages.<ref name="SMT">{{cite book|title=Surface mount technology: principles and practice|last=Prasad|first=Ray|year=1997|isbn=0412129213|page=121}}</ref> | |||
| The PLCC utilizes a "J"-] with pin spacings of 0.05" (1.27 mm). Lead counts range from 20 to 84.<ref name="EMH">{{cite book |title=Electronic Materials Handbook |last=Minges |first=Merrill L. |year=1989 |publisher=CRC Publishing |isbn=0871702851 |page=173}}</ref> PLCC packages can be square or rectangular. Body widths range from 0.35" to 1.15". The PLCC “J” Lead configuration requires less board space versus equivalent gull leaded components. The PLCC is preferred over ] style chip carriers when lead counts exceed 40 pins due to the PLCC's more efficient use of board surface area. | |||
| The heatspreader versions are identical in form factor to the standard non-heatspreader versions. Both versions are JEDEC compliant in all respects. The heatspreader versions give the system designer greater latitude in thermally enhanced board level and / or system design. RoHs compliant, lead-free & green material sets are now qualified standards. | |||
| A PLCC circuit may either be installed in a PLCC socket or ]. PLCC sockets may in turn be surface mounted, or use ]. The motivation for a surface-mount PLCC socket would be when working with devices that cannot withstand the heat involved during the ] process, or to allow for component replacement without reworking. Using a PLCC socket may be necessary in situations where the device requires stand-alone programming, such as some ] devices. Some through-hole sockets are designed for prototyping with ]ping. | |||
| A specialized tool called a ''PLCC extractor'' facilitates the removal of a PLCC from a socket. | |||
| This package is still used for a wide variety of device types, which would include memory, processors, controllers, ASIC, DSP, etc. Applications range from consumer products through automotive and aerospace. | |||
| == Leadless== | |||
| ] | |||
| A ''leadless chip carrier'' (''LCC'') has no "]", but instead has rounded pins through the edges of the ] or molded ] package. | |||
| Prototypes and devices intended for extended temperature environments are typically packaged in ceramic, while high-volume products for consumer and commercial markets are typically packaged in plastic. | |||
| ==See also== | ==See also== | ||
Revision as of 20:04, 29 December 2011
In electronics, a chip carrier is one of several kinds of surface mount technology packages for integrated circuits. Connections are made on all four edges of a square package. 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. Chip carriers are smaller than Dual in-line packages and since they use all four edges of the package 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 are proprietary to one or two manufacturers.
Plastic leaded chip carrier
A plastic leaded chip carrier (PLCC) has a rectangular plastic housing. It is a reduced cost evolution of the ceramic leadless chip carrier (CLCC).
A premolded PLCC was originally released in 1976, but did not see much market adoption. Texas Instruments later released a postmolded variant that was soon adopted by most major semiconductor companies. The JEDEC trade group started a task force in 1981 to categorize PLCCs, with the MO-047 standard released in 1984 for square packages and the MO-052 standard released in 1985 for rectangular packages.
The PLCC utilizes a "J"-lead with pin spacings of 0.05" (1.27 mm). Lead counts range from 20 to 84. PLCC packages can be square or rectangular. Body widths range from 0.35" to 1.15". The PLCC “J” Lead configuration requires less board space versus equivalent gull leaded components. The PLCC is preferred over DIP style chip carriers when lead counts exceed 40 pins due to the PLCC's more efficient use of board surface area.
The heatspreader versions are identical in form factor to the standard non-heatspreader versions. Both versions are JEDEC compliant in all respects. The heatspreader versions give the system designer greater latitude in thermally enhanced board level and / or system design. RoHs compliant, lead-free & green material sets are now qualified standards.
A PLCC circuit may either be installed in a PLCC socket or surface-mounted. PLCC sockets may in turn be surface mounted, or use through-hole technology. The motivation for a surface-mount PLCC socket would be when working with devices that cannot withstand the heat involved during the reflow process, or to allow for component replacement without reworking. Using a PLCC socket may be necessary in situations where the device requires stand-alone programming, such as some flash memory devices. Some through-hole sockets are designed for prototyping with wire wrapping.
A specialized tool called a PLCC extractor facilitates the removal of a PLCC from a socket.
This package is still used for a wide variety of device types, which would include memory, processors, controllers, ASIC, DSP, etc. Applications range from consumer products through automotive and aerospace.
Leadless
A leadless chip carrier (LCC) has no "leads", but instead has rounded pins through the edges of the ceramic or molded plastic package.
Prototypes and devices intended for extended temperature environments are typically packaged in ceramic, while high-volume products for consumer and commercial markets are typically packaged in plastic.
See also
- Prasad, Ray (1997). Surface mount technology: principles and practice. p. 121. ISBN 0412129213.
- Minges, Merrill L. (1989). Electronic Materials Handbook. CRC Publishing. p. 173. ISBN 0871702851.
- http://www.cpu-world.com/CPUs/80286/Intel-R80286-8.html "Intel R80286-8; Package 68-pin ceramic LCC"