electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...

, a chip carrier is one of several kinds of

surface-mount technology 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 ...

packages for

integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

s (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 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 ( ...

s 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 The JEDEC Solid State Technology Association is an independent semiconductor engineering trade organization and standardization body headquartered in Arlington County, Virginia, United States. JEDEC has over 300 members, including some of the w ...

. Other forms are proprietary to one or two manufacturers. Sometimes the term "chip carrier" is used to refer generically to any package for an integrated circuit. Types of chip-carrier package are usually referred to by initialisms and include: * BCC: Bump chip carrier * CLCC: Ceramic leadless chip carrier * Leadless chip carrier (LLCC): Leadless chip carrier, contacts are recessed vertically. * LCC: Leaded chip carrier * LCCC: Leaded ceramic chip carrier * DLCC: Dual lead-less chip carrier (ceramic) * PLCC:

Plastic leaded 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 mount ...

* PoP: Package on package

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

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 Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, ...

with pin spacings of 0.05" (1.27 mm). The metal strip forming the lead is wrapped around and under the edge of the package, resembling the letter J in cross-section. 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, which have flat leads that extend out perpendicularly to the narrow edge of the package. 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 and green material sets are now qualified standards. Tool used to extract leaded chip carriers from sockets

Tool used to extract leaded chip carriers from sockets

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 In electronics, through-hole technology (also spelled "thru-hole") is a manufacturing scheme in which leads on the components are inserted through holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side, eithe ...

. 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 Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use ...

devices. Some through-hole sockets are designed for prototyping with

wire wrap Wire wrap is an electronic component assembly technique that was invented to wire telephone crossbar switches, and later adapted to construct electronic circuit boards. Electronic components mounted on an insulating board are interconnected by ...

ping. A specialized tool called a PLCC extractor facilitates the removal of a PLCC from a socket. PLCCs continue to be used for a wide variety of device types, which would include memory, processors, controllers, ASICs, DSPs, etc. It is particularly common for read-only memories, as it provides an easily swappable socketed chip. Applications range from consumer products through automotive and aerospace.

Leadless

A leadless chip carrier (LCC) has no "

leads Lead is a chemical element with symbol Pb and atomic number 82. Lead or The Lead may also refer to: Animal handling * Leash, or lead * Lead (leg), the leg that advances most in a quadruped's cantering or galloping stride * Lead (tack), a lin ...

", but instead has rounded pins through the edges of the

ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, ...

or molded

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...

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.

References

{{Semiconductor packages

Types

Plastic-leaded chip carrier

Leadless

See also

References