A quad flat package (QFP) is a
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 ...
ed
integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
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 first QFPs were introduced in Japan in 1977 in order to provide more pins on a small package to allow a greater number of digits on
electronic calculator
An electronic calculator is typically a portable Electronics, electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.
The first solid-state electronic calculator was created in the early 1960s. ...
s. It soon spread to other
consumer electronic
Consumer electronics, also known as home electronics, are electronic devices intended for everyday household use. Consumer electronics include those used for entertainment, communications, and recreation. Historically, these products were refer ...
s in that country.
The QPF only became common in
Europe
Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...
and
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
during the early nineties. It is often mixed with
hole mounted, and sometimes
socket
Socket may refer to:
Mechanics
* Socket wrench, a type of wrench that uses separate, removable sockets to fit different sizes of nuts and bolts
* Socket head screw, a screw (or bolt) with a cylindrical head containing a socket into which the hexag ...
ed, components on the same
printed circuit board
A printed circuit board (PCB), also called printed wiring board (PWB), is a Lamination, laminated sandwich structure of electrical conduction, conductive and Insulator (electricity), insulating layers, each with a pattern of traces, planes ...
(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.
Limitations
The quad flat-pack has connections only around the periphery of the package. To increase the number of pins, the spacing was decreased from 50 mil (as found on
small outline packages) to 20 and later 12 (1.27 mm, 0.51 mm and 0.30 mm respectively). However, this close lead spacing made
solder bridges more likely and put higher demands on the soldering process and alignment of parts during assembly.
The later
pin grid array (PGA) and
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 pu ...
(BGA) packages, by allowing connections to be made over the area of the package and not just around the edges, allowed for higher pin counts with similar package sizes, and reduced the problems with close lead spacing.
Variants
Cyrix cx9210 gfdl (cropped).jpg, 144-pin low profile quad flat package (LQFP)
PIC18F8720.jpg, 80-pin thin quad flat package (TQFP) – PIC microcontroller
PIC (usually pronounced as /pɪk/) is a family of microcontrollers made by Microchip Technology, derived from the PIC1640 originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to ''Peripher ...
Sega 304-pin QFP.jpg, 304-pin plastic quad flat package (QFP) with exposed thermal pad (TP)
Cyrix Cx486SLCe-V25MP DF7339E top.jpg, 100-pin bumpered quad flat package (BQFP) – 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 comparab ...
CRQFP80 UV ST62E40.jpg, 80-pin ceramic quad flat package (TQFP) – ST6 microcontroller
The basic form is a flat rectangular (often square) body with leads on four sides but with numerous variation in the design. These differ usually only in lead number, pitch, dimensions, and materials used (usually to improve thermal characteristics). A clear variation is bumpered quad flat package (BQFP) with extensions at the four corners to protect the leads against mechanical damage before the unit is soldered.
Heat sink quad flat package, ''heatsink very thin quad flat-pack no-leads'' (''
HVQFN'') is a package with no component leads extending from the IC. Pads are spaced along the sides of the IC with an exposed die that can be used as ground.
Spacing between pins can vary.
A thin quad flat pack (TQFP) provides the same benefits as the metric QFP, but is thinner. Regular QFP are 2.0 to 3.8 mm thick depending on size. TQFP packages range from 32 pins with a 0.8 mm lead pitch, in a package 5 mm by 5 mm by 1 mm thick, to 256 pins, 28 mm square, 1.4 mm thick and a lead pitch of 0.4 mm.
TQFPs help solve issues such as increasing board density, die shrink programs, thin end-product profile and portability. Lead counts range from 32 to 176. Body sizes range from to . Copper lead-frames are used in TQFPs. Lead pitches available for TQFPs are 0.4 mm, 0.5 mm, 0.65 mm, 0.8 mm, and 1.0 mm. ''PQFP'', or plastic quad flat pack, is a type of QFP, as is the thinner TQFP package. PQFP packages can vary in thickness from 2.0 mm to 3.8 mm. A low-profile quad flat package (LQFP) is a
surface mount integrated circuit
An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
package format with component leads extending from each of the four sides. Pins are numbered counter-clockwise from the index dot.
Spacing between pins can vary; common spacings are 0.4, 0.5, 0.65 and 0.80 mm intervals.
Some QFP packages have an
exposed pad. The exposed pad is an extra pad underneath or on top of the QFP that may act as a ground connection and/or as a heat sink for the package. The pad is typically 10 or more mm
2, and with the pad soldered down onto the ground plane, heat is passed into the PCB. This exposed pad also gives a solid ground connection. These types of QFP packages often have a -EP suffix (e.g. a LQFP-EP 64), or they have an odd number of leads, (e.g. a TQFP-101).
Ceramic QFP package
Ceramic QFP packages come in two variants, CERQUAD and CQFP:
CERQUAD packages
Hereby the leadframe is attached between two ceramic layers of the package. The leadframe is attached using glass. This package is a variant of the CERDIP package. CERQUAD packages are the "low cost" alternative for CQFP packages, and are mainly used for terrestrial applications.
Main ceramic package manufacturers are Kyocera, NTK,... and offer the full pincount range
CQFP packages
Hereby the leads are soldered on top of the package. The package is a multilayer package, and is offered as HTCC (high temperature co-fired ceramic). The number of bonding decks can be one, two or three. Package is finished with a nickel plus a ''thick'' gold layer, except where the leads are soldered and decoupling capacitors are soldered on top of the package. These packages are hermetic. Two methods are used in order to make the hermetic sealing: eutectic gold-tin alloy (melting point 280°C) or seam welding. Seam welding gives rise to significantly less temperature rise in the internal of the package (e.g., the die attach). This package is the main package used for Space projects.
Due to the large body size of CQFP packages, parasitics are important for this package. Power supply decoupling is improved by having the decoupling capacitors mounted on top of this package. E.g. TI offers 256-pin CQFP packages where decoupling capacitors can be soldered on top of the package
E.g. Test-expert 256-pin CQFP packages where decoupling capacitors can be soldered on top of the package.
The main ceramic package manufacturers are Kyocera (Japan), NTK (Japan), Test-Expert (Russia), etc. and offer the full pincount range. Maximum pin count is 352 pins.
See also
*
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 ...
*
Pin grid array - an alternative integrated circuit pin arrangement design
*
Dual in-line package
In microelectronics, a dual in-line package (DIP or DIL) is an Semiconductor package, electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole technology, throu ...
References
External links
HVQFN Documentation at NXP SemiconductorsMore about HQVFNPQFP packaging information from Integrated Silicon Solution, Inc.(
PDF
Portable document format (PDF), standardized as ISO 32000, is a file format developed by Adobe Inc., Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, computer hardware, ...
)
{{Semiconductor packages
Chip carriers