Chip carrier

Plastic Leaded Chip Carrier ( PLCC ) ( JEDEC ), or Quad Flat J- lead chip carrier ( QFJ ) is introduced in 1976 and 1984 standard IC package with a so-called J -lead terminals ( J-shaped inwardly bent SMD terminals ). It is also the flash memory in this design, available, they are often used in PC BIOS.

Variants

Usually QFJs are square but on all four sides the same number of connections, some types have a rectangular base with two longer sides, the more connections than the two shorter sides, since the distance between the terminals always 1.27 mm ( 1 / is 20 inches). The number of connections is evident from the figure behind the design name: QFJ52 ( PLCC52 ). The following housing types are common:

  • QFJ20 ( PLCC20 ) - (4 × 5 pins)
  • QFJ28 ( PLCC28 ) - (4 × 7 pins)
  • QFJ32 ( PLCC32 ) - (2 × 2 × 7 and 9 pins )
  • QFJ44 ( PLCC44 ) - (4 × 11 pins)
  • QFJ52 ( PLCC52 ) - (4 × 13 pins)
  • QFJ68 ( PLCC68 ) - (4 × 17 pins)
  • QFJ84 ( PLCC84 ) - (4 × 21 pins)

Besides that, there the variants PLCC2 and PLCC4 (also known as PLCC -4 hereinafter), which are also square, but only on two sides has connections. These variations are mainly used for Surface Mounted Device LEDs.

Areas of application

As with any IC package form many different ICs are available in such cases. Because it has long been a reliable base there for this design, it frequently hosts circuits with non-volatile memory. Such include:

  • Microcontroller
  • Flash memory, for example: BIOS
  • CPLDs
  • PICC
  • Before the introduction of the PGA design for microprocessors and chipsets in personal computers

Due to the high design, it is not used in highly integrated devices.

Benefits

  • Base available.
  • Part orientation clearly visible due to the high design.
  • Hardly short circuit formation during reflow soldering.

Disadvantages

  • Excessive component height
  • Solder joint hidden under the connection, therefore to inspect bad.
  • QFJs can not or only very poorly processed together with components in modern cases, such as TQFP, TSSOP or less in the same process ( stencil printing / Reflow ) due to overlay specifications.
  • Soldering in the shaft is only possible with restrictions.
  • Lead-free versions ( RoHS) are not as good as offered by the chip manufacturers, as this form of housing is no longer used so often.
  • The unilateral contact via spring contacts is especially in mobile applications is a constant uncertainty

Packaging and Processing

Available in bars or straps. If automated pick -and-place or (usually manually ) pressed into previously soldered socket.

ISO/IEC 14443
653136
de