Basic knowledge of integrated circuit packaging QFP packaging

What is QFP packaging?

The full English name of QFP is Quad Flat Package (four side pin flat package). The pins are led out from the four sides of the package. The leads are gull-wing ("L" shaped), mostly plastic packaging (as shown in the figure below), but also metal and ceramic packaging. The pin spacing is 1.0mm, 0.8mm, 0.65mm, 0.5mm, 0.4mm, 0.3mm and other specifications.

Characteristics of QFP:

1) The distance between chip pins is very small, and the pins are very thin. Generally, the number of pins is more than 100, and the size is small, which is suitable for high-frequency applications, such as CPU.

2) Easy operation and high reliability.

It is not necessary to punch holes on the main board for installation. Generally, the solder joint of the corresponding pins designed on the surface of the main board can be welded with the main board by aligning each pin of the chip with the corresponding solder joint.

3) QFP packaging is not only used for digital logic LSI circuits such as microprocessors, but also for analog LSI circuits such as VTR signal processing and audio signal processing.

New division standard of QFP:

In the past, the Japanese electronic and mechanical industry called QFP (FP) with pin spacing less than 0.65mm, but various manufacturers re-evaluated it because of the confusion of pin spacing naming

Improved QFP

When the pin center distance is less than 0.65mm, the pin is easy to bend. In order to prevent pin deformation, an improved QFP type appears:

1) BQFP (Quad Flat Package With Bumper) QFP with protective ring. The four corners of the package body are provided with protrusions (cushions) to prevent pin bending and deformation during transportation. As shown below:

2) GQFP (Quad Flat Package With Guard Ring) QFP with guard ring. The pins are covered with resin protection rings to prevent bending and deformation