QFN package features

QFN (Quad Flat No-lead Package) is an emerging surface mount chip packaging technology with small pad size, small volume and plastic as sealing material. QFN has excellent electrical and thermal performance due to the large exposed pad at the bottom being soldered to the heat-dissipation pad of the PCB.

QFN Package component

QFN is a leadless package that is square or rectangular. There is a large area of exposed pad at the center of the bottom of the package. It has a heat transfer function.There are conductive pads on the periphery of the large pad package for electrical connection. Because the QFN package does not have gull-wing leads like the traditional SOIC and TSOP packages, the conductive path between the internal leads and the pads is short, the self-inductance coefficient and the wiring resistance in the package are very low, so it can provide excellent electrical performance. . In addition, it provides excellent heat-dissipation performance through exposed lead frame pads, the pads have direct heat dissipation channels to dissipate heat from the package. Typically, the heat-dissipation pad is soldered directly to the board, and the heat-dissipation vias in the PCB help to dissipate excess power into the copper ground plane to absorb excess heat. Due to its small size, light weight, and outstanding electrical and thermal properties, this package is ideal for any application that requires size, weight and performance.

You can vaguely think of it as a reduced PLCC package. Let's compare the 32-pin QFN to the traditional 28-pin PLCC package. The area (5mm × 5mm) is reduced by 84% and the thickness is (0.9mm) reduced by 80%, weight (0.06g) reduced by 95%, and electronic package parasitics reduced by 50%, so it is ideal for high-density printed circuit boards used in mobile phones, digital cameras, PDAs, and other portable small electronic devices.

The main features of QFN are:

1. Surface mount package
2. Leadless pad design occupies a smaller PCB area
3. Very thin components (<1mm) for applications where space is critical
4. Very low impedance, self-inductance for high speed or microwave applications
5. Excellent thermal performance, mainly because of the large area of thermal pad on the bottom
6. Lightweight for portable applications
7. Leadless design