The primary difference between QFN and QFP packages lies in how they make electrical connections: QFP packages use external leads, while QFN packages use contacts on the underside.
Key Distinction: Leads vs. Underside Contacts
Based on the provided reference, the defining characteristic separating these two common types of electronic component packaging is the presence and form of their electrical contacts.
- QFP (Quad Flat Package): These packages feature leads that extend outwards from all four sides. The reference specifically mentions these leads are typically in a gull-wing (or L) shape. These external leads are soldered directly onto the surface of a printed circuit board (PCB).
- QFN (Quad Flat No-lead) Package: As the name suggests ("no-lead package"), QFN packages do not have external pin leads. Instead, the electrical connections are made through metalized contacts located on the underside of the package. These contacts connect directly to pads on the PCB.
This fundamental difference in connection method impacts various aspects of board design, manufacturing, and the physical size of the component.
Comparing QFN and QFP Features
Here's a quick comparison based on the details provided:
| Feature | QFP (Quad Flat Package) | QFN (Quad Flat No-lead) Package |
|---|---|---|
| Electrical Connection | External leads extending outwards | Metalized contacts on the underside |
| Lead Type/Shape | Typically gull-wing (L) shape | No external leads |
| Package Name Meaning | Quad Flat Package | Quad Flat No-lead Package |
This distinction is crucial for engineers selecting components and designing PCBs, as it dictates the required footprint and soldering process.
