QFN (QUAD FLAT no-Leadpackage, square flat without quotes), one of the surface packaging packaging. Most of them are now called LCC. QFN is the name stipulated by the Japanese Electronic Machinery Industry Association. The enclosure is equipped with an electrode contact. Because there is no pitch, the stickers are smaller than QFP and the height is lower than QFP. However, when the printed substrate and the package are generated, it cannot be relieved at the electrode contact. Therefore, the electrode contact is difficult to get the pins of QFP, generally from 14 to 100. There are two types of materials: ceramics and plastic. When there are LCC marks, they are basically ceramic QFN. The center of the electrode contact is 1.27mm. Plastic QFN is a low -cost packaging of glass epoxy resin printing substrate substrate. In addition to 1.27mm, there are two types: 0.65mm and 0.5mm. This packaging is also called plastic LCC, PCLC, P-LCC, etc.