For special pin chip package, it is a kind of chip package. The pin of this kind of package bends inward at the bottom of the chip, so the chip pin is not visible in the top view of the chip. This kind of chip adopts reflow soldering process, which requires special welding equipment. It is very troublesome to remove the chip during debugging, which is rarely used now. PLCC (plastic LED chip carrier) is a kind of plastic chip carrier with lead. It is one of the surface mount packages. It is square in shape and 32 pin in package. The pins are led from four sides of the package in a T shape. It is a plastic product and its overall dimension is much smaller than that of dip package. PLCC package is suitable for SMT surface mounting technology to install wiring on PCB. It has the advantages of small size and high reliability.