TO-220

The TO-220 is a style of electronic package used for high-powered, through-hole components with 0.1 inches (2.54 mm) pin spacing.

Common TO-220-packaged components include discrete semiconductors such as transistors and silicon-controlled rectifiers, as well as integrated circuits.

The top of the package has a metal tab with a hole used to mount the component to a heat sink.

Many materials may be used to electrically isolate the TO-220 package, some of which have the added benefit of high thermal conductivity.

There also some vendor-specific variations such as International Rectifier's SUPER-220, which dispenses with the hole in favor of clip-mounting, thus claiming TO-247-like thermal performance in a TO-220 footprint.