TO-220 Package
Transistor Package TO-220 Case style [5-Terminals, Straight leads]
TO-220 5-Terminal Package Drawing
Tab mount. A type of package which provides a method of readily attaching one surface of the
semiconductor device to a heat dissipater [heat sink] to achieve thermal management of the case temperature. Other factors that may effect the mounting include using a Mica washer, copper washer, and thermal grease. In many cases a large heat sink is attached to the metal tab, in other cases the TO-220 is installed near the side of a PWB and the tab is attached to an infinite heat sink as in the panel of a metal chassis or case.
When attached to a PWB a copper pad or island should be located underneath the thermal tab of the TO-220.
Use a washer between the tab and the screw, or use a screw with a large diameter head, and do not over-tighten. If the tab is bent, becomes deformed or non-flat then the surface area between the metal tab and the heat sink will be reduced. Also don't counter-sink the hole in the board or heat-sink, as the screw would not use it and it's not required.
In many cases when a device is offered in a straight lead TO-220 package, the same device is offered in a bent and staggered lead TO-220 package.
Unlike the 3-Terminal TO-220 Package, the 5-lead package is used for semiconductors other than transistors or FETs; for example, Voltage regulators having control pins.
The surface mount version of a 5-lead TO-220 is the 5-Terminal TO-263.
There are also other sizes of the TO-263 package.
Regardless of the number of pins [shown to the left], the TO-220 package is widely used with voltage regulators and to a lesser extent power amplifiers.