TO-52 Package

The TO-52 is a type of 'metal can' package that is hermetically sealed to protect the device from environmental factors such as contaminants and moisture.  It is commonly used in housing transistors and integrated circuits with low lead counts such as voltage reference IC's.

The TO-52 is made primarily of metal, with the microchip mounted on the die pad of its metal can base and then covered with a metal cap.  Sealing of the cap over the base is achieved by welding. The TO-52 is similar to the TO-72 but it is slightly smaller than the latter because of its smaller cap. 

Most TO-52 packages come with three terminals, since this type of package is commonly used in three-terminal devices such as transistors.  However, TO-52 packages with only two terminals are also quite common.

Table 1. Properties of a Typical TO-52 Package