TO-66 Transistor Package

TO-66 Package

Transistor Package TO-66 Case style, 3-Terminal

TO-66 Package Outline TO-66 Dimensions 3-Terminal TO-66 Dual-Base Darlington Circuit example TO-66 Lead Designation: [Pin out] Terminal 1, Emitter. Terminal 2, Base [B1]. Terminal 3, Base [B2]. Case, Collector. 3-Terminal TO-66 Semiconductors; NPN Power Darlington Transistor; 2N6352, 2N6353

TO-66 Package, Package Details

The TO-66 style case is a through-hole flange-mount device in a metal package, similar to a TO-3 Case package, but with 3 terminals instead of two.
The diagram above shows the terminal locations for a 3-lead TO-66 package, with the case tied to the collector. The picture below shows the normal case attachment method for the TO-66 metal can. Note that the collector lead or metal case of the TO-66 is attached to a metal heat sink via two screws. Additional semiconductors may also use a TO-66 package [other than the schematic shown above]. A more common variant of the TO-66 case uses only two terminals; 2-Terminal TO-66. A 4 terminal TO-66 is also possible [but not shown].

Case mount. [Flange Mount] A style of package which allows the case to be attached to a heat dissipater or heat sink to achieve thermal management of the case temperature. The case of a 2-Terminal TO-66 device [and some 3-leaded TO-66] is connected to the Collector to aid in heat dissipation. Case temperature. The component body or case temperature is that temperature measured at a specified point on the case of a semiconductor device.

Diamond Metal Case

The picture of the TO-3 is only shown to provide a relative shape, as the TO-66 package is a much smaller package but still in the diamond shaped metal package.

Normal TO-66 heat sinks are a Black Anodized Aluminum Alloy with 2 mounting holes. However any metal panel or metal plate may be used as a heat sink. In fact in many cases the TO-66 package is mounted external to a chassis to allow for better air flow [assuming a metal chassis.