TO-5, T0-18 and other related related package sizes

A drawing of a ZN414 IC in a TO-18 package.

Construction

They are small, usually unpainted steel or aluminium can with 3 to 8 steel or copper wires coming out bottom of the steel base plate. The container is sealed with resin and filled with either resin, glass dust, epoxy or a puff of argon gas.

Tables

Properties of a Typical 3-lead TO-5 Package

Base Diameter	Cap Diameter	Cap Height	Lead Length	Lead Pitch	Leads
8.9 mm	8.1 mm	6.3 mm	38.1 mm	5.08 mm	3 to 9

 

Properties of a Typical 3-lead TO-18 Package

Base Diameter	Cap Diameter	Cap Height	Min. Lead Length	Max. Lead Pitch	Leeds
5.5 mm	4.7 mm	4.8 mm	12.7 mm	2.97 mm	3

   

 

Properties of a Typical 3-lead TO-46 Package

Base Diameter	Cap Diameter	Cap Height	Min. Lead Length	Lead Pitch	Leads
5.45 mm	4.7 mm	2.35 mm	12.7 mm	2.54 mm	3

 

 

Properties of a Typical TO-52 Package

Base Diameter	Cap Diameter	Cap Height	Lead Length	Lead Pitch	Leads
5.6 mm	4.7 mm	3.4 mm	12.7 mm	2.54 mm	3

   

 

Properties of a Typical 4-lead TO-72 Package

Base Diameter	Cap Diameter	Cap Height	Min. Lead Length	Lead Pitch	Leeds
5.55 mm	4.73 mm	4.83 mm	12.7 mm	2.54 mm	4

 

Also see

1. Transistors
2. Transistor and IC packages

Sources

1. http://eesemi.com/to46.htm
2. http://eesemi.com/to18.htm
3. http://eesemi.com/to5.htm
4. http://eesemi.com/to52.htm
5. http://eesemi.com/to72.htm
6. https://www.wikiwand.com/en/Electronic_packaging
7. https://www.wikiwand.com/en/Transistor