Diode Package Styles

DO-8 High Power Diode Package

Diode Package DO-8 Case style, Bolt-Mount

DO-8 Style Package Drawing
DO-8 Diode Package

The DO-8 package is a Through-Hole device, in that the threaded stud will mount through a surface, either a PWB or metal plate. Because this high power device may mount to a metal wall or surface, it's also called a Panel mount component.
The newer JEDEC term for this style package is a DO-205AA, while the older designation is the DO-8 name. The dimensions are listed on the DO-205 Outline page. The DO-8 style package is similar to a DO-9 and DO-30 package. The earlier numbers being released first.
Normally for packages of this type, terminal 2 will be connected to a metal panel, but because terminal 1 is connected via a metal cable and has a bolt hole that terminal may also be secured to a metal plate.

Case Mount. A style of package which provides a method of readily attaching one or more surfaces of the semiconductor device to a heat sink to achieve thermal management of the case temperature. In the case of a DO-8 both the threaded metal stud and the bolt-hole of the flexible lead may be connected to a heat sink.
The heat dissipater could be a heat sink or the metal wall of a chassis or panel.
This package style or mounting type is also called a Screw Mount, Stud Mount, Bolt Mount, Chassis Mount or Panel Mount package.

Editor note; for the devices listed [1N3289..] the common internal connection is to have the cathode connected to the stud, while reverse types [notated by a -R] have their anode connected to the stud. The same device in both cases, but connected in reverse. When these devices have a polarity band, the indication by a contrasting color band to denote the cathode end.
Also note that these are high-power devices allowing up to 100 amps DC for temperatures up to 134 degrees C. Of course the absolute power rating depends on the device.

Editor note; JEDEC has retired package numbers in the past. However that does not mean that you will not find a package using an older designation, it really just means that no new devices will use the old package designation. So newer products would use the DO-205 designation, mature parts would still use the D0-8 designation and parts released around the time JEDEC changed the designation might show both designations.

Example diode types;
Power Rectifier Diodes:
1N3289, 1N3291, 1N3293,
1N3294, 1N3295

Related topics:
Types of Diode cases
Diode Derating Guidelines
Diode Derating Curves
Diode Manufacturers

SD Threads:
375-24 UNF-2A

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Modified 6/13/15
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