TO-218 Component Package

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The TO-218 (Transistor Outline 218, JEDEC) component package is a small family of through-hole packages commonly used for BJTs and MOSFETs. The 3-lead variant is the most common, but mention of a 1-lead variant exists (I’ve not found any real components which use this package!).


  • TO-218-1 (1 lead variant, have not found any components in this package, only a reference to it’s dimensions)
  • TO-218-3 (3 lead variant, most common)

Similar To:

  • TO-247 (the TO-247 is considered the “upgrade” from this package)

TO-218-3 (3 Lead Variant)


  • CASE 340D-02 (On Semi)1
  • SOT-93 (On Semi)2

Pitch: 5.45mm (0.215")1

Package LxWxH: 15.20x4.90x20.35mm (max)3

Common Uses:

  • BJTs

The below figure shows the dimensions of the TO-218-3 component package:

Package dimensions of the TO-218 component package[^bib-on-semi-sot-93].

Package dimensions of the TO-218 component package2.

When housing a BJT, the pinout is usually:

  • 1: Base
  • 2: Collector
  • 3: Emitter
  • 4 (Tab): Collector

TO-218-1 (1 Lead Variant)

Fairchild Semiconductor has dimensions for a “single-lead” TO-218 package, as shown below. Curiously, I have not found any components that use this package.

Dimensions for a single-lead TO-218 component package[^bib-fairchild-to-218-single-lead].

Dimensions for a single-lead TO-218 component package4.


  1. On Semiconductor (2012, Jun 9). Final Product/Process Change Notification #16827: Package change from TO-218 to TO-247 for all Bipolar Power Transistors. Retrieved 2021-12-24, from↩︎ ↩︎

  2. On Semi (2002, Mar 1). SOT-93 (TO-218): Mechanical Case Outline. Retrieved 2021-12-25, from↩︎ ↩︎

  3. EESemi (2008). TO-218 Package. Retrieved 2021-12-24, from↩︎

  4. Fairchild (2001, Oct). TO-218 Single Lead JEDEC Style TO-218 Plastic Package. Retrieved 202-12-24, from↩︎


Geoffrey Hunter

Dude making stuff.

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