TO-5

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Standardized metal semiconductor package

title: "TO-5" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["semiconductor-packages"] description: "Standardized metal semiconductor package" topic_path: "general/semiconductor-packages" source: "https://en.wikipedia.org/wiki/TO-5" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Standardized metal semiconductor package ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c7/SF122C_HFO.jpg" caption="Transistor in a TO-5 package with 25 mm leads."] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/b5/TO-5_Heatsinks.jpg" caption="Gear-shaped [[heat sink]]s for TO-5 packages."] ::

In electronics, TO-5 (Transistor Outline 5) is a designation for a standardized metal semiconductor package used for transistors and some integrated circuits. The TO element stands for "transistor outline" and refers to a series of technical drawings produced by JEDEC. The first commercial silicon transistors, the 2N696 and 2N697 from Fairchild Semiconductor, came in a TO-5 package.

Construction and orientation

The tab is located 45° from pin 1, which is typically the emitter. The typical TO-5 package has a base diameter of 8.9 mm, a cap diameter of 8.1 mm, a cap height of 6.3 mm. The pins are isolated from the package by individual glass-metal seals, or by a single resin potting. Sometimes one pin is connected directly to the metal case.

Variants

Several variants of the original TO-5 package have the same cap dimensions but differ in the number and length of the leads (wires). Somewhat incorrectly, TO-5 and TO-39 are often used in manufacturer's literature as synonyms for any package with the cap dimensions of TO-5, regardless of the number of leads, or even for any package with the diameter of TO-5, regardless of the cap height and the number of leads. Compared to TO-5, for the other variants (except TO-33 and TO-42) the minimum length of the leads was shortened from 38.1 mm to 12.7 mm which is sufficient for through-hole technology and leads to a cost reduction, whereas the longer leads were needed for point-to-point construction. Lead lengths of 25.4 mm and 19.05 mm are quite common but were not standardized separately by JEDEC. There are variants with between 2 and 12 leads. The leads are arranged in a circle with a diameter of 5.08 mm (except TO-96, TO-97, TO-100, TO-101). Before the introduction of dual in-line packages in 1965, integrated circuits were packaged mostly in metal can packages such as the TO-5 variants with more than 3 leads.

{{anchor|TO-39|TO-9|TO-16|TO-42}}TO-39 / TO-9 / TO-16 / TO-42

The TO-39, TO-9, and TO-16 packages have 3 leads and differ in the shortened leads mentioned above from TO-5. Additionally, the TO-9 and TO-16 packages do not have a tab. The TO-42 package is almost identical to the TO-5 package (including the long leads) but has four stand-offs at the bottom of the base that keep the base about 0.5 mm above the circuit board. Possibly the TO-16 and TO-42 designations were not actually used.

{{anchor|TO-12|TO-33}}TO-12 / TO-33

::figure[src="https://upload.wikimedia.org/wikipedia/commons/7/72/Perkin_Elmer_VTL2C1_cm.jpg" caption="[[Resistive opto-isolator]] VTL2C1 in a TO-33 package"] ::

The TO-12 and TO-33 packages have 4 leads. TO-33 has 38.1 mm leads like TO-5 while TO-12 has 12.7 mm leads. For transistors, the fourth wire is typically connected to the metal case as a means of electromagnetic shielding for radio frequency applications.

TO-75

The TO-75 package has 6 leads (at most one of those may be omitted). The minimum angle between two adjacent leads is 60°.

{{anchor|TO-76|TO-77}}TO-76 / TO-77

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c8/Tesla_MAA723.jpg" caption="Tesla]] MAA723) in a TO-76 package."] ::

The TO-76 and TO-77 packages have 8 leads (up to three of those may be omitted). The minimum angle between two adjacent leads is 45°. The TO-77 package differs from the TO-76 package only in that the bottom of a TO-77 package can sit directly on a circuit board whereas the TO-76 package requires a distance of up to 1.02 mm between circuit board and package.

{{anchor|TO-78|TO-79|TO-80|TO-99}}TO-78 / TO-79 / TO-80 / TO-99

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/bb/Tesla_MAC198.jpg" caption="Tesla]] MAC198) in a reduced-height TO-99 package."] ::

The TO-78, TO-79, TO-80, and TO-99 packages have 8 leads (up to three of those may be omitted). The minimum angle between two adjacent leads is 45°. These packages differ from other variants in the height of the cap. Instead of 6.3 mm the cap height is only 4.45 mm for TO-78 / TO-99, 3.81 mm for TO-79, and 2.41 mm for TO-80. The TO-78 package differs from the TO-99 package only in that the bottom of a TO-78 package can sit directly on a circuit board whereas the TO-99 package requires a distance of up to 1.02 mm between circuit board and package.

TO-74

The TO-74 package has 10 leads (at most one of those may be omitted). The minimum angle between two adjacent leads is 36°.

{{anchor|TO-96|TO-97|TO-100}}TO-96 / TO-97 / TO-100

The TO-96, TO-97, and TO-100 packages have 10 leads (at most one of those may be omitted). The minimum angle between two adjacent leads is 36°. For these packages the diameter of the circle of leads is increased from 5.08 mm to 5.84 mm. This allows a slightly increased chip area in a cap of unchanged diameter. TO-96 has the standard cap height of 6.3 mm, while TO-100 and TO-97 have reduced cap heights of 4.45 mm (like TO-78) and 3.81 mm (like TO-79), respectively.

TO-73

The TO-73 package has 12 leads (at most one of those may be omitted). The minimum angle between two adjacent leads is 30°.

TO-101

The TO-101 package has 12 leads (at most one of those may be omitted). The minimum angle between two adjacent leads is 30°. For this package the diameter of the circle of leads is increased from 5.08 mm to 5.84 mm. This allows a slightly increased chip area in a cap of unchanged diameter. TO-101 has a reduced cap height of 4.45 mm (like TO-78).

TO-205

::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/25/NatSemi_LH0070.jpg" caption="Voltage reference integrated circuit ([[National Semiconductor]] LH0070) in a TO-205-AF package"] ::

TO-205 is intended to replace previous definitions of packages with leads arranged in a circle with a diameter of 5.08 mm. The different outlines are now defined as variants of TO-205: TO-5 is renamed to TO-205-AA, TO-12 to TO-205-AB, TO-33 to TO-205-AC, TO-39 to TO-205-AD. A new package with 3 leads and a cap height of 4.32 mm (similar to TO-78 / TO-99) is added as TO-205-AF.

National Standards

::data[format=table]

Standards organizationStandardDesignation forTO-5TO-12TO-33TO-39TO-77
JEDECJEP95TO-205-AATO-205-ABTO-205-ACTO-205-AD—
IECIEC 60191C4/B4AC4/B6CC4/B6AC4/B4CC4/B7C
DINDIN 418735A35C45A45C35C8
EIAJ / JEITAED-7500ATC5/TB-5ATC5/TB-14CTC5/TB-14ATC5/TB-5CTC5/TB-15C
British StandardsBS 3934SO-3/SB3-3ASO-3/SB4-1BSO-3/SB4-1ASO-3/SB3-3BSO-3/SB8-1B
GosstandartGOST 18472—88—KT-2-12—KT-2-7—
RosstandartGOST R 57439
Kombinat Mikroelektronik Erfurturl=https://www.bbr-server.de/bauarchivddr/archiv/tglarchiv/tgl20001bis30000/tgl26501bis27000/tgl-26713-7-jun-1988.pdftitle=TGL 26713/07: Gehäuse für Halbleiterbauelemente - Bauform Fpublisher=Verlag für Standardisierungplace=Leipzigdate=June 1988language=deaccessdate=2021-06-15}}
TGL 26713/07———F1BC3—
::

References

References

  1. "Fairchild 2N697". Transistor Museum.
  2. (August 1999). "Metal Can Packages". National Semiconductor / Texas Instruments.
  3. "1965: Package is the first to accommodate system design considerations". Computer History Museum.
  4. "TO-39". JEDEC.
  5. "TO-9". JEDEC.
  6. "TO-42". JEDEC.
  7. "TO-12". JEDEC.
  8. "TO-33". JEDEC.
  9. "TO-75". JEDEC.
  10. "TO-76". JEDEC.
  11. "TO-77". JEDEC.
  12. "TO-78". JEDEC.
  13. "TO-79". JEDEC.
  14. "TO-80". JEDEC.
  15. "TO-99". JEDEC.
  16. "TO-74". JEDEC.
  17. "TO-96". JEDEC.
  18. "TO-97". JEDEC.
  19. "TO-100". JEDEC.
  20. "TO-73". JEDEC.
  21. "TO-101". JEDEC.
  22. (October 2010). "JEDEC Publication No. 95". JEDEC.
  23. (November 1982). "JEDEC Publication No. 95". JEDEC.
  24. (1978). "Semiconductors". [[Pro Electron]].
  25. "Semiconductor Databook". AEG-Telefunken.
  26. (1996). "EIAJ ED-7500A Standards for the Dimensions of Semiconductor Devices". JEITA.
  27. (1968). "Semiconductor and Photoelectric Devices". Mullard.
  28. (1988). "ГОСТ 18472—88 ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры". Rosstandart.
  29. (2017). "ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры". Rosstandart.
  30. (June 1988). "TGL 26713/07: Gehäuse für Halbleiterbauelemente - Bauform F". Verlag für Standardisierung.
  31. "JEDEC TO-5 package specification".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

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