TO-92

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TO-92 Front with Pin Numbers.svg
TO-92 front view [1]
TO-92 Back with Pin Numbers.svg
TO-92 back view [1]

The TO-92 is a widely used style of semiconductor package mainly used for transistors. The case is often made of epoxy or plastic, and offers compact size at a very low cost.

Contents

History and origin

The JEDEC TO-92 descriptor is derived from the original full name for the package: Transistor Outline Package, Case Style 92. [1] The package is also known by the designation SOT54. By 1966 the package was being used by Motorola for their 2N3904 devices among others. [2]

Construction and orientation

Size comparison of BJT transistor packages, from left to right: SOT-23, TO-92, TO-126, TO-3 Transistorer (cropped).jpg
Size comparison of BJT transistor packages, from left to right: SOT-23, TO-92, TO-126, TO-3

The case is molded around the transistor elements in two parts; the face is flat, usually bearing a machine-printed part number (some early examples had the part number printed on the top surface instead). The back is semi-circularly-shaped. A line of moulding flash from the injection-moulding process can be seen around the case.

The leads protrude from the bottom of the case. When looking at the face of the transistor, the leads are commonly configured from left-to-right as the emitter, base, and collector for 2N series (JEDEC) transistors, however, other configurations are possible, such as emitter, collector, and base commonly used for 2S series (Japanese) transistors or collector, base, and emitter for many of the BC series (Pro Electron) types.

If the face has a part name made up of only one letter and a few numbers, it can be either a Japanese or a Pro Electron part number. Thus, "C1234" would likely be a 2SC1234 device, but "C547" is usually short for "BC547".

TO-92 packages with pre-bent wires; on the left to emulate a TO-18 footprint (SO-97 in BS 3934, 10A3 in DIN 41868) To-92 footprint.jpg
TO-92 packages with pre-bent wires; on the left to emulate a TO-18 footprint (SO-97 in BS 3934, 10A3 in DIN 41868)

The leads coming out of the case are spaced 0.05" (1.27 mm) apart. It is often convenient to bend them outward to a 0.10" (2.54 mm) spacing to make more room for wiring. [3] Units with their leads pre-bent may be ordered to fit specific board layouts, depending on the application. Otherwise, the leads may be bent manually; however, care must be taken as they can break easily, as with any other device that is manually configured.

The physical dimensions of the TO-92 housing may vary slightly depending on the manufacturer, however, the 1.27mm lead spacing must be respected.

Advantages

Disadvantages

The main disadvantage of this style of case is the lack of heat sinking.

Voltage and current

Although TO-92 devices are mainly used in low-voltage / low-current (<30 V; <1 A) applications, high-voltage (600 Volt Vce) and high-current (5 A Ic) devices are available. Nominal maximum power dissipation is less than one watt (600 mW).

Variants

For diodes or integrated circuits with two connections (e.g. temperature sensors) the middle lead is either not connected or omitted entirely.

Comparison between the E-Line/Miniplast package and the TO-92 package Miniplast vs TO-92.jpg
Comparison between the E-Line/Miniplast package and the TO-92 package

In the late 1960s, Ferranti introduced a smaller package with a compatible footprint, called "E-Line". [4] [5] This package was later standardized as a British Standard (but not by JEDEC) and remained in production with Ferranti Semiconductors' successor companies (Plessey, Zetex Semiconductors, Diodes Incorporated [6] ). In East Germany the E-Line package was known as the "Miniplast" package and widely used by Kombinat Mikroelektronik Erfurt.

Standards

Standards organizationStandardDesignation for
TO-92E-Line/Miniplast
3-lead2-lead
IEC IEC 60191 [7] A68
DIN DIN 41868 [8] 10B3 [lower-alpha 1]
EIAJ / JEITA ED-7500A [9] [10] SC-43A
British Standards BS 3934 [11] SO-94 [lower-alpha 2]
Gosstandart GOST 18472—88 [12] KT-26 [lower-alpha 3] KD-129 [lower-alpha 4]
Rosstandart GOST R 57439—2017 [13]
Kombinat Mikroelektronik Erfurt TGL 200-8380 [14] L2
TGL 11811 [7] L3
TGL 26713/07 [7] F2F3F4
  1. DIN 41868 also defines variants with the leads bent to emulate the footprint of other packages: 10A3 (TO-18 footprint).
  2. BS-3934 also defines variants with the leads bent to emulate the footprint of other packages: SO-95 (TO-5 footprint), SO-96 (for flat mounting), and SO-97 (TO-18 footprint).
  3. Russian: КТ-26
  4. Russian: КД-129

Common components in a TO-92 package

Common transistors:

Other common components:

Related Research Articles

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Pro Electron or EECA is the European type designation and registration system for active components.

<span class="mw-page-title-main">TO-220</span> Power semiconductor through-hole package

The TO-220 is a style of electronic package used for high-powered, through-hole components with 0.1 inches (2.54 mm) pin spacing. The "TO" designation stands for "transistor outline". TO-220 packages have three leads. Similar packages with two, four, five or seven leads are also manufactured. A notable characteristic is a metal tab with a hole, used to mount the case to a heatsink, allowing the component to dissipate more heat than one constructed in a TO-92 case. Common TO-220-packaged components include discrete semiconductors such as transistors and silicon-controlled rectifiers, as well as integrated circuits.

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<span class="mw-page-title-main">TO-3</span> Metal can semiconductor package for power semiconductors

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<span class="mw-page-title-main">2N3904</span> Common NPN bipolar junction transistor

The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications. It is designed for low current and power, medium voltage, and can operate at moderately high speeds. It is complementary to the 2N3906 PNP transistor. Both types were registered by Motorola Semiconductor in the mid-1960s.

<span class="mw-page-title-main">2N2222</span> Common NPN bipolar junction transistor

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<span class="mw-page-title-main">2N3906</span> Common PNP bipolar junction transistor

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<span class="mw-page-title-main">BC548</span>

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<span class="mw-page-title-main">TO-18</span>

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<span class="mw-page-title-main">DO-204</span>

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<span class="mw-page-title-main">TO-5</span> Standardized metal semiconductor package

In electronics, TO-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.

<span class="mw-page-title-main">TO-126</span>

TO-126 is a type of semiconductor package for devices with three pins, such as transistors. The package is rectangular with a hole in the middle to allow for easy mounting to a board or a heat sink. On one side of the package typically a metal sheet is exposed, with the transistor die bonded to the other side of the metal sheet inside the package. This allows for an efficient heat transfer from the transistor die to an external heat sink but also implies that the metal sheet is electrically connected to the die.

<span class="mw-page-title-main">TO-66</span> Smaller variant of the TO-3 package

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<span class="mw-page-title-main">TO-8</span>

In electronics, TO-8 is a designation for a standardized metal semiconductor package. TO in TO-8 stands for "transistor outline" and refers to a series of technical drawings produced by JEDEC. The TO-8 package is noticeably larger than the more common TO-5 package. While originally designed for medium power transistors such as the 2N1483 series or the AD136, it is more commonly used for integrated circuits and sensors.

References

  1. 1 2 3 "JEDEC TO-92 package specification" (PDF). JEDEC . Archived from the original (PDF) on June 18, 2017.
  2. The semiconductor data book. Motorola. August 1966. Retrieved 2021-07-09.
  3. Bourns. "Package Mechanical Information, TO-92" (PDF). Retrieved 28 February 2016.
  4. Applications of the E-Line Plastic Encapsulated Transistor. Oldham: Ferranti Ltd. June 1969. Retrieved 2021-07-10.
  5. "E-Line – The ultimate TO-92". Quick Reference Guide (PDF). Ferranti Semiconductors. February 1983. p. E2. Retrieved 2021-07-10.
  6. "E-Line Package Information" (PDF). Diodes Incorporated. March 2017. Retrieved 2021-07-10.
  7. 1 2 3 "TGL 26713/07: Gehäuse für Halbleiterbauelemente - Bauform F" [Outline drawings for semiconductor devices; Type F](PDF) (in German). Leipzig: Verlag für Standardisierung. June 1988. Retrieved 2021-06-15.
  8. "Semiconductor Databook" (PDF). Heilbronn: AEG-Telefunken. pp. 17, 19. Retrieved 2021-08-20.
  9. "EIAJ ED-7500A Standards for the Dimensions of Semiconductor Devices" (PDF). JEITA. 1996. p. 120. Retrieved 2021-06-14.
  10. "TO-92 (SOT54)". Nexperia. 2004-11-16. Archived from the original on 2017-12-13. Retrieved 2021-07-12.
  11. "Package Outlines". Quick Reference Guide (PDF). Ferranti Semiconductors. February 1983. p. PO14. Retrieved 2021-07-10.
  12. "ГОСТ 18472—88 ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры" [GOST 18472—88 Semiconductor devices - basic dimensions](PDF) (in Russian). Rosstandart. 1988. p. 33-34,55. Retrieved 2021-06-17.
  13. "ГОСТ Р 57439—2017 ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры" [GOST R 57439—2017 Semiconductor devices - basic dimensions](PDF) (in Russian). Gosstandart. 2017. p. 41-42,68-69. Retrieved 2021-06-17.
  14. "TGL 200-8380: Halbleiterbauelemente - Halbleiterdioden Verlustleistung unter 1 Watt - Bauformen" [Semiconductor Devices - Designs for Semiconductor Diodes - Dissipation power less 1 Watt](PDF) (in German). Leipzig: Verlag für Standardisierung. 1981. Retrieved 2021-07-12.