TO-3

Last updated
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

In electronics, TO-3 is a designation for a standardized metal semiconductor package used for power semiconductors, including transistors, silicon controlled rectifiers, and, integrated circuits. TO stands for "Transistor Outline" and relates to a series of technical drawings produced by JEDEC. [1]

Contents

The TO-3 case has a flat surface which can be attached to a heatsink, normally via a thermally conductive but electrically insulating washer. The design originated at Motorola around 1955 from a group headed by Dr. Virgil E. Bottom. [2] who was director of research of the Motorola Semiconductor Division. The first use of this design was for the germanium alloy-junction power transistor 2N176 – the first power transistor to be put into quantity production. [2] [3] The lead spacing was originally intended to allow plugging the device into a then-common tube socket. [4]

Typical applications

Typical TO-3 mounting profile, with insulator from chassis TO-3 mounting.png
Typical TO-3 mounting profile, with insulator from chassis

The metal package can be attached to a heat sink, making it suitable for devices dissipating several watts of heat. Thermal compound is used to improve heat transfer between the device case and the heat sink. Since the device case is one of the electrical connections, an insulator may be required to electrically isolate the component from the heatsink. Insulating washers may be made of mica or other materials with good thermal conductivity.

The case is used with high-power and high-current devices, on the order of a few tens of amperes current and up to a hundred watts of heat dissipation. The case surfaces are metal for good heat conductivity and durability. The metal-to-metal and metal-to-glass joints provide hermetic seals that protect the semiconductor from liquids and gases.

Compared with equivalent plastic packages, the TO-3 is more costly. The spacing and dimensions of the case leads make it unsuitable for higher frequency (radio frequency) devices.

Construction

Inside of an MJ1000 Darlington transistor in TO-3 package Darlington transistor MJ1000.jpg
Inside of an MJ1000 Darlington transistor in TO-3 package

The semiconductor die component is mounted on a raised platform on a metal plate, with the metal can welded on top of it; providing high heat conductivity and durability. The metal case is connected to the internal device and the leads are connected to the die with bonding wires.

The TO-3 package consists of a diamond-shaped base plate with diagonals of 40.13 mm (1.580 in) and 27.17 mm (1.070 in). The plate has two mounting holes on the long diagonal, with the centers spaced 30.15 mm (1.187 in) apart. [5] The cap attached to one side of the plate brings the total height to up to 11.43 mm (0.450 in). Two pins on the other side of the plate are isolated from the package by individual glass-metal seals. The metal case forms the third connection (in the case of a bipolar junction transistor this is typically the collector).

Variants

Power amplifier integrated circuit (CEMI UL1403) in a TO-3 package variant Wzmacniacze.jpg
Power amplifier integrated circuit (CEMI UL1403) in a TO-3 package variant

TO-3 package variants for integrated circuits can have more than two leads. The height of the cap and the thickness of the leads differs between variants of the TO-3 package.

TO-41

AD133 transistor in a TO-41 package. The third pin connected to the case AD133.jpg
AD133 transistor in a TO-41 package. The third pin connected to the case

The two pins of the TO-41 package end in soldering pads with holes in them to make it easier to solder wires to the pins for point-to-point construction (as opposed to soldering a TO-3 package on a printed circuit board). Otherwise the TO-41 package has the same dimensions as the TO-3 package. [6] Some variants of the TO-41 package have a third pin with a soldering pad connected to the case (e.g. AD133, [7] :64 AUY21 [7] :69). This 3-pin package was standardized by IEC as C14B/B28. [7] :215

TO-204

TO-204 is intended to replace previous definitions of flange-mounted packages with a 10.92 mm (0.430 in) pin spacing. [8] [9] The different outlines are now defined as variants of TO-204: TO-3 is renamed to TO-204-AA, TO-41 to TO-204-AB. A new package with a reduced maximum height of 7.62 mm (0.300 in) is added as TO-204-AC. Two additional variants specify pins thicker than the original 1.02 mm (0.040 in) to allow higher currents: 1.27 mm (0.050 in) for TO-204-AD and 1.52 mm (0.060 in) for TO-204-AE.

National standards

Standards organizationStandardDesignation for
TO-3TO-41
JEDEC JEP95 [9] TO-204-AATO-204-ABTO-204-ACTO-204-AD
IEC IEC 60191 [lower-alpha 1] [7] :215C14A/B18C14B/B18
DIN DIN 41872 [10] [11] 3A23B2 [lower-alpha 2]
EIAJ / JEITA ED-7500A [lower-alpha 1] [12] TC-3/TB-3TC-3A/TB-3 [lower-alpha 2]
British Standards BS 3934 [lower-alpha 1] [13] [14] SO-5A/SB2-2SO-5B/SB2-2 [lower-alpha 2]
Gosstandart GOST 18472—88 [15] KT-9 [lower-alpha 3] KT-9B
Rosstandart GOST R 57439 [16] KT-9C
Kombinat Mikroelektronik Erfurt TGL 11811 [17] EebEea
TGL 26713/11 [17] L2A2L2A1
  1. 1 2 3 These standards have separate drawings for the package case and the base.
  2. 1 2 3 The maximum height is 8.63 mm (0.340 in).
  3. Russian: КТ-9

Common components in a TO-3 package

Common voltage regulator integrated circuits:

Common transistors:

See also

Related Research Articles

<span class="mw-page-title-main">Dual in-line package</span> Type of electronic component package

In microelectronics, a dual in-line package is an electronic component package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board (PCB) or inserted in a socket. The dual-inline format was invented by Don Forbes, Rex Rice and Bryant Rogers at Fairchild R&D in 1964, when the restricted number of leads available on circular transistor-style packages became a limitation in the use of integrated circuits. Increasingly complex circuits required more signal and power supply leads ; eventually microprocessors and similar complex devices required more leads than could be put on a DIP package, leading to development of higher-density chip carriers. Furthermore, square and rectangular packages made it easier to route printed-circuit traces beneath the packages.

<span class="mw-page-title-main">7400-series integrated circuits</span> Series of transistor–transistor logic integrated circuits

The 7400 series is a popular logic family of transistor–transistor logic (TTL) integrated circuits (ICs).

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

<span class="mw-page-title-main">Small outline integrated circuit</span> Surface mount variant of DIP

A small outline integrated circuit (SOIC) is a surface-mounted integrated circuit (IC) package which occupies an area about 30–50% less than an equivalent dual in-line package (DIP), with a typical thickness being 70% less. They are generally available in the same pin-outs as their counterpart DIP ICs. The convention for naming the package is SOIC or SO followed by the number of pins. For example, a 14-pin 4011 would be housed in an SOIC-14 or SO-14 package.

<span class="mw-page-title-main">TO-92</span> Small and cheap semiconductor package often used for transistors

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.

<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.

<span class="mw-page-title-main">2N3055</span> Early power transistor

The 2N3055 is a silicon NPN power transistor intended for general purpose applications. It was introduced in the early 1960s by RCA using a hometaxial power transistor process, transitioned to an epitaxial base in the mid-1970s. Its numbering follows the JEDEC standard. It is a transistor type of enduring popularity.

Open collector, open drain, open emitter, and open source refer to integrated circuit (IC) output pin configurations that process the IC's internal function through a transistor with an exposed terminal that is internally unconnected. One of the IC's internal high or low voltage rails typically connects to another terminal of that transistor. When the transistor is off, the output is internally disconnected from any internal power rail, a state called "high-impedance" (Hi-Z). Open outputs configurations thus differ from push–pull outputs, which use a pair of transistors to output a specific voltage or current.

<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

The 2N2222 is a common NPN bipolar junction transistor (BJT) used for general purpose low-power amplifying or switching applications. It is designed for low to medium current, low power, medium voltage, and can operate at moderately high speeds. It was originally made in the TO-18 metal can as shown in the picture.

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

The BC548 is a general-purpose NPN bipolar junction transistor commonly used in European and American electronic equipment. It is notably often the first type of bipolar transistor hobbyists encounter and is often featured in designs in hobby electronics magazines where a general-purpose transistor is required. The BC548 is low in cost and widely available.

A semiconductor package is a metal, plastic, glass, or ceramic casing containing one or more discrete semiconductor devices or integrated circuits. Individual components are fabricated on semiconductor wafers before being diced into die, tested, and packaged. The package provides a means for connecting it to the external environment, such as printed circuit board, via leads such as lands, balls, or pins; and protection against threats such as mechanical impact, chemical contamination, and light exposure. Additionally, it helps dissipate heat produced by the device, with or without the aid of a heat spreader. There are thousands of package types in use. Some are defined by international, national, or industry standards, while others are particular to an individual manufacturer.

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

In electronics, TO-18 is a designation for a style of transistor metal case. The case is more expensive than the similarly sized plastic TO-92 package. The name is from JEDEC, signifying Transistor Outline Package, Case Style 18.

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

DO-204 is a family of diode semiconductor packages defined by JEDEC. This family comprises lead-mounted axial devices with round leads. Generally a diode will have a line painted near the cathode end.

<span class="mw-page-title-main">Chip carrier</span> Surface mount technology package for integrated circuits

In electronics, a chip carrier is one of several kinds of surface-mount technology packages for integrated circuits. Connections are made on all four edges of a square package; compared to the internal cavity for mounting the integrated circuit, the package overall size is large.

<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

TO-66 is a type of semiconductor package for devices with three connections, such as transistors. The shape is similar to the TO-3 package, but the size is smaller. The TO-66 package is made entirely of metal and is commonly used by silicon controlled rectifiers and power transistors. In Europe, it was popularly used by the complementary germanium power transistors AD161/AD162.

<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. "JEDEC TO-3 package specification" (PDF). JEDEC . Archived from the original (PDF) on June 18, 2017.
  2. 1 2 Bottom, Virgil (November 1992). "XIII Phoenix 1953–1958". FROM POSSUM HOLLER TO SINGAPORE The Autobiography of VIRGIL E. BOTTOM. Self published. p. 177. Archived from the original (DOC) on 2016-03-15. Retrieved 2022-08-22.
  3. Ward, Jack (2007). "Motorola 2N176". www.semiconductormuseum.com. Retrieved 2022-08-22.
  4. Greenburg, Ralph (2008). "Transistor Museum Oral History". www.semiconductormuseum.com. Retrieved 2021-07-14.
  5. Hubert Biagi. "Mounting Considerations for TO-3 Packages" (PDF). Burr-Brown. p. 3. Retrieved 2021-06-30.
  6. "TO-41" (PDF). JEDEC. Archived from the original (PDF) on 2016-04-10. Retrieved 2021-06-21.
  7. 1 2 3 4 "Semiconductors" (PDF). Pro Electron. 1978. Retrieved 2021-06-17.
  8. "Index by Device Type of Registered Transistor Outlines (TO)". JEDEC Publication No. 95 (PDF). JEDEC. October 2010. Retrieved 2021-07-13.
  9. 1 2 "Flange Mounted Header Family 0.430 Pin Spacing". JEDEC Publication No. 95 (PDF). JEDEC. November 1982. pp. 174–177. Retrieved 2021-07-13.
  10. "NPN Transistor for Powerful AF Output Stages 2N3055" (PDF). Siemens. Retrieved 2021-08-20.
  11. "Silicon NPN Power Transistor BU546" (PDF). Telefunken. Retrieved 2021-08-20.
  12. "EIAJ ED-7500A Standards for the Dimensions of Semiconductor Devices" (PDF). JEITA. 1996. Retrieved 2021-06-14.
  13. "Semiconductor and Photoelectric Devices" (PDF). Mullard. 1968. p. 539. Retrieved 2021-06-14.
  14. "Mullard Technical Handbook Book 1 Part 1" (PDF). Mullard. 1974. p. 516. Retrieved 2021-06-14.
  15. "ГОСТ 18472—88 ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры" [GOST 18472—88 Semiconductor devices - basic dimensions](PDF) (in Russian). Rosstandart. 1988. p. 42. Retrieved 2021-06-17.
  16. "ПРИБОРЫ ПОЛУПРОВОДНИКОВЫЕ - Основные размеры" [Semiconductor devices - basic dimensions](PDF) (in Russian). Rosstandart. 2017. pp. 50–52. Retrieved 2021-06-17.
  17. 1 2 "TGL 26713/11: Gehäuse für Halbleiterbauelemente - Bauform L" (PDF) (in German). Leipzig: Verlag für Standardisierung. June 1988. Retrieved 2021-06-15.
  18. Kluwers Internationale Transistor Gids (4 ed.). Kluwer Technische Boeken B.V. 1991. p. 55. ISBN   9020125192.