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. [1] Its numbering follows the JEDEC standard. [2] It is a transistor type of enduring popularity. [3] [4] [5]
The exact performance characteristics depend on the manufacturer and date; before the move to the epitaxial base version in the mid-1970s the fT could be as low as 0.8 MHz, for example.
| manufacturer | Date | VCEO | VCBO | VCER (100 ohms) | IC | IB | PD @ TC=25 deg. | hfe (pulsed test) | fT |
|---|---|---|---|---|---|---|---|---|---|
| RCA | 1967 | 60 VCEO(sus) | 100 VCBO | 70 VCER(sus) | 15 A | 7 A | 115 W | 20–70 (at IC = 4 Apulsed) | not given |
| ON-Semiconductor | 2005 [6] | 60 VCEO | 100 VCBO | 70 VCER | 15 A (continuous) | 7 A | 115 W | 20–70 (at IC = 4 A) | 2.5 MHz |
Packaged in a TO-3 case style, it is a 15 amp, 60 volt (or more, see below), 115 watt power transistor with a β (forward current gain) of 20 to 70 at a collector current of 4 A (this may be over 100 when testing at lower currents [6] ). It often has a transition frequency of around 3.0 MHz and 6 MHz is typical for the 2N3055A; at this frequency the calculated current gain (beta) drops to 1, indicating the transistor can no longer provide useful amplification in common emitter configuration. The frequency at which gain begins to drop off may be much lower, see below.
The maximum collector-to-emitter voltage for the 2N3055, like other transistors, depends on the resistance path the external circuit provides between the base and emitter of the transistor; with 100 ohms a 70 volt breakdown rating, VCER, and the Collector-Emitter Sustaining voltage, VCEO(sus), is given by ON Semiconductor. [6] Sometimes the 100 VCBO breakdown voltage (the maximum voltage between collector and base, with the emitter open, an unrealistic arrangement in practical circuits) is given as the only voltage rating, which can cause confusion. Manufacturers rarely specify the VCES voltage rating for the 2N3055.
The total power dissipation (written PD in most American datasheets, Ptot in European ones) depends on the heatsink to which the 2N3055 is connected. With an "infinite" heatsink, that is: when the case temperature is certain to be 25 degrees, the power rating is about 115 W (some manufacturers specify 117 W), but most applications (and certainly when the ambient temperature is high) a significantly lower power rating would be expected, as per the manufacturer's power derating curve. The device is designed to operate with an efficient heatsink, but care must be taken to mount the device properly, [7] [8] [9] else physical damage or worsened power handling may result, especially with cases or heatsinks that are not perfectly flat.
The 1967 RCA Transistor Manual, SC-13, did not mention any measure of high frequency performance for the 2N3055; by the 1971 SC-15 manual a transition frequency, fT, of at least 800 kHz was specified (at IC = 1 A) and fhfe (the frequency at which the small-signal current gain drops by 3 dB) was also specified at 1 A to be 10 kHz minimum. Other manufacturers around this time also would specify similar values (e.g. in 1973 Philips gave fT > 0.8 MHz and fhfe > 15 kHz for their 2N3055 device).
RCA by 1977 had changed their specification to give 2.5 for the minimum magnitude of the small-signal gain at f = 1 MHz, essentially giving a minimum fT of 2.5 MHz (and 4 MHz for their MJ2955). Modern 2N3055 datasheets often, but not always, specify fT of 2.5 MHz (minimum) because some improvements have been made over time (especially the move to the epitaxial manufacturing process). Nevertheless, a 2N3055 (and many other power transistors originating from this era) cannot be assumed to have great high-frequency performance and there can be degradation of phase-shift and open-loop gain even within the audio frequency range. Modern successors to the 2N3055 can be much more suitable in fast-switching circuits or high-end audio power amplifiers.
The historically-significant 2N3055 was designed by Herb Meisel's engineering group with RCA; it was the first multi-amp silicon power transistor to sell for less than one dollar, and became an industry workhorse standard. [10] The 2N3054 and 2N3055 were derived from the 2N1486 and 2N1490 after package redesigns by Milt Grimes. The team of design, production, and applications engineers received RCA Electronic Components achievement awards in 1965. The 2N3055 remains very popular as a series pass transistor in linear power supplies and is still used in for medium-current and high-power circuits generally, including low frequency power converters although its use in audio power amplifiers and DC-to-AC inverters is now less common and its use in higher frequency switch-mode applications never was very practical. It was second sourced by other manufacturers; Texas Instruments listed a single-diffused mesa version of the device in an August 1967 datasheet. [11] One limitation was that its frequency response was rather low (typically the unity-gain frequency or transition frequency, fT, was 1 MHz). Although this was adequate for most of the low-frequency "workhorse" applications, and par with other high power transistors around 1970, it did bring some difficulty to high fidelity power amplifier designs around 20 kHz, as the gain begins to fall and phase shift increases.
With changes to semiconductor manufacturing technology, the original process became economically uncompetitive in the mid-1970s, and a similar device was created using epitaxial base technology. [1] The maximum voltage and current ratings of this device are the same as the original, but it is not as immune from secondary breakdown; the power handling (safe operating area) is limited at high voltage to a lower current than the original. [1] However, the cut-off frequency is higher, allowing the newer type of 2N3055 to be more efficient at higher frequencies. Also the higher frequency response has improved performance when used in audio amplifiers. [1]
Although the original 2N3055 went into decline relative to epitaxial-base transistors because of high manufacturing costs, the epitaxial-base version continued to be used in both linear amplifiers and switching supplies. [1] Several versions of the 2N3055 remain in production; it is used in audio power amplifiers delivering up to 40 W into an 8 ohm load [12] in a push–pull output configuration.
 | This section needs additional citations for verification .(August 2020) |
Variants with higher voltage ratings (e.g. 2N3055HV, with a 100 Vceo rating), different case material or type (e.g. steel, aluminium, or plastic with metal tab), and other variations exist, in addition to the minor variations in ratings (such as a power dissipation of 115 or 117 Watts) between 2N3055-marked devices from various manufacturers since RCA's original.
An MJ2955 (PNP) (not to be confused with a 2N2955 which is a small signal PNP transistor [13] )), which is also manufactured using the epitaxial process today, is a complementary transistor to the 2N3055.
In the sixties and early seventies, Philips produced similar devices encapsulated in TO-3 packages under the reference BDY20 (described as being for "hifi" purposes) and BDY38 (although the BDY38 has lower voltage ratings than the 2N3055).
A TO-3 P (plastic case) version of the 2N3055 and its complementary device MJ2955 are available as the TIP3055 and TIP2955 respectively, with slightly reduced power dissipation ratings.
The 10 amp (15 amp peak), 80 watt TIP33 (NPN) and TIP34 (PNP) are plastic-cased transistors with somewhat similar characteristics to the 2N3055 and MJ2955 respectively, and available in variants with 40/60/80/100 Vceo breakdown voltage ratings.
The 2N3773, with a TO-3 case has slightly lower gain but significantly higher maximum ratings (150 W, 140 Vceo, 16 amps).
The 2N3054 is a much lower power version of the 2N3055, rated at 25 W, 55 V and 4 A, but became almost obsolete about the late 1980s when many TO-66 devices were withdrawn from mainstream manufacturers's lists. In many cases a TO-220 packaged version, such as MJE3055T, can be used instead of the 2N3054 as well as in some 2N3055 applications.
KD503 is a higher power equivalent used in Eastern Bloc countries, and is intended for general purpose applications. It was produced exclusively by the Czechoslovakian electronics company Tesla. KD503 are packaged in a TO-3 case style (called T41 by Tesla), it is a 20 amp, 80 volt, 150 watt power transistor. It has a transition frequency of 2.0 MHz;. The KD503 have higher power and higher current than 2N3055. [14] They were used extensively in the former Eastern Bloc countries in audio power amplifiers made by Czechoslovakian Tesla, Polish Unitra.
| device | manufacturer | type | case/package | Vceo(BR) | Ic (continuous) | PD(@ case=25 deg) | hfe | fT (MHz) |
|---|---|---|---|---|---|---|---|---|
| 2N3055 | RCA 1977 [15] ON Semiconductor 2005 | NPN | TO-3 (=TO-204AA) | 60 VCEO(sus) | 15 A | 115 W | 20–70 at 4 A | 2.5 MHz min (hfe at 1 MHz) fhfe >= 20 kHz @ 1 A |
| 2N3055G | ON Semiconductor 2005 | NPN | TO-3 (Lead-free) | 60 VCEO(sus) | 15 A | 115 W | 20–70 at 4 A | 2.5 MHz min (hfe at 1 MHz) fhfe >= 20 kHz @ 1 A |
| 2N3055H | RCA | NPN | TO-3 | 60VCEO(sus) | 15 A | 115 W | 20–70 at 4 A | 2.5 MHz min (hfe at 1 MHz) |
| 2N3055HV | CDIL | NPN | TO-3 | 100 V | 15 A | 100 W (some say 90 W) | 20–100 at 4 A | 2.5 MHz min @0.5 A |
| 2N3772 | RCA | NPN | TO-3 | 60 V | 20 A | 150 W | 16–60 at 10 A | 0.2 MHz min (hfe >=4 at 0.05 MHz) fhfe >= 10 kHz @ 1 A |
| 2N3773 | RCA | NPN | TO-3 | 140V | 16 A | 150 W | 16–60 at 8 A | 0.2 MHz min (hfe >=4 at 0.05 MHz) fhfe >= 10 kHz @ 1 A |
| 2N6253 | RCA | NPN | TO-3 | 45 VCEO(sus) | 15 A | 115 W | 20–70 at 3 A | 0.8 MHz min (hfe >=2 at 0.4 MHz) fhfe >= 10 kHz @ 1 A |
| 2N6254 | RCA | NPN | TO-3 | 80VCEO(sus) | 15 A | 150 W | 20–70 at 5 A | 0.8 MHz min (hfe >=2 at 0.4 MHz) fhfe >= 10 kHz @ 1 A |
| 2N6371 | RCA | NPN | TO-3 | 40VCEO(sus) | 15 A | 117 W | 15–60 at 8 A | 0.8 MHz min (hfe >=2 at 0.4 MHz) fhfe >= 10 kHz @ 1 A |
| 2N6371HV | Transys | NPN | TO-3 | 100 V | 15 A | 117 W | 15–60 at 8 A | 2.5 MHz min |
| BDP620 | UNITRA CEMI | NPN | TO-3 | 60 V | 15 A | 115 W | 20–40 at 4 A | 0,8 MHz min |
| KD502 | Tesla | NPN | T41 case | 60 V | 20 A | 150 W | 40-? @ 1 A | 2.0 MHz min |
| KD503 | Tesla [16] | NPN | T41 case | 80 V | 20 A | 150 W | 40-? @ 1 A | 2.0 MHz min |
| KD3055 | Tesla | NPN | T42 case | 60 V | 15 A | 117 W | 20–70 @ 4 A | 1.0 MHz min |
| KD3442 | Tesla | NPN | T42 case | 140 V | 10 A | 117 W | 20–70 @ 4 A | 1.0 MHz min |
| MJ2955A | Motorola | PNP | TO-3 | 60 V | 15 A | 115 W | 20–100 at 4 A | 2.2 MHz min @ 1 A |
| MJ15015G | ON Semiconductor | NPN | TO-3 | 120 V | 15 A | 180 W | 20–100 at 4 A | 0.8 MHz min @ 1 A |
| MJ15016G | On Semiconductor | PNP | TO-3 | 120 V | 15 A | 180 W | 20–100 at 4 A | 2.2 MHz min @ 1 A |
| MJE2955T | Fairchild, Central Semiconductor Corp. | PNP | TO-220 | 60VCEO(sus) | 10 A | 75 W | 20–100 at 4 A | 2.0 MHz min (hfe at 1 MHz) fhfe >= 20 kHz @ 1 A |
| MJE3055T | Fairchild, Central Semiconductor Corp. | NPN | TO-220 | 60 VCEO(sus) | 10 A | 75 W | 20–100 at 4 A | 2.0 MHz min (hfe at 1 MHz) fhfe >= 20 kHz @ 1 A |
| RCS617 | RCA | NPN | TO-3 | 80 VCEO(sus) | 15 A | 115 W | 20–70 at 4 A | 2.5 MHz min (hfe at 1 MHz) |
| TIP2955 | Texas Instr, Central Semiconductor Corp | PNP | TO-218AA/SOT-93 | 70 VCER(RBE <= 100 Ohms) | 15 A | 90 W | 20–70 at 4 A | 3.0 MHz min |
| TIP2955 | Motorola | PNP | 340D-02 plastic | 60 VCEO 70VCER(RBE = 100 Ohms) | 15 A | 90 W | 20–70 at 4 A | 2.5 MHz min |
| TIP3055 | Texas Instr, Philips, Central Semiconductor Corp | NPN | TO-218AA/SOT-93 | 70 VCER(RBE <= 100 Ohms) | 15 A | 90 W | 20–70 at 4 A | 3.0 MHz min |
| TIP3055 | Motorola | NPN | 340D-02 plastic | 60VCEO 70VCER(RBE = 100 Ohms) | 15 A | 90 W | 20–70 at 4 A | 2.5 MHz min |
A transistor is a semiconductor device used to amplify or switch electrical signals and power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits.
A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipolar transistor allows a small current injected at one of its terminals to control a much larger current flowing between the terminals, making the device capable of amplification or switching.
In electronics, a multi-transistor configuration called the Darlington configuration is a circuit consisting of two bipolar transistors with the emitter of one transistor connected to the base of the other, such that the current amplified by the first transistor is amplified further by the second one. The collectors of both transistors are connected together. This configuration has a much higher current gain than each transistor taken separately. It acts like and is often packaged as a single transistor. It was invented in 1953 by Sidney Darlington.
The Schottky diode, also known as Schottky barrier diode or hot-carrier diode, is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. The cat's-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes.
A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by solid state amplifiers in the 1960s and 1970s. Valve amplifiers can be used for applications such as guitar amplifiers, satellite transponders such as DirecTV and GPS, high quality stereo amplifiers, military applications and very high power radio and UHF television transmitters.
A TRIAC is a three terminal electronic component that conducts current in either direction when triggered. The term TRIAC is a genericised trademark.
A power semiconductor device is a semiconductor device used as a switch or rectifier in power electronics. Such a device is also called a power device or, when used in an integrated circuit, a power IC.
IC power-supply pins denote a voltage and current supply terminals in electric, electronics engineering, and in Integrated circuit design. Integrated circuits (ICs) have at least two pins that connect to the power rails of the circuit in which they are installed. These are known as the power-supply pins. However, the labeling of the pins varies by IC family and manufacturer. The double subscript notation usually corresponds to a first letter in a given IC family (transistors) notation of the terminals.
A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IGBT) or a thyristor, its main advantages are high switching speed and good efficiency at low voltages. It shares with the IGBT an isolated gate that makes it easy to drive. They can be subject to low gain, sometimes to a degree that the gate voltage needs to be higher than the voltage under control.
Crossover distortion is a type of distortion which is caused by switching between devices driving a load. It is most commonly seen in complementary, or "push-pull", Class-B amplifier stages, although it is occasionally seen in other types of circuits as well.
In electronics, the Sziklai pair, also known as a complementary feedback pair, is a configuration of two bipolar transistors, similar to a Darlington pair. In contrast to the Darlington arrangement, the Sziklai pair has one NPN and one PNP transistor, and so it is sometimes also called the "complementary Darlington". The configuration is named for George C. Sziklai, thought to be its inventor.
Texas Instruments Power, known more popularly by its acronym TIP, is a series of bipolar junction transistors manufactured by Texas Instruments. The series was introduced in the 1960s, and still sees some use today due to their simplicity, their durability, and their ease of use. A Texas Instruments catalog in 1966 lists the TIP04 and TIP14 part numbers.
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.
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.
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.
The 2N2907 is a commonly available PNP bipolar junction transistor 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. This transistor was made by several manufacturers; Texas Instruments released a data sheet for their version of this part dated March 1973. An "A" suffix indicates a slightly higher breakdown voltage. These transistors have an enduring popularity with electronics hobbyists.
The 2N3906 is a commonly used PNP bipolar junction transistor intended for general purpose low-power amplifying or switching applications. It is designed for low electric current and power and medium voltage, and can operate at moderately high speeds. It is complementary to the 2N3904 NPN transistor. Both types were registered by Motorola Semiconductor in the mid-1960s.
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.
The BC107, BC108 and BC109 are general-purpose low power silicon NPN bipolar junction transistors found very often in equipment and electronics books/articles from Europe, Australia and many other countries from the 1960s. They were created by Philips and Mullard in 1963 and introduced in April 1966. Initially in metal (TO-18) packages, the range expanded over time to include other package types, higher voltage ratings, and a better selection of gain groupings, as well as complementary PNP types. Some manufacturers have specified their parts with a higher power dissipation rating (Ptot) than others.
The diamond buffer or diamond follower is a four-transistor, two-stage, push-pull, translinear emitter follower, or less commonly source follower, in which the input transistors are folded, or placed upside-down with respect to the output transistors. Like any unity buffer, the diamond buffer does not alter the phase and magnitude of input voltage signal; its primary purpose is to interface a high-impedance voltage source with a low-impedance, high-current load. Unlike the more common compound emitter follower, where each input transistor drives the output transistor of the same polarity, each input transistor of a diamond buffer drives the output transistor of the opposite polarity. When the transistors operate in close thermal contact, the input transistors stabilize the idle current of the output pair, eliminating the need for a bias spreader.
the ever-popular 2N3055
For high-power jobs, the NPN transistor that's almost universally used is the 2N3055
The 2N2222, 2N2905, and 2N3055 devices, for example, which date back to the 1960s but have been improved, are still useful in new designs and are still popular for experimenters.
