2N3055


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.
insulator electrically isolates the transistor case from the heatsink.|right|thumb

Specifications

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.
manufacturerDateVCEOVCBOVCER ICIBPD @ TC=25 deg.hfe fT
RCA196760 VCEO100 VCBO70 VCER15A7A115W20-70 not given
ON-Semiconductor200560 VCEO100 VCBO70 VCER15A 7A115W20-70 2.5 MHz

Packaged in a TO-3 case style, it is a 15 amp, 60 volt, 115 watt power transistor with a β of 20 to 70 at a collector current of . 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 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.

Maximum Ratings

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, is given by ON Semiconductor. Sometimes the 100 VCBO breakdown voltage 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 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, but most applications 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, else physical damage or worsened power handling may result, especially with cases or heatsinks that are not perfectly flat.

Transition Frequency, fT

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 and fhfe was also specified at 1A to be 10 kHz minimum. Other manufacturers around this time also would specify similar values.
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. Modern 2N3055 datasheets often, but not always, specify fT of 2.5 MHz because some improvements have been made over time. Nevertheless, a 2N3055 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.

History

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. 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. One limitation was that its frequency response was rather low. 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.

Mid 1970s

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. 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 is limited at high voltage to a lower current than the original. 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.
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.
Several versions of the 2N3055 remain in production; it is used in audio power amplifiers delivering up to into an load
in a push–pull output configuration.

Related devices

Variants with higher voltage ratings, different case material or type, and other variations exist, in addition to the minor variations in ratings between 2N3055-marked devices from various manufacturers since RCA's original.
An MJ2955, 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 and BDY38.
A TO-3 P 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, 80 watt TIP33 and TIP34 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.
The 2N3054 is a much lower power version of the 2N3055, rated at, and, 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, 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. They were used extensively in the former Eastern Bloc countries in audio power amplifiers made by Czechoslovakian Tesla, Polish Unitra.
devicemanufacturertypecase/packageVceoIc PD hfefT
2N3055RCA 1977
ON Semiconductor 2005		NPNTO-3 60 VCEO15 A115 W20-70 at 4 A2.5 MHz min
fhfe >= 20 kHz @ 1A
2N3055GON Semiconductor 2005NPNTO-3 60 VCEO15 A115 W20-70 at 4 A2.5 MHz min
fhfe >= 20 kHz @ 1A
2N3055HRCANPNTO-360VCEO15 A115 W20-70 at 4 A2.5 MHz min
2N3055HVCDILNPNTO-3100 V15 A100 W 20-100 at 4 A2.5 MHz min @0.5A
2N3772RCANPNTO-360 V20 A150 W16-60 at 10 A0.2 MHz min
fhfe >= 10 kHz @ 1A
2N3773RCANPNTO-3140V16 A150 W16-60 at 8 A0.2 MHz min
fhfe >= 10 kHz @ 1A
2N6253RCANPNTO-345 VCEO15 A115 W20-70 at 3A0.8 MHz min
fhfe >= 10 kHz @ 1A
2N6254RCANPNTO-380VCEO15 A150 W20-70 at 5A0.8 MHz min
fhfe >= 10 kHz @ 1A
2N6371RCANPNTO-340VCEO15 A117 W15-60 at 8A0.8 MHz min
fhfe >= 10 kHz @ 1A
2N6371HVTransysNPNTO-3100 V15 A117 W15-60 at 8 A2.5 MHz min
BDP620UNITRA CEMINPNTO-360 V15 A115 W20-40 at 4A0,8 MHz min
KD502TeslaNPNT41 case60 V20 A150 W40-? @ 1 A2.0 MHz min
KD503TeslaNPNT41 case80 V20 A150 W40-? @ 1 A2.0 MHz min
KD3055TeslaNPNT42 case60 V15 A117 W20-70 @ 4 A1.0 MHz min
KD3442TeslaNPNT42 case140 V10 A117 W20-70 @ 4 A1.0 MHz min
MJ2955AMotorolaPNPTO-360 V15 A115 W20-100 at 4 A2.2 MHz min @ 1 A
MJ15015GON SemiconductorNPNTO-3120 V15 A180 W20-100 at 4 A0.8 MHz min @ 1 A
MJ15016GOn SemiconductorPNPTO-3120 V15 A180 W20-100 at 4 A2.2 MHz min @ 1 A
MJE2955TFairchild,
Central Semiconductor Corp.		PNPTO-22060VCEO10 A75 W20-100 at 4 A2.0 MHz min
fhfe >= 20 kHz @ 1A
MJE3055TFairchild,
Central Semiconductor Corp.		NPNTO-22060 VCEO10 A75 W20-100 at 4 A2.0 MHz min
fhfe >= 20 kHz @ 1A
RCS617RCANPNTO-380 VCEO15 A115 W20-70 at 4 A2.5 MHz min
TIP2955Texas Instr,
Central Semiconductor Corp		PNPTO-218AA/SOT-9370 VCER 15 A90 W20-70 at 4 A3.0 MHz min
TIP2955MotorolaPNP340D-02 plastic60 VCEO
70VCER 		15 A90 W20-70 at 4 A2.5 MHz min
TIP3055Texas Instr,
Philips,
Central Semiconductor Corp		NPNTO-218AA/SOT-9370 VCER 15 A90 W20-70 at  4A3.0 MHz min
TIP3055MotorolaNPN340D-02 plastic60VCEO
70VCER 		15 A90 W20-70 at 4 A2.5 MHz min