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. The team of design, production, and applications engineers received RCA Electronic Components achievement awards in 1965. The 2N3054 and 2N3055 were derived from the 2N1486 and 2N1490 after package redesigns by Milt Grimes. 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. Modern successors to the 2N3055 can be much more suitable in fast-switching circuits or high-end audio power amplifiers. 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 2N3055 datasheets often, but not always, specify f T of 2.5 MHz (minimum) because some improvements have been made over time (especially the move to the epitaxial manufacturing process). 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 f T of 2.5 MHz (and 4 MHz for their MJ2955). in 1973 Philips gave f T > 0.8 MHz and f hfe > 15 kHz for their 2N3055 device). Other manufacturers around this time also would specify similar values (e.g.
2N3055 TRANSISTOR MANUAL
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, f T, of at least 800 kHz was specified (at I C = 1 A) and f hfe (the frequency at which the small-signal current gain drops by 3 dB) was also specified at 1 A to be 10 kHz minimum. A mica insulator electrically isolates the transistor case from the heatsink. 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.ĢN3055 transistor mounted on an aluminum heat sink. 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 total power dissipation (written P D in most American datasheets, P tot in European ones) depends on the heatsink to which the 2N3055 is connected. Manufacturers rarely specify the V CES voltage rating for the 2N3055. Sometimes the 100 V CBO 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. 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, V CER, and the Collector-Emitter Sustaining voltage, V CEO(sus), is given by ON Semiconductor. The frequency at which gain begins to drop off may be much lower, see below.ĢN3055 transistor internals. 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. 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 ). The exact performance characteristics depend on the manufacturer and date before the move to the epitaxial base version in the mid-1970s the f T could be as low as 0.8 MHz, for example.
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