Here are the specifications of the BJT 2N2222 transistor, it is a low-power, general purpose silicon transistor. In the 60’s it was a very famous semiconductor triode, standing out among others for its rather high power efficiency and ability to operate at high speeds. Nowadays it is mainly used in switching circuits, linear dc supplies and for amplification of low frequency signals. Manufactured by epitaxial-planar technology. The crystal is made of silicon and has NPN structure.
The pinout of the 2N2222 in the TO-18 is shown in the figure below. The pin assignment is as follows (clockwise from the small protrusion):
- emitter (E);
- base (B);
- collector (C).
You should note that the “K” pin is physically connected to the metal case.
Let’s take a closer look at the 2N2222 transistor, its specifications and features. They are true at ambient temperature (TA) of no more than +25oC. The datasheet states that the device is designed to operate at high switching speeds and provide effective amplification over a wide frequency range.
The maximum technical specifications of 2N2222 (at TA < +25oC):
- Collector-base Voltage VCBO (IE = 0) 60 V;
- Collector-emitter VCEO Voltage (IB = 0) 30 V;
- Emitter-base Voltage VEBO (IC = 0) 5 V;
- Collector Current IC8 A;
- Total Power Dissipation Ptot at T amb £ 25 °C 0.5 W;
- Storage Temperature T stg – 65 to 200 °C;
- Junction Temperature Tj 175 °C.
Exceeding the maximum parameters during operation is not allowed and can lead to failure of the device.
New devices are manufactured using lead-free technology (Lead Free) and comply with the European RoHS standard. According to the datasheet, some of them have an operating crystal temperature (TJ) of up to +200 oC.
The electrical characteristics of 2N2222 are summarized in a single table below. Their values as for the maximum are given for temperature (TA) not more than +25 oC. In a separate column the measuring conditions are shown.
DC Current Gain
The current gain (HFE) of the triode in question, like most similar electronic components from the 60’s, varies greatly and ranges from 100 to 300. Even devices of the same manufacturer may have different HFE values. Usually their HFE is found out beforehand, often with a multimeter and just before use in a project.
The complementary pair is considered to be 2N2907(TO-18). We can say that the latter has “mirror” characteristics with respect to the one in question and differs only in PNP structure. Externally they are very similar to each other and are quite often found together in differential amplification stages schemes.
The most famous equivalents of 2N2222 are:
Russian equivalents are also suitable:
- KT3117B(Б) in TO-92 package;
The developer of the 2N222222 in the TO-18 package is considered to be the American company Motorola. An employee of the company (Jack Heinichen) invented the annular structure in the manufacture of semiconductor triodes, which allowed to increase the p-n junction voltage to 100 V.
A number of products made with the new technology, including the transistor in question, were first demonstrated at the Institute of Radio Engineering (IRE) conference in March 1962 in New York. Since 1965, it was produced in a plastic package TO-92.
Motorola had it marked PN222222 and then PN2222A. The latter won great popularity, both among electronics enthusiasts and manufacturers. At that time it was as famous for the foreign industry as, for example, in the Soviet Union, the KT315. Later, along with the introduction of surface mount technology (SMD), 2N222222 appeared in SOT-23, SOT-223 packages. These transistors include: MMBT222222(Motorola), PMBT222222(Philips), FMMT222222(Zetex), etc.
Other companies are currently engaged in their production. Later modifications of the transistor in question are marked 2N2222ADCSM. They are manufactured in a sealed ceramic LCC package (for surface mounting on a board) by the British company Semelab.
Statistically, there are over a billion very similar transistors in the world with the numbers “2222” in the designation, especially in the TO-92 package. They come in a variety of designs and modifications. Newer samples are constantly appearing, which are improved and upgraded by manufacturers. At the same time, the demand for such devices is still stably high. Many modern transistors, which have numbers “2222” in their marking, are more advanced 2N2222.
The many semiconductor manufacturers are currently producing them. A list of all their Datasheet PDFs are available for download in this section.