Onsemi MJ15024G NPN Power Transistor: Datasheet, Pinout, and Application Circuits

The Onsemi MJ15024G is a robust and industry-standard NPN power bipolar junction transistor (BJT) designed for high-power applications. Housed in a robust TO-3 package, it is renowned for its high current and voltage handling capabilities, making it a preferred choice for audio amplifiers, power supplies, and linear regulators.

Datasheet Overview and Key Specifications

The MJ15024G is built for performance and reliability. Its key absolute maximum ratings define the boundaries of its operation:

Collector-Emitter Voltage (VCEO): 400 V

Collector Current (IC): 16 A

Power Dissipation (PD): 250 W (with an adequate heatsink)

DC Current Gain (hFE): 8 to 75 (at IC = 8 A, VCE = 4 V)

Transition Frequency (fT): 4 MHz

These specifications highlight its suitability for high-voltage series pass elements, power amplifier output stages, and any circuit requiring substantial power control. The high safe operating area (SOA) is a critical feature, ensuring the device can handle simultaneous high current and high voltage without failure, a common challenge in linear circuits.

Pinout Configuration

The MJ15024G utilizes a classic TO-3 metal package, known for its excellent thermal performance. The pinout is straightforward:

Pin 1 (Base): The control terminal. A small current into this pin controls a much larger current between the collector and emitter.

Pin 2 (Emitter): The output terminal. The current flowing out of this pin is the sum of the base and collector currents.

The Metal Case: This is electrically connected to the Collector terminal. This is a crucial consideration for mounting; the device must be insulated from the heatsink unless the heatsink is at the same potential as the collector.

Application Circuits

1. Linear Power Supply Series Pass Element:

In a linear voltage regulator, the MJ15024G acts as a variable resistor, dropping the excess voltage to maintain a constant output. Its high VCEO rating makes it ideal for regulating voltages derived from high AC inputs. A driver transistor is typically used to provide the necessary base current to the MJ15024G.

2. Audio Power Amplifier Output Stage:

The transistor is a classic component in the output stages of high-fidelity audio amplifiers, particularly in complementary symmetry configurations with its PNP counterpart, the MJ15025G. Its high current capability allows it to drive low-impedance loudspeakers with significant power, while its linearity helps in maintaining low distortion.

3. Constant Current Source:

When configured with a zener diode and a low-value sense resistor, the MJ15024G can form a high-power constant current source. This circuit is useful for battery charging or laser diode driving, where a stable, regulated current is required regardless of load variance.

ICGOOODFIND

The Onsemi MJ15024G remains a cornerstone of power electronics design. Its proven reliability, high voltage capability, and robust TO-3 package make it an excellent choice for designers who need a rugged, high-performance transistor for demanding linear applications. While newer technologies exist, the MJ15024G continues to be a go-to component for its ability to handle significant power in a predictable and stable manner.

Keywords: Power Transistor, NPN, TO-3 Package, Audio Amplifier, Linear Regulator.