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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi MJ15020

Name: MJ15020
Brand: onsemi
SKU: MJ15020
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJ15020

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-204AA, TO-3

Datasheet:: MJ15020.pdf

Description:: TRANS NPN 250V 4A TO204

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJ15020 from onsemi is an NPN silicon power transistor designed for high-frequency driver stages in audio amplifier output circuits. It delivers 4.0 A continuous collector current, sustains 250 V collector-emitter voltage, and exhibits a minimum current-gain bandwidth product of 20 MHz - enabling stable operation in Class AB and Class B linear audio output stages.

For engineers reviewing the MJ15020 datasheet, pinout, applications, or equivalent options, key selection considerations include safe operating area (SOA) validation at 50 V/3.0 A for 1.0 second, thermal resistance of 1.17 °C/W (junction-to-case), and complementary pairing with MJ15021 for push-pull amplifier topologies.

Technical Context

The MJ15020 operates as a linear bipolar junction transistor with fixed-base drive architecture, requiring external bias networks for stable quiescent point control. Its SOA is 100% tested to 50 V and 3.0 A for non-repetitive pulses, and its f_T ≥ 20 MHz supports mid-band audio fidelity without phase shift degradation up to 10 MHz.

Thermal management is critical: rated at 150 W total dissipation at T_C = 25°C with 0.86 W/°C derating above that temperature, and junction temperature range spans −65°C to +200°C - making it suitable for high-bias, high-power discrete amplifier rails where thermal cycling resilience is required.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	250 Vdc - supports rail voltages up to ±100 V in dual-supply audio amplifiers without breakdown
I_C (continuous)	4.0 Adc - enables >100 W RMS output into 8 Ω loads with proper heatsinking
f_T	≥20 MHz - preserves transient response and harmonic integrity through 20 kHz audio band
R_θJC	1.17 °C/W - mandates mechanical interface <0.2 mm thermal paste gap and ≥12 cm² copper pour for 150 W operation
h_FE @ 1.0 A	30 min - determines base drive current requirement (~33 mA per transistor at I_C = 1.0 A)
V_CE(sat)	≤1.0 Vdc @ I_C = 1.0 A, I_B = 0.1 A - limits conduction loss to ≤1 W at 1 A output stage current
SOA Tested	50 V / 3.0 A / 1.0 sec - validates single-pulse robustness during clipping or short-circuit transients

Pinout & Package

Package: TO-204AA (TO-3) metal can, case-isolated, with collector connected to the case (mechanical mounting surface). Dimensions per Case 1−07, Issue Z; mounting hole center-to-center spacing 1.187 inches (30.15 mm).

Pin/Terminal	Circuit Role	Design Meaning
1. Base	Control electrode	Receives forward-biased current to modulate collector-emitter conduction; requires current-limiting resistor in series with driver stage
2. Emitter	Current source return path	Connected to ground or negative rail in common-emitter configuration; carries full load current and must be routed with low-inductance trace
Case (Collector)	Main power terminal	Electrically tied to collector; must be electrically isolated from chassis unless circuit design explicitly grounds collector; thermal path to heatsink is primary cooling route

Key Features

Feature	Design Value
100% SOA tested	Guarantees pulse survivability at 50 V/3.0 A for 1.0 second - eliminates need for external SOA verification in production test
f_T ≥ 20 MHz	Ensures minimal gain roll-off and phase margin retention across full audio spectrum, supporting wideband feedback stability
V_CEO = 250 V	Permits use in high-voltage discrete amplifiers (e.g., ±85 V rails) without derating or series stacking
Pb-free option (MJ15020G)	Enables RoHS-compliant manufacturing without thermal or reliability trade-offs vs. legacy leaded version
Junction temp range −65°C to +200°C	Supports operation in sealed, high-ambient environments (e.g., powered speaker enclosures) without thermal shutdown risk

Applications

High-Fidelity Audio Amplifiers	Professional Power Amplifier Output Stages
Use Scenario: Discrete Class AB output stage in stereo power amplifiers delivering 50–200 W per channel into 4–8 Ω loads. IC Role / Device Role / Timing Role: NPN power switching element in complementary pair with MJ15021; handles positive half-cycle current delivery. Use Value: High f_T and SOA-tested ruggedness ensure clean transient reproduction and clipping tolerance without secondary breakdown.	Use Scenario: Output devices in touring-grade 3U rack-mount amplifiers operating continuously at elevated ambient temperatures. IC Role / Device Role / Timing Role: Primary current-handling transistor in quasi-complementary output stage; mounted directly to extruded aluminum heatsink. Use Value: 200°C max junction rating and 1.17 °C/W R_θJC enable sustained 150 W dissipation with predictable thermal headroom.
Studio Monitor Power Sections	Discrete Guitar Amplifier Output Stages
Use Scenario: Bi-amplified near-field studio monitors requiring low-noise, high-slew-rate output drivers. IC Role / Device Role / Timing Role: Final gain stage transistor in active crossover-fed low-frequency section; biased at 100–200 mA quiescent current. Use Value: h_FE ≥30 at 1 A ensures consistent base drive requirements across production lots, simplifying bias network calibration.	Use Scenario: Output stage in hand-wired tube-hybrid guitar amplifiers where solid-state reliability replaces aging vacuum tubes. IC Role / Device Role / Timing Role: High-voltage switching transistor replacing EL34/6L6 in cathode-follower or transformerless output topologies. Use Value: 250 V V_CEO safely accommodates B+ rails up to 450 V DC when used in grounded-cathode configurations with appropriate snubbing.

High-Fidelity Audio Amplifiers

Professional Power Amplifier Output Stages

Use Scenario: Discrete Class AB output stage in stereo power amplifiers delivering 50–200 W per channel into 4–8 Ω loads.

IC Role / Device Role / Timing Role: NPN power switching element in complementary pair with MJ15021; handles positive half-cycle current delivery.

Use Value: High f_T and SOA-tested ruggedness ensure clean transient reproduction and clipping tolerance without secondary breakdown.

Use Scenario: Output devices in touring-grade 3U rack-mount amplifiers operating continuously at elevated ambient temperatures.

IC Role / Device Role / Timing Role: Primary current-handling transistor in quasi-complementary output stage; mounted directly to extruded aluminum heatsink.

Use Value: 200°C max junction rating and 1.17 °C/W R_θJC enable sustained 150 W dissipation with predictable thermal headroom.

Studio Monitor Power Sections

Discrete Guitar Amplifier Output Stages

Use Scenario: Bi-amplified near-field studio monitors requiring low-noise, high-slew-rate output drivers.

IC Role / Device Role / Timing Role: Final gain stage transistor in active crossover-fed low-frequency section; biased at 100–200 mA quiescent current.

Use Value: h_FE ≥30 at 1 A ensures consistent base drive requirements across production lots, simplifying bias network calibration.

Use Scenario: Output stage in hand-wired tube-hybrid guitar amplifiers where solid-state reliability replaces aging vacuum tubes.

IC Role / Device Role / Timing Role: High-voltage switching transistor replacing EL34/6L6 in cathode-follower or transformerless output topologies.

Use Value: 250 V V_CEO safely accommodates B+ rails up to 450 V DC when used in grounded-cathode configurations with appropriate snubbing.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N3055	f_T = 0.8 MHz (vs. 20 MHz); V_CEO = 60 V (vs. 250 V); SOA not 100% tested	Limited to low-voltage, low-bandwidth applications (e.g., DC motor control); unsuitable for high-fidelity audio output	Select MJ15020 when audio bandwidth, high-voltage swing, or SOA assurance is required
KSC1845F	TO-220 package (vs. TO-3); P_D = 100 W (vs. 150 W); V_CEO = 230 V; f_T = 15 MHz	Smaller footprint but lower thermal mass; less suited for sustained high-power operation without forced air	Choose MJ15020 for higher power density, superior thermal coupling, and proven SOA in legacy amplifier designs

Compared with 2N3055 and KSC1845F, the MJ15020 provides significantly higher frequency response, wider safe operating area validation, and greater voltage headroom - making it the preferred choice for high-performance linear audio output stages where signal integrity and ruggedness are co-prioritized.

Availability

MJ15020 is available at Aetrix Electronics and suitable for high-fidelity audio amplifiers, professional power amplifier output stages, and studio monitor power sections requiring stable component supply and long-term obsolescence resilience.

Supply support for MJ15020 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MJ15020 belongs to onsemi's legacy high-power discrete transistor family, engineered specifically for high-fidelity linear audio amplifier output stages where SOA integrity, thermal robustness, and wideband gain stability are essential design requirements.

FAQ

What is the maximum continuous collector current rating for the MJ15020?

The MJ15020 is rated for 4.0 Adc continuous collector current at T_C = 25°C. Derating is required above this temperature at 0.86 W/°C, and actual usable current depends on heatsink efficiency and ambient conditions. The device also supports 3.0 A for 1.0 second under SOA testing at 50 V, confirming short-duration overload capability. Always verify thermal design using the 1.17 °C/W junction-to-case resistance value specified in the MJ15020 datasheet.

Is the MJ15020 pin-compatible with the MJ15021?

No - the MJ15020 (NPN) and MJ15021 (PNP) share identical TO-204AA (TO-3) packaging and pinout (Base, Emitter, Collector-case), but they are complementary devices, not pin-compatible replacements. Both use Pin 1 = Base, Pin 2 = Emitter, and Collector = case, enabling matched layout in push-pull amplifier designs. However, substituting one for the other without circuit reconfiguration will result in functional failure due to polarity inversion.

Does the MJ15020 have Pb-free packaging options?

Yes - the MJ15020G variant is the Pb-free version of the MJ15020, manufactured in the same TO-204AA (TO-3) package with identical electrical and thermal specifications. The "G" suffix denotes RoHS compliance, and the device meets onsemi's Pb-free soldering and mounting guidelines. No performance or reliability differences exist between MJ15020 and MJ15020G; the choice depends solely on environmental compliance requirements.

What is the safe operating area (SOA) test condition for the MJ15020?

The MJ15020 undergoes 100% SOA testing at 50 V collector-emitter voltage, 3.0 A collector current, for 1.0 second under non-repetitive conditions. This verifies robustness against secondary breakdown during transient overloads such as speaker short-circuits or amplifier clipping. The SOA curve in the MJ15020 datasheet shows thermal, wire bond, and secondary breakdown limits - all validated per Figure 3 in the official onsemi document MJ15020/D Rev. 2.

Can the MJ15020 be used in switching power supplies?

The MJ15020 is optimized for linear operation in audio amplifier output stages, not high-frequency switching. While its 20 MHz f_T suggests potential switching use, its relatively slow turn-off characteristics, lack of specified switching times (t_on/t_off), and SOA validation focused on linear pulse stress make it unsuitable for SMPS applications. For switching, purpose-built MOSFETs or faster BJTs like MJE13009 are recommended instead of the MJ15020.

MJ15020 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-204AA, TO-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 4 A

Voltage - Collector Emitter Breakdown (Max):: 250 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 100mA, 1A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30 @ 1A, 4V

Power - Max:: 150 W

Frequency - Transition:: 20MHz

Operating Temperature:: -65°C ~ 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-204 (TO-3)

MJ15020 FAQ

1.How can I place an order for MJ15020 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJ15020 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MJ15020 reliable?

The price and inventory of MJ15020 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJ15020 is usually 5 days.

3.What payment methods are accepted for MJ15020?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJ15020 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJ15020?

MJ15020 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJ15020 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MJ15020?

For technical support, including MJ15020 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJ15020 requirements.

6.How does Aetrix verify that MJ15020 is sourced from the original manufacturer or authorized distributors?

All MJ15020 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MJ15020 meets industry standards.

7.What is the process for return or replacement of MJ15020?

All MJ15020 units undergo pre-shipment inspection (PSI). If there is an issue with MJ15020, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MJ15020 part is unused and in its original packaging.

Return procedure for MJ15020:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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