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

onsemi MJL4281A

Name: MJL4281A
Brand: onsemi
SKU: MJL4281A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJL4281A

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-264-3, TO-264AA

Datasheet:: MJL4281A.pdf

Description:: TRANS NPN 350V 15A TO-264

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJL4281A from onsemi is an NPN silicon power bipolar transistor designed for high-power audio amplifier output stages, featuring 350 V_CEO, 15 A continuous collector current, 230 W power dissipation at T_C = 25°C, and high DC current gain (h_FE = 80–250) across 100 mA to 5 A operating range.

For engineers reviewing the MJL4281A datasheet, pinout, applications, or equivalent options, this device is selected for linear Class AB audio output stages requiring high safe operating area, low harmonic distortion, and robust second-breakdown performance in discrete power amplifier designs.

Technical Context

The MJL4281A operates as a linear power switch in analog audio output circuits, with complementary PNP pairing to MJL4302A for push-pull configurations. Its high f_T (35 MHz typical) supports wide bandwidth signal fidelity, while its SOA extends to 1.0 A/100 V for 1 second under non-repetitive conditions.

Designed for fixed-bias or emitter-follower driver topologies, it delivers stable h_FE linearity from 100 mA to 5 A at V_CE = 5 V, and maintains V_CE(sat) ≤ 1.0 V at I_C = 8 A / I_B = 0.8 A - enabling efficient thermal management in high-current output stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	350 V - Withstands rail voltages up to ±175 V in split-supply audio amplifiers without breakdown.
I_C (continuous)	15 A - Supports >300 W RMS output into 4 Ω loads in dual-rail Class AB designs.
P_D @ T_C = 25°C	230 W - Enables high-power dissipation with external heatsink mounting via TO-264 case.
h_FE @ I_C = 8 A	50 (min) - Ensures sufficient base drive margin and predictable bias stability at full output current.
V_CE(sat)	≤1.0 V @ I_C = 8 A, I_B = 0.8 A - Minimizes conduction loss and thermal stress in saturated output operation.
f_T	35 MHz - Preserves transient response and high-frequency linearity up to 20 kHz+ audio bandwidth.
R_JC	0.54 °C/W - Allows precise junction temperature estimation using heatsink thermal resistance and ambient conditions.

Pinout & Package

Package: TO-264 (Case 340G, Style 2), isolated metal tab, Pb-free option available (MJL4281AG). Mounting surface is electrically connected to collector.

Pin/Terminal	Circuit Role	Design Meaning
1 - Base	Control input terminal	Receives base current to modulate collector-emitter conduction; requires current-limited drive to avoid saturation delay or thermal runaway.
2 - Collector	High-current output node	Electrically tied to metal tab; must be mounted to heatsink with insulating washer if isolation from chassis is required.
3 - Emitter	Reference/output return path	Serves as common reference for emitter-follower or grounded-emitter configurations; carries full load current.

Key Features

Feature	Design Value
High SOA (1.0 A/100 V, 1 s)	Enables reliable handling of speaker impedance dips and transient overload without secondary breakdown.
Gain linearity (100 mA–5 A)	Reduces intermodulation distortion in wide-dynamic-range audio signals by maintaining consistent h_FE.
Low harmonic distortion	Results from optimized doping profile and epitaxial structure, critical for Hi-Fi and professional audio fidelity.
h_FE = 80–250 (typical)	Provides flexible bias design options - from low-base-current Class A to high-efficiency Class AB operation.
TO-264 mechanical robustness	Supports high-reliability industrial and pro-audio applications with proven thermal cycling and vibration resistance.

Applications

Professional Audio Amplifiers	Hi-Fi Stereo Receivers
Use Scenario: High-fidelity 200–500 W per channel power amplifiers used in studio monitoring and live sound reinforcement. IC Role / Device Role / Timing Role: NPN output transistor in complementary push-pull pair driving low-impedance loudspeakers (4–8 Ω). Use Value: Delivers low THD+N (<0.05% at 1 kHz, 100 W) and wide bandwidth due to high f_T and SOA integrity.	Use Scenario: Dual-mono integrated amplifiers with discrete output stages targeting audiophile-grade linearity and damping factor. IC Role / Device Role / Timing Role: Primary NPN power switch in emitter-follower output topology with local feedback. Use Value: Maintains stable open-loop gain and phase margin across audible spectrum thanks to predictable h_FE vs. I_C behavior.
Public Address Systems	Instrument Amplifiers
Use Scenario: 70 V/100 V constant-voltage distributed audio systems requiring rugged, thermally stable output devices. IC Role / Device Role / Timing Role: Final-stage power transistor in transformer-coupled or direct-coupled output stage. Use Value: Survives sustained high-current demand during speech/music transients due to 1-second SOA rating at 100 V.	Use Scenario: Guitar/bass amplifiers demanding high headroom, clean dynamic response, and reliability under clipping conditions. IC Role / Device Role / Timing Role: Linear output device in Class AB topology with adjustable quiescent current. Use Value: Delivers tight bass control and low crossover distortion via high h_FE linearity and low V_CE(sat).

Professional Audio Amplifiers

Hi-Fi Stereo Receivers

Use Scenario: High-fidelity 200–500 W per channel power amplifiers used in studio monitoring and live sound reinforcement.

IC Role / Device Role / Timing Role: NPN output transistor in complementary push-pull pair driving low-impedance loudspeakers (4–8 Ω).

Use Value: Delivers low THD+N (<0.05% at 1 kHz, 100 W) and wide bandwidth due to high f_T and SOA integrity.

Use Scenario: Dual-mono integrated amplifiers with discrete output stages targeting audiophile-grade linearity and damping factor.

IC Role / Device Role / Timing Role: Primary NPN power switch in emitter-follower output topology with local feedback.

Use Value: Maintains stable open-loop gain and phase margin across audible spectrum thanks to predictable h_FE vs. I_C behavior.

Public Address Systems

Instrument Amplifiers

Use Scenario: 70 V/100 V constant-voltage distributed audio systems requiring rugged, thermally stable output devices.

IC Role / Device Role / Timing Role: Final-stage power transistor in transformer-coupled or direct-coupled output stage.

Use Value: Survives sustained high-current demand during speech/music transients due to 1-second SOA rating at 100 V.

Use Scenario: Guitar/bass amplifiers demanding high headroom, clean dynamic response, and reliability under clipping conditions.

IC Role / Device Role / Timing Role: Linear output device in Class AB topology with adjustable quiescent current.

Use Value: Delivers tight bass control and low crossover distortion via high h_FE linearity and low V_CE(sat).

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SC5200	V_CEO = 230 V (lower), I_C = 15 A, h_FE = 80–240, TO-3P package	Lower voltage rating limits use in ±150 V rail designs; requires derating in high-voltage audio applications.	Select when cost sensitivity outweighs need for 350 V capability and SOA margin.
MJE15030	V_CEO = 300 V, I_C = 8 A (lower), h_FE = 40–120, TO-220 package	Reduced current/power handling and smaller SOA; unsuitable for >200 W output stages.	Choose only for lower-power, space-constrained designs where TO-220 mounting suffices.

Compared with 2SC5200 and MJE15030, the MJL4281A provides superior voltage headroom and SOA robustness for high-rail professional audio, while maintaining compatible gain structure and thermal interface requirements for drop-in heatsink reuse.

Availability

MJL4281A is available at Aetrix Electronics and suitable for professional audio amplifiers, Hi-Fi stereo receivers, public address systems, and instrument amplifiers requiring stable component supply and long-term production continuity.

Supply support for MJL4281A 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 focused on energy-efficient, high-performance analog, power, and sensor solutions for automotive, industrial, cloud, and consumer markets.

The MJL4281A belongs to onsemi's high-voltage power bipolar transistor family, engineered specifically for linear audio output stages where SOA integrity, gain linearity, and low distortion are essential design criteria.

FAQ

What is the maximum safe collector-emitter voltage for MJL4281A in continuous operation?

The MJL4281A has a rated V_CEO of 350 Vdc at T_J = 25°C. This is the maximum continuous collector-emitter sustaining voltage with base open. Derating applies above 25°C junction temperature, and second-breakdown limits must be observed under transient conditions - consult Figure 11 (SOA curve) in the official onsemi datasheet for time-dependent voltage/current boundaries. The MJL4281A must not exceed 350 V in any steady-state condition.

Does MJL4281A require a heatsink, and what thermal resistance is needed for 15 A operation?

Yes, the MJL4281A requires a heatsink for any sustained current above ~1 A. With R_JC = 0.54 °C/W and maximum T_J = +150°C, a typical design targeting T_C ≤ 85°C at 15 A continuous must maintain total thermal resistance (R_CS + R_SA) ≤ 1.2 °C/W. This typically requires a large finned heatsink with forced air or low-thermal-resistance mounting interface. The MJL4281A's TO-264 package is designed for bolt-down heatsink integration.

Is MJL4281A pin-compatible with MJL4302A for complementary circuit design?

No - the MJL4281A (NPN) and MJL4302A (PNP) share identical TO-264 package and pinout (Base–Collector–Emitter), but they are complementary devices, not pin-compatible replacements. Their electrical polarities differ: MJL4281A pin 1 is Base, pin 2 is Collector, pin 3 is Emitter; MJL4302A uses the same pin assignment but with opposite carrier polarity. They are intended for matched push-pull pairs, not substitution.

What is the minimum h_FE of MJL4281A at 8 A collector current, and how does it affect base drive design?

The MJL4281A guarantees h_FE ≥ 50 at I_C = 8 A, V_CE = 5 V, T_C = 25°C. This defines the worst-case base current requirement: I_B ≥ 160 mA. Designers must ensure driver stage compliance - including voltage headroom and current sourcing capability - to maintain linear operation. At higher temperatures or lower V_CE, h_FE may decrease further, so the MJL4281A benefits from conservative base drive margining.

Can MJL4281A be used in switching power supplies, or is it strictly for linear audio?

The MJL4281A is optimized for linear operation - its SOA, gain linearity, and low-distortion characteristics target audio amplification. While it can switch at low frequencies (<10 kHz), its relatively slow turn-off (due to minority-carrier storage) and lack of specified switching parameters make it unsuitable for modern SMPS designs. For switching applications, dedicated power MOSFETs or IGBTs with defined t_on/t_off, Q_g, and avalanche ratings are preferred over the MJL4281A.

MJL4281A Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-264-3, TO-264AA

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 15 A

Voltage - Collector Emitter Breakdown (Max):: 350 V

Vce Saturation (Max) @ Ib, Ic:: 1V @ 800mA, 8A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 80 @ 5A, 5V

Power - Max:: 230 W

Frequency - Transition:: 35MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-264

MJL4281A FAQ

1.How can I place an order for MJL4281A through Aetrix?

Please submit a Request for Quotation (RFQ) for MJL4281A 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 MJL4281A reliable?

The price and inventory of MJL4281A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJL4281A is usually 5 days.

3.What payment methods are accepted for MJL4281A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJL4281A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJL4281A?

MJL4281A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJL4281A 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 MJL4281A?

For technical support, including MJL4281A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJL4281A requirements.

6.How does Aetrix verify that MJL4281A is sourced from the original manufacturer or authorized distributors?

All MJL4281A 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 MJL4281A meets industry standards.

7.What is the process for return or replacement of MJL4281A?

All MJL4281A units undergo pre-shipment inspection (PSI). If there is an issue with MJL4281A, 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 MJL4281A part is unused and in its original packaging.

Return procedure for MJL4281A:

1.Submit a request within 90 days.

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

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