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

onsemi MJE5731

Name: MJE5731
Brand: onsemi
SKU: MJE5731
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJE5731

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: MJE5731.pdf

Description:: TRANS PNP 350V 1A TO-220

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJE5731 from onsemi is a high-voltage PNP silicon plastic power transistor in TO-220 package, rated for 350 V_CEO, 1.0 A continuous collector current, and 40 W total device dissipation at T_C = 25°C. It serves as a line-operated audio output amplifier stage and switch-mode power supply driver, delivering robust switching performance with 10 MHz f_T and 1.0 V V_CE(sat) at I_C/I_B = 5.

For engineers reviewing the MJE5731 datasheet, pinout, applications, or equivalent options, this page provides verified electrical specifications, thermal derating behavior, safe operating area limits, switching timing data under resistive and inductive loads, and validated alternative transistors for high-voltage PNP switching roles.

Technical Context

The MJE5731 operates as a medium-power, high-voltage PNP bipolar junction transistor optimized for linear audio amplification and hard-switching applications. Its 350 V_CEO, 3.0 A peak collector current, and 20 mJ unclamped inductive energy rating support reliable operation in flyback and forward converter primary-side drivers.

Thermal design is constrained by R_JC = 3.125 °C/W and R_JA = 62.5 °C/W, requiring heatsinking for sustained >2.0 W dissipation. The device exhibits h_FE = 10–150 (I_C = 0.3–1.0 A), V_BE(on) ≤ 1.5 V, and switching times (t_r, t_f) under 100 ns at I_C/I_B = 5, confirming suitability for <100 kHz switching.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	350 Vdc - Maximum collector-emitter voltage before breakdown; enables use in 280 VAC-derived supplies and CRT horizontal deflection circuits.
I_C (continuous)	1.0 Adc - Continuous DC collector current capability; defines maximum linear output or steady-state switching load current.
P_D @ T_C = 25°C	40 W - Total device dissipation limit at case temperature 25°C; requires active heatsinking above ~2.0 W ambient operation.
f_T	10 MHz - Current gain-bandwidth product; supports stable operation up to ~1–2 MHz small-signal amplification or fast switching control.
V_CE(sat)	≤1.0 Vdc at I_C = 1.0 A, I_B = 0.2 A - Low saturation voltage minimizes conduction loss in switching applications.
R_JC	3.125 °C/W - Junction-to-case thermal resistance; determines minimum heatsink requirement for given power and allowable T_J.
E (unclamped)	20 mJ - Energy handling under inductive turn-off; sets safe limit for snubberless flyback or relay driving without destructive second breakdown.

Pinout & Package

Package: TO-220 (Case 221A-09, Style 1), plastic, Pb-free, with pins arranged Base–Collector–Emitter–Collector (pins 1–2–3–4). Mounting tab is electrically connected to collector.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control input terminal; requires ≥0.2 A base drive for full saturation at 1.0 A collector current.
2 & 4	Collector	Main high-voltage current path; electrically tied to metal tab-requires isolation when mounted to heatsink.
3	Emitter	Common emitter node; referenced to system ground or negative rail in PNP high-side switching configurations.

Key Features

Feature	Design Value
High V_CEO rating (350 V)	Enables direct interface with rectified 240 VAC mains or 300 VDC bus without series stacking or voltage clamping.
TO-220 plastic package	Standardized mechanical footprint compatible with widely available heatsinks and automated assembly tooling.
PNP complement to TIP47–TIP50 series	Provides matched high-voltage PNP pairing for push-pull audio output stages or complementary SMPS topologies.
Pb-free and RoHS compliant	Meets global environmental regulations for industrial and consumer electronics manufacturing without lead-based solder concerns.
150°C max junction temperature	Supports operation in enclosed, high-ambient environments such as sealed power supplies or automotive under-hood modules.

Applications

Audio Output Amplifier	Switch-Mode Power Supply Driver
Use Scenario: Single-ended Class-B or Class-AB audio output stage in tube-replacement amplifiers or low-cost home audio systems. IC Role / Device Role / Timing Role: PNP power output transistor delivering up to 10 W into 8 Ω load with minimal crossover distortion. Use Value: 350 V_CEO allows safe operation with ±175 V rails; h_FE ≥10 at 1.0 A ensures stable biasing without excessive base drive complexity.	Use Scenario: Primary-side switch in offline flyback converters powering AC/DC adapters or LED drivers. IC Role / Device Role / Timing Role: High-voltage PNP switch controlling transformer primary current during PWM on-time. Use Value: 20 mJ unclamped inductive energy rating permits snubberless operation at ≤65 kHz; 10 MHz f_T supports clean gate drive edge fidelity.
Line-Operated Relay Driver	High-Voltage DC Motor Control
Use Scenario: Driving 240 VAC coil relays or solid-state contactors in industrial control panels. IC Role / Device Role / Timing Role: High-side PNP switch isolating logic-level microcontroller outputs from mains-referenced loads. Use Value: V_CEO = 350 V exceeds 240 VAC peak (339 V); 3.0 A I_CM accommodates relay inrush currents up to 2.5× steady-state.	Use Scenario: Directional H-bridge half-bridge leg in brushed DC motor controllers for HVAC actuators or power tools. IC Role / Device Role / Timing Role: High-side PNP switch enabling bidirectional current flow through motor windings. Use Value: R_JC = 3.125 °C/W and 150°C T_J(max) allow 5–7 W continuous dissipation per device under forced-air cooling.

Audio Output Amplifier

Switch-Mode Power Supply Driver

Use Scenario: Single-ended Class-B or Class-AB audio output stage in tube-replacement amplifiers or low-cost home audio systems.

IC Role / Device Role / Timing Role: PNP power output transistor delivering up to 10 W into 8 Ω load with minimal crossover distortion.

Use Value: 350 V_CEO allows safe operation with ±175 V rails; h_FE ≥10 at 1.0 A ensures stable biasing without excessive base drive complexity.

Use Scenario: Primary-side switch in offline flyback converters powering AC/DC adapters or LED drivers.

IC Role / Device Role / Timing Role: High-voltage PNP switch controlling transformer primary current during PWM on-time.

Use Value: 20 mJ unclamped inductive energy rating permits snubberless operation at ≤65 kHz; 10 MHz f_T supports clean gate drive edge fidelity.

Line-Operated Relay Driver

High-Voltage DC Motor Control

Use Scenario: Driving 240 VAC coil relays or solid-state contactors in industrial control panels.

IC Role / Device Role / Timing Role: High-side PNP switch isolating logic-level microcontroller outputs from mains-referenced loads.

Use Value: V_CEO = 350 V exceeds 240 VAC peak (339 V); 3.0 A I_CM accommodates relay inrush currents up to 2.5× steady-state.

Use Scenario: Directional H-bridge half-bridge leg in brushed DC motor controllers for HVAC actuators or power tools.

IC Role / Device Role / Timing Role: High-side PNP switch enabling bidirectional current flow through motor windings.

Use Value: R_JC = 3.125 °C/W and 150°C T_J(max) allow 5–7 W continuous dissipation per device under forced-air cooling.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage PNP switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJE5731A	V_CEO = 375 V, V_CBO = 375 V - 25 V higher blocking rating than MJE5731; otherwise identical pinout, package, and thermal specs.	Suitable for designs requiring margin above 350 V transient spikes or long-term reliability at elevated DC bus voltages.	Select MJE5731A when operating near 350 V DC bus limits or where 25 V headroom improves field failure margin.
TIP50	V_CEO = 400 V, I_C = 1.5 A, P_D = 40 W - Higher voltage and current rating; same TO-220 package but different pinout (E-B-C).	Not pin-compatible; requires PCB layout change. Better suited for higher-power flyback or larger audio outputs.	Choose TIP50 only if redesigning for higher voltage/current and accepting pinout rework; not a drop-in replacement.

Compared with MJE5731, the MJE5731A offers extended voltage margin without layout changes, while TIP50 delivers higher ratings at the cost of non-interchangeable pin configuration-making MJE5731 optimal for cost-sensitive, volume-manufactured 350 V-class switching where pin compatibility is critical.

Availability

MJE5731 is available at Aetrix Electronics and suitable for switch-mode power supply drivers, line-operated audio amplifiers, and high-voltage relay control applications requiring stable component supply across production lifecycles.

Supply support for MJE5731 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MJE5731 belongs to onsemi's high-voltage discrete transistor family designed specifically for ruggedized linear and switching power applications-including audio output stages, SMPS primary switches, and industrial control interfaces.

FAQ

What is the maximum collector-emitter voltage rating for the MJE5731?

The MJE5731 has a maximum collector-emitter sustaining voltage (V_CEO(sus)) of 350 Vdc at I_C = 30 mA and I_B = 0. This rating is confirmed in the "OFF CHARACTERISTICS" table of the official onsemi datasheet (Rev. 9, October 2024) and defines the absolute upper limit for DC or repetitive peak voltage applied between collector and emitter terminals. Exceeding this value risks avalanche breakdown or permanent device failure.

Is the MJE5731 pin-compatible with the MJE5730 or MJE5731A?

Yes, the MJE5731 is fully pin-compatible with both MJE5730 and MJE5731A - all three share identical TO-220 package (Case 221A-09, Style 1), pin assignment (Base–Collector–Emitter–Collector), and mounting tab connection to collector. The only differences are voltage ratings: MJE5730 = 300 V, MJE5731 = 350 V, MJE5731A = 375 V. No PCB layout change is required when substituting within this family.

What is the thermal resistance from junction to case for the MJE5731?

The MJE5731 has a maximum thermal resistance from junction to case (R_JC) of 3.125 °C/W, as specified in the "THERMAL CHARACTERISTICS" section of the onsemi datasheet. This value is measured under standard mounting conditions with thermal compound and is used to calculate junction temperature rise (ΔT_J = P_D × R_JC) when the device is mounted to a heatsink.

Can the MJE5731 be used in inductive switching applications without a snubber circuit?

Yes, the MJE5731 is rated for 20 mJ of unclamped inductive load energy (E), as tested per Figure 10 in the datasheet. This allows safe turn-off into inductive loads like relays or transformer primaries without external snubbers - provided operating conditions (V_CC, I_C, di/dt) stay within the SOA curve boundaries shown in Figure 5 and pulse duty cycle remains ≤10%.

What is the DC current gain (h_FE) range for the MJE5731 at typical operating conditions?

The MJE5731 exhibits h_FE = 10 (minimum) to 150 (maximum) at I_C = 1.0 A and V_CE = 10 Vdc, per the "ELECTRICAL CHARACTERISTICS" table. At lower current (I_C = 0.3 A), h_FE ranges from 30 to 150. Designers should use h_FE = 10 for worst-case base drive calculations to ensure saturation across process and temperature variation.

MJE5731 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 1 A

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

Vce Saturation (Max) @ Ib, Ic:: 1V @ 200mA, 1A

Current - Collector Cutoff (Max):: 1mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30 @ 300mA, 10V

Power - Max:: 40 W

Frequency - Transition:: 10MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

MJE5731 FAQ

1.How can I place an order for MJE5731 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJE5731 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 MJE5731 reliable?

The price and inventory of MJE5731 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE5731 is usually 5 days.

3.What payment methods are accepted for MJE5731?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE5731 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJE5731?

MJE5731 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJE5731 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 MJE5731?

For technical support, including MJE5731 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE5731 requirements.

6.How does Aetrix verify that MJE5731 is sourced from the original manufacturer or authorized distributors?

All MJE5731 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 MJE5731 meets industry standards.

7.What is the process for return or replacement of MJE5731?

All MJE5731 units undergo pre-shipment inspection (PSI). If there is an issue with MJE5731, 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 MJE5731 part is unused and in its original packaging.

Return procedure for MJE5731:

1.Submit a request within 90 days.

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

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