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

STMicroelectronics MJ4035

Name: MJ4035
Brand: STMicroelectronics
SKU: MJ4035
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJ4035

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-204AA, TO-3

Datasheet:: MJ4035.pdf

Description:: TRANS NPN DARL 100V 16A TO-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJ4035 from STMicroelectronics is a silicon epitaxial-base NPN power Darlington transistor in monolithic configuration, housed in a TO-3 metal package. It delivers 16 A collector current, 100 V V_CEO, 150 W total dissipation at T_c ≤ 25°C, and h_FE ≥ 1000 at IC = 10 A - designed for high-current switching and linear amplification in industrial motor drives and audio output stages.

For engineers reviewing the MJ4035 datasheet, MJ4035 pinout, MJ4035 application, or MJ4035 equivalent, key selection factors include its integrated antiparallel C–E diode, 1.17°C/W junction-to-case thermal resistance, 2.5 V V_CE(sat) at 10 A/40 mA drive, and complementary pairing with MJ4032 for push-pull topologies.

Technical Context

The MJ4035 implements a monolithic Darlington pair with built-in base-emitter resistor network (R1 ≈ 6 kΩ, R2 ≈ 55 Ω) enabling simplified biasing and improved turn-off speed. Its integrated antiparallel collector-emitter diode supports inductive load commutation without external flyback components.

Rated for T_j up to 200°C and T_stg from –65°C to +200°C, it operates under pulsed conditions (300 µs, 1.5% duty cycle) for peak current handling. Voltage ratings follow PNP/NPN sign convention: all NPN values are positive, including V_CBO = 100 V and V_EBO = 5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - maximum safe collector-emitter voltage with base open; enables use in 80 V DC bus systems with margin.
I_C	16 A - continuous collector current rating at T_c = 25°C; defines maximum sustained load-handling capability.
P_tot	150 W - total power dissipation at case temperature ≤25°C; requires heatsinking for >50 W operation.
R_thj-case	1.17 °C/W - thermal resistance from junction to case; determines temperature rise per watt dissipated into heatsink.
h_FE	≥1000 at I_C = 10 A - high DC current gain reduces required base drive current to ~10 mA for 10 A output.
V_CE(sat)	2.5 V at I_C = 10 A, I_B = 40 mA - low saturation voltage minimizes conduction loss in switching applications.
Integrated Diode	Antiparallel C–E diode - eliminates need for external freewheeling diode in relay/motor driver circuits.

Pinout & Package

Package: TO-3 metal case (JEDEC standard), with electrically isolated collector tab requiring insulating mounting hardware.

Pin/Terminal	Circuit Role	Design Meaning
Collector (Tab)	Main current output path, electrically connected to metal case	Must be insulated from heatsink unless system ground reference permits direct mounting; primary thermal path.
Base	Control input for Darlington pair	Internally biased via R1/R2 network; accepts TTL/CMOS-compatible drive when combined with appropriate series resistor.
Emitter	Current return path and reference node	Provides low-impedance emitter connection; used as common terminal in grounded-emitter amplifier or switch configurations.

Key Features

Feature	Design Value
Monolithic Darlington structure	Single-die integration ensures matched transistor characteristics and eliminates inter-device wiring inductance.
Integrated antiparallel C–E diode	Enables self-commutating operation with inductive loads; reduces BOM count and PCB area in motor control designs.
High h_FE (≥1000)	Reduces base drive requirements by >10× vs. single bipolar transistors, easing interface with microcontrollers or logic gates.
TO-3 metal package	Provides robust mechanical integrity and superior thermal performance versus plastic packages for high-power analog switching.
1.17 °C/W R_thj-case	Supports >100 W continuous operation with properly sized heatsink; critical for reliability in sealed enclosures.

Applications

Industrial Motor Control

Audio Power Amplifier Output Stage

Use Scenario: Driving 24–48 V DC brushed motors in conveyor systems and valve actuators with PWM switching.

IC Role / Device Role / Timing Role: High-current NPN switch in half-bridge or H-bridge output stage, paired with MJ4032 for complementary operation.

Use Value: Integrated antiparallel diode handles back-EMF during PWM off-time, eliminating discrete flyback diodes and reducing layout complexity.

Use Scenario: Delivering 10–15 W RMS into 4 Ω loudspeakers in Class AB audio amplifiers.

IC Role / Device Role / Timing Role: Linear output device operating in active region with fixed bias; provides high-current, low-distortion signal amplification.

Use Value: h_FE ≥1000 ensures stable quiescent current setting and minimal thermal drift across temperature range.

DC Power Supply Regulator

High-Power Relay Driver

Use Scenario: Series pass element in adjustable linear regulators delivering up to 12 A at 5–30 V output.

IC Role / Device Role / Timing Role: Voltage-controlled current source regulating output by varying base voltage; dissipates heat directly into chassis-mounted heatsink.

Use Value: 150 W P_tot and 200°C T_j(max) support continuous operation under worst-case dropout conditions.

Use Scenario: Direct-driving 12 V/24 V industrial relays with coil currents up to 15 A in PLC output modules.

IC Role / Device Role / Timing Role: Saturated switch turning relay on/off with minimal V_CE(sat)-induced heating.

Use Value: 2.5 V V_CE(sat) at 10 A limits power loss to 25 W, enabling compact heatsink design in space-constrained DIN-rail enclosures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-current Darlington switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TIP142	Lower P_tot (125 W), higher R_thj-case (1.92°C/W), no integrated diode	Requires external flyback diode; less suitable for high-duty-cycle inductive switching	Select when cost sensitivity outweighs thermal performance and BOM simplification needs
BUX87	Higher V_CEO (160 V), same TO-3 package, no integrated diode, h_FE ≈ 750	Better for 100+ V bus systems but demands more base drive and external protection	Prefer for higher-voltage industrial supplies where MJ4035's 100 V rating is marginal

Compared with TIP142 and BUX87, the MJ4035 offers superior thermal efficiency (1.17°C/W), built-in diode functionality, and highest h_FE, making it optimal for thermally constrained, high-reliability 80 V-class switching where drive simplicity and layout density matter.

Availability

MJ4035 is available at Aetrix Electronics and suitable for industrial motor control, audio power amplifiers, and DC power supply regulators requiring stable component supply and long-term manufacturing continuity.

Supply support for MJ4035 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The MJ4035 belongs to ST's legacy high-power bipolar transistor family, engineered specifically for ruggedized linear and switching applications demanding high current, high voltage, and proven thermal reliability in harsh environments.

FAQ

Is the MJ4035 pin-compatible with the MJ4032?

No - MJ4035 (NPN) and MJ4032 (PNP) share identical TO-3 mechanical footprint and terminal arrangement (collector-tab/base/emitter), but polarity reversal means they are complementary, not interchangeable. Their internal schematics mirror each other, enabling push-pull operation when mounted on the same heatsink with proper isolation.

Does the MJ4035 require an external base resistor?

Yes - although it includes internal base-emitter resistors (R1 ≈ 6 kΩ, R2 ≈ 55 Ω), an external series base resistor is required to limit drive current and ensure stable turn-on/turn-off timing. Typical value ranges from 470 Ω to 2.2 kΩ depending on driving source voltage and desired switching speed.

Can the MJ4035 be used without a heatsink?

No - even at modest power levels, junction temperature rises rapidly without heatsinking. At 10 A and 2.5 V V_CE(sat), dissipation exceeds 25 W, which would exceed 200°C junction limit within seconds in free air. A minimum heatsink with thermal resistance ≤ 4°C/W is required for reliable continuous operation.

What is the function of the integrated antiparallel diode?

The integrated collector-emitter diode conducts reverse current during inductive load turn-off, clamping negative voltage spikes and preventing transistor breakdown. It replaces discrete flyback diodes in relay, solenoid, and DC motor drive circuits - confirmed by schematic symbol and "integrated antiparallel collector-emitter diode" in official ST documentation.

MJ4035 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 16 A

Voltage - Collector Emitter Breakdown (Max):: 100 V

Vce Saturation (Max) @ Ib, Ic:: 4V @ 80mA, 16A

Current - Collector Cutoff (Max):: 3mA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 1000 @ 10A, 3V

Power - Max:: 150 W

Frequency - Transition:: -

Operating Temperature:: 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Chassis Mount

Supplier Device Package:: TO-3

MJ4035 FAQ

1.How can I place an order for MJ4035 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJ4035 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 MJ4035 reliable?

The price and inventory of MJ4035 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJ4035 is usually 5 days.

3.What payment methods are accepted for MJ4035?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJ4035 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJ4035?

MJ4035 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJ4035 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 MJ4035?

For technical support, including MJ4035 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJ4035 requirements.

6.How does Aetrix verify that MJ4035 is sourced from the original manufacturer or authorized distributors?

All MJ4035 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 MJ4035 meets industry standards.

7.What is the process for return or replacement of MJ4035?

All MJ4035 units undergo pre-shipment inspection (PSI). If there is an issue with MJ4035, 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 MJ4035 part is unused and in its original packaging.

Return procedure for MJ4035:

1.Submit a request within 90 days.

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

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