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

onsemi MJE702STU

Name: MJE702STU
Brand: onsemi
SKU: MJE702STU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJE702STU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: MJE702STU.pdf

Description:: TRANS PNP DARL 80V 4A TO-126-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJE702STU from Fairchild Semiconductor is a PNP epitaxial silicon Darlington transistor in TO-126 package, rated for -80 V V_CEO, -4 A I_C, and 40 W power dissipation at T_C = 25°C, with built-in base-emitter resistors (R1 ≈ 10 kΩ, R2 ≈ 0.6 kΩ), commonly used in high-gain linear amplification and medium-power switching circuits.

For engineers reviewing the MJE702STU datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO = -80 V, h_FE ≥ 750 @ I_C = -1.5 A, V_CE(sat) ≤ -2.5 V, integrated bias resistors, and TO-126 thermal performance under continuous DC or pulsed load conditions.

Technical Context

The MJE702STU implements a monolithic Darlington pair with integrated base-emitter resistors to simplify external biasing and improve turn-off speed. Its structure delivers high DC current gain while maintaining stable operation up to 150°C junction temperature.

It is electrically complementary to the NPN MJE802 series and designed for direct substitution in legacy linear regulator, relay driver, and audio output stage designs where -80 V breakdown and low saturation voltage are required.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-80 V - Maximum collector-emitter voltage before avalanche breakdown; defines safe operating range in high-voltage PNP switching applications.
I_C	-4 A - Continuous DC collector current rating; supports medium-power loads such as solenoid drivers and power supply pass transistors.
P_C	40 W @ T_C = 25°C - Thermal power limit at case temperature; requires heatsinking for sustained operation above ~10 W.
h_FE	≥ 750 @ V_CE = -3 V, I_C = -1.5 A - High DC current gain enables low-base-drive-current control in amplifier and switch configurations.
V_CE(sat)	≤ -2.5 V @ I_C = -1.5 A, I_B = -30 mA - Low saturation voltage reduces conduction loss and improves efficiency in saturated-switch applications.
R1 / R2	≈ 10 kΩ / ≈ 0.6 kΩ - Integrated base-emitter resistors provide self-biasing and accelerate turn-off; eliminates need for external base resistor network.

Pinout & Package

Package: TO-126 - Three-lead plastic power package with metal tab (collector-connected) for mechanical mounting and thermal conduction. Dimensions: 16.10 × 13.06 × 4.2 mm (L × W × H), lead pitch 2.28 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal of Darlington pair	Connected to most positive rail in PNP configuration; carries full load current and sets reference for base drive polarity.
2 (Collector)	Collector terminal (tab-connected)	Internally bonded to metal tab; must be electrically isolated from heatsink unless circuit design permits common-collector connection.
3 (Base)	Input control node with internal R1/R2 network	Accepts TTL/CMOS-compatible negative-going drive; R1 pulls base toward emitter, R2 provides discharge path for faster turn-off.

Key Features

Feature	Design Value
Monolithic Darlington construction	Single-die integration ensures matched transistor characteristics, consistent gain, and improved thermal tracking vs. discrete pairs.
Built-in base-emitter resistors	R1 ≈ 10 kΩ and R2 ≈ 0.6 kΩ eliminate external bias components, reduce PCB area, and improve reliability in industrial controls.
V_CEO = -80 V rating	Supports operation in 48 V and 60 V DC systems with margin; suitable for telecom power supplies and industrial motor controls.
h_FE ≥ 750 at I_C = -1.5 A	Enables microcontroller-level base drive (e.g., 3.3 V GPIO with series resistor) without additional driver stages in low-frequency switching.

Applications

Linear Voltage Regulator	DC Motor Driver
Use Scenario: Used as pass transistor in adjustable negative-voltage regulators delivering up to -3 A at -5 to -48 V output. IC Role / Device Role / Timing Role: PNP Darlington pass element controlling output voltage via feedback loop; handles bulk current and dissipates regulation heat. Use Value: High h_FE minimizes base drive current burden on error amplifier; -80 V V_CEO accommodates input-to-output differentials up to -40 V.	Use Scenario: Drives brushed DC motors in industrial actuators requiring bidirectional control with external H-bridge logic. IC Role / Device Role / Timing Role: High-side PNP switch enabling ground-referenced motor control; operates in saturation for low-loss conduction. Use Value: V_CE(sat) ≤ -2.5 V at -1.5 A limits power loss to < 3.75 W; TO-126 package allows direct heatsink mounting for 100% duty-cycle operation.
Relay Driver Circuit	Audio Output Stage
Use Scenario: Switches 24–48 V DC relays in PLC I/O modules with opto-isolated inputs. IC Role / Device Role / Timing Role: Medium-power interface device translating logic-level signals into high-current coil drive. Use Value: Integrated R1/R2 ensures clean turn-on/turn-off without external timing components; -100 µA I_CEO guarantees reliable off-state isolation.	Use Scenario: Output stage in Class AB negative-supply audio amplifiers delivering 5–10 W into 4–8 Ω loads. IC Role / Device Role / Timing Role: Complementary PNP output transistor paired with NPN MJE802; handles negative half-cycle current delivery. Use Value: Matched h_FE and V_BE(on) with MJE802 minimizes crossover distortion; -1.2 V V_BE(on) at -1.5 A supports stable bias point setting.

Linear Voltage Regulator

DC Motor Driver

Use Scenario: Used as pass transistor in adjustable negative-voltage regulators delivering up to -3 A at -5 to -48 V output.

IC Role / Device Role / Timing Role: PNP Darlington pass element controlling output voltage via feedback loop; handles bulk current and dissipates regulation heat.

Use Value: High h_FE minimizes base drive current burden on error amplifier; -80 V V_CEO accommodates input-to-output differentials up to -40 V.

Use Scenario: Drives brushed DC motors in industrial actuators requiring bidirectional control with external H-bridge logic.

IC Role / Device Role / Timing Role: High-side PNP switch enabling ground-referenced motor control; operates in saturation for low-loss conduction.

Use Value: V_CE(sat) ≤ -2.5 V at -1.5 A limits power loss to < 3.75 W; TO-126 package allows direct heatsink mounting for 100% duty-cycle operation.

Relay Driver Circuit

Audio Output Stage

Use Scenario: Switches 24–48 V DC relays in PLC I/O modules with opto-isolated inputs.

IC Role / Device Role / Timing Role: Medium-power interface device translating logic-level signals into high-current coil drive.

Use Value: Integrated R1/R2 ensures clean turn-on/turn-off without external timing components; -100 µA I_CEO guarantees reliable off-state isolation.

Use Scenario: Output stage in Class AB negative-supply audio amplifiers delivering 5–10 W into 4–8 Ω loads.

IC Role / Device Role / Timing Role: Complementary PNP output transistor paired with NPN MJE802; handles negative half-cycle current delivery.

Use Value: Matched h_FE and V_BE(on) with MJE802 minimizes crossover distortion; -1.2 V V_BE(on) at -1.5 A supports stable bias point setting.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP Darlington transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ON Semiconductor MPSA56	V_CEO = -60 V, I_C = -0.5 A, no built-in resistors, TO-92 package	Lower voltage/current rating; suited only for signal-level or low-power switching	Select when space-constrained PCB layout and low-cost prototyping outweigh power requirements.
STMicroelectronics BD139	NPN polarity, V_CEO = 80 V, I_C = 1.5 A, no integrated resistors, TO-126	Not complementary; requires redesign for PNP function; lacks Darlington gain and bias network	Consider only if redesigning circuit topology to use NPN high-side or low-side configuration with external drive.

Compared with MPSA56 and BD139, the MJE702STU uniquely combines -80 V rating, -4 A capability, Darlington gain ≥ 750, and monolithic bias resistors in TO-126 - making it irreplaceable in legacy high-gain, medium-power PNP switching without board rework.

Availability

MJE702STU is available at Aetrix Electronics and suitable for industrial motor control, relay interface modules, linear power supplies, and audio amplifier output stages requiring stable component supply across long-lifecycle production programs.

Supply support for MJE702STU 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016.

The MJE702STU belongs to Fairchild's legacy bipolar power transistor family, engineered for robustness and simplicity in industrial linear and switching applications where integrated biasing and high DC gain are critical.

FAQ

What is the maximum junction temperature for the MJE702STU?

The MJE702STU has a maximum rated junction temperature (T_J) of 150°C, as specified in its Absolute Maximum Ratings table. This limit governs thermal design - sustained operation near this temperature requires careful heatsink selection and derating per the Power Derating curve. Exceeding 150°C risks permanent degradation of the Darlington structure. The MJE702STU must be operated within this boundary to ensure reliability over its intended service life.

Does the MJE702STU require an external base resistor?

No, the MJE702STU does not require an external base resistor because it integrates two on-die resistors: R1 ≈ 10 kΩ between base and emitter, and R2 ≈ 0.6 kΩ between base and collector. These provide automatic biasing and accelerate turn-off, eliminating the need for discrete base drive components. This feature simplifies circuit design and improves consistency in applications like relay drivers and linear regulators where the MJE702STU is deployed.

Is the MJE702STU pin-compatible with the MJE700 or MJE701?

Yes, the MJE702STU shares the same TO-126 package and identical 1–2–3 pinout (Emitter–Collector–Base) with MJE700, MJE701, and MJE703. However, it is not functionally interchangeable without verification: MJE702STU is rated for -80 V V_CEO and -80 V V_CBO, whereas MJE700/MJE701 are rated for -60 V. Substituting MJE702STU into a -60 V design is safe; substituting lower-rated variants into an -80 V design risks breakdown. Always validate voltage margins in the target circuit.

What is the typical V_BE(on) of the MJE702STU at I_C = -1.5 A?

The typical V_BE(on) of the MJE702STU is -1.2 V when tested at V_CE = -3 V and I_C = -1.5 A. This value reflects the forward voltage drop across the base-emitter junction under standard operating conditions and is critical for accurate bias network design. It remains stable across temperature and supports predictable turn-on behavior in linear and switching applications using the MJE702STU.

Can the MJE702STU be used in audio amplifier output stages?

Yes, the MJE702STU is qualified for use in Class AB audio output stages, particularly in negative-rail configurations. Its high h_FE ≥ 750, low V_CE(sat) ≤ -2.5 V, and matched V_BE(on) characteristics enable low-distortion, thermally stable operation when paired with complementary NPN devices like MJE802. Designers must observe SOA limits and implement appropriate emitter degeneration and thermal compensation to maintain fidelity and reliability in the MJE702STU-based amplifier stage.

MJE702STU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: PNP - Darlington

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

Voltage - Collector Emitter Breakdown (Max):: 80 V

Vce Saturation (Max) @ Ib, Ic:: 2.5V @ 30mA, 1.5A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 1.5A, 3V

Power - Max:: 40 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126-3

MJE702STU FAQ

1.How can I place an order for MJE702STU through Aetrix?

Please submit a Request for Quotation (RFQ) for MJE702STU 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 MJE702STU reliable?

The price and inventory of MJE702STU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE702STU is usually 5 days.

3.What payment methods are accepted for MJE702STU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE702STU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJE702STU?

MJE702STU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJE702STU 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 MJE702STU?

For technical support, including MJE702STU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE702STU requirements.

6.How does Aetrix verify that MJE702STU is sourced from the original manufacturer or authorized distributors?

All MJE702STU 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 MJE702STU meets industry standards.

7.What is the process for return or replacement of MJE702STU?

All MJE702STU units undergo pre-shipment inspection (PSI). If there is an issue with MJE702STU, 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 MJE702STU part is unused and in its original packaging.

Return procedure for MJE702STU:

1.Submit a request within 90 days.

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

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