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

onsemi MJE802G

Name: MJE802G
Brand: onsemi
SKU: MJE802G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJE802G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MJE802G.pdf

Description:: TRANS NPN DARL 80V 4A TO-126

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJE802G from onsemi is an NPN silicon Darlington power transistor in TO-225 package, rated for 80 V_CEO, 4.0 A collector current, and 40 W power dissipation at T_C = 25°C, with typical DC current gain (h_FE) of 750 at I_C = 1.5 A and V_CE = 3.0 V - used in low-speed switching and linear amplifier stages of industrial control power supplies.

For engineers reviewing the MJE802G datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 80 V, I_C = 4.0 A, h_FE ≥ 750, V_CE(sat) ≤ 2.5 V at I_C/I_B = 250, and thermal resistance R_JC = 3.12 °C/W - all critical for robust thermal design and drive efficiency in discrete power stage implementations.

Technical Context

The MJE802G is a monolithic NPN Darlington pair with built-in base-emitter resistors to suppress leakage multiplication, enabling stable high-gain operation without external bias stabilization. It operates in linear and saturation regions with defined safe operating area (SOA) limits up to 150°C junction temperature, validated by second-breakdown and thermally limited curves in Figures 5–6 of the datasheet.

Its switching behavior is characterized by turn-on/turn-off times measured under pulsed conditions (t_r, t_f ≤ 10 ns), with test circuit parameters including V_CC = 30 V, I_C/I_B = 250, and T_J = 25°C. The device is Pb-free, RoHS-compliant, and designed for mounting on heatsinks via its metal tab (Pin 2/4 collector-connected).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 Vdc - maximum collector-emitter voltage before breakdown under open-base condition; defines upper rail limit in switch-mode or linear regulator output stages.
I_C	4.0 Adc - continuous collector current rating at T_C = 25°C; sets peak load-handling capability in motor drivers or relay drivers.
P_D	40 W - total power dissipation at case temperature 25°C; requires heatsink design supporting ≥3.12 °C/W thermal resistance to maintain T_J ≤ 150°C.
h_FE	750 (min) @ I_C = 1.5 A, V_CE = 3.0 V - high DC current gain reduces required base drive current, easing microcontroller GPIO or logic-level driver interface.
V_CE(sat)	2.5 V max @ I_C = 1.5 A, I_B = 30 mA - low saturation voltage minimizes conduction loss and heat generation in switching applications.
R_JC	3.12 °C/W - junction-to-case thermal resistance; determines minimum heatsink thermal performance needed for reliable long-term operation.

Pinout & Package

Package: TO-225 (Case 77-09, Style 1), plastic molded with metal tab connected to collector (Pins 2 and 4). Mounting tab is electrically active and must be isolated from chassis unless referenced to collector potential.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main emitter terminal; connects to load return path or ground reference in low-side switch configurations.
Pins 2 & 4	Collector	Common collector terminals tied internally; mounted to heatsink; requires electrical isolation if heatsink is grounded.
Pin 3	Base	Control input; driven with current-limited source to achieve target I_C; base-emitter resistors integrated for leakage suppression.

Key Features

Feature	Design Value
High DC current gain	h_FE ≥ 750 at I_C = 1.5 A enables low-base-drive designs compatible with 3.3 V/5 V logic outputs.
Integrated base-emitter resistors	Suppresses leakage multiplication, improving thermal stability and reducing need for external bias compensation networks.
Monolithic Darlington construction	Single-die integration ensures matched transistor characteristics and eliminates inter-device parameter variation in gain and V_BE.
Pb-free and RoHS-compliant	Meets global environmental compliance requirements without derating or process change; suitable for export-controlled industrial systems.

Applications

Industrial Relay Driver	DC Motor Speed Control
Use Scenario: Driving 24 VDC industrial relays with coil currents up to 3.5 A in PLC output modules. IC Role / Device Role / Timing Role: NPN Darlington switch providing high-current, low-saturation switching with logic-level base drive. Use Value: V_CE(sat) ≤ 2.5 V ensures <10 W conduction loss at full load, reducing heatsink size versus single-transistor alternatives.	Use Scenario: PWM-based speed control of brushed 24–48 V DC motors in factory automation conveyors. IC Role / Device Role / Timing Role: Low-speed switching element in half-bridge or single-ended chopper topology. Use Value: SOA-rated up to 150°C junction temperature supports sustained 4 A pulses without second-breakdown failure under 10% duty cycle.
Linear Power Supply Pass Transistor	Heater Temperature Controller
Use Scenario: Series pass element in adjustable 0–30 V, 3 A bench power supply with analog feedback loop. IC Role / Device Role / Timing Role: Linear amplifier operating in active region with fixed V_CE and variable I_C. Use Value: High h_FE (≥750) reduces base drive current demand, minimizing error amplifier loading and improving regulation accuracy.	Use Scenario: Proportional control of resistive heating elements in HVAC zone controllers or lab ovens. IC Role / Device Role / Timing Role: Analog current amplifier modulating heater power based on PID output voltage. Use Value: R_JC = 3.12 °C/W allows direct mounting to aluminum chassis for passive cooling, eliminating fan requirement in Class II enclosures.

Industrial Relay Driver

DC Motor Speed Control

Use Scenario: Driving 24 VDC industrial relays with coil currents up to 3.5 A in PLC output modules.

IC Role / Device Role / Timing Role: NPN Darlington switch providing high-current, low-saturation switching with logic-level base drive.

Use Value: V_CE(sat) ≤ 2.5 V ensures <10 W conduction loss at full load, reducing heatsink size versus single-transistor alternatives.

Use Scenario: PWM-based speed control of brushed 24–48 V DC motors in factory automation conveyors.

IC Role / Device Role / Timing Role: Low-speed switching element in half-bridge or single-ended chopper topology.

Use Value: SOA-rated up to 150°C junction temperature supports sustained 4 A pulses without second-breakdown failure under 10% duty cycle.

Linear Power Supply Pass Transistor

Heater Temperature Controller

Use Scenario: Series pass element in adjustable 0–30 V, 3 A bench power supply with analog feedback loop.

IC Role / Device Role / Timing Role: Linear amplifier operating in active region with fixed V_CE and variable I_C.

Use Value: High h_FE (≥750) reduces base drive current demand, minimizing error amplifier loading and improving regulation accuracy.

Use Scenario: Proportional control of resistive heating elements in HVAC zone controllers or lab ovens.

IC Role / Device Role / Timing Role: Analog current amplifier modulating heater power based on PID output voltage.

Use Value: R_JC = 3.12 °C/W allows direct mounting to aluminum chassis for passive cooling, eliminating fan requirement in Class II enclosures.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TIP122	V_CEO = 100 V, h_FE = 1000 (min), R_JC = 3.0 °C/W, same TO-225 package	Higher voltage margin and gain; slightly better thermal performance	Preferred where >80 V rail tolerance or higher gain stability across temperature is required.
BD679A	V_CEO = 80 V, I_C = 4 A, h_FE = 750 (min), but TO-126 package with lower P_D = 30 W and R_JC = 5.0 °C/W	Limited power handling and thermal capability; unsuitable for sustained 4 A operation without oversized heatsink	Select only for space-constrained PCBs where TO-225 mounting is impractical and average power <20 W.

Compared with TIP122 and BD679A, the MJE802G offers balanced 80 V/4 A capability with industry-standard TO-225 mechanical interface and verified SOA performance up to 150°C - making it optimal for cost-sensitive industrial controls requiring proven reliability and straightforward thermal management.

Availability

MJE802G is available at Aetrix Electronics and suitable for industrial relay drivers, DC motor controllers, linear power supply pass stages, and heater temperature regulators requiring stable component supply and long-term manufacturability.

Supply support for MJE802G 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 manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MJE802G belongs to onsemi's legacy plastic Darlington power transistor family, engineered for general-purpose amplifier and low-speed switching applications where high DC gain, rugged SOA, and thermal reliability are prioritized over RF or high-frequency switching.

FAQ

What is the maximum junction temperature rating for the MJE802G?

The MJE802G has an operating and storage junction temperature range of –55°C to +150°C. This rating is confirmed in the Maximum Ratings table on page 1 of the official datasheet (Rev. 12, December 2013), and the Safe Operating Area curves in Figure 6 assume T_J(pk) ≤ 150°C for pulse operation. Exceeding this limit risks permanent degradation of h_FE and increased leakage.

Does the MJE802G have built-in base-emitter resistors?

Yes, the MJE802G features monolithic construction with built-in base-emitter resistors to limit leakage multiplication - explicitly stated in the Features section of the datasheet. These resistors stabilize bias under temperature variation and reduce sensitivity to external leakage paths, eliminating the need for discrete base-shunt resistors in most linear and switching applications.

What is the collector-emitter saturation voltage (V_CE(sat)) specification for the MJE802G?

The MJE802G specifies V_CE(sat) ≤ 2.5 V at I_C = 1.5 A and I_B = 30 mA, per the Electrical Characteristics table on page 2 of the datasheet. This value applies to the MJE802G and MJE800G variants; higher-current variants (MJE803G) specify up to 3.0 V at I_C = 4.0 A.

Is the MJE802G pin-compatible with the MJE803G?

No - while both share the same TO-225 package and pinout (Style 1: E-C-B-C), the MJE802G and MJE803G differ in electrical ratings: MJE802G is rated for I_C = 4.0 A with h_FE ≥ 750 at I_C = 1.5 A, whereas MJE803G is specified for h_FE ≥ 100 at I_C = 2.0 A and has higher V_CE(sat). They are not drop-in replacements due to divergent gain and saturation behavior.

Can the MJE802G be used in high-frequency switching applications?

No - the MJE802G is explicitly designed for low-speed switching and general-purpose amplifier use, as stated in the product overview. Its dynamic characteristics (e.g., small-signal current gain h_fe = 1.0 at f = 1.0 MHz) and lack of specified switching frequency limits confirm suitability only for applications below ~10 kHz, such as relay driving or slow PWM motor control.

MJE802G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN - 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:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126

MJE802G FAQ

1.How can I place an order for MJE802G through Aetrix?

Please submit a Request for Quotation (RFQ) for MJE802G 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 MJE802G reliable?

The price and inventory of MJE802G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE802G is usually 5 days.

3.What payment methods are accepted for MJE802G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE802G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJE802G?

MJE802G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJE802G 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 MJE802G?

For technical support, including MJE802G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE802G requirements.

6.How does Aetrix verify that MJE802G is sourced from the original manufacturer or authorized distributors?

All MJE802G 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 MJE802G meets industry standards.

7.What is the process for return or replacement of MJE802G?

All MJE802G units undergo pre-shipment inspection (PSI). If there is an issue with MJE802G, 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 MJE802G part is unused and in its original packaging.

Return procedure for MJE802G:

1.Submit a request within 90 days.

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

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