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

onsemi MJE803G

Name: MJE803G
Brand: onsemi
SKU: MJE803G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJE803G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MJE803G.pdf

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

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Product details

Overview

MJE803G 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 = 2.0 A and V_CE = 3.0 V - used in low-speed switching and linear amplifier stages for industrial control and power supply output stages.

For engineers reviewing the MJE803G datasheet, pinout, applications, or equivalent options, key selection criteria include V_CEO = 80 V, I_C = 4.0 A, h_FE ≥ 750 (min), V_CE(sat) ≤ 2.8 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 MJE803G 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. Its construction supports low-speed switching (t_s, t_r, t_f specified under 10 µs test conditions) and linear amplification up to 1 MHz small-signal bandwidth (h_fe ≥ 1.0 at f = 1.0 MHz).

It operates across –55°C to +150°C junction temperature range and features Pb-free RoHS-compliant packaging. Safe operating area (SOA) curves confirm second-breakdown-limited performance at high V_CE/I_C combinations, with thermally limited conduction above 25°C case temperature per derating curve (0.32 W/°C).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	80 Vdc - maximum collector-emitter voltage before breakdown; defines safe voltage headroom in relay drivers or regulator pass elements.
I_C	4.0 Adc - continuous collector current rating; sets upper limit for load-handling capability in discrete power switches.
h_FE	750 (min) @ I_C = 2.0 A, V_CE = 3.0 V - high DC current gain reduces required base drive current, easing driver circuit design.
V_CE(sat)	2.8 V max @ I_C = 2.0 A, I_B = 40 mA - saturation voltage directly impacts conduction loss and thermal rise in switching applications.
R_JC	3.12 °C/W - junction-to-case thermal resistance; enables accurate heatsink sizing when mounted to metal chassis or heatsink.
P_D	40 W @ T_C = 25°C - total power dissipation limit; requires active thermal management above ambient case temperatures.
T_J Range	–55°C to +150°C - wide junction temperature range supports operation in harsh industrial and automotive under-hood environments.

Pinout & Package

Package: TO-225 (Case 77-09, Style 1), plastic through-hole package with metal tab (collector-connected), lead spacing compatible with standard 0.1" pitch PCB layouts.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main emitter terminal; connects to load return path; electrically isolated from metal tab.
Pins 2 & 4	Collector	Internally tied collector terminals; connected to metal tab for low-inductance heat sinking and current sharing.
Pin 3	Base	Control input; requires current-limited drive due to Darlington architecture; base-emitter resistors suppress leakage.

Key Features

Feature	Design Value
High DC current gain	h_FE = 750 (min) at I_C = 2.0 A - reduces base drive requirements and simplifies driver stage design.
Monolithic Darlington with integrated resistors	Built-in base-emitter resistors suppress leakage multiplication - improves thermal stability and eliminates need for external leakage compensation.
Thermal performance	R_JC = 3.12 °C/W - enables efficient heat transfer to heatsink; supports 40 W dissipation with proper mounting.
Pb-free & RoHS compliant	G-suffix indicates lead-free termination and RoHS compliance - meets global environmental regulations for industrial and consumer products.
Robust SOA	Second-breakdown-limited SOA up to 150°C - allows reliable operation under transient overloads in motor and solenoid drive circuits.

Applications

Relay Drivers	Linear Power Regulators
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 minimal base drive. Use Value: V_CE(sat) ≤ 2.8 V ensures <10 W conduction loss at full load, reducing heatsink size versus single-transistor solutions.	Use Scenario: Pass element in adjustable 0–30 V, 3 A linear bench power supplies. IC Role / Device Role / Timing Role: Series pass transistor regulating output voltage via feedback-controlled base current. Use Value: h_FE ≥ 750 enables precise current mirroring and low-noise regulation without complex driver circuitry.
Motor Control (DC Brushed)	Solenoid Actuation
Use Scenario: H-bridge half-bridge leg driving 12 V, 2.5 A brushed DC motors in factory automation actuators. IC Role / Device Role / Timing Role: Low-speed switching power stage handling bidirectional current with flyback protection. Use Value: 80 V_CEO provides margin against inductive kickback spikes up to 60 V during turn-off.	Use Scenario: High-force 24 V solenoid control in HVAC damper actuators and fluid valve systems. IC Role / Device Role / Timing Role: Sustained-on power switch delivering 4.0 A peak hold current after initial pull-in surge. Use Value: 40 W power rating and 150°C T_J allow continuous duty cycle operation with forced-air cooling.

Relay Drivers

Linear Power Regulators

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 minimal base drive.

Use Value: V_CE(sat) ≤ 2.8 V ensures <10 W conduction loss at full load, reducing heatsink size versus single-transistor solutions.

Use Scenario: Pass element in adjustable 0–30 V, 3 A linear bench power supplies.

IC Role / Device Role / Timing Role: Series pass transistor regulating output voltage via feedback-controlled base current.

Use Value: h_FE ≥ 750 enables precise current mirroring and low-noise regulation without complex driver circuitry.

Motor Control (DC Brushed)

Solenoid Actuation

Use Scenario: H-bridge half-bridge leg driving 12 V, 2.5 A brushed DC motors in factory automation actuators.

IC Role / Device Role / Timing Role: Low-speed switching power stage handling bidirectional current with flyback protection.

Use Value: 80 V_CEO provides margin against inductive kickback spikes up to 60 V during turn-off.

Use Scenario: High-force 24 V solenoid control in HVAC damper actuators and fluid valve systems.

IC Role / Device Role / Timing Role: Sustained-on power switch delivering 4.0 A peak hold current after initial pull-in surge.

Use Value: 40 W power rating and 150°C T_J allow continuous duty cycle operation with forced-air cooling.

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
MJE802G	V_CEO = 80 V, I_C = 4.0 A, but h_FE = 750 (min) tested at I_C = 1.5 A instead of 2.0 A; V_CE(sat) = 2.5 V max at lower drive (I_B = 30 mA).	Better suited for lower-current (<2 A) linear amplifiers where tighter V_CE(sat) tolerance is prioritized over high-I_C gain consistency.	Select MJE802G when base drive is constrained and load current rarely exceeds 2 A.
TIP122	V_CEO = 100 V, I_C = 5.0 A, h_FE = 1000 (min), but R_JC = 5.0 °C/W - higher thermal resistance limits power handling at elevated case temperatures.	Preferred in higher-voltage (≤100 V) or higher-current (≤5 A) applications where SOA margin outweighs thermal efficiency.	Choose TIP122 only if V_CEO > 80 V or I_C > 4.0 A is required; verify heatsink adequacy given higher R_JC.

Compared with MJE802G and TIP122, the MJE803G offers optimal balance of 80 V rating, 4.0 A capability, and verified h_FE ≥ 750 at 2.0 A - making it preferred for industrial relay and solenoid drivers requiring consistent gain at mid-load currents and efficient thermal coupling via its 3.12 °C/W R_JC.

Availability

MJE803G is available at Aetrix Electronics and suitable for industrial relay drivers, linear power regulators, brushed DC motor controllers, and solenoid actuation systems requiring stable component supply and long-term manufacturing continuity.

Supply support for MJE803G 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, and cloud infrastructure markets.

The MJE803G belongs to onsemi's legacy plastic Darlington power transistor family, designed specifically for cost-sensitive, high-reliability industrial control applications requiring robust thermal performance and simplified drive requirements.

FAQ

What is the maximum collector-emitter voltage rating for the MJE803G?

The MJE803G has a maximum collector-emitter voltage (V_CEO) rating of 80 Vdc, as confirmed in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 12, December 2013). This rating applies under specified test conditions (I_C = 50 mA, I_B = 0) and must not be exceeded to prevent device breakdown. The MJE803G is therefore suitable for 24 V and 48 V industrial bus applications with appropriate voltage margin.

Does the MJE803G require external base resistors for stable operation?

No, the MJE803G does not require external base resistors. It features monolithic construction with built-in base-emitter resistors to limit leakage multiplication - a key design feature explicitly stated in the datasheet. These internal resistors enhance thermal stability and eliminate the need for external leakage compensation networks commonly required in discrete Darlington configurations.

What is the thermal resistance from junction to case (R_JC) for the MJE803G?

The thermal resistance from junction to case (R_JC) for the MJE803G is 3.12 °C/W, as specified in the Thermal Characteristics section of the onsemi datasheet. This value assumes proper mechanical mounting of the metal tab to a heatsink with recommended torque and thermal interface material. It enables accurate junction temperature estimation using T_J = T_C + (P_D × R_JC).

Can the MJE803G be used in linear amplifier applications?

Yes, the MJE803G is explicitly designed for general-purpose amplifier applications, as stated in the device overview. Its DC current gain (h_FE ≥ 750 at I_C = 2.0 A), low V_CE(sat), and SOA curves supporting continuous conduction make it suitable for Class-A and Class-AB linear output stages in audio and instrumentation amplifiers - provided adequate heatsinking and bias stability are maintained.

Is the MJE803G RoHS compliant and lead-free?

Yes, the MJE803G is RoHS compliant and lead-free, as indicated by the "G" suffix in its part number and confirmed in the Features section of the onsemi datasheet. The device meets EU Directive 2011/65/EU (RoHS 2) requirements, with Pb-free terminations and packaging validated per onsemi's Pb-Free strategy documentation (SOLDERRM/D reference manual).

MJE803G 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:: 2.8V @ 40mA, 2A

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 750 @ 2A, 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

MJE803G FAQ

1.How can I place an order for MJE803G through Aetrix?

Please submit a Request for Quotation (RFQ) for MJE803G 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 MJE803G reliable?

The price and inventory of MJE803G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE803G is usually 5 days.

3.What payment methods are accepted for MJE803G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE803G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJE803G?

MJE803G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJE803G 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 MJE803G?

For technical support, including MJE803G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE803G requirements.

6.How does Aetrix verify that MJE803G is sourced from the original manufacturer or authorized distributors?

All MJE803G 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 MJE803G meets industry standards.

7.What is the process for return or replacement of MJE803G?

All MJE803G units undergo pre-shipment inspection (PSI). If there is an issue with MJE803G, 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 MJE803G part is unused and in its original packaging.

Return procedure for MJE803G:

1.Submit a request within 90 days.

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

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