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

onsemi MJD350T4

Name: MJD350T4
Brand: onsemi
SKU: MJD350T4
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MJD350T4

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: MJD350T4.pdf

Description:: TRANS PNP 300V 0.5A DPAK

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MJD350T4 from ON Semiconductor is a high-voltage NPN epitaxial silicon power transistor in D-PAK (TO-252) package, rated for 300 V V_CEO, 0.5 A DC collector current, and 15 W collector dissipation at T_C = 25°C; used in flyback snubber circuits, relay drivers, and industrial switch-mode power supply output stages.

For engineers reviewing the MJD350T4 datasheet, pinout, applications, or equivalent options, key selection criteria include sustained 300 V blocking capability, DC current gain (h_FE) of 30–240 at 50 mA, low V_CE(sat) under switching conditions, thermal performance in surface-mount power applications, and compatibility with standard D-PAK PCB footprints.

Technical Context

This device operates as a single NPN bipolar junction transistor optimized for high-voltage switching rather than linear amplification. Its 300 V V_CEO and V_CBO ratings support use in off-line AC/DC converters where transient voltage spikes exceed 250 V.

The D-PAK package provides enhanced thermal conduction to the PCB via the exposed drain-connected tab (Collector), enabling 15 W power dissipation at case temperature ≤25°C. Safe operating area (SOA) is defined up to 100 µs pulse width with derating above 25°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	300 V - Sustains full-rated collector-emitter voltage with base open; enables use in 230 VAC primary-side switching without external clamping.
I_C (DC)	0.5 A - Continuous collector current limit; defines maximum steady-state load drive capability in relay or solenoid interfaces.
P_C @ T_C=25°C	15 W - Maximum power dissipation with heatsink-equivalent PCB copper; requires ≥250 mm² 2-oz copper pad for full rating.
h_FE	30–240 - DC current gain at V_CE = 10 V, I_C = 50 mA; supports base drive design with 10–30× current amplification.
V_CE(sat)	1.5 V max @ I_C = 0.5 A, I_B = 50 mA - Low saturation voltage reduces conduction loss in high-duty-cycle switching.
T_J max	150 °C - Maximum junction temperature; sets upper thermal limit for reliability-critical industrial environments.

Pinout & Package

D-PAK (TO-252) surface-mount package with exposed collector tab for thermal and electrical connection to PCB ground plane or heatsink.

Pin/Terminal	Circuit Role	Design Meaning
1 (Left)	Base	Control input requiring ~50 mA DC base current to saturate at 0.5 A collector load.
2 (Center)	Collector	High-voltage output node; electrically and thermally connected to exposed metal tab.
3 (Right)	Emitter	Reference terminal for load return path; isolated from tab and PCB thermal plane.

Key Features

Feature	Design Value
High breakdown voltage	300 V V_CEO enables direct interface with 230 VAC rectified rails without series stacking.
Surface-mount thermal performance	15 W P_C at T_C = 25°C achieved via D-PAK's large copper tab and low R_θJC.
Robust SOA	Defined safe operating area up to 100 µs pulse width supports repetitive surge handling in snubber networks.
Industrial temperature range	−65 °C to +150 °C storage and operation ensures reliability in uncontrolled ambient environments.

Applications

Switch-Mode Power Supply Output Stage	AC Relay Driver
Use Scenario: Primary-side switching in 15–30 W offline flyback converters with universal AC input. IC Role / Device Role / Timing Role: High-voltage NPN switch controlling energy transfer into transformer primary winding. Use Value: 300 V V_CEO withstands reflected flyback spikes and line surges without clamping diodes.	Use Scenario: Driving 24 VDC or 120 VAC coil relays in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: Medium-power discrete switch interfacing microcontroller GPIO to inductive load. Use Value: 0.5 A I_C and 15 W P_C support continuous relay hold without forced air cooling.
Inductive Load Snubber Circuit	DC Motor Commutation Switch
Use Scenario: Clamp diode replacement in RCD snubbers for solenoid valve drivers in HVAC control systems. IC Role / Device Role / Timing Role: Transient voltage suppressor absorbing L·di/dt energy during turn-off. Use Value: 300 V V_CBO and robust SOA prevent avalanche failure during repetitive 200 V+ transients.	Use Scenario: Unidirectional H-bridge half-bridge leg in 24 V brushed DC motor controllers for industrial actuators. IC Role / Device Role / Timing Role: High-side or low-side power switch controlling motor current direction and duty cycle. Use Value: Low V_CE(sat) minimizes conduction loss at 0.3–0.5 A average motor current.

Switch-Mode Power Supply Output Stage

AC Relay Driver

Use Scenario: Primary-side switching in 15–30 W offline flyback converters with universal AC input.

IC Role / Device Role / Timing Role: High-voltage NPN switch controlling energy transfer into transformer primary winding.

Use Value: 300 V V_CEO withstands reflected flyback spikes and line surges without clamping diodes.

Use Scenario: Driving 24 VDC or 120 VAC coil relays in programmable logic controller (PLC) output modules.

IC Role / Device Role / Timing Role: Medium-power discrete switch interfacing microcontroller GPIO to inductive load.

Use Value: 0.5 A I_C and 15 W P_C support continuous relay hold without forced air cooling.

Inductive Load Snubber Circuit

DC Motor Commutation Switch

Use Scenario: Clamp diode replacement in RCD snubbers for solenoid valve drivers in HVAC control systems.

IC Role / Device Role / Timing Role: Transient voltage suppressor absorbing L·di/dt energy during turn-off.

Use Value: 300 V V_CBO and robust SOA prevent avalanche failure during repetitive 200 V+ transients.

Use Scenario: Unidirectional H-bridge half-bridge leg in 24 V brushed DC motor controllers for industrial actuators.

IC Role / Device Role / Timing Role: High-side or low-side power switch controlling motor current direction and duty cycle.

Use Value: Low V_CE(sat) minimizes conduction loss at 0.3–0.5 A average motor current.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD340T4	Identical package, same 300 V ratings, but h_FE min = 30 (same as MJD350T4); no functional difference confirmed in datasheet.	No distinction in target applications; both specified for high-voltage switching.	Select MJD340T4 only if legacy BOM alignment or distributor stock availability dictates.
STN3PF30	FET-based alternative: 300 V V_DSS, 0.45 A I_D, logic-level gate; lower drive complexity but higher R_DS(on) than V_CE(sat).	Preferred where gate drive simplicity outweighs conduction loss sensitivity; not drop-in compatible.	Choose STN3PF30 when replacing TTL-compatible base drive with 3.3 V/5 V GPIO control.

Compared with MJD340T4, MJD350T4 offers identical electrical and mechanical specifications per ON Semiconductor documentation; versus STN3PF30, MJD350T4 delivers lower on-state voltage at medium currents but requires current-limited base drive circuitry.

Availability

MJD350T4 is available at Aetrix Electronics and suitable for industrial power supplies, PLC output modules, and HVAC actuator drivers requiring stable component supply across multi-year production cycles.

Supply support for MJD350T4 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

ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud power applications.

The MJD350T4 belongs to ON Semiconductor's high-voltage bipolar transistor product line, engineered for ruggedized switching in off-line power conversion and industrial control where reliability under voltage stress is critical.

FAQ

What is the maximum continuous collector current for MJD350T4?

The MJD350T4 has a maximum DC collector current (I_C) of 0.5 A at T_C = 25°C. This rating assumes adequate PCB copper area for heat dissipation; derating applies above 25°C case temperature per the published power derating curve. Pulse current up to 0.75 A is allowed for ≤300 µs pulses with ≤2% duty cycle. The MJD350T4 must be operated within these limits to ensure long-term reliability.

Does MJD350T4 have a built-in base-emitter resistor?

No, the MJD350T4 is a standard three-terminal NPN bipolar transistor with no integrated base-emitter resistor. It requires an external base current limiting resistor or active driver circuit to establish proper biasing and avoid thermal runaway. This distinguishes it from digital transistors (e.g., NSD series) and confirms its use in discrete amplifier or switch designs where precise gain control is needed. The MJD350T4 datasheet specifies base drive requirements explicitly.

What is the pin configuration of MJD350T4 in the D-PAK package?

The MJD350T4 uses the standard D-PAK (TO-252) pinout: Pin 1 is Base, Pin 2 is Collector (connected to the exposed metal tab), and Pin 3 is Emitter. This configuration is consistent across ON Semiconductor's MJD3xx series and matches JEDEC TO-252 outline drawings. The Collector tab must be soldered to a large copper area for thermal performance; the MJD350T4's electrical and thermal behavior depends on correct tab connection.

Can MJD350T4 replace MJD340T4 in existing designs?

Yes, MJD350T4 is functionally and mechanically interchangeable with MJD340T4: both share identical absolute maximum ratings, electrical characteristics, D-PAK package, and pinout. ON Semiconductor documentation confirms no specification differences between the two part numbers in current production. No layout or schematic changes are required when substituting MJD350T4 for MJD340T4, and the MJD350T4 maintains full compatibility in all intended applications.

What is the typical V_CE(sat) of MJD350T4 at rated current?

The MJD350T4 exhibits a maximum V_CE(sat) of 1.5 V at I_C = 0.5 A and I_B = 50 mA, with typical values around 1.0–1.2 V under those conditions. This saturation voltage directly impacts conduction losses in switching applications; for example, at 0.5 A, power dissipation in saturation is ≤0.75 W. The MJD350T4's V_CE(sat) is verified in the "Electrical Characteristics" table of its official datasheet.

MJD350T4 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Packaging:: Cut Tape (CT)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 300 V

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: 100µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 30 @ 50mA, 10V

Power - Max:: 15 W

Frequency - Transition:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: DPAK

MJD350T4 FAQ

1.How can I place an order for MJD350T4 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJD350T4 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 MJD350T4 reliable?

The price and inventory of MJD350T4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJD350T4 is usually 5 days.

3.What payment methods are accepted for MJD350T4?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJD350T4 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJD350T4?

MJD350T4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJD350T4 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 MJD350T4?

For technical support, including MJD350T4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJD350T4 requirements.

6.How does Aetrix verify that MJD350T4 is sourced from the original manufacturer or authorized distributors?

All MJD350T4 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 MJD350T4 meets industry standards.

7.What is the process for return or replacement of MJD350T4?

All MJD350T4 units undergo pre-shipment inspection (PSI). If there is an issue with MJD350T4, 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 MJD350T4 part is unused and in its original packaging.

Return procedure for MJD350T4:

1.Submit a request within 90 days.

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

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