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

onsemi 2N4401_J18Z

Name: 2N4401_J18Z
Brand: onsemi
SKU: 2N4401_J18Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N4401_J18Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: 2N4401_J18Z.pdf

Description:: TRANS NPN 40V 0.6A TO-92-3

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Product details

Overview

2N4401_J18Z from ON Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for medium-power amplification and switching applications with a 600 mA continuous collector current rating, 40 V collector-emitter breakdown voltage, and 250 MHz transition frequency-commonly used in low-voltage DC-DC converter drivers and signal buffering stages.

For engineers reviewing the 2N4401_J18Z datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92 package thermal resistance (R_θJA = 200 °C/W), DC current gain range (h_FE = 40–300 at I_C = 1–150 mA), saturation voltage (V_CE(sat) = 0.40 V @ I_C = 150 mA), and suitability for discrete logic-level switching in industrial control interfaces.

Technical Context

This device operates as a single-element NPN BJT with fixed emitter-base and collector-base junctions, supporting common-emitter, common-base, and common-collector configurations. Its design emphasizes robust DC current gain linearity across 0.1–500 mA collector currents and stable switching performance up to 100 MHz with verified t_d = 15 ns and t_f = 30 ns.

Thermal behavior is defined by a maximum junction temperature of +150 °C and derating of 5.0 mW/°C above 25 °C ambient. Absolute maximum ratings include V_CBO = 60 V, V_EBO = 6.0 V, and P_D = 625 mW under free-air conditions-consistent with JEDEC TO-92 mechanical compliance.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; sets upper rail limit in switch-mode circuits.
I_C (max)	600 mA - Continuous collector current handling; supports relay drivers and small-solenoid actuation.
h_FE	40–300 - DC current gain range at I_C = 1–150 mA; enables predictable base drive sizing in linear and saturated operation.
V_CE(sat)	0.40 V @ I_C = 150 mA - Low saturation voltage reduces conduction loss in high-duty-cycle switching.
f_T	250 MHz - Transition frequency confirms usable bandwidth for audio-frequency amplification and fast digital edge shaping.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in TO-92 package; determines max power dissipation at given ambient temperature.

Pinout & Package

2N4401_J18Z is housed in a through-hole TO-92 3-lead package with standard straight-lead configuration per JEDEC TO-92. Pin identification follows EBC (Emitter-Base-Collector) order when viewed with flat side facing outward and leads pointing downward.

Pin/Terminal	Circuit Role	Design Meaning
1 (Left)	Emitter	Current sink node; connects to ground or low-side return path in common-emitter switches.
2 (Center)	Base	Control input; requires current-limited drive (e.g., 15 mA typical for 150 mA collector switching).
3 (Right)	Collector	Current source node; ties to load supply rail or pull-up resistor in amplifier output stages.

Key Features

Feature	Design Value
Medium-power switching capability	Rated for 600 mA continuous collector current and 625 mW dissipation-enables direct drive of LEDs, small relays, and MOSFET gates without buffer stages.
Wide DC current gain range	h_FE = 40–300 across 1–150 mA ensures consistent biasing across production lots and temperature extremes (−55 to +150 °C).
Fast switching performance	Verified t_d = 15 ns, t_r = 20 ns, t_s = 225 ns, t_f = 30 ns supports PWM frequencies up to ~1 MHz in non-critical timing applications.
Low V_BE(sat)	0.75–0.95 V @ I_C = 150 mA simplifies TTL/CMOS-compatible base drive design using standard logic-level outputs.

Applications

LED Driver Circuits	DC-DC Converter Switches
Use Scenario: Driving high-brightness indicator LEDs or LED strings in industrial HMIs and instrumentation panels. IC Role / Device Role / Timing Role: Discrete NPN switch controlling current flow through LED anode/cathode paths. Use Value: Low V_CE(sat) minimizes forward voltage drop and heat generation; h_FE stability ensures consistent brightness across operating temperature range.	Use Scenario: Acting as the main switching element in low-cost, low-power buck or flyback converters for auxiliary rails. IC Role / Device Role / Timing Role: Primary power switch modulating energy transfer between primary inductor and output capacitor. Use Value: 250 MHz f_T and sub-30 ns fall time support efficient operation at 100–500 kHz switching frequencies with minimal switching loss.
Logic-Level Interface Buffers	Relay and Solenoid Drivers
Use Scenario: Level-shifting and current amplification between microcontroller GPIO pins and higher-current external loads. IC Role / Device Role / Timing Role: Signal translator and current booster enabling 3.3 V/5 V logic to control 12 V/24 V peripherals. Use Value: Verified V_BE(sat) ≤ 0.95 V at I_C = 150 mA allows direct drive from standard CMOS outputs without series resistors exceeding 1 kΩ.	Use Scenario: Activating electromechanical relays or solenoids in PLC I/O modules and HVAC control boards. IC Role / Device Role / Timing Role: High-current switch interfacing low-power controller signals with inductive coil loads. Use Value: 600 mA I_C rating and 60 V V_CBO accommodate typical 12–24 V relay coils with flyback protection diodes.

LED Driver Circuits

DC-DC Converter Switches

Use Scenario: Driving high-brightness indicator LEDs or LED strings in industrial HMIs and instrumentation panels.

IC Role / Device Role / Timing Role: Discrete NPN switch controlling current flow through LED anode/cathode paths.

Use Value: Low V_CE(sat) minimizes forward voltage drop and heat generation; h_FE stability ensures consistent brightness across operating temperature range.

Use Scenario: Acting as the main switching element in low-cost, low-power buck or flyback converters for auxiliary rails.

IC Role / Device Role / Timing Role: Primary power switch modulating energy transfer between primary inductor and output capacitor.

Use Value: 250 MHz f_T and sub-30 ns fall time support efficient operation at 100–500 kHz switching frequencies with minimal switching loss.

Logic-Level Interface Buffers

Relay and Solenoid Drivers

Use Scenario: Level-shifting and current amplification between microcontroller GPIO pins and higher-current external loads.

IC Role / Device Role / Timing Role: Signal translator and current booster enabling 3.3 V/5 V logic to control 12 V/24 V peripherals.

Use Value: Verified V_BE(sat) ≤ 0.95 V at I_C = 150 mA allows direct drive from standard CMOS outputs without series resistors exceeding 1 kΩ.

Use Scenario: Activating electromechanical relays or solenoids in PLC I/O modules and HVAC control boards.

IC Role / Device Role / Timing Role: High-current switch interfacing low-power controller signals with inductive coil loads.

Use Value: 600 mA I_C rating and 60 V V_CBO accommodate typical 12–24 V relay coils with flyback protection diodes.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching and amplification applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT4401	SOT-23 surface-mount package; lower P_D = 350 mW; R_θJA = 357 °C/W; identical electrical specs except reduced thermal capability.	Preferred for space-constrained PCBs where reflow assembly is required; unsuitable for >250 mA continuous loads without heatsinking.	Select MMBT4401 only when board area and assembly method demand SMT; verify thermal margin at target I_C.
2N2222A	Higher V_CEO = 40 V (same), but lower f_T = 250–300 MHz (similar), h_FE min = 35–75 (narrower), and P_D = 500 mW (lower).	Legacy alternative with broader industry familiarity but tighter h_FE tolerance and reduced power handling.	Choose 2N2222A only if legacy design reuse or second-source qualification mandates it; expect higher base drive variability.

Compared with MMBT4401 and 2N2222A, the 2N4401_J18Z offers superior thermal performance in TO-92 packaging and wider h_FE range-making it optimal for new through-hole designs requiring reliable 500 mA switching with minimal thermal derating.

Availability

2N4401_J18Z is available at Aetrix Electronics and suitable for LED driver circuits, DC-DC converter switches, and logic-level interface buffers requiring stable component supply and long-term industrial lifecycle support.

Supply support for 2N4401_J18Z 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 devices for automotive, industrial, and consumer applications.

The 2N4401_J18Z belongs to ON Semiconductor's legacy general-purpose BJT product line, engineered for cost-sensitive, high-reliability discrete switching and amplification in industrial control, power conversion, and interface circuitry.

FAQ

What is the maximum continuous collector current rating for the 2N4401_J18Z?

The 2N4401_J18Z has a maximum continuous collector current (I_C) rating of 600 mA at T_A = 25 °C. This rating decreases linearly with ambient temperature at 5.0 mW/°C derating above 25 °C, and actual usable current depends on PCB layout, airflow, and thermal interface. The 2N4401_J18Z maintains reliable operation up to its absolute maximum junction temperature of +150 °C.

Does the 2N4401_J18Z have a documented pinout configuration, and what is the terminal order?

Yes, the 2N4401_J18Z uses the standard TO-92 package with EBC (Emitter-Base-Collector) pinout when viewed with the flat side facing outward and leads pointing downward: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This configuration is confirmed in ON Semiconductor's official datasheet (MMBT4401/D, Rev. 2, September 2017) and matches JEDEC TO-92 mechanical specifications.

What is the DC current gain (h_FE) range for the 2N4401_J18Z across operating conditions?

The 2N4401_J18Z exhibits a DC current gain (h_FE) range of 40 to 300, measured at V_CE = 1.0 V. Minimum values are specified at I_C = 1.0 mA (h_FE ≥ 40), I_C = 10 mA (≥ 80), and I_C = 150 mA (≥ 100); maximum is 300 at I_C = 1.0 mA. The 2N4401_J18Z maintains usable gain down to −55 °C and up to +125 °C per typical performance curves.

Can the 2N4401_J18Z be used in switching applications above 100 kHz?

Yes, the 2N4401_J18Z supports switching applications up to approximately 1 MHz due to its 250 MHz transition frequency (f_T) and verified switching times: t_d = 15 ns, t_r = 20 ns, t_s = 225 ns, and t_f = 30 ns. In practice, the 2N4401_J18Z delivers efficient performance in 100–500 kHz DC-DC converters when paired with appropriate base drive and snubbing.

What is the thermal resistance (R_θJA) of the 2N4401_J18Z in its TO-92 package?

The 2N4401_J18Z has a junction-to-ambient thermal resistance (R_θJA) of 200 °C/W under standard test conditions (FR-4 PCB, 76 mm × 114 mm, minimum land pattern). This value assumes natural convection cooling; adding copper pour or airflow reduces effective R_θJA. The 2N4401_J18Z's 625 mW power dissipation rating is directly derived from this thermal resistance and its 150 °C maximum junction temperature.

2N4401_J18Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 600 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 750mV @ 50mA, 500mA

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 150mA, 1V

Power - Max:: 625 mW

Frequency - Transition:: 250MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

2N4401_J18Z FAQ

1.How can I place an order for 2N4401_J18Z through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N4401_J18Z 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 2N4401_J18Z reliable?

The price and inventory of 2N4401_J18Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N4401_J18Z is usually 5 days.

3.What payment methods are accepted for 2N4401_J18Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N4401_J18Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N4401_J18Z?

2N4401_J18Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N4401_J18Z 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 2N4401_J18Z?

For technical support, including 2N4401_J18Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N4401_J18Z requirements.

6.How does Aetrix verify that 2N4401_J18Z is sourced from the original manufacturer or authorized distributors?

All 2N4401_J18Z 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 2N4401_J18Z meets industry standards.

7.What is the process for return or replacement of 2N4401_J18Z?

All 2N4401_J18Z units undergo pre-shipment inspection (PSI). If there is an issue with 2N4401_J18Z, 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 2N4401_J18Z part is unused and in its original packaging.

Return procedure for 2N4401_J18Z:

1.Submit a request within 90 days.

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

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