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

onsemi 2N3904NLBU

Name: 2N3904NLBU
Brand: onsemi
SKU: 2N3904NLBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N3904NLBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N3904NLBU.pdf

Description:: TRANS NPN 40V 0.2A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2N3904NLBU from ON Semiconductor is an NPN general-purpose bipolar junction transistor (BJT) designed for amplification and switching in low-power analog and digital circuits. It delivers DC current gain (h_FE) of 70–300 at I_C = 1.0 mA, supports 100 MHz current-gain bandwidth (f_T), withstands 40 V collector-emitter voltage (V_CEO), and operates across −55 °C to +150 °C. It is commonly used in signal conditioning stages of sensor interfaces and discrete logic level translation.

For engineers reviewing the 2N3904NLBU datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO/I_C ratings, thermal resistance (R_θJA = 200 °C/W), TO-92 package mechanical compatibility, and h_FE variation across operating current range.

Technical Context

The 2N3904NLBU implements a planar epitaxial NPN structure optimized for stable DC gain and fast switching. Its base-emitter saturation voltage (V_BE(sat)) ranges from 0.65 V to 0.95 V depending on drive conditions, and collector-emitter saturation voltage (V_CE(sat)) is specified at 0.2 V (I_C = 10 mA, I_B = 1 mA) and 0.3 V (I_C = 50 mA, I_B = 5 mA).

Switching performance is characterized by delay time (t_d) ≤ 35 ns, rise time (t_r) ≤ 35 ns, storage time (t_s) ≤ 200 ns, and fall time (t_f) ≤ 50 ns under defined test conditions (V_CC = 3.0 V, I_C = 10 mA). Small-signal parameters include input capacitance (C_ibo) = 8.0 pF and output capacitance (C_obo) = 4.0 pF at f = 100 kHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; defines upper rail limit in switch/amplifier designs.
I_C (max)	200 mA - Continuous collector current rating; sets maximum load-handling capability in linear or saturated operation.
h_FE	70–300 - DC current gain range at I_C = 1.0 mA, V_CE = 1.0 V; critical for bias stability and amplifier gain predictability.
f_T	300 MHz - Current-gain bandwidth product; determines usable frequency limit for small-signal amplification.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in TO-92 package on standard FR-4 PCB; governs power derating above 25 °C.
V_CE(sat)	0.2 V @ I_C=10 mA/I_B=1 mA - Low saturation voltage enables efficient switching with minimal conduction loss.
NF	5.0 dB @ I_C=100 μA, R_S=1 kΩ - Noise figure in audio-band applications; suitable for low-noise preamplifier front-ends.

Pinout & Package

2N3904NLBU is housed in a through-hole TO-92 3-lead plastic package with EBC (Emitter-Base-Collector) terminal arrangement. The package conforms to JEDEC TO-92 outline and supports manual soldering and wave soldering processes.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink node	Reference terminal for bias network; connects to ground or low-impedance return path in common-emitter configurations.
2 (Base)	Control input	Receives forward-bias current to turn on transistor; requires current-limiting resistor to prevent overdrive.
3 (Collector)	Current source node	Drives load toward supply rail; placed at top of schematic symbol in standard NPN orientation.

Key Features

Feature	Design Value
High DC current gain consistency	h_FE ≥ 70 at I_C = 1.0 mA ensures reliable bias point establishment in discrete amplifier stages.
Low V_CE(sat) at moderate currents	0.2 V saturation voltage minimizes power dissipation in switching applications up to 10 mA load.
100 MHz small-signal bandwidth	f_T = 300 MHz supports RF amplifier use up to ~100 MHz with adequate gain margin.
Wide operating temperature range	−55 °C to +150 °C junction range enables deployment in industrial and automotive under-hood environments.
Low noise performance	5.0 dB noise figure at audio frequencies supports high-fidelity preamplifier and sensor signal conditioning.

Applications

Audio Signal Amplification	Discrete Logic Level Translation
Use Scenario: Amplifying microphone or line-level analog signals in portable audio equipment before ADC sampling. IC Role / Device Role / Timing Role: NPN BJT configured as common-emitter voltage amplifier with fixed bias or emitter-degeneration. Use Value: 5.0 dB noise figure and 300 MHz f_T preserve signal integrity while enabling compact, low-cost gain stages without op-amps.	Use Scenario: Converting 3.3 V logic outputs to interface with 5 V TTL inputs in mixed-voltage microcontroller systems. IC Role / Device Role / Timing Role: Saturated switch operating in cutoff/saturation regions to translate logic states. Use Value: 35 ns rise/fall times and 0.2 V V_CE(sat) ensure fast, low-loss level shifting with minimal propagation delay.
Low-Power Sensor Interface	Relay/LED Driver Stage
Use Scenario: Buffering and amplifying output from thermistors, photodiodes, or bridge-based pressure sensors. IC Role / Device Role / Timing Role: Transimpedance or common-collector buffer stage providing impedance transformation and current gain. Use Value: High h_FE (≥70) and low input capacitance (8.0 pF) maintain sensor signal fidelity and minimize loading effects.	Use Scenario: Driving 12 V relay coils or high-brightness LEDs from MCU GPIO pins with limited current sourcing capability. IC Role / Device Role / Timing Role: Switching element in common-emitter configuration with base current limiting and collector flyback protection. Use Value: 200 mA I_C rating and 40 V V_CEO safely handle typical relay coil inductance and back-EMF transients.

Audio Signal Amplification

Discrete Logic Level Translation

Use Scenario: Amplifying microphone or line-level analog signals in portable audio equipment before ADC sampling.

IC Role / Device Role / Timing Role: NPN BJT configured as common-emitter voltage amplifier with fixed bias or emitter-degeneration.

Use Value: 5.0 dB noise figure and 300 MHz f_T preserve signal integrity while enabling compact, low-cost gain stages without op-amps.

Use Scenario: Converting 3.3 V logic outputs to interface with 5 V TTL inputs in mixed-voltage microcontroller systems.

IC Role / Device Role / Timing Role: Saturated switch operating in cutoff/saturation regions to translate logic states.

Use Value: 35 ns rise/fall times and 0.2 V V_CE(sat) ensure fast, low-loss level shifting with minimal propagation delay.

Low-Power Sensor Interface

Relay/LED Driver Stage

Use Scenario: Buffering and amplifying output from thermistors, photodiodes, or bridge-based pressure sensors.

IC Role / Device Role / Timing Role: Transimpedance or common-collector buffer stage providing impedance transformation and current gain.

Use Value: High h_FE (≥70) and low input capacitance (8.0 pF) maintain sensor signal fidelity and minimize loading effects.

Use Scenario: Driving 12 V relay coils or high-brightness LEDs from MCU GPIO pins with limited current sourcing capability.

IC Role / Device Role / Timing Role: Switching element in common-emitter configuration with base current limiting and collector flyback protection.

Use Value: 200 mA I_C rating and 40 V V_CEO safely handle typical relay coil inductance and back-EMF transients.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT3904	SOT-23 surface-mount package; R_θJA = 357 °C/W; same electrical specs but lower power dissipation (350 mW vs. 625 mW).	Preferred for space-constrained PCBs where reflow assembly is used; unsuitable for through-hole prototyping or high-temperature ambient layouts.	Select MMBT3904 when board area is constrained and thermal management via copper pour is feasible.
PZT3904	SOT-223 package with 4-pin footprint; higher power rating (1000 mW); R_θJA = 125 °C/W; identical electrical characteristics.	Used in higher-current switching applications (e.g., fan control, solenoid drivers) requiring >200 mA pulsed loads or extended thermal margin.	Choose PZT3904 when continuous power dissipation exceeds 300 mW or ambient temperature exceeds 70 °C.

Compared with MMBT3904 and PZT3904, the 2N3904NLBU offers optimal balance of manufacturability (TO-92 through-hole), thermal performance (625 mW PD, 200 °C/W R_θJA), and legacy design compatibility-making it ideal for educational kits, service replacements, and low-volume industrial controls.

Availability

2N3904NLBU is available at Aetrix Electronics and suitable for audio signal conditioning, discrete logic interfacing, and low-power sensor buffering requiring stable component supply and long-term obsolescence resilience.

Supply support for 2N3904NLBU 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 energy-efficient power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.

The 2N3904NLBU belongs to ON Semiconductor's legacy general-purpose transistor product line, originally developed by Fairchild Semiconductor to serve cost-sensitive, high-reliability discrete circuit needs in consumer, industrial, and educational electronics.

FAQ

What is the pin configuration of the 2N3904NLBU?

The 2N3904NLBU uses a TO-92 package with EBC (Emitter-Base-Collector) pinout: Pin 1 is Emitter, Pin 2 is Base, and Pin 3 is Collector. This arrangement is standardized across all 2N3904 variants and must be verified against physical marking before PCB layout. The 2N3904NLBU datasheet confirms this pinout in the mechanical drawing section and absolute maximum ratings table.

Does the 2N3904NLBU support switching applications up to 100 mA?

Yes, the 2N3904NLBU is rated for continuous collector current up to 200 mA and is routinely used in switching applications at 100 mA with appropriate base drive. At I_C = 100 mA and I_B = 10 mA, V_CE(sat) remains below 0.3 V per the datasheet's ON CHARACTERISTICS table. Derating for temperature and reliability is recommended in sustained 100 mA operation, especially above 70 °C ambient.

How does the 2N3904NLBU compare to the MMBT3904 in terms of thermal performance?

The 2N3904NLBU has significantly better thermal performance than the MMBT3904: its R_θJA is 200 °C/W versus 357 °C/W for the SOT-23 variant. This means the 2N3904NLBU can dissipate more power before reaching thermal limits-625 mW vs. 350 mW at 25 °C. The difference arises from the larger TO-92 package mass and leadframe thermal path, making the 2N3904NLBU preferable in non-reflow, higher-power, or elevated-temperature environments.

Is the 2N3904NLBU RoHS compliant and lead-free?

Yes, the 2N3904NLBU is RoHS compliant and lead-free. ON Semiconductor's official product change notice and packaging data confirm that all current 2N3904 variants-including the 2N3904NLBU-meet EU RoHS Directive 2011/65/EU and are manufactured using lead-free terminations and halogen-free molding compounds. Compliance documentation is available in the ON Semiconductor Product Compliance Portal under part number 2N3904NLBU.

Can the 2N3904NLBU be used in linear amplifier designs requiring low distortion?

The 2N3904NLBU is suitable for low-distortion linear amplification at modest gains and frequencies due to its 300 MHz f_T, low C_ibo/C_obo, and predictable h_FE behavior. However, harmonic distortion is not explicitly characterized in the datasheet; designers should verify THD performance empirically in their specific bias and load conditions. For precision low-distortion requirements, dedicated low-noise transistors or op-amps may be preferred-but the 2N3904NLBU remains widely used in cost-sensitive, medium-fidelity analog stages.

2N3904NLBU 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):: 200 mA

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

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 10mA, 1V

Power - Max:: 625 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

2N3904NLBU FAQ

1.How can I place an order for 2N3904NLBU through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N3904NLBU 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 2N3904NLBU reliable?

The price and inventory of 2N3904NLBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N3904NLBU is usually 5 days.

3.What payment methods are accepted for 2N3904NLBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N3904NLBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N3904NLBU?

2N3904NLBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N3904NLBU 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 2N3904NLBU?

For technical support, including 2N3904NLBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N3904NLBU requirements.

6.How does Aetrix verify that 2N3904NLBU is sourced from the original manufacturer or authorized distributors?

All 2N3904NLBU 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 2N3904NLBU meets industry standards.

7.What is the process for return or replacement of 2N3904NLBU?

All 2N3904NLBU units undergo pre-shipment inspection (PSI). If there is an issue with 2N3904NLBU, 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 2N3904NLBU part is unused and in its original packaging.

Return procedure for 2N3904NLBU:

1.Submit a request within 90 days.

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

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