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

NXP Semiconductors 2N3904,412

Name: 2N3904,412
Brand: NXP Semiconductors
SKU: 2N3904,412
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N3904,412

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: 2N3904,412.pdf

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

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Product details

Overview

2N3904,412 from Nexperia (formerly Philips Semiconductors) is an NPN general-purpose switching transistor in TO-92 (SOT54) package, rated for 40 V V_CEO, 200 mA I_C, and 500 mW P_tot, widely used in low-power digital logic interfacing, signal amplification, and discrete amplifier stages in consumer and industrial electronics.

For engineers reviewing the 2N3904,412 datasheet, 2N3904,412 pinout, 2N3904,412 application, or 2N3904,412 equivalent, key selection considerations include DC current gain (h_FE = 100–300 at I_C = 10 mA), switching speed (t_off = 240 ns), saturation voltage (V_CEsat ≤ 200 mV), thermal resistance (R_th(j-a) = 250 K/W), and TO-92 mechanical compatibility.

Technical Context

The 2N3904,412 operates as a silicon NPN bipolar junction transistor with base-controlled current amplification. Its design supports linear amplification (h_FE specified across 0.1–100 mA I_C) and fast switching (f_T = 300 MHz, t_on/t_off < 70/240 ns) under standard bias conditions (V_CE = 1–20 V).

It features low leakage (I_CBO ≤ 50 nA), moderate noise figure (F ≤ 5 dB), and defined capacitances (C_c = 4 pF, C_e = 8 pF), enabling stable operation in audio preamps, pulse generators, and level-shifting circuits where predictable gain and turn-on/turn-off behavior are required.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - maximum collector-emitter voltage before breakdown; defines safe operating range in common-emitter switch configurations.
I_C (DC)	200 mA - continuous collector current limit; sets upper bound for steady-state load driving capability.
h_FE	100–300 at I_C = 10 mA - DC current gain range; determines base drive requirement for saturated switching or linear amplification.
V_CEsat	≤ 200 mV at I_C = 10 mA / I_B = 1 mA - low saturation voltage enables efficient on-state power dissipation in switching applications.
f_T	300 MHz - transition frequency; indicates usable bandwidth for small-signal amplification up to ~100 MHz with gain >1.
R_th(j-a)	250 K/W - junction-to-ambient thermal resistance on FR4 PCB; informs derating needed above 25 °C ambient.
t_off	240 ns - total turn-off time (10%–90%); critical for high-frequency digital switching up to ~1 MHz repetition rate.

Pinout & Package

Package: TO-92 (SOT54), plastic single-ended leaded through-hole package with 3 leads; standardized mechanical outline per IEC 60134, 5.2 mm height, 4.8 mm body width, 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1	Collector	Main current output terminal; connects to load or supply rail in common-emitter configuration.
2	Base	Control input; requires current-limited drive (typically via resistor) to bias transistor into active/saturation region.
3	Emitter	Current return path; commonly grounded in low-side switch or tied to reference in amplifier topologies.

Key Features

Feature	Design Value
Low-voltage switching	Rated for 40 V V_CEO and 6 V V_EBO, suitable for 3.3 V/5 V logic-level interface without level shifters.
High-speed response	Turn-off time of 240 ns and f_T = 300 MHz support reliable operation in pulse-width modulation and clock buffering.
Predictable DC gain	h_FE guaranteed 100–300 at 10 mA allows consistent base resistor calculation across production lots.
Thermally robust packaging	TO-92 package with R_th(j-a) = 250 K/W enables operation up to +125 °C ambient with appropriate PCB copper area.

Applications

LED Driver Circuit	Digital Logic Level Shifter
Use Scenario: Driving 20 mA indicator LEDs from microcontroller GPIO pins. IC Role / Device Role / Timing Role: Low-side NPN switch controlled by TTL/CMOS logic levels. Use Value: V_CEsat ≤ 200 mV minimizes LED series resistor power loss; h_FE ≥ 100 ensures full saturation with ≤200 µA base drive.	Use Scenario: Translating 3.3 V logic signals to 5 V domains in mixed-voltage systems. IC Role / Device Role / Timing Role: Active-high level translator using common-emitter topology. Use Value: f_T = 300 MHz and t_off = 240 ns support clean translation of signals up to 1 MHz without distortion.
Audio Pre-amplifier Stage	Pulse Generator Buffer
Use Scenario: First-stage amplification of microphone or sensor signals in battery-powered audio devices. IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier biased in linear region. Use Value: Low noise figure (F ≤ 5 dB) and stable h_FE across 0.1–10 mA enable high SNR and repeatable gain calibration.	Use Scenario: Isolating and strengthening TTL clock pulses before distribution to multiple loads. IC Role / Device Role / Timing Role: Emitter-follower buffer providing low-output-impedance drive. Use Value: C_e = 8 pF and C_c = 4 pF minimize capacitive loading; fast switching preserves edge integrity in 10–100 ns pulse trains.

LED Driver Circuit

Digital Logic Level Shifter

Use Scenario: Driving 20 mA indicator LEDs from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Low-side NPN switch controlled by TTL/CMOS logic levels.

Use Value: V_CEsat ≤ 200 mV minimizes LED series resistor power loss; h_FE ≥ 100 ensures full saturation with ≤200 µA base drive.

Use Scenario: Translating 3.3 V logic signals to 5 V domains in mixed-voltage systems.

IC Role / Device Role / Timing Role: Active-high level translator using common-emitter topology.

Use Value: f_T = 300 MHz and t_off = 240 ns support clean translation of signals up to 1 MHz without distortion.

Audio Pre-amplifier Stage

Pulse Generator Buffer

Use Scenario: First-stage amplification of microphone or sensor signals in battery-powered audio devices.

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier biased in linear region.

Use Value: Low noise figure (F ≤ 5 dB) and stable h_FE across 0.1–10 mA enable high SNR and repeatable gain calibration.

Use Scenario: Isolating and strengthening TTL clock pulses before distribution to multiple loads.

IC Role / Device Role / Timing Role: Emitter-follower buffer providing low-output-impedance drive.

Use Value: C_e = 8 pF and C_c = 4 pF minimize capacitive loading; fast switching preserves edge integrity in 10–100 ns pulse trains.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC547B,412	Higher h_FE (200–450), same V_CEO/I_C, TO-92 package.	Better suited for low-base-drive applications; slightly higher leakage (I_CBO ≤ 100 nA).	Select when higher DC gain reduces base resistor count or improves margin in marginal drive conditions.
MPS2222A	Higher I_C (600 mA), higher V_CEO (40 V), same TO-92 footprint but different pinout (E-B-C vs C-B-E).	Not pin-compatible; requires PCB layout change; preferred for higher-current switching.	Choose only if load current exceeds 200 mA and board revision permits pinout rework.

Compared with BC547B,412 and MPS2222A, the 2N3904,412 offers tighter h_FE consistency at mid-currents and proven reliability in legacy designs, while maintaining lowest cost and broadest second-source availability among TO-92 NPN transistors.

Availability

2N3904,412 is available at Aetrix Electronics and suitable for LED driver circuits, digital logic level shifting, audio pre-amplifier stages, and pulse generator buffering requiring stable component supply and long-term obsolescence management.

Supply support for 2N3904,412 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

Nexperia is a global semiconductor expert in discrete, logic, and MOSFET devices, formed from the former Standard Products division of Philips Semiconductors and now part of Beijing JianGuang Asset Management Co., Ltd.

The 2N3904,412 belongs to Nexperia's legacy bipolar transistor portfolio, designed specifically for cost-sensitive, high-volume general-purpose switching and amplification in consumer, industrial, and automotive auxiliary systems.

FAQ

What is the maximum continuous collector current rating for the 2N3904,412?

The 2N3904,412 has a maximum continuous DC collector current (I_C) rating of 200 mA at T_amb ≤ 25 °C. Derating is required above this temperature per its thermal resistance of 250 K/W; at 75 °C ambient, the usable I_C drops to approximately 120 mA to maintain junction temperature below 150 °C. This rating applies under standard FR4 PCB mounting conditions as defined in the datasheet.

Is the 2N3904,412 pin-compatible with the 2N3906?

No, the 2N3904,412 is not pin-compatible with the 2N3906 despite sharing the same TO-92 package. Both use the same physical pinout (collector-base-emitter for 2N3904,412; emitter-base-collector for 2N3906), but their complementary polarity means direct substitution without circuit redesign will result in incorrect biasing or device failure. The 2N3906 serves as the PNP complement-not a drop-in replacement-for the 2N3904,412.

What is the typical DC current gain (h_FE) of the 2N3904,412 at 10 mA collector current?

The 2N3904,412 exhibits a typical DC current gain (h_FE) of 100–300 at V_CE = 1 V and I_C = 10 mA, as specified in the Philips/Nexperia datasheet. This range reflects production lot variation and ensures sufficient gain margin for reliable saturation in switching applications using standard base resistors. Gain decreases at lower and higher currents-e.g., 80 at 1 mA and 60 at 50 mA.

Can the 2N3904,412 be used in linear amplifier configurations?

Yes, the 2N3904,412 is qualified for linear amplifier use, with characterized h_FE, noise figure (≤5 dB), and capacitances (C_c = 4 pF, C_e = 8 pF) supporting stable small-signal operation. It is commonly deployed in audio pre-amplifiers and sensor signal conditioning where gain stability and low noise at 100 µA–10 mA bias points are required. Avoid operation near absolute maximum ratings to preserve linearity.

What is the thermal resistance (R_th(j-a)) of the 2N3904,412 and how does it affect PCB layout?

The 2N3904,412 has a junction-to-ambient thermal resistance (R_th(j-a)) of 250 K/W when mounted on a standard FR4 PCB with minimal copper. To improve heat dissipation, increase copper area around the emitter pad and use thermal vias-each additional 1 cm² of 2-oz copper can reduce R_th(j-a) by ~30–50 K/W. This directly impacts allowable power dissipation: at 75 °C ambient, max P_tot drops from 500 mW to ~300 mW without enhanced cooling.

2N3904,412 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

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

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:: 200mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 50nA (ICBO)

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

Power - Max:: 500 mW

Frequency - Transition:: 300MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

2N3904,412 FAQ

1.How can I place an order for 2N3904,412 through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N3904,412 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 2N3904,412 reliable?

The price and inventory of 2N3904,412 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N3904,412 is usually 5 days.

3.What payment methods are accepted for 2N3904,412?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N3904,412 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N3904,412?

2N3904,412 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N3904,412 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 2N3904,412?

For technical support, including 2N3904,412 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N3904,412 requirements.

6.How does Aetrix verify that 2N3904,412 is sourced from the original manufacturer or authorized distributors?

All 2N3904,412 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 2N3904,412 meets industry standards.

7.What is the process for return or replacement of 2N3904,412?

All 2N3904,412 units undergo pre-shipment inspection (PSI). If there is an issue with 2N3904,412, 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 2N3904,412 part is unused and in its original packaging.

Return procedure for 2N3904,412:

1.Submit a request within 90 days.

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

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