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

onsemi 2N3904_J05Z

Name: 2N3904_J05Z
Brand: onsemi
SKU: 2N3904_J05Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2N3904_J05Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: 2N3904_J05Z.pdf

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

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Product details

Overview

2N3904_J05Z from ON Semiconductor is an NPN general-purpose bipolar junction transistor used for amplification and switching in low-power analog and digital circuits, with 40 V V_CEO, 200 mA I_C, 300 MHz f_T, 0.2 V V_CE(sat) at 10 mA/1 mA, and TO-92 3L package - widely deployed in signal conditioning, logic-level translation, and discrete amplifier stages.

For engineers reviewing the 2N3904_J05Z datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specifications, thermal derating behavior, switching timing (t_d/t_r/t_s/t_f), h_FE vs. I_C curves, and real-world substitution guidance for legacy Fairchild/ON Semi BJT designs.

Technical Context

The 2N3904_J05Z operates as a silicon NPN BJT with epitaxial base construction, optimized for linear amplification up to 100 MHz and fast-switching operation with 35 ns delay time and 50 ns fall time under standard test conditions (V_CC = 3.0 V, I_C = 10 mA). Its DC current gain spans 40–300 across collector currents from 0.1 mA to 100 mA, supporting both small-signal and medium-current switching roles.

Thermal performance is defined by R_θJA = 200°C/W on FR-4 PCB (1.6" × 1.6"), enabling stable operation up to +125°C ambient when power dissipation remains within the 625 mW limit at 25°C, derated at 5.0 mW/°C above that temperature - critical for thermally constrained consumer and industrial PCB layouts.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; sets upper rail limit for common-emitter amplifier or switch stage.
I_C (max)	200 mA - Continuous collector current rating; defines maximum load drive capability in saturated switching applications.
f_T	300 MHz - Unity-gain bandwidth; determines usable frequency range for RF amplification or high-speed pulse shaping.
V_CE(sat)	0.2 V @ I_C=10 mA, I_B=1 mA - Low saturation voltage enables efficient low-drop switching in 3.3 V/5 V logic interfaces.
h_FE	100 @ I_C=10 mA, V_CE=1 V - Confirmed DC current gain for bias design; supports predictable base resistor sizing in amplifier configurations.
P_D	625 mW @ T_A=25°C - Total power dissipation limit; requires thermal derating above 25°C (5.0 mW/°C) to maintain T_J ≤ 150°C.
t_s	200 ns @ I_C=10 mA - Storage time directly impacts turn-off speed in saturated switching; critical for PWM duty cycle fidelity.

Pinout & Package

2N3904_J05Z is housed in a through-hole TO-92 3L package with EBC (Emitter-Base-Collector) lead configuration, standardized per JEDEC TO-92 outline. The package supports manual soldering and wave soldering, with mechanical dimensions of 4.6 mm × 3.3 mm × 4.0 mm (L × W × H) and 2.54 mm lead pitch.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or low-impedance return path in common-emitter topology.
2 (Base)	Control input	Receives forward-biased current to enable conduction; requires series resistor to limit I_B and ensure proper h_FE-based saturation.
3 (Collector)	Current source terminal	Drives load toward V_CC; must be rated for V_CEO and peak I_C in switching applications.

Key Features

Feature	Design Value
DC current gain range	h_FE = 40–300 across 0.1–100 mA I_C, enabling consistent bias design over wide operating current range.
Low saturation voltage	V_CE(sat) ≤ 0.3 V up to 50 mA I_C, minimizing power loss and heat generation in switching regulators and digital drivers.
High-frequency response	f_T = 300 MHz ensures stable small-signal amplification in audio preamps, oscillator buffers, and RF front-end stages.
Fast switching performance	Combined t_d + t_r + t_s + t_f < 325 ns supports >1 MHz digital signal routing and pulse-width modulation without distortion.
Robust thermal margin	R_θJA = 200°C/W and T_J(max) = 150°C allow reliable operation in enclosed enclosures up to +70°C ambient with minimal heatsinking.

Applications

Audio Signal Amplification	Microcontroller GPIO Expansion
Use Scenario: Boosting weak microphone or line-level signals prior to ADC sampling in portable audio devices. IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with fixed bias or emitter degeneration. Use Value: 300 MHz f_T and 5 dB noise figure at 100 μA support clean amplification across 20 Hz–20 kHz with minimal added distortion.	Use Scenario: Driving LEDs, relays, or MOSFET gates from low-current MCU outputs (e.g., 3.3 V GPIO). IC Role / Device Role / Timing Role: Digital switch in common-emitter saturation mode, controlled by microcontroller output pin. Use Value: 0.2 V V_CE(sat) at 10 mA reduces power loss and enables direct interface with 3.3 V logic without level-shifting circuitry.
Linear Voltage Regulation	Pulse Generator Buffer Stage
Use Scenario: Pass element in discrete adjustable LDOs or shunt regulators requiring precise current control. IC Role / Device Role / Timing Role: Series-pass transistor regulating output voltage via feedback-controlled base current. Use Value: Stable h_FE vs. temperature and 6.0 V V_EBO rating support robust base-drive design under varying load and thermal conditions.	Use Scenario: Isolating and amplifying TTL/CMOS clock pulses before distribution to multiple loads. IC Role / Device Role / Timing Role: Emitter-follower buffer providing low-output-impedance drive while preserving edge integrity. Use Value: 35 ns rise/fall times and 4.0 pF C_obo minimize pulse skew and jitter in multi-load clock trees.

Audio Signal Amplification

Microcontroller GPIO Expansion

Use Scenario: Boosting weak microphone or line-level signals prior to ADC sampling in portable audio devices.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier in common-emitter configuration with fixed bias or emitter degeneration.

Use Value: 300 MHz f_T and 5 dB noise figure at 100 μA support clean amplification across 20 Hz–20 kHz with minimal added distortion.

Use Scenario: Driving LEDs, relays, or MOSFET gates from low-current MCU outputs (e.g., 3.3 V GPIO).

IC Role / Device Role / Timing Role: Digital switch in common-emitter saturation mode, controlled by microcontroller output pin.

Use Value: 0.2 V V_CE(sat) at 10 mA reduces power loss and enables direct interface with 3.3 V logic without level-shifting circuitry.

Linear Voltage Regulation

Pulse Generator Buffer Stage

Use Scenario: Pass element in discrete adjustable LDOs or shunt regulators requiring precise current control.

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

Use Value: Stable h_FE vs. temperature and 6.0 V V_EBO rating support robust base-drive design under varying load and thermal conditions.

Use Scenario: Isolating and amplifying TTL/CMOS clock pulses before distribution to multiple loads.

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

Use Value: 35 ns rise/fall times and 4.0 pF C_obo minimize pulse skew and jitter in multi-load clock trees.

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; P_D = 350 mW; same electrical specs except thermal limits.	Required for space-constrained PCBs; unsuitable for through-hole prototyping or high-power analog stages.	Select MMBT3904 only when board area is limited and power dissipation stays below 250 mW.
PZT3904	SOT-223 package; R_θJA = 125°C/W; P_D = 1000 mW; identical h_FE, V_CEO, and f_T but higher thermal capacity.	Preferred for higher-current switching (e.g., >150 mA loads) where TO-92 thermal limits are exceeded.	Choose PZT3904 when continuous I_C exceeds 120 mA or ambient temperature exceeds 60°C.

Compared with MMBT3904 and PZT3904, the 2N3904_J05Z provides optimal balance of manufacturability, thermal headroom, and legacy compatibility in through-hole designs - offering higher power handling than SOT-23 and lower cost/mounting complexity than SOT-223 for mid-range current applications.

Availability

2N3904_J05Z is available at Aetrix Electronics and suitable for audio preamplifiers, microcontroller peripheral drivers, linear voltage regulation, and pulse buffering requiring stable component supply and long-term obsolescence management.

Supply support for 2N3904_J05Z 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, sensor, and logic solutions for automotive, industrial, cloud computing, and consumer markets.

The 2N3904_J05Z belongs to ON Semiconductor's legacy general-purpose BJT product line, originally developed by Fairchild Semiconductor and maintained for broad compatibility in discrete amplifier and switching applications across decades of electronic design.

FAQ

What is the maximum collector-emitter voltage rating for the 2N3904_J05Z?

The 2N3904_J05Z has a V_CEO rating of 40 V, meaning it can safely withstand up to 40 volts between collector and emitter with the base open. This rating is critical for selecting appropriate supply rails and ensuring reliability in amplifier or switching circuits - exceeding this voltage risks avalanche breakdown and permanent device failure. Always verify operating V_CE remains below 40 V under all transient and steady-state conditions for the 2N3904_J05Z.

Does the 2N3904_J05Z support high-frequency amplification?

Yes, the 2N3904_J05Z delivers a current gain–bandwidth product (f_T) of 300 MHz under standard test conditions (I_C = 10 mA, V_CE = 20 V), making it suitable for RF amplification up to ~100 MHz and high-fidelity audio signal processing. Its 8.0 pF C_ibo and 4.0 pF C_obo contribute to stable impedance matching in tuned circuits - confirm layout parasitics and bias stability for your specific 2N3904_J05Z implementation.

What is the typical DC current gain (h_FE) of the 2N3904_J05Z at 10 mA collector current?

The 2N3904_J05Z exhibits a minimum h_FE of 100 and a maximum of 300 at I_C = 10 mA and V_CE = 1.0 V, with typical values around 150–200 in production lots. This wide gain spread necessitates design margining - use worst-case h_FE = 100 for saturation assurance and h_FE = 300 for linear amplifier bias stability. Always validate h_FE in-circuit for your specific 2N3904_J05Z application.

Can the 2N3904_J05Z be used in switching applications?

Yes, the 2N3904_J05Z is explicitly characterized for switching use, with documented t_d = 35 ns, t_r = 35 ns, t_s = 200 ns, and t_f = 50 ns under V_CC = 3.0 V, I_C = 10 mA conditions. Its low V_CE(sat) (0.2 V) and fast storage time make it effective in digital logic interfacing, LED drivers, and PWM-controlled loads - ensure base drive meets I_B ≥ I_C/10 for hard saturation in your 2N3904_J05Z design.

What is the thermal resistance (R_θJA) of the 2N3904_J05Z in its TO-92 package?

The 2N3904_J05Z has an R_θJA of 200°C/W when mounted on a standard FR-4 PCB (1.6" × 1.6" × 0.06"). This means junction temperature rises 200°C per watt of dissipated power above ambient - at 25°C ambient and 625 mW dissipation, T_J reaches 150°C (maximum rated). Derate linearly above 25°C at 5.0 mW/°C to stay within safe limits for long-term reliability of the 2N3904_J05Z.

2N3904_J05Z 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

2N3904_J05Z FAQ

1.How can I place an order for 2N3904_J05Z through Aetrix?

Please submit a Request for Quotation (RFQ) for 2N3904_J05Z 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_J05Z reliable?

The price and inventory of 2N3904_J05Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2N3904_J05Z is usually 5 days.

3.What payment methods are accepted for 2N3904_J05Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2N3904_J05Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2N3904_J05Z?

2N3904_J05Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2N3904_J05Z 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_J05Z?

For technical support, including 2N3904_J05Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2N3904_J05Z requirements.

6.How does Aetrix verify that 2N3904_J05Z is sourced from the original manufacturer or authorized distributors?

All 2N3904_J05Z 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_J05Z meets industry standards.

7.What is the process for return or replacement of 2N3904_J05Z?

All 2N3904_J05Z units undergo pre-shipment inspection (PSI). If there is an issue with 2N3904_J05Z, 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_J05Z part is unused and in its original packaging.

Return procedure for 2N3904_J05Z:

1.Submit a request within 90 days.

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

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