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

NXP Semiconductors MPS3904,126

Name: MPS3904,126
Brand: NXP Semiconductors
SKU: MPS3904,126
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPS3904,126

Manufacturer:: NXP Semiconductors

Category:: Single Bipolar Transistors

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

Datasheet:: MPS3904,126.pdf

Description:: TRANS NPN 40V 0.1A TO-92-3

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Product details

Overview

MPS3904,126 from Nexperia (formerly Philips Semiconductors) is an NPN general-purpose switching transistor in a TO-92 (SOT54/SC-43A) through-hole package, rated for 40 V V_CEO, 100 mA I_C, and 500 mW P_tot; used in low-voltage logic-level switching, signal amplification, and discrete bias networks in consumer and industrial control circuits.

For engineers reviewing the MPS3904,126 datasheet, MPS3904,126 pinout, MPS3904,126 application, or MPS3904,126 equivalent, key selection considerations include DC current gain (h_FE = 70–300 at I_C = 1–10 mA), saturation voltage (V_CEsat ≤ 300 mV), thermal resistance (R_th(j-a) = 250 K/W), and compatibility with legacy TO-92 PCB footprints.

Technical Context

The MPS3904,126 operates as a silicon NPN bipolar junction transistor optimized for linear amplification and saturated switching in low-power analog and digital circuits. Its h_FE variation across collector current (40–300) and low V_CEsat (≤300 mV at I_C = 50 mA) support stable biasing and efficient on-state conduction.

Designed for ambient temperatures from −65 °C to +150 °C and junction temperatures up to 150 °C, it features low leakage (I_CBO ≤ 50 nA), high transition frequency (f_T = 180 MHz), and fast switching (t_off ≤ 1200 ns), making it suitable for audio preamplifiers, relay drivers, and pulse-width modulation interfaces.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum collector-emitter voltage before breakdown under open-base conditions; defines safe operating range in common-emitter switch configurations.
I_C (DC)	100 mA - Continuous collector current limit; sets maximum steady-state load drive capability without thermal runaway.
P_tot	500 mW - Total power dissipation at T_amb ≤ 25 °C; determines heatsinking requirements on FR4 PCBs.
h_FE	70–300 - DC current gain at V_CE = 1 V; enables predictable base drive sizing for switching or amplification stages.
V_CEsat	≤300 mV - Collector-emitter saturation voltage at I_C = 50 mA / I_B = 5 mA; ensures low conduction loss in saturated switch operation.
f_T	180 MHz - Transition frequency at V_CE = 20 V, I_C = 10 mA; supports small-signal amplification up to VHF band.
R_th(j-a)	250 K/W - Junction-to-ambient thermal resistance on FR4 board; informs temperature rise under load (ΔT = P × R_th).

Pinout & Package

Package: TO-92 (SOT54 / SC-43A), plastic single-ended leaded through-hole package with 3 leads, 2.54 mm lead pitch, and JEDEC-compliant outline.

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 (e.g., via series resistor) to bias transistor into active or saturation region.
3	Emiter	Current return path; typically tied to ground or negative rail in low-side switch or amplifier topologies.

Key Features

Feature	Design Value
Low-voltage switching	Rated for 40 V V_CEO and 60 V V_CBO, enabling use in 3.3 V, 5 V, and 12 V logic-compatible systems without derating.
Wide h_FE range	h_FE = 70–300 across 1–10 mA I_C supports consistent gain behavior in production batches and varying bias conditions.
Fast switching performance	Turn-off time ≤1200 ns and storage time ≤1000 ns allow reliable operation in PWM frequencies up to ~100 kHz.
Low noise figure	F ≤ 5 dB at 100 µA I_C and 1 kHz–15.7 kHz bandwidth, supporting use in low-noise preamplifier front-ends.

Applications

Audio Signal Amplification	Microcontroller GPIO Interface
Use Scenario: Low-noise preamplification of microphone or sensor signals in portable audio devices. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration. Use Value: h_FE ≥ 70 and F ≤ 5 dB ensure sufficient gain and minimal added noise at µA-level bias currents.	Use Scenario: Driving LEDs, relays, or MOSFET gates from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: Low-side saturated switch controlled by MCU GPIO pin. Use Value: V_CEsat ≤ 300 mV minimizes power loss and heat generation during continuous on-state operation.
Discrete Bias Network	Legacy Logic-Level Translation
Use Scenario: Setting reference currents or bias points in analog ICs, op-amp circuits, or voltage regulators. IC Role / Device Role / Timing Role: Current source/sink element in precision bias string or active load configuration. Use Value: Tight I_CBO ≤ 50 nA and stable h_FE enable predictable DC operating point over temperature.	Use Scenario: Level-shifting between TTL/CMOS logic families with differing supply voltages (e.g., 3.3 V MCU to 5 V peripheral). IC Role / Device Role / Timing Role: Inverting buffer stage using common-emitter topology with pull-up resistor. Use Value: Fast t_off ≤ 1200 ns and f_T = 180 MHz support clean edge transitions up to 1 MHz data rates.

Audio Signal Amplification

Microcontroller GPIO Interface

Use Scenario: Low-noise preamplification of microphone or sensor signals in portable audio devices.

IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration.

Use Value: h_FE ≥ 70 and F ≤ 5 dB ensure sufficient gain and minimal added noise at µA-level bias currents.

Use Scenario: Driving LEDs, relays, or MOSFET gates from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: Low-side saturated switch controlled by MCU GPIO pin.

Use Value: V_CEsat ≤ 300 mV minimizes power loss and heat generation during continuous on-state operation.

Discrete Bias Network

Legacy Logic-Level Translation

Use Scenario: Setting reference currents or bias points in analog ICs, op-amp circuits, or voltage regulators.

IC Role / Device Role / Timing Role: Current source/sink element in precision bias string or active load configuration.

Use Value: Tight I_CBO ≤ 50 nA and stable h_FE enable predictable DC operating point over temperature.

Use Scenario: Level-shifting between TTL/CMOS logic families with differing supply voltages (e.g., 3.3 V MCU to 5 V peripheral).

IC Role / Device Role / Timing Role: Inverting buffer stage using common-emitter topology with pull-up resistor.

Use Value: Fast t_off ≤ 1200 ns and f_T = 180 MHz support clean edge transitions up to 1 MHz data rates.

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,114	Same TO-92 package; h_FE = 200–450 at I_C = 2 mA; V_CEO = 45 V; slightly higher gain and voltage rating.	Better suited for higher-gain amplification stages; marginally improved voltage headroom in 5 V systems.	Select BC547B,114 when tighter h_FE tolerance or extended V_CEO margin is required without footprint change.
PN2222A PBFREE	TO-92 package; V_CEO = 40 V; I_C = 800 mA (peak); P_tot = 625 mW; higher current/power capability but wider h_FE spread (100–300).	Preferred for higher-current switching (e.g., solenoid drivers); less optimal for low-noise amplification due to higher F ≈ 10 dB.	Choose PN2222A PBFREE where load current exceeds 100 mA or thermal margin is critical, accepting trade-offs in noise and gain consistency.

Compared with BC547B,114 and PN2222A PBFREE, the MPS3904,126 offers the best balance of low-noise performance (F ≤ 5 dB), tight h_FE control at low I_C, and proven reliability in space-constrained TO-92 layouts-making it ideal for cost-sensitive, low-power signal conditioning and interface circuits.

Availability

MPS3904,126 is available at Aetrix Electronics and suitable for audio preamplification, microcontroller GPIO interfacing, and discrete bias network design requiring stable component supply, long-term obsolescence management, and full traceability.

Supply support for MPS3904,126 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 delivering high-performance, reliable discrete, logic, and MOSFET solutions rooted in its heritage as Philips Semiconductors.

The MPS3904,126 belongs to Nexperia's legacy general-purpose bipolar transistor product line, engineered for robustness, manufacturability, and compatibility with decades-old industrial and consumer designs.

FAQ

What is the maximum collector-emitter voltage rating for the MPS3904,126?

The MPS3904,126 has a maximum collector-emitter voltage (V_CEO) rating of 40 V under open-base conditions. This value is defined per IEC 60134 Absolute Maximum Ratings and must not be exceeded in circuit operation to prevent device breakdown. Derating is recommended above 25 °C ambient temperature per the thermal characteristics table in the official datasheet.

Does the MPS3904,126 have a PNP complement, and what is its part number?

Yes, the MPS3904,126 has a direct PNP complement: the MPS3906,126. Both share identical TO-92 (SOT54) packaging, complementary pinout (emitter and collector swapped), and matched electrical specifications including V_CEO, I_C, and h_FE ranges-enabling balanced push-pull or differential pair implementations using the same footprint.

What is the typical DC current gain (h_FE) of the MPS3904,126 at 10 mA collector current?

At V_CE = 1 V and I_C = 10 mA, the MPS3904,126 exhibits a typical DC current gain (h_FE) of 100–300. This range reflects production batch variation and ensures adequate drive margin for base-resistor calculations in switching applications while maintaining linearity in low-distortion amplification stages.

Can the MPS3904,126 be used in surface-mount designs?

No-the MPS3904,126 is exclusively offered in the through-hole TO-92 (SOT54/SC-43A) package and lacks a surface-mount variant. For SMT equivalents, consider the PBSS4041T (SOT23) or MMBT3904 (SOT23), which share similar electrical specs but require PCB layout revision and requalification.

What is the thermal resistance from junction to ambient for the MPS3904,126 on a standard FR4 PCB?

The thermal resistance from junction to ambient (R_th(j-a)) for the MPS3904,126 is 250 K/W when mounted on a standard FR4 printed-circuit board, as specified in the thermal characteristics section. This value assumes no additional copper pour or heatsinking and directly determines junction temperature rise (ΔT_j = P_diss × 250) under steady-state operation.

MPS3904,126 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 100 mA

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

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

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

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

Power - Max:: 500 mW

Frequency - Transition:: 180MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

MPS3904,126 FAQ

1.How can I place an order for MPS3904,126 through Aetrix?

Please submit a Request for Quotation (RFQ) for MPS3904,126 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 MPS3904,126 reliable?

The price and inventory of MPS3904,126 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPS3904,126 is usually 5 days.

3.What payment methods are accepted for MPS3904,126?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPS3904,126 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPS3904,126?

MPS3904,126 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPS3904,126 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 MPS3904,126?

For technical support, including MPS3904,126 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPS3904,126 requirements.

6.How does Aetrix verify that MPS3904,126 is sourced from the original manufacturer or authorized distributors?

All MPS3904,126 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 MPS3904,126 meets industry standards.

7.What is the process for return or replacement of MPS3904,126?

All MPS3904,126 units undergo pre-shipment inspection (PSI). If there is an issue with MPS3904,126, 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 MPS3904,126 part is unused and in its original packaging.

Return procedure for MPS3904,126:

1.Submit a request within 90 days.

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

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