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

onsemi MMBT3904TT1H

Name: MMBT3904TT1H
Brand: onsemi
SKU: MMBT3904TT1H
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBT3904TT1H

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: SC-75, SOT-416

Datasheet:: MMBT3904TT1H.pdf

Description:: TRANS NPN 40V 0.2A SC75 SOT416

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MMBT3904TT1 from onsemi is an NPN silicon general-purpose amplifier transistor in SOT-416/SC-75 package, rated for V_CEO = 40 V, I_C = 200 mA, and f_T = 300 MHz, used in low-power signal amplification and switching circuits on compact PCBs.

For engineers reviewing the MMBT3904TT1 datasheet, pinout, applications, or equivalent options, key selection criteria include its 300 MHz f_T, low-input capacitance (C_ibo ≤ 8.0 pF), SOT-416 thermal performance (R_JA = 400 °C/W with 1.0 × 1.0 inch pad), and verified h_FE range of 40–300 across 0.1–100 mA I_C.

Technical Context

This device operates as a discrete NPN bipolar junction transistor optimized for linear amplification and fast switching in portable and space-constrained electronics. Its electrical behavior is defined by h_FE variation with collector current, V_CE(sat) ≤ 0.3 V at I_C = 50 mA/I_B = 5 mA, and noise figure ≤ 5.0 dB at 1 kHz with 100 µA I_C.

Thermal design relies on two dissipation modes: 200 mW (minimum pad) or 300 mW (1.0 × 1.0 inch FR-4 pad), with corresponding R_JA values of 600 °C/W and 400 °C/W. Junction temperature must remain within −55 °C to +150 °C for reliable operation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown under open-base conditions
I_C (continuous)	200 mA - Continuous DC collector current limit defining usable output drive capability
f_T	300 MHz - Transition frequency indicating usable bandwidth for RF or high-speed switching
C_ibo	≤ 8.0 pF - Input capacitance affecting high-frequency input impedance and stability margins
h_FE @ I_C = 10 mA	100–300 - DC current gain determining base drive requirements for saturation or linear bias
V_CE(sat)	≤ 0.3 V @ I_C = 50 mA/I_B = 5 mA - Low saturation voltage enabling efficient switching with minimal power loss
R_JA (1.0″ pad)	400 °C/W - Thermal resistance enabling 300 mW dissipation at T_A = 25 °C without exceeding T_J = 150 °C

Pinout & Package

SOT-416/SC-75 three-terminal surface-mount package (Case 463, Style 1), 1.6 mm × 1.2 mm footprint, 0.9 mm height, with gull-wing leads for reflow soldering on FR-4 PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal accepting forward-biased current to modulate collector current flow
2	Emitter	Current sink reference node; connected to ground or low-impedance return path in common-emitter configurations
3	Collector	Output current source node; delivers amplified or switched load current with voltage headroom up to 40 V

Key Features

Feature	Design Value
Pb-Free packaging	RoHS-compliant SOT-416 construction meeting JEDEC J-STD-020 moisture sensitivity level 1 (MSL1)
High f_T	300 MHz enables use in 2.4 GHz ISM-band pre-driver stages and audio bandpass filters
Low C_obo	≤ 4.0 pF minimizes Miller effect in high-gain CE amplifiers, improving stability above 10 MHz
Wide h_FE range	40–300 across operating currents supports both precision biasing and robust digital switching designs
Low-noise operation	NF ≤ 5.0 dB at 1 kHz allows use in microphone preamps and sensor signal conditioning where SNR > 70 dB is required

Applications

Portable Audio Amplifiers	LED Driver Switches
Use Scenario: Amplifying line-level signals in Bluetooth earbuds and hearing aids with battery supply < 5 V. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration providing 20–30 dB voltage gain. Use Value: 300 MHz f_T ensures flat response to 20 kHz with margin; low V_CE(sat) extends battery life by reducing quiescent loss.	Use Scenario: Driving indicator LEDs and status lights in handheld medical devices and IoT sensors. IC Role / Device Role / Timing Role: Digital switch controlling LED current up to 100 mA via GPIO-driven base. Use Value: Verified h_FE ≥ 100 at I_C = 20 mA ensures full saturation with 200 µA base drive, minimizing MCU I/O loading.
RF Signal Conditioning	Industrial Sensor Interfaces
Use Scenario: Biasing and buffering 2.4 GHz Wi-Fi front-end components in compact wireless modules. IC Role / Device Role / Timing Role: Pre-driver stage amplifying local oscillator harmonics before mixer input. Use Value: C_ibo ≤ 8.0 pF and f_T = 300 MHz support stable gain up to 100 MHz, sufficient for IF filtering and harmonic suppression.	Use Scenario: Isolating and amplifying analog outputs from pressure, temperature, or current-sense ICs in PLC I/O modules. IC Role / Device Role / Timing Role: Unity-gain buffer or level shifter interfacing between low-voltage sensors and 5 V ADC inputs. Use Value: V_CEO = 40 V provides headroom for transient protection; h_FE consistency across −40 °C to +85 °C ensures calibration stability.

Portable Audio Amplifiers

LED Driver Switches

Use Scenario: Amplifying line-level signals in Bluetooth earbuds and hearing aids with battery supply < 5 V.

IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration providing 20–30 dB voltage gain.

Use Value: 300 MHz f_T ensures flat response to 20 kHz with margin; low V_CE(sat) extends battery life by reducing quiescent loss.

Use Scenario: Driving indicator LEDs and status lights in handheld medical devices and IoT sensors.

IC Role / Device Role / Timing Role: Digital switch controlling LED current up to 100 mA via GPIO-driven base.

Use Value: Verified h_FE ≥ 100 at I_C = 20 mA ensures full saturation with 200 µA base drive, minimizing MCU I/O loading.

RF Signal Conditioning

Industrial Sensor Interfaces

Use Scenario: Biasing and buffering 2.4 GHz Wi-Fi front-end components in compact wireless modules.

IC Role / Device Role / Timing Role: Pre-driver stage amplifying local oscillator harmonics before mixer input.

Use Value: C_ibo ≤ 8.0 pF and f_T = 300 MHz support stable gain up to 100 MHz, sufficient for IF filtering and harmonic suppression.

Use Scenario: Isolating and amplifying analog outputs from pressure, temperature, or current-sense ICs in PLC I/O modules.

IC Role / Device Role / Timing Role: Unity-gain buffer or level shifter interfacing between low-voltage sensors and 5 V ADC inputs.

Use Value: V_CEO = 40 V provides headroom for transient protection; h_FE consistency across −40 °C to +85 °C ensures calibration stability.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT3904LT1G	SOT-23 package (larger footprint, higher R_JA = 450 °C/W), same electrical specs	Preferred where board area permits larger pads and thermal relief is less critical	Select when legacy SOT-23 layout exists or higher power derating margin is needed
PMBT3904,115	SC-70 package (SOT-323), identical pinout but 0.2 mm smaller width; h_FE min = 100 @ I_C = 10 mA	Better suited for ultra-dense layouts requiring sub-1.2 mm width; tighter h_FE binning	Choose for space-constrained wearables where 0.1 mm width reduction improves routing density

Compared with MMBT3904TT1, MMBT3904LT1G offers easier hand-soldering and higher thermal mass but requires 40% more board area; PMBT3904,115 matches pinout and size closely but specifies narrower h_FE range, simplifying gain-critical bias design at the cost of lower minimum gain at low currents.

Availability

MMBT3904TT1 is available at Aetrix Electronics and suitable for portable audio amplifiers, LED driver switches, RF signal conditioning, and industrial sensor interfaces requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.

Supply support for MMBT3904TT1 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

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MMBT3904TT1 belongs to onsemi's General Purpose Transistor product line, designed for cost-sensitive, space-constrained linear amplification and digital switching in consumer and industrial electronics.

FAQ

What is the maximum continuous collector current rating for the MMBT3904TT1?

The MMBT3904TT1 has a maximum continuous collector current (I_C) rating of 200 mA at T_A = 25 °C. This value assumes proper PCB thermal management-specifically, a 1.0 × 1.0 inch copper pad-to maintain junction temperature within −55 °C to +150 °C. Derating applies above 25 °C ambient per the 2.4 mW/°C specification.

Does the MMBT3904TT1 support Pb-free assembly processes?

Yes, the MMBT3904TT1 is offered in a Pb-free SOT-416 package compliant with RoHS Directive 2011/65/EU. The device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL1), allowing unlimited floor life and standard reflow profiles without baking. The "G" suffix (e.g., MMBT3904TT1G) explicitly denotes the Pb-free variant.

What is the typical transition frequency (f_T) of the MMBT3904TT1 and how is it measured?

The MMBT3904TT1 has a minimum f_T of 300 MHz, measured under standardized conditions: I_C = 10 mA, V_CE = 20 V, and f = 100 MHz. This parameter reflects the frequency at which the small-signal current gain (h_fe) drops to unity, confirming suitability for VHF amplification and fast-switching applications up to ~100 MHz with gain margin.

How does the thermal resistance (R_JA) of the MMBT3904TT1 vary with PCB layout?

The MMBT3904TT1 exhibits two R_JA values depending on PCB copper area: 600 °C/W with minimum pad (FR-4), and 400 °C/W with a 1.0 × 1.0 inch pad. This 200 °C/W improvement directly enables 50% higher power dissipation (300 mW vs. 200 mW) at T_A = 25 °C, making pad size a critical layout decision for thermal reliability in sustained operation.

Can the MMBT3904TT1 be used as a direct replacement for the PN2222A in SOT-416 form factor?

No-the MMBT3904TT1 is not a direct replacement for the PN2222A. While both are NPN transistors, the PN2222A has higher V_CEO (40 V vs. 30 V), higher I_C (800 mA vs. 200 mA), and different h_FE profile. The MMBT3904TT1 is optimized for low-power, high-frequency use; substituting it for PN2222A in high-current switching risks saturation failure and thermal runaway.

MMBT3904TT1H Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: SC-75, SOT-416

Packaging:: Bulk

Product Status:: Active

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:: 300 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SC-75, SOT-416

MMBT3904TT1H FAQ

1.How can I place an order for MMBT3904TT1H through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBT3904TT1H 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 MMBT3904TT1H reliable?

The price and inventory of MMBT3904TT1H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT3904TT1H is usually 5 days.

3.What payment methods are accepted for MMBT3904TT1H?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT3904TT1H transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBT3904TT1H?

MMBT3904TT1H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBT3904TT1H 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 MMBT3904TT1H?

For technical support, including MMBT3904TT1H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT3904TT1H requirements.

6.How does Aetrix verify that MMBT3904TT1H is sourced from the original manufacturer or authorized distributors?

All MMBT3904TT1H 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 MMBT3904TT1H meets industry standards.

7.What is the process for return or replacement of MMBT3904TT1H?

All MMBT3904TT1H units undergo pre-shipment inspection (PSI). If there is an issue with MMBT3904TT1H, 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 MMBT3904TT1H part is unused and in its original packaging.

Return procedure for MMBT3904TT1H:

1.Submit a request within 90 days.

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

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