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

Diodes Incorporated MMST3904Q-7-F

Name: MMST3904Q-7-F
Brand: Diodes Incorporated
SKU: MMST3904Q-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMST3904Q-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: MMST3904Q-7-F.pdf

Description:: TRANS NPN 40V 0.2A SOT-323

Quantity:: RFQ Add To RFQ list

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Inventory:2,030

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Product details

Overview

MMST3904Q-7-F from Diodes Incorporated is a 40V NPN small-signal transistor in SOT323 package, rated for 200mA collector current, 200mW power dissipation, and qualified to AEC-Q101 for automotive reliability. It delivers DC current gain (h_FE) of 40–300 across 100µA–100mA bias, with V_CE(SAT) ≤ 0.30V at I_C = 50mA/I_B = 5mA, and is used in low-power switching and amplification stages of automotive sensor interfaces and LED drivers.

For engineers reviewing the MMST3904Q-7-F datasheet, MMST3904Q-7-F pinout, MMST3904Q-7-F application, or MMST3904Q-7-F equivalent, key selection criteria include its AEC-Q101 qualification, SOT323 thermal resistance (625°C/W), V_CEO = 40V rating, h_FE variation vs. I_C, and complementary pairing with MMST3906.

Technical Context

This NPN bipolar junction transistor uses epitaxial planar die construction for stable gain and low leakage. Its 60V V_CBO, 40V V_CEO, and 6V V_EBO support moderate-voltage signal routing in 3.3V/5V/12V domains, while ESD ratings (HBM 4kV, MM 400V) meet industrial handling requirements.

Switching performance includes t_d/t_r ≤ 35ns and t_f ≤ 50ns under V_CC = 3V, enabling use in <1MHz digital logic interfacing and PWM-controlled loads. f_T = 300MHz confirms suitability for RF pre-driver and broadband amplifier roles up to UHF.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40V - supports operation in 24V automotive subsystems with margin against transients
I_C	200mA - sufficient for driving LEDs, relays, and logic-level MOSFET gates
P_D	200mW - limits continuous dissipation in SOT323 without heatsinking
h_FE	40–300 - wide gain spread requires bias design tolerance for production consistency
V_CE(SAT)	≤0.30V @ I_C=50mA - ensures <15mW saturation loss in switching applications
f_T	300MHz - enables use as RF amplifier or high-speed switch up to ~100MHz
ESD HBM	4000V - meets IEC 61000-4-2 Level 4 for board-level robustness

Pinout & Package

SOT323 is a 3-pin ultra-small surface-mount plastic package (2.15 × 2.10 × 0.95 mm), optimized for high-density PCB layouts and automated assembly. Its matte tin-plated leads comply with MIL-STD-202 Method 208 solderability standards.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Connected to ground or low-impedance return path; defines reference for base drive
2 (Base)	Control input	Receives current-limited drive (typically 1/10 to 1/20 of I_C) to saturate or cut off
3 (Collector)	Current source terminal	Connects to load and supply rail; voltage swing limited by V_CEO = 40V

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive temperature range (−55°C to +150°C) and mechanical stress
Ultra-small SOT323 footprint	Reduces PCB area by >50% vs. SOT23, critical for space-constrained modules
Complementary PNP pair (MMST3906)	Enables matched push-pull output stages without cross-manufacturer sourcing
Halogen- and antimony-free "Green" construction	Meets JEDEC J-STD-020 moisture sensitivity Level 1 and RoHS 3 (2015/863/EU)

Applications

Automotive Cabin Sensors

Industrial IO Modules

Use Scenario: Signal conditioning for analog temperature/humidity sensors in HVAC control units.

IC Role / Device Role / Timing Role: NPN switch amplifying sensor output into microcontroller ADC input with gain stabilization.

Use Value: Low V_CE(SAT) minimizes offset error; AEC-Q101 ensures operation across −40°C to +105°C ambient.

Use Scenario: Isolated digital input buffering for 24V PLC field-side signals.

IC Role / Device Role / Timing Role: Level-shifting interface converting 24V logic to 3.3V/5V MCU-compatible signals.

Use Value: 40V V_CEO provides headroom against industrial transients; 4kV HBM withstands ESD in factory environments.

LED Driver Circuits

Low-Power Audio Preamps

Use Scenario: Constant-current switching for indicator and backlight LEDs in infotainment displays.

IC Role / Device Role / Timing Role: Saturated switch controlling LED anode current with PWM dimming.

Use Value: 200mA I_C supports multi-LED strings; fast t_f ≤ 50ns enables clean PWM edges up to 20kHz.

Use Scenario: Single-transistor preamplifier stage for MEMS microphone outputs.

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with 100–400 h_fe gain bandwidth.

Use Value: f_T = 300MHz ensures flat response to 20kHz audio; NF ≤ 5dB preserves SNR in low-noise designs.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN small-signal transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC847BW,115	V_CEO = 45V, h_FE = 110–220 (tighter bin), SOT323 package	Higher minimum h_FE improves bias stability in precision amplifiers	Preferred where tighter gain distribution reduces calibration overhead
MMBT3904LT1G	V_CEO = 40V, same h_FE range, SOT23 package (larger footprint)	Larger thermal resistance (R_θJA ≈ 300°C/W less efficient than SOT323)	Chosen when legacy SOT23 layout reuse outweighs size/thermal trade-offs

Compared with BC847BW and MMBT3904LT1G, MMST3904Q-7-F offers AEC-Q101 qualification and superior thermal resistance in SOT323-critical for automotive modules where space and reliability are co-constrained.

Availability

MMST3904Q-7-F is available at Aetrix Electronics and suitable for automotive cabin sensors, industrial IO modules, LED driver circuits, and low-power audio preamps requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MMST3904Q-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in Taiwan and China.

The MMST3904Q-7-F belongs to Diodes' AEC-Q101-qualified small-signal transistor product line, engineered for automotive and industrial applications demanding high reliability, compact packaging, and consistent parametric performance across temperature extremes.

FAQ

Is MMST3904Q-7-F pin-compatible with standard SOT323 NPN transistors?

Yes-MMST3904Q-7-F uses the industry-standard SOT323 pinout (Emitter-Base-Collector on pins 1-2-3), matching BC847 series, MMBT3904 variants, and other SOT323-packaged NPN transistors. Mechanical dimensions and pad layout align with JEDEC MO-203AA, enabling direct PCB footprint reuse.

What is the maximum operating temperature for continuous use?

The device is rated for junction temperature (T_J) from −55°C to +150°C per AEC-Q101. For continuous operation at full 200mA I_C, ambient must remain ≤ +85°C when mounted on a 1oz copper FR-4 PCB with minimal pad area, due to its 625°C/W R_θJA.

Does MMST3904Q-7-F support PWM switching at 20kHz?

Yes-its switching times (t_d, t_r, t_f ≤ 35–50ns) and f_T = 300MHz allow clean 20kHz PWM operation with minimal rise/fall distortion. At I_C = 50mA, V_CE(SAT) remains ≤ 0.30V, limiting conduction loss to <15mW per cycle.

How does the "Q" suffix in MMST3904Q-7-F differ from MMST3904-7-F?

The "Q" denotes AEC-Q101 qualification-verified through accelerated stress testing including HTOL, TC, and ESD per automotive standards. Non-Q versions lack this validation and are not approved for automotive applications, though electrically identical in nominal parameters.

MMST3904Q-7-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

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:: 200 mW

Frequency - Transition:: 300MHz

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

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

MMST3904Q-7-F FAQ

1.How can I place an order for MMST3904Q-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for MMST3904Q-7-F 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 MMST3904Q-7-F reliable?

The price and inventory of MMST3904Q-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST3904Q-7-F is usually 5 days.

3.What payment methods are accepted for MMST3904Q-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST3904Q-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMST3904Q-7-F?

MMST3904Q-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMST3904Q-7-F 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 MMST3904Q-7-F?

For technical support, including MMST3904Q-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST3904Q-7-F requirements.

6.How does Aetrix verify that MMST3904Q-7-F is sourced from the original manufacturer or authorized distributors?

All MMST3904Q-7-F 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 MMST3904Q-7-F meets industry standards.

7.What is the process for return or replacement of MMST3904Q-7-F?

All MMST3904Q-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMST3904Q-7-F, 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 MMST3904Q-7-F part is unused and in its original packaging.

Return procedure for MMST3904Q-7-F:

1.Submit a request within 90 days.

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

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