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

Diodes Incorporated MMST4124-7-F

Name: MMST4124-7-F
Brand: Diodes Incorporated
SKU: MMST4124-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMST4124-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: MMST4124-7-F.pdf

Description:: TRANS NPN 25V 0.2A SOT-323

Quantity:: RFQ Add To RFQ list

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Inventory:738

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Product details

Overview

MMST4124-7-F from Diodes Incorporated is an NPN small-signal transistor in SOT323 package, rated for 25V V_CEO, 200mA I_C, and 200mW power dissipation, with DC current gain (h_FE) of 120–600 at I_C = 2–50mA and V_CE = 1V, used in low-power switching and amplification stages of portable audio, sensor interface, and voltage-level translation circuits.

For engineers reviewing the MMST4124-7-F datasheet, MMST4124-7-F pinout, MMST4124-7-F application, or MMST4124-7-F equivalent, key selection considerations include its 300MHz f_T, 4kV HBM ESD rating, AEC-Q101 qualification, ultra-small SOT323 footprint, and complementary PNP pairing with MMST4126.

Technical Context

This NPN bipolar junction transistor employs epitaxial planar die construction for stable gain and low leakage. It operates across –55°C to +150°C with 5V V_EBO and 30V V_CBO, supporting linear amplification and saturated switching modes under pulsed test conditions (≤300µs, ≤2% duty cycle).

Its 4pF C_OBO and 8pF C_IBO enable high-frequency signal handling up to 300MHz f_T; thermal resistance R_θJA = 625°C/W reflects performance on minimal 1oz copper FR-4 PCB, requiring derating above 25°C ambient per published curve.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	25V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C	200mA - Continuous collector current limit defining usable load drive capability
P_D	200mW - Steady-state power dissipation limit on standard PCB layout
h_FE	120–600 - DC current gain range enabling predictable base drive sizing across operating currents
f_T	300MHz - Transition frequency indicating usable bandwidth for RF or fast-switching applications
ESD HBM	4,000V - Human Body Model robustness supporting handling in non-ESD-controlled assembly environments
R_θJA	625°C/W - Thermal resistance from junction to ambient, guiding heatsinking and layout decisions

Pinout & Package

Package: SOT323 - ultra-small surface-mount plastic case (2.15 × 2.10 × 0.95 mm), weight 0.006 g, moisture sensitivity level 1, matte tin-plated leads solderable per MIL-STD-202 Method 208.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Low-impedance output path in emitter-follower; referenced to ground in common-emitter switch
2 (Base)	Control input	Requires ~0.7–0.95V forward bias and µA–mA drive to saturate or linearly bias transistor
3 (Collector)	Current source terminal	Connected to load or supply rail; voltage swing limited by V_CEO = 25V rating

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTOL, and ESD stress
Ultra-small SOT323 footprint	Enables high-density PCB layouts in space-constrained portable and wearable electronics
Complementary PNP pair (MMST4126)	Supports matched push-pull or differential pair designs without cross-manufacturer sourcing
Halogen- and antimony-free "Green" construction	Meets <900ppm Br/Cl and <1000ppm Sb limits for environmental compliance and end-of-life processing

Applications

Portable Audio Amplifiers

Sensor Signal Conditioning

Use Scenario: Biasing and gain stages in headphone driver IC support circuitry or microphone preamplifier front-ends.

IC Role / Device Role / Timing Role: NPN small-signal amplifier providing 20–40dB voltage gain with low noise and distortion at 1–10kHz.

Use Value: Stable h_FE and low C_IBO/C_OBO preserve audio fidelity; SOT323 enables compact dual-channel layout.

Use Scenario: Level-shifting and buffering analog outputs from MEMS accelerometers or temperature sensors.

IC Role / Device Role / Timing Role: Emitter-follower buffer isolating high-impedance sensor output from downstream ADC input.

Use Value: Low V_BE(SAT) (≤0.95V) and 5V V_EBO ensure compatibility with 3.3V/5V sensor rails and logic interfaces.

Low-Power Switching Loads

Industrial Control Interface

Use Scenario: Driving LED indicators, small relays, or optocoupler inputs in battery-powered IoT nodes.

IC Role / Device Role / Timing Role: Saturated switch controlling ≤200mA loads with V_CE(SAT) ≤0.3V to minimize power loss.

Use Value: 200mW P_D and 625°C/W R_θJA allow reliable operation without heatsink at ambient ≤60°C.

Use Scenario: Isolating microcontroller GPIO pins from 12–24V industrial fieldbus or PLC input circuits.

IC Role / Device Role / Timing Role: Level translator and current amplifier converting 3.3V logic to 25V-tolerant open-collector output.

Use Value: 25V V_CEO and 30V V_CBO provide margin against transients; AEC-Q101 ensures long-term stability in harsh environments.

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
MMST3904-7-F	Higher h_FE (100–300), same SOT323, lower V_CEO (40V), not AEC-Q101 qualified	Preferred for general-purpose amplification where automotive qualification is unnecessary	Select when higher gain consistency at low I_C is needed and AEC-Q101 is not mandated
BC847BW,115	Same V_CEO (45V), higher f_T (300MHz), SOT323, AEC-Q101 qualified, different marking and packaging	Broad industrial use with tighter h_FE binning and extended temp range support	Choose for production programs requiring full automotive traceability and tighter parametric control

Compared with MMST3904-7-F, MMST4124-7-F offers AEC-Q101 validation and higher V_CEO margin (25V vs. 40V rated but typically used at ≤20V), while BC847BW provides broader automotive compliance scope and tighter h_FE distribution-making MMST4124-7-F optimal for cost-sensitive automotive subsystems needing verified reliability without premium binning.

Availability

MMST4124-7-F is available at Aetrix Electronics and suitable for portable audio amplifiers, sensor signal conditioning, and low-power switching loads requiring stable component supply and legacy design continuity.

Supply support for MMST4124-7-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, specializing in high-reliability components for automotive, industrial, and consumer markets.

The MMST4124 belongs to Diodes' small-signal transistor product line, designed specifically for space-constrained, high-volume applications demanding AEC-Q101 qualification, low-profile packaging, and consistent parametric performance.

FAQ

Is MMST4124-7-F still in active production?

No-MMST4124-7-F is officially obsolete and discontinued per Diodes' datasheet revision 11-4 (June 2021). Diodes recommends MMST3904-7-F as a functional replacement. Aetrix Electronics maintains limited legacy stock for design continuity and last-time buys, with full traceability and documentation.

What is the pin configuration for MMST4124-7-F in SOT323?

The MMST4124-7-F uses standard SOT323 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (top view, marking side up, flat edge left). This matches JEDEC MO-203AA and Diodes' package outline drawing for SOT323, confirmed in DS30163 Rev. 11-4 page 2.

Can MMST4124-7-F replace BC847B in existing designs?

Yes, with verification: both are NPN SOT323 transistors with overlapping V_CEO (25V vs. 45V), I_C (200mA vs. 100mA), and h_FE ranges. However, BC847B has lower max I_C and different gain binning-designers must confirm saturation voltage and thermal margins under actual load conditions before substitution.

Does MMST4124-7-F support lead-free reflow soldering?

Yes-MMST4124-7-F is fully RoHS-compliant with matte tin-plated leads, qualified for lead-free reflow per J-STD-020 (MSL Level 1), and compatible with peak temperatures up to 260°C. Its green molding compound meets UL 94V-0 flammability rating and halogen/antimony-free specifications.

MMST4124-7-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 200 mA

Voltage - Collector Emitter Breakdown (Max):: 25 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 2mA, 1V

Power - Max:: 200 mW

Frequency - Transition:: 300MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

MMST4124-7-F FAQ

1.How can I place an order for MMST4124-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for MMST4124-7-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 MMST4124-7-F reliable?

The price and inventory of MMST4124-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST4124-7-F is usually 5 days.

3.What payment methods are accepted for MMST4124-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST4124-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMST4124-7-F?

MMST4124-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMST4124-7-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 MMST4124-7-F?

For technical support, including MMST4124-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST4124-7-F requirements.

6.How does Aetrix verify that MMST4124-7-F is sourced from the original manufacturer or authorized distributors?

All MMST4124-7-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 MMST4124-7-F meets industry standards.

7.What is the process for return or replacement of MMST4124-7-F?

All MMST4124-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMST4124-7-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 MMST4124-7-F part is unused and in its original packaging.

Return procedure for MMST4124-7-F:

1.Submit a request within 90 days.

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

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