Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Diodes Incorporated MMST4126-7-F

Name: MMST4126-7-F
Brand: Diodes Incorporated
SKU: MMST4126-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MMST4126-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: MMST4126-7-F.pdf

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

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:1,023

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

MMST4126-7-F from Diodes Incorporated is a PNP small-signal transistor in SOT323 package, rated for -25V V_CEO, -200mA I_C, and 200mW power dissipation, with h_FE of 120–360 at -2mA/-1V, used in low-power switching and amplification circuits in portable electronics and sensor interfaces.

For engineers reviewing the MMST4126-7-F datasheet, MMST4126-7-F pinout, MMST4126-7-F application, or MMST4126-7-F equivalent, key selection considerations include its AEC-Q101 qualification, ultra-small SOT323 footprint, complementary pairing with MMST4124, and obsolescence status requiring migration to MMST3906.

Technical Context

This PNP bipolar junction transistor uses epitaxial planar die construction for stable gain and low leakage, with V_EBO = -4V and BVEBO = 5V enabling reliable base-emitter biasing in low-voltage analog stages. Its f_T = 250MHz supports RF preamplifier and high-speed switching up to ~100MHz.

Thermal resistance R_θJA = 625°C/W reflects its ultra-small SOT323 thermal profile; derating begins above +25°C ambient, and ESD ratings (HBM 4kV, MM 400V) meet industrial handling requirements without additional protection circuitry in most board-level designs.

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 DC collector current rating defining maximum load drive capability
P_D	200mW - Power dissipation limit at +25°C ambient, requiring thermal derating above that temperature
h_FE	120–360 - DC current gain range at -2mA/-1V, critical for bias stability in amplifier and switch designs
f_T	250MHz - Transition frequency indicating usable bandwidth for small-signal amplification
V_CE(sat)	-0.40V @ -50mA/-5mA - Low saturation voltage enabling efficient switching with minimal conduction loss
ESD HBM	4,000V - Human Body Model rating confirming robustness against typical assembly-level electrostatic discharge

Pinout & Package

Package: SOT323 - ultra-small surface-mount plastic package (2.15 × 2.10 × 0.95 mm), moisture sensitivity level 1, matte tin-plated leads, weight ≈ 0.006 g.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal	Current exit path for PNP operation; connects to higher potential node in active circuits
2 (Base)	Control terminal	Input for bias current; polarity reversal vs NPN enables complementary switching topologies
3 (Collector)	Collector terminal	Current entry path; typically tied to ground or low-side return in PNP switch configurations

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD stress per JESD22 standards
Ultra-small SOT323 footprint	Enables high-density PCB layouts in space-constrained applications like wearables and IoT sensors
Complementary NPN pair (MMST4124)	Allows matched design of push-pull, differential, or totem-pole output stages without gain or timing mismatch
Halogen- and antimony-free "Green" construction	Meets environmental compliance requirements (<900ppm Br/Cl, <1000ppm Sb) for global RoHS-regulated markets

Applications

Portable Audio Amplifiers

Automotive Door Module Switches

Use Scenario: Low-noise preamplifier stage in headphone drivers and microphone bias circuits.

IC Role / Device Role / Timing Role: PNP small-signal amplifier providing voltage gain and impedance matching between transducer and ADC input.

Use Value: NF = 4.0dB at 1kHz and h_FE >120 ensure minimal signal degradation in battery-powered audio paths.

Use Scenario: Load switching for interior lighting and window motor control in door modules.

IC Role / Device Role / Timing Role: Low-side PNP switch controlling 12V loads via microcontroller GPIO with inverted logic interface.

Use Value: V_CE(sat) ≤ -0.40V at -50mA ensures <20mW conduction loss, reducing thermal load in sealed enclosures.

Industrial Sensor Signal Conditioning

Consumer Remote Control IR Drivers

Use Scenario: Current-source biasing for thermistor and RTD front-ends in PLC analog input cards.

IC Role / Device Role / Timing Role: Precision constant-current source using emitter-degeneration and h_FE stability across -40°C to +125°C.

Use Value: Tight h_FE spread (120–360) and T_j range (-55°C to +150°C) support accurate 4–20mA loop calibration.

Use Scenario: High-speed switching of IR LED anodes in TV remote PCBs.

IC Role / Device Role / Timing Role: Fast-turn-on/off PNP driver synchronized with 38kHz carrier modulation.

Use Value: f_T = 250MHz enables clean square-wave edge integrity at 38kHz with <100ns rise/fall times.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMST3906-7-F	V_CEO = -40V, I_C = -200mA, h_FE = 100–300, same SOT323 package	Higher breakdown margin suits 24V industrial systems; slightly lower h_FE min affects bias stability in precision analog	Direct replacement per Diodes' obsolescence notice; validated for AEC-Q101 and identical footprint
BC807-25LT1G	V_CEO = -45V, I_C = -500mA, h_FE = 160–400, SOT23 package (larger footprint)	Higher current and voltage headroom; incompatible pinout (SOT23 vs SOT323) requires PCB redesign	Use only when board layout allows SOT23; preferred where higher I_C or thermal margin is needed

Compared with MMST4126-7-F, MMST3906-7-F offers higher voltage safety margin and identical mounting, while BC807-25LT1G delivers greater current capacity but demands mechanical rework - making MMST3906-7-F the recommended drop-in migration path.

Availability

MMST4126-7-F is available at Aetrix Electronics and suitable for portable audio amplifiers, automotive door module switches, and industrial sensor signal conditioning requiring stable component supply despite its obsolete status.

Supply support for MMST4126-7-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 MMST4126-7-F belongs to Diodes' small-signal transistor product line, designed for space-constrained, low-power linear and switching applications requiring AEC-Q101 qualification and green material compliance.

FAQ

Is MMST4126-7-F still in production?

No - Diodes Incorporated has discontinued MMST4126-7-F and marked it obsolete as of June 2021. The official replacement is MMST3906-7-F, which shares the SOT323 package and AEC-Q101 qualification while offering improved -40V V_CEO rating and verified compatibility in existing designs.

What is the pinout configuration for SOT323 package?

The SOT323 package for MMST4126-7-F has three terminals: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector, viewed from top with marking dot at top-left corner. This matches JEDEC standard SOT323 orientation and is confirmed in Diodes' DS30161 Rev. 10, page 2 (top view diagram).

Can MMST4126-7-F be used in automotive applications?

Yes - it is qualified to AEC-Q101 standards, with operating temperature range of -55°C to +150°C, HBM ESD rating of 4,000V, and tested for mechanical shock, temperature cycling, and high-temperature reverse bias. It was commonly deployed in automotive body electronics prior to discontinuation.

How does MMST4126-7-F compare to MMST4124?

MMST4124 is its complementary NPN counterpart: same SOT323 package, -25V V_CEO, +200mA I_C, and matched h_FE range (120–360). They share identical thermal characteristics and environmental specs, enabling balanced push-pull, differential pair, or H-bridge driver designs without gain or timing skew.

MMST4126-7-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:: PNP

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

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

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 5mA, 50mA

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

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

Power - Max:: 200 mW

Frequency - Transition:: 250MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

MMST4126-7-F FAQ

1.How can I place an order for MMST4126-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for MMST4126-7-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 MMST4126-7-F reliable?

The price and inventory of MMST4126-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST4126-7-F is usually 5 days.

3.What payment methods are accepted for MMST4126-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST4126-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMST4126-7-F?

MMST4126-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMST4126-7-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 MMST4126-7-F?

For technical support, including MMST4126-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST4126-7-F requirements.

6.How does Aetrix verify that MMST4126-7-F is sourced from the original manufacturer or authorized distributors?

All MMST4126-7-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 MMST4126-7-F meets industry standards.

7.What is the process for return or replacement of MMST4126-7-F?

All MMST4126-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMST4126-7-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 MMST4126-7-F part is unused and in its original packaging.

Return procedure for MMST4126-7-F:

1.Submit a request within 90 days.

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

Tech Hub

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…

2026-08-11 LDO Regulator: Dropout Voltage, Noise, PSRR and Power Dissipation

LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…

2026-08-06 Conditional Access Module: CAM, CI/CI+ and DVB Security

Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…

2026-08-03 Electronic Component Obsolescence: EOL Risks, Replacement Options and Last-Time Buy Strategy

Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.

2026-07-29 18650 Battery: Voltage, Capacity, Charging and Pack Design

18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…

2026-07-27 Hall Effect Sensor: Working Principle, Types, Circuits and Applications

Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…

2026-07-20 Product Change Notification (PCN) in Electronic Components: Meaning and Supply Chain Response

Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…

2026-07-19 Blend Door Actuator: Symptoms, Location, Reset and Replacement Guide

A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…