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Diodes Incorporated MMST4126-7
- Part No.:
- MMST4126-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- -
- Datasheet:
-
MMST4126-7.pdf
- Description:
- TRANS PNP 25V 0.2A SC70-3
- Quantity:
- Payment:
- Shipping:
Inventory:34
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Product details
Overview
MMST4126-7 from Diodes Incorporated is a PNP small-signal transistor in SOT323 package, rated for -25V VCEO, -200mA IC, and 200mW power dissipation. It features epitaxial planar die construction, AEC-Q101 qualification for automotive reliability, and operates across -55°C to +150°C. It is commonly used in low-power switching and amplification circuits in space-constrained consumer and automotive modules.
For engineers reviewing the MMST4126-7 datasheet, MMST4126-7 pinout, MMST4126-7 application, or MMST4126-7 equivalent, key selection considerations include its complementary NPN pairing with MMST4124, VCE(sat) of -0.40V at -50mA/-5mA drive, hFE range of 120–360, fT of 250MHz, and ESD robustness (4kV HBM).
Technical Context
This PNP bipolar junction transistor employs epitaxial planar die construction for stable gain and low leakage. Its -25V VCEO and -4V VEBO support moderate-voltage biasing in discrete amplifier and switch stages, while the 250MHz fT enables audio-frequency and low-speed digital signal handling.
The device is qualified to AEC-Q101, confirming suitability for automotive environments, and exhibits 4.0dB noise figure at 1kHz with 100µA collector current - indicating low-noise capability for preamplifier front-ends where signal integrity is critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -25 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration |
| IC | -200 mA - Continuous DC collector current rating under thermal limits |
| PD | 200 mW - Power dissipation limit on standard 1oz copper PCB under still-air conditions |
| hFE | 120–360 - DC current gain range at IC = -2mA and -50mA, enabling predictable bias design |
| fT | 250 MHz - Transition frequency defining usable bandwidth for small-signal amplification |
| VCE(sat) | -0.40 V @ IC = -50mA, IB = -5mA - Low saturation voltage ensures minimal conduction loss in switching applications |
| ESD HBM | 4,000 V - Robustness against human-body model electrostatic discharge during handling and assembly |
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 |
|---|---|---|
| Emitter (E) | Current source terminal in PNP operation | Connected to higher potential; sets reference for base-emitter forward bias |
| Base (B) | Control electrode | Receives negative current to turn on; requires ~-0.95V VBE(sat) at full drive |
| Collector (C) | Current sink terminal | Connected to load and supply return; handles up to -200mA continuous current |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, humidity, and mechanical shock |
| Ultra-small SOT323 footprint | Enables high-density PCB layouts in compact modules such as sensor signal conditioning boards |
| Complementary pair with MMST4124 | Allows matched PNP/NPN implementation in push-pull or differential amplifier topologies |
| Halogen- and antimony-free "Green" construction | Meets strict environmental compliance: <900ppm Br, <900ppm Cl, <1000ppm Sb |
| Low VCE(sat) and high fT | Supports efficient switching with minimal voltage drop and usable bandwidth up to 250MHz |
Applications
| Automotive Door Module Switching | Portable Audio Preamp Stage |
|---|---|
Use Scenario: Controlling window lift motor enable logic and LED status indicators in door control units. IC Role / Device Role / Timing Role: Discrete PNP switch driving 12V loads with logic-level base control from MCU GPIO. Use Value: -25V VCEO safely withstands automotive load dump transients; -0.40V VCE(sat) minimizes heat generation in thermally constrained modules. | Use Scenario: Low-noise voltage amplification of microphone signals in Bluetooth headsets. IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with emitter degeneration for gain stability. Use Value: 4.0dB NF at 1kHz and 100µA IC preserves SNR; 250MHz fT ensures flat response across audio band. |
| Industrial Sensor Signal Conditioning | Consumer IoT Battery Monitor Circuit |
Use Scenario: Level-shifting and buffering analog outputs from pressure/temperature sensors in PLC I/O modules. IC Role / Device Role / Timing Role: Emitter-follower buffer providing high input impedance and low output impedance. Use Value: hFE ≥120 ensures stable current gain across -40°C to +85°C; AEC-Q101 qualification supports extended industrial temperature operation. | Use Scenario: Enabling/disabling battery voltage sensing paths in smart thermostats and wearables. IC Role / Device Role / Timing Role: Low-leakage PNP switch isolating ADC inputs when not actively measuring. Use Value: ICBO ≤ -50nA at -20V VCB prevents measurement drift; SOT323 footprint saves board space in coin-cell-powered designs. |
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 | VCEO = -40V, hFE = 100–300, VCE(sat) = -0.4V @ -50mA/-5mA, same SOT323 package | Higher voltage rating allows use in 24V industrial systems; slightly lower hFE spread affects bias stability margin | Select when >25V system margin is required; verify base drive sufficiency for target hFE min |
| BC807-25LT1G | VCEO = -45V, hFE = 160–400, PD = 310mW, SOT23 package (larger footprint) | Higher power and gain support more demanding linear stages; SOT23 requires layout revision | Choose for improved thermal margin or gain consistency; confirm PCB pad compatibility |
Compared with MMST4126-7, MMST3906-7 offers higher voltage tolerance but narrower hFE range, while BC807-25LT1G delivers greater power handling and gain spread at the cost of larger footprint - both require validation of base drive and thermal layout in replacement scenarios.
Availability
MMST4126-7 is available at Aetrix Electronics and suitable for automotive door modules, portable audio preamps, industrial sensor interfaces, and consumer IoT battery monitoring circuits requiring stable component supply and long-term sourcing continuity.
Supply support for MMST4126-7 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, manufacturing, and sales operations across Asia, Europe, and North America.
The MMST4126-7 belongs to Diodes' small-signal transistor product line, engineered for high-reliability, space-constrained applications in automotive, industrial, and portable electronics where AEC-Q101 compliance and ultra-small packaging are essential.
FAQ
Is MMST4126-7 still in active production?
No - MMST4126-7 is officially obsolete per Diodes' datasheet DS30161 Rev. 10-4 (June 2021). Diodes recommends MMST3906 as the direct replacement. Aetrix Electronics maintains legacy inventory and provides cross-reference support, including technical validation for migration to MMST3906-7 or BC807-25LT1G.
What is the pin configuration for MMST4126-7 in SOT323?
The SOT323 package has three terminals: Emitter (left pin, marked side), Base (center pin), and Collector (right pin) when viewing the top side with marking code "K2B" right-aligned. Pin 1 is Emitter, Pin 2 is Base, Pin 3 is Collector - confirmed by Diodes' official top-view diagram and package outline drawing.
Can MMST4126-7 be used in place of a generic PNP transistor like 2N3906?
Yes, functionally - but with critical differences: MMST4126-7 uses SOT323 (vs. TO-92 for 2N3906), has tighter hFE range (120–360 vs. 100–300), and is AEC-Q101 qualified. Layout, thermal, and mechanical constraints must be verified; it is not a drop-in replacement without PCB redesign due to package size and lead pitch.
Does MMST4126-7 support lead-free reflow soldering?
Yes - MMST4126-7 is fully RoHS-compliant and lead-free, with matte tin-plated leads qualified per MIL-STD-202, Method 208. It supports standard Pb-free reflow profiles (J-STD-020 Level 1), and its moisture sensitivity level is rated at MSL 1, allowing unlimited floor life at ≤30°C/60% RH without dry-pack requirements.
MMST4126-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- *
- Package/Case:
- -
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Transistor Type:
- -
- Current - Collector (Ic) (Max):
- -
- Voltage - Collector Emitter Breakdown (Max):
- -
- Vce Saturation (Max) @ Ib, Ic:
- -
- Current - Collector Cutoff (Max):
- -
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- -
- Power - Max:
- -
- Frequency - Transition:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MMST4126-7 FAQ
1.How can I place an order for MMST4126-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMST4126-7 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 reliable?
The price and inventory of MMST4126-7 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 is usually 5 days.
3.What payment methods are accepted for MMST4126-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST4126-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMST4126-7?
MMST4126-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMST4126-7 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?
For technical support, including MMST4126-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST4126-7 requirements.
6.How does Aetrix verify that MMST4126-7 is sourced from the original manufacturer or authorized distributors?
All MMST4126-7 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 meets industry standards.
7.What is the process for return or replacement of MMST4126-7?
All MMST4126-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMST4126-7, 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 part is unused and in its original packaging.
Return procedure for MMST4126-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMST4126-7 Tags
-
MMBT3906LT1G
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MMBT3904-7-F
Diodes Incorporated
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Diodes Incorporated
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Micro Commercial Co
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MMBT2222A-7-F
Diodes Incorporated
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BC847B,215
Nexperia USA Inc.
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SMMBT3904LT1G
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MMBT2222A-TP
Micro Commercial Co
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