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

Diodes Incorporated MMBT4126-7

Name: MMBT4126-7
Brand: Diodes Incorporated
SKU: MMBT4126-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBT4126-7

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: -

Datasheet:: MMBT4126-7.pdf

Description:: TRANS PNP 25V 0.2A SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:6,336

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Product details

Overview

MMBT4126-7 from Diodes Incorporated is a PNP small-signal transistor in SOT23 package, rated for -25 V V_CEO, -200 mA I_C, and 200 mW power dissipation, with h_FE = 120–360 at I_C = -2 mA, used in medium-power switching and amplification circuits in industrial control and power management modules.

For engineers reviewing the MMBT4126-7 datasheet, MMBT4126-7 pinout, MMBT4126-7 application, or MMBT4126-7 equivalent, key selection criteria include verified PNP polarity, SOT23 mechanical compatibility, guaranteed -25 V breakdown rating, -0.4 V V_CE(SAT) at -50 mA, and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This PNP bipolar junction transistor employs epitaxial planar die construction to ensure stable gain and low leakage across temperature. Its complementary pairing with MMBT4124 enables matched push-pull configurations in analog signal conditioning and discrete logic level translation.

The device operates within -55°C to +150°C ambient range and delivers f_T = 250 MHz at V_CE = -20 V, supporting high-frequency switching up to several tens of MHz in DC-DC feedback paths and sensor interface stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-25 V - maximum safe collector-emitter voltage before avalanche conduction
I_C	-200 mA - continuous collector current limit defining medium-power switching capability
P_D	200 mW - thermal power budget on FR-4 PCB with 1 oz copper, limiting sustained drive strength
h_FE	120–360 - DC current gain range at -2 mA, enabling predictable base drive sizing
V_CE(SAT)	-0.4 V - saturation voltage at -50 mA/-5 mA, determining on-state power loss in switch mode
f_T	250 MHz - transition frequency confirming usable bandwidth in RF bias and oscillator bias networks
ESD HBM	4000 V - human-body-model robustness supporting manual handling and board-level assembly

Pinout & Package

Package: SOT23 - surface-mount plastic package with 3-pin configuration, 0.008 g mass, UL 94V-0 flammability rating, and moisture sensitivity level 1.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	E	Current source terminal for PNP operation; connects to higher potential node in switching topology
2 (Base)	B	Control input requiring negative bias relative to emitter to turn on device
3 (Collector)	C	Current sink terminal; ties to load or lower-potential rail in common-emitter amplifier or switch

Key Features

Feature	Design Value
Epitaxial planar die construction	Ensures consistent h_FE distribution and low parameter drift over temperature and lifetime
AEC-Q101 qualification	Validated for automotive applications including body electronics and powertrain subsystems
Complementary NPN pairing (MMBT4124)	Enables matched differential pairs and push-pull output stages without external matching
Halogen- and antimony-free "Green" compound	Meets strict environmental compliance: <900 ppm Br, <900 ppm Cl, <1000 ppm Sb
Matte tin-plated leads	Guarantees solderability per MIL-STD-202 Method 208, reducing voiding risk in reflow profiles

Applications

Automotive Body Control Module

Industrial Sensor Signal Conditioning

Use Scenario: Driving LED indicators and relay coils in door module PCBs under 12 V battery supply.

IC Role / Device Role / Timing Role: PNP switch controlling current flow from battery rail to load, operating in saturation region.

Use Value: -0.4 V V_CE(SAT) minimizes heat generation during continuous duty, extending PCB life in sealed enclosures.

Use Scenario: Level-shifting and buffering analog signals from thermistors and potentiometers in PLC I/O cards.

IC Role / Device Role / Timing Role: Common-emitter amplifier providing gain and impedance isolation between sensor and ADC front-end.

Use Value: h_FE = 120–360 ensures stable bias point across -40°C to +125°C, maintaining linearity without recalibration.

DC-DC Converter Feedback Path

Legacy Microcontroller GPIO Expansion

Use Scenario: Biasing optocoupler LED in isolated flyback controller feedback loop.

IC Role / Device Role / Timing Role: Current source transistor regulating opto-LED forward current via base resistor network.

Use Value: 250 MHz f_T supports fast transient response to output voltage deviations, improving regulation accuracy.

Use Scenario: Adding discrete high-side drive capability to 3.3 V microcontroller outputs unable to source sufficient current.

IC Role / Device Role / Timing Role: High-side switch translating logic-high to 5 V/12 V rail for peripheral enable lines.

Use Value: -25 V V_CEO and -25 V V_CBO provide margin against voltage spikes in noisy industrial environments.

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
MMBT3906-7-F	Same SOT23 package; h_FE = 100–300 at -10 mA, V_CE(SAT) = -0.4 V (same test condition), but lower f_T = 250 MHz (typ) vs. MMBT4126-7's 250 MHz (min)	Approved replacement per Diodes' obsolescence notice; validated in identical footprint and bias networks	Select when legacy design reuse is required and full MMBT4126-7 parametric range is not needed
BC807-25,215	NXP part in SOT23; h_FE = 160–400 at -100 mA, V_CE(SAT) = -0.7 V @ -500 mA - higher saturation voltage, different gain binning	Used in consumer power supplies; lacks AEC-Q101 qualification and automotive traceability	Choose only for cost-sensitive non-automotive applications where -0.7 V drop is acceptable

Compared with MMBT3906-7-F and BC807-25,215, the MMBT4126-7 offers tighter h_FE consistency at low currents and guaranteed AEC-Q101 compliance, making it preferable for automotive signal integrity-critical nodes despite its discontinued status.

Availability

MMBT4126-7 is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, and DC-DC feedback circuits requiring stable component supply and long-term BOM continuity.

Supply support for MMBT4126-7 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, specializing in high-reliability components for automotive, industrial, and computing markets.

The MMBT4126-7 belongs to Diodes' general-purpose bipolar transistor product line, designed specifically for medium-power linear amplification and robust switching in space-constrained, thermally demanding environments.

FAQ

Is MMBT4126-7 still in active production?

No - Diodes Incorporated officially discontinued MMBT4126-7 as of June 2021. Aetrix Electronics maintains limited legacy stock and supports last-time-buy programs with full traceability and documentation for ongoing production runs.

What is the recommended replacement for MMBT4126-7?

Diodes specifies MMBT3906-7-F as the direct replacement. It shares identical SOT23 packaging, pinout, and AEC-Q101 qualification, with closely matched V_CEO, I_C, and V_CE(SAT); minor h_FE variation is accommodated by standard design margins.

Does MMBT4126-7 support lead-free reflow soldering?

Yes - MMBT4126-7 features matte tin-plated leads compliant with MIL-STD-202 Method 208 and qualified for Pb-free reflow profiles up to 260°C peak, with moisture sensitivity level 1 ensuring no bake requirement prior to assembly.

Can MMBT4126-7 be used in high-frequency oscillator circuits?

Yes - with f_T = 250 MHz (min), it supports fundamental oscillation up to ~50 MHz in Colpitts or Hartley topologies when biased properly; layout parasitics and external component Q become limiting factors above that range.

MMBT4126-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: *

Package/Case:: -

Packaging:: Tape & Reel (TR)

Product Status:: Discontinued at Digi-Key

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:: -

MMBT4126-7 FAQ

1.How can I place an order for MMBT4126-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBT4126-7 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 MMBT4126-7 reliable?

The price and inventory of MMBT4126-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT4126-7 is usually 5 days.

3.What payment methods are accepted for MMBT4126-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT4126-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBT4126-7?

MMBT4126-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBT4126-7 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 MMBT4126-7?

For technical support, including MMBT4126-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT4126-7 requirements.

6.How does Aetrix verify that MMBT4126-7 is sourced from the original manufacturer or authorized distributors?

All MMBT4126-7 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 MMBT4126-7 meets industry standards.

7.What is the process for return or replacement of MMBT4126-7?

All MMBT4126-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMBT4126-7, 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 MMBT4126-7 part is unused and in its original packaging.

Return procedure for MMBT4126-7:

1.Submit a request within 90 days.

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

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