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

Diodes Incorporated MMBT6427-7-F

Name: MMBT6427-7-F
Brand: Diodes Incorporated
SKU: MMBT6427-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBT6427-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: MMBT6427-7-F.pdf

Description:: TRANS NPN DARL 40V 0.5A SOT-23-3

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Product details

Overview

MMBT6427-7-F from Diodes Incorporated is a 40V NPN Darlington transistor in SOT23 package, optimized for low-power amplification and switching with h_FE up to 200,000 at I_C = 500mA, V_CE = 5V, and V_CE(sat) = 1.2V (max) at I_C = 500mA/I_B = 0.5mA. It serves as a high-gain interface device in signal conditioning, relay drivers, and LED load control circuits.

For engineers reviewing the MMBT6427-7-F datasheet, MMBT6427-7-F pinout, MMBT6427-7-F application, or MMBT6427-7-F equivalent, key selection criteria include its Darlington architecture enabling microampere-level base drive, 40V V_CEO/V_CB0, 500mA continuous collector current, and SOT23 thermal performance with R_θJA = 403°C/W on minimum pad layout.

Technical Context

This Darlington pair integrates two NPN transistors monolithically to deliver ultra-high DC current gain while maintaining single-device simplicity. Its structure supports low-input-current switching-base current as low as 0.5mA drives 500mA collector load-with V_BE(sat) = 2.0V (max) confirming dual-junction forward bias behavior.

The device operates across –55°C to +150°C, with ESD robustness of 4kV HBM and 400V MM, and is rated for automotive-grade change control per AEC-Q101 when specified. Thermal derating begins above 25°C ambient, with safe operating area constrained by V_CE(sat) limits below 100µs pulse width.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum collector-emitter voltage before breakdown; defines upper rail limit in switching applications.
h_FE	10,000–200,000 - Ultra-high DC current gain enables µA-range base drive for mA–A loads; critical for low-power MCU interfacing.
V_CE(sat)	0.68–1.5 V - Saturation voltage range determines power loss and heat generation at full load; impacts efficiency in linear-mode operation.
I_C	500 mA - Continuous collector current rating sets maximum steady-state load-handling capability in driver stages.
R_θJA	403 °C/W - Junction-to-ambient thermal resistance on minimal FR4 pad; defines temperature rise per watt dissipated in PCB-limited layouts.
ESD HBM	4,000 V - Human Body Model rating confirms robustness against handling-induced electrostatic discharge during assembly.

Pinout & Package

Package: SOT23 - Surface-mount plastic package with 3-pin configuration, 0.008 g mass, UL 94V-0 flammability rating, and matte tin-plated leads solderable per MIL-STD-202.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitting terminal of Darlington pair	Connected to ground or low-side return path; carries full load current with minimal voltage drop.
2 (Base)	Control input for Darlington pair	Accepts low-current drive (e.g., MCU GPIO); internal resistor-free design requires external current limiting.
3 (Collector)	Output terminal sourcing load current	Connects to load and supply rail; voltage swing limited by V_CEO = 40V and saturation behavior.

Key Features

Feature	Design Value
Epitaxial planar die construction	Ensures consistent h_FE distribution and stable gain across production lots and temperature ranges.
Darlington topology	Delivers >10× higher h_FE than standard NPN transistors, reducing base drive requirements in space-constrained designs.
Lead-free & RoHS 3 compliant	Meets EU Directive 2015/863 with <900ppm Br, <900ppm Cl, <1000ppm Sb-enabling global commercial and industrial deployment.
Moisture sensitivity Level 1	Eliminates bake requirements prior to reflow; compatible with standard SMT assembly without floor-life constraints.

Applications

Relay Driver Circuit

LED Current Switch

Use Scenario: Driving 12V electromagnetic relay coils requiring 20–50mA hold current with 3.3V/5V MCU GPIO output.

IC Role / Device Role / Timing Role: High-gain Darlington switch providing isolation and current amplification between logic-level controller and inductive load.

Use Value: Eliminates need for external base resistors or secondary transistor stages; reduces BOM count and PCB footprint.

Use Scenario: Controlling multi-segment LED arrays in industrial status indicators where precise current regulation is not required.

IC Role / Device Role / Timing Role: Low-side constant-current switch enabling ON/OFF control with minimal MCU resource usage.

Use Value: Supports direct drive from 3.3V microcontrollers without level-shifting; V_CE(sat) ≤ 1.5V ensures ≥10.5V headroom for 12V LED strings.

Low-Power Sensor Interface

Thermal Cut-Off Monitor

Use Scenario: Amplifying weak analog signals from thermistors or photodiodes in battery-powered environmental sensors.

IC Role / Device Role / Timing Role: Linear-mode amplifier stage configured with emitter degeneration for stable DC gain and offset control.

Use Value: h_FE ≥ 10,000 allows sub-1µA base bias, minimizing quiescent current in always-on sensing nodes.

Use Scenario: Implementing overtemperature shutdown in motor controllers using NTC thermistor feedback to disable gate drive.

IC Role / Device Role / Timing Role: Fast-response comparator substitute using V_BE temperature coefficient to trigger cutoff at preset junction temperature.

Use Value: Leverages inherent –2.2 mV/°C V_BE(on) drift to achieve passive thermal trip without dedicated ICs or calibration.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Darlington transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT6428-7-F	Same SOT23 package but PNP Darlington; V_CEO = –40V, h_FE = 10,000–140,000, V_EC(sat) = 1.2V (max)	Used in high-side switching or complementary push-pull stages-not interchangeable in low-side configurations.	Select only when sourcing current from V_CC rather than sinking to ground.
ZTX1051A	SOT89 package; higher P_D = 1.5W, R_θJA = 125°C/W, h_FE = 10,000–50,000 at I_C = 500mA	Supports higher continuous power dissipation and improved thermal management in board-level heatsinked designs.	Choose when >310mW steady-state dissipation or lower thermal resistance is required; not drop-in due to package mismatch.

Compared with MMBT6427-7-F, the MMBT6428-7-F provides complementary polarity for high-side use but cannot replace it in low-side roles, while the ZTX1051A offers superior thermal handling in larger packages-making the MMBT6427-7-F optimal for compact, low-power, ground-referenced switching where ultra-high h_FE is prioritized over power density.

Availability

MMBT6427-7-F is available at Aetrix Electronics and suitable for relay drivers, LED load switches, sensor interface amplifiers, and thermal monitoring circuits requiring stable component supply, RoHS-compliant packaging, and SOT23 footprint compatibility.

Supply support for MMBT6427-7-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, manufacturing, and sales operations across Asia, Europe, and North America.

The MMBT6427-7-F belongs to Diodes' general-purpose bipolar transistor product line, engineered for cost-sensitive, space-constrained applications demanding high current gain and reliable low-power switching performance.

FAQ

What is the maximum continuous collector current for MMBT6427-7-F?

The MMBT6427-7-F is rated for 500 mA continuous collector current (I_C) at T_A = +25°C with proper PCB thermal relief. Derating applies above 25°C ambient-power dissipation drops linearly to zero at 150°C junction temperature per the published derating curve.

Does MMBT6427-7-F have built-in base resistors?

No, the MMBT6427-7-F is a bare Darlington transistor without integrated base resistors. External base current limiting must be provided-typically via a series resistor sized to deliver 0.5 mA base drive for 500 mA collector load under worst-case h_FE conditions.

Can MMBT6427-7-F be used in automotive applications?

The base MMBT6427-7-F is not AEC-Q101 qualified. However, Diodes offers automotive-grade variants (e.g., MMBT6427Q-7-F) with PPAP documentation, IATF 16949 manufacturing, and extended qualification testing-contact Diodes or Aetrix for qualified part numbers and change-control support.

What is the typical V_BE(sat) at full load?

V_BE(sat) is 1.55 V (typical) and 2.0 V (maximum) at I_C = 500 mA and I_B = 0.5 mA. This reflects the combined forward voltage of two series-connected base-emitter junctions, confirming true Darlington behavior and informing minimum drive voltage requirements.

MMBT6427-7-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 1.5V @ 500µA, 500mA

Current - Collector Cutoff (Max):: 1µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 20000 @ 100mA, 5V

Power - Max:: 300 mW

Frequency - Transition:: -

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

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

MMBT6427-7-F FAQ

1.How can I place an order for MMBT6427-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBT6427-7-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 MMBT6427-7-F reliable?

The price and inventory of MMBT6427-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT6427-7-F is usually 5 days.

3.What payment methods are accepted for MMBT6427-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT6427-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBT6427-7-F?

MMBT6427-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBT6427-7-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 MMBT6427-7-F?

For technical support, including MMBT6427-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT6427-7-F requirements.

6.How does Aetrix verify that MMBT6427-7-F is sourced from the original manufacturer or authorized distributors?

All MMBT6427-7-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 MMBT6427-7-F meets industry standards.

7.What is the process for return or replacement of MMBT6427-7-F?

All MMBT6427-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMBT6427-7-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 MMBT6427-7-F part is unused and in its original packaging.

Return procedure for MMBT6427-7-F:

1.Submit a request within 90 days.

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

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