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Diodes Incorporated MMST6427-7
- Part No.:
- MMST6427-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- SC-70, SOT-323
- Datasheet:
-
MMST6427-7.pdf
- Description:
- TRANS NPN DARL 40V 0.5A SOT-323
- Quantity:
- Payment:
- Shipping:
Inventory:6,858
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Product details
Overview
MMST6427-7 from Diodes Incorporated is an NPN surface-mount Darlington transistor in SOT-323 package, rated for 40 V VCEO, 500 mA IC, and 200 mW PD, with hFE up to 200,000 at IC = 500 mA. It serves as a high-gain switching or low-power amplification device in compact portable electronics and sensor interface circuits.
For engineers reviewing the MMST6427-7 datasheet, MMST6427-7 pinout, MMST6427-7 application, or MMST6427-7 equivalent, key selection criteria include its Darlington architecture enabling microampere-level base drive, ultra-small SOT-323 footprint, guaranteed VCE(sat) ≤ 1.5 V at 500 mA, and RoHS-compliant "Green" construction.
Technical Context
This Darlington pair integrates two NPN transistors monolithically using epitaxial planar die construction, delivering cascaded current gain without external biasing components. Its VEBO = 12 V and BVEBO rating support reliable turn-on control under low-voltage logic drive.
The device operates across –55°C to +150°C with RθJA = 625°C/W on standard FR4 PCB, and exhibits Cobo = 8.0 pF and Cibo = 15 pF for predictable high-frequency behavior in signal-switching roles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 40 V - Maximum safe collector-emitter voltage before breakdown during switching |
| IC (max) | 500 mA - Continuous collector current capacity for load-driving capability |
| hFE (max) | 200,000 - High Darlington gain enables µA-range base drive for efficient logic-level control |
| VCE(sat) | ≤1.5 V @ IC=500 mA - Low saturation voltage minimizes power loss in switching applications |
| PD | 200 mW - Power dissipation limit defining thermal derating on standard PCB layout |
| RθJA | 625 °C/W - Junction-to-ambient thermal resistance guides heatsinking requirements |
Pinout & Package
Package: SOT-323 - ultra-small plastic surface-mount package (2.1 mm × 1.3 mm × 0.9 mm), lead-free, halogen-free, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emitter terminal of Darlington pair | Reference node for current return; connected to ground or low-side reference in switch configurations |
| 2 (Base) | Input control terminal | Accepts low-current drive (e.g., from MCU GPIO) to activate full Darlington conduction |
| 3 (Collector) | Output current terminal | Delivers amplified load current; connects to positive rail or load in low-side switch topology |
Key Features
| Feature | Design Value |
|---|---|
| Darlington architecture | Monolithic dual-NPN structure eliminates external resistor networks and improves gain stability |
| High hFE range | 10,000–200,000 across 10 mA–500 mA ensures robust turn-on margin with weak drive sources |
| Low VBE(on) | ≤1.75 V @ IC=50 mA enables compatibility with 1.8 V/3.3 V logic families |
| SOT-323 footprint | 0.006 g weight and 2.1 mm × 1.3 mm outline supports space-constrained portable PCB layouts |
Applications
| LED Driver Circuit | Microcontroller I/O Expander |
|---|---|
Use Scenario: Driving multi-segment LED displays from low-current GPIO pins. IC Role / Device Role: Low-side Darlington switch amplifying MCU output to sink up to 500 mA per segment. Use Value: Eliminates need for discrete base resistors and secondary transistors while maintaining <1.5 V dropout at full load. | Use Scenario: Extending digital output capability of resource-limited microcontrollers. IC Role / Device Role: Single-transistor buffer enabling direct connection of 3.3 V GPIO to 5 V relay coils or solenoids. Use Value: Delivers >100× current gain with guaranteed VCE(sat) ≤ 0.9 V at 100 mA, reducing heat generation in dense I/O modules. |
| Portable Sensor Interface | Low-Power Alarm Output |
Use Scenario: Enabling wake-up signaling from battery-powered environmental sensors. IC Role / Device Role: Ultra-low-quiescent switch activating piezo buzzer or indicator LED only during event detection. Use Value: ICEO ≤ 1.0 µA ensures sub-µA standby leakage, preserving coin-cell battery life over multi-year deployments. | Use Scenario: Generating audible alerts in smoke detectors and security panels. IC Role / Device Role: High-gain driver interfacing between low-power comparator outputs and 8 Ω piezoelectric transducers. Use Value: VCEO = 40 V withstands transient spikes in unregulated 12 V alarm rails while maintaining fast turn-off via base discharge path. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Darlington transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| NSV6427MUT1G | Same SOT-323 package; hFE min = 10,000 @ IC = 10 mA but no spec at 500 mA; VCE(sat) = 1.3 V max @ IC = 100 mA | Limited high-current gain validation; less suitable for 500 mA continuous loads | Select when design operates below 100 mA and requires ON Semiconductor sourcing |
| MMDT6427 | SC-70 package (slightly larger); hFE = 14,000–140,000 @ IC = 500 mA; VCE(sat) = 1.4 V max @ same condition | Compatible gain/saturation performance but 20% larger footprint and higher RθJA (700°C/W) | Choose if board layout allows SC-70 and requires second-source availability from Diodes Inc. |
Compared with NSV6427MUT1G and MMDT6427, MMST6427-7 offers the highest verified hFE at full 500 mA load and lowest thermal resistance in its class, making it optimal for thermally constrained, high-gain switching where consistent saturation voltage is critical.
Availability
MMST6427-7 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller I/O expansion, portable sensor interfaces, and low-power alarm outputs requiring stable component supply and long-term manufacturability.
Supply support for MMST6427-7 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, serving automotive, industrial, computing, and consumer markets with high-reliability components.
The MMST6427-7 belongs to Diodes' general-purpose bipolar transistor product line, engineered specifically for space-constrained, low-power switching and amplification tasks where high DC gain and minimal board area are essential.
FAQ
What is the maximum continuous collector current for MMST6427-7?
The MMST6427-7 is rated for 500 mA continuous collector current (IC) at TA = 25°C with specified derating above 25°C. This rating assumes mounting on a 25 mm × 22 mm × 1.6 mm FR4 PCB with 1 oz copper on one side, per datasheet Note 4.
Does MMST6427-7 require an external base resistor?
No external base resistor is required for basic switching operation, as the Darlington configuration provides sufficient current gain (hFE ≥ 10,000) to be driven directly by logic-level signals. However, a small series resistor (e.g., 10 kΩ) is recommended to limit base current during transient conditions and improve noise immunity.
Is MMST6427-7 suitable for linear amplification?
While electrically capable of small-signal amplification due to its high hFE, the MMST6427-7 is optimized for switching applications per its datasheet features and characterization. Its gain variation across current and temperature makes it less ideal than dedicated RF or audio transistors for precision linear amplification.
What is the moisture sensitivity level (MSL) for MMST6427-7?
The MMST6427-7 has a moisture sensitivity level of MSL 1 per J-STD-020, meaning it may be stored indefinitely at ambient conditions (≤30°C / 60% RH) without baking prior to reflow soldering. No floor life limitation applies under standard handling.
MMST6427-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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:
- 200 mW
- Frequency - Transition:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
MMST6427-7 FAQ
1.How can I place an order for MMST6427-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMST6427-7 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 MMST6427-7 reliable?
The price and inventory of MMST6427-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMST6427-7 is usually 5 days.
3.What payment methods are accepted for MMST6427-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMST6427-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMST6427-7?
MMST6427-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMST6427-7 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 MMST6427-7?
For technical support, including MMST6427-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMST6427-7 requirements.
6.How does Aetrix verify that MMST6427-7 is sourced from the original manufacturer or authorized distributors?
All MMST6427-7 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 MMST6427-7 meets industry standards.
7.What is the process for return or replacement of MMST6427-7?
All MMST6427-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMST6427-7, 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 MMST6427-7 part is unused and in its original packaging.
Return procedure for MMST6427-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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