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Diodes Incorporated SMF4L18A-7
- Part No.:
- SMF4L18A-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L18A-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
SMF4L18A-7 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in power rails and I/O lines. It features a 18V working peak reverse voltage (VRWM), 20–22.1V breakdown voltage (VBR), 29.2V maximum clamping voltage (VC) at 13.7A peak pulse current, and <0.5µA reverse leakage at VRWM - optimized for automotive battery contacts and industrial power management systems.
For engineers reviewing the SMF4L18A-7 datasheet, SMF4L18A-7 pinout, SMF4L18A-7 application, or SMF4L18A-7 equivalent, key selection criteria include clamping performance under 10/1000µs surge, unidirectional polarity confirmation via cathode band marking, DO-219AA package thermal resistance (RθJA = 96°C/W), and compliance with IEC61000-4-2 ±30kV ESD immunity.
Technical Context
This TVS diode operates as a fast-acting shunt protector, triggering when transient voltage exceeds its breakdown threshold to divert surge energy away from sensitive downstream circuitry. Its unidirectional configuration enables integration on DC-biased lines such as automotive 12V/24V supply rails and USB VBUS paths.
It delivers sub-1ns response time for unidirectional transients and sustains 400W peak pulse power per the standardized 10/1000µs waveform. The device is rated for operation from –55°C to +175°C and qualified to JEDEC reliability standards for high-reliability applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 18V - Maximum continuous reverse operating voltage before clamping begins; sets safe DC bias margin for 12V/24V automotive systems. |
| VBR (min/max) | 20V / 22.1V @ 1mA - Confirmed breakdown range ensures reliable turn-on without premature conduction during normal operation. |
| VC @ IPP | 29.2V @ 13.7A - Clamping voltage limits downstream IC stress during 400W transient events; critical for protecting 3.3V/5V logic interfaces. |
| PPK | 400W (10/1000µs) - Peak pulse power rating defines surge handling capacity for lightning-induced or load-dump transients. |
| IR @ VRWM | <0.5µA - Ultra-low leakage preserves battery life in always-on automotive modules and low-power sensor nodes. |
| Response Time | <1.0ns - Enables suppression of nanosecond-scale ESD events before damage occurs to CMOS inputs or communication transceivers. |
| Operating Temp | –55°C to +175°C - Supports under-hood automotive placement and industrial environments with wide thermal cycling. |
Pinout & Package
Package: DO-219AA - ultra-compact surface-mount plastic package (2.80mm × 1.90mm × 0.60mm height), matte tin-plated copper alloy lead frame, RoHS-compliant, halogen-free, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; completes shunt path during transient conduction. |
| Cathode | High-side transient input terminal | Connected to protected line (e.g., battery rail); cathode band marking confirms unidirectional polarity. |
Key Features
| Feature | Design Value |
|---|---|
| IEC61000-4-2 ESD Protection | ±30kV air discharge, ±30kV contact discharge - meets highest system-level ESD immunity requirements without external shielding. |
| Fast Response Time | <1.0ns rise-to-conduction - intercepts ESD pulses before propagation into microcontroller GPIO or CAN transceiver pins. |
| Thermal Performance | RθJA = 96°C/W on 1"×1" FR-4 board - enables stable operation in compact PCB layouts without forced airflow or heatsinking. |
| Automotive Readiness | Qualified to JEDEC high-reliability standards; supports AEC-Q200 qualification path via Q-suffix variants - suitable for PPAP-capable production. |
| Green Compliance | Halogen- and antimony-free (<900ppm Br/Cl, <1000ppm Sb), RoHS 3 compliant - satisfies Tier-1 automotive and EU environmental mandates. |
Applications
| Automotive Battery Protection | USB Power Line Protection |
|---|---|
Use Scenario: Protecting 12V/24V battery-fed ECUs from load dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between battery rail and power management IC input. Use Value: Clamps 29.2V at 13.7A to prevent overvoltage damage to buck converters and CAN transceivers during ISO 7637-2 Pulse 5a events. |
Use Scenario: Safeguarding USB Type-C VBUS lines against hot-plug surges and ESD. IC Role / Device Role / Timing Role: Standalone TVS mounted directly at connector entry point, ahead of USB PD controller. Use Value: Sub-1ns response and ±30kV ESD rating ensure compliance with USB-IF ESD test plans without degrading signal integrity. |
| Industrial Sensor Interface | DC Power Supply Input |
Use Scenario: Shielding 4–20mA loop-powered sensors from field wiring transients. IC Role / Device Role / Timing Role: Bidirectional-capable variant not applicable; this unidirectional part used on DC-biased analog front-end rails. Use Value: 0.5µA max leakage avoids offset errors in precision current-sense amplifiers while clamping induced surges up to 400W. |
Use Scenario: Front-end protection for 24V industrial PLC power supplies exposed to switching noise and inductive kickback. IC Role / Device Role / Timing Role: Primary shunt suppressor across bulk input capacitor, coordinated with upstream fuse and common-mode choke. Use Value: 29.2V clamping voltage maintains safe margin below 30V-rated input capacitors and rectifier bridges under surge conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | DO-214AC package; higher RθJA (110°C/W); 29.2V VC same, but lower IPP (13.1A) | Larger footprint; less effective thermal dissipation in dense layouts; same clamping but reduced surge margin | Prefer SMF4L18A-7 where board space and thermal performance are constrained |
| SMF4L18CA | Bi-directional variant; identical VRWM (18V), VBR (20–22.1V), VC (29.2V), but symmetrical clamping for AC-coupled lines | Required only for floating or bidirectional signal lines (e.g., RS-485, CAN FD differential pairs) | Select SMF4L18A-7 for DC-biased rails; choose SMF4L18CA only when polarity reversal or AC transients are present |
Compared with SMAJ18A, SMF4L18A-7 offers superior thermal performance and smaller footprint; versus SMF4L18CA, it provides tighter leakage control and optimized clamping for unidirectional power rails - making it the preferred choice for automotive battery and industrial DC supply protection.
Availability
SMF4L18A-7 is available at Aetrix Electronics and suitable for automotive battery protection, USB power line hardening, and industrial DC power supply input stages requiring stable component supply and full traceability.
Supply support for SMF4L18A-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 integrated circuits, specializing in high-performance, high-reliability components for automotive, industrial, and consumer markets.
The SMF4L series belongs to Diodes' high-power TVS portfolio, engineered specifically for space-constrained, high-surge environments including automotive power distribution and industrial interface protection.
FAQ
What is the polarity configuration of SMF4L18A-7?
SMF4L18A-7 is a unidirectional TVS diode, indicated by a visible cathode band on the DO-219AA package. It conducts only when the cathode is at a higher potential than the anode - making it suitable for DC-biased lines like automotive battery rails and USB VBUS. This configuration ensures zero forward conduction during normal operation.
How does SMF4L18A-7 perform under high-temperature conditions?
SMF4L18A-7 is rated for junction temperatures from –55°C to +175°C and exhibits derated surge capability above +25°C ambient, per Figure 1 in DS43394. At +125°C, its 400W peak pulse power drops to ~240W, while leakage remains below 1µA - enabling reliable use in engine-control units and industrial motor drives without thermal runaway.
Can SMF4L18A-7 replace SMAJ18A in existing designs?
Yes, with layout adaptation: SMF4L18A-7 uses the smaller DO-219AA package versus SMAJ18A's DO-214AC, requiring revised pad geometry. Electrical parameters (VRWM, VBR, VC, IPP) are functionally identical, but thermal resistance improves from 110°C/W to 96°C/W - allowing higher sustained surge tolerance in thermally dense PCBs.
Is SMF4L18A-7 qualified for automotive production use?
SMF4L18A-7 is qualified to JEDEC high-reliability standards and manufactured in IATF 16949-certified facilities. While the standard -7 suffix is not AEC-Q200 qualified, Diodes offers automotive-grade Q-suffix variants (e.g., SMF4L18AQ-7) with full PPAP documentation - recommended for safety-critical Tier-1 applications.
SMF4L18A-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-219AA
- Series:
- SMF4L
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 13.7A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AA
SMF4L18A-7 FAQ
1.How can I place an order for SMF4L18A-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L18A-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 SMF4L18A-7 reliable?
The price and inventory of SMF4L18A-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L18A-7 is usually 5 days.
3.What payment methods are accepted for SMF4L18A-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L18A-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L18A-7?
SMF4L18A-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L18A-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 SMF4L18A-7?
For technical support, including SMF4L18A-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L18A-7 requirements.
6.How does Aetrix verify that SMF4L18A-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L18A-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 SMF4L18A-7 meets industry standards.
7.What is the process for return or replacement of SMF4L18A-7?
All SMF4L18A-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L18A-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 SMF4L18A-7 part is unused and in its original packaging.
Return procedure for SMF4L18A-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L18A-7 Tags
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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