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Vishay General Semiconductor - Diodes Division SMA6F18A-M3/6B
- Part No.:
- SMA6F18A-M3/6B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA6F18A-M3/6B.pdf
- Description:
- TVS DIODE 18VWM 33.2VC DO221AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,836
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Product details
Overview
SMA6F18A-M3/6B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) in SlimSMA (DO-221AC) package, designed for clamping voltage transients on power and signal lines. It features 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 28.3 V max clamping voltage at 10/1000 μs (IPP = 21.2 A), 600 W peak pulse power, and ESD immunity per IEC 61000-4-2 level 4 (15 kV air / 8 kV contact). It protects MOSFETs and ICs in industrial sensor interfaces.
For engineers reviewing the SMA6F18A-M3/6B datasheet, SMA6F18A-M3/6B pinout, SMA6F18A-M3/6B application, or SMA6F18A-M3/6B equivalent, key selection criteria include clamping voltage at rated surge current, thermal resistance (RθJA = 120–150 °C/W), unidirectional polarity, MSL level 1 rating, and compatibility with automated SMT placement on FR4 PCBs with 2 oz copper.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents <0.2 μA leakage at 18 V; during transient events exceeding VBR, it avalanches to clamp voltage at VC ≤28.3 V (10/1000 μs) or ≤33.2 V (8/20 μs), diverting up to 21.2 A or 102 A respectively. Its dynamic resistance is 0.292 Ω, enabling fast response to sub-microsecond surges.
The device uses silicon avalanche junction technology in a planar construction, housed in a halogen-free, RoHS-compliant SlimSMA package with matte tin-plated leads. It meets J-STD-020 MSL level 1 and withstands peak reflow temperatures up to 260 °C, supporting high-volume automated assembly without solderability degradation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before significant leakage; defines safe working margin below clamping threshold. |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - Confirmed avalanche onset range; ensures predictable turn-on across temperature and unit variation. |
| VC @ IPP (10/1000 μs) | 28.3 V at 21.2 A - Clamped voltage seen by protected circuit during standard lightning surge; limits stress on downstream components. |
| PPPM (10/1000 μs) | 600 W - Peak transient energy handling capacity under IEC 61000-4-5 waveform; determines survivability of common industrial surges. |
| ID @ VWM | ≤0.2 μA - Ultra-low leakage ensures minimal standby power loss and no interference with high-impedance signal paths. |
| TJ max. | 175 °C - Maximum junction temperature; enables operation in high-ambient environments such as motor drives or outdoor enclosures. |
| ESD Rating | IEC 61000-4-2 level 4: 15 kV air / 8 kV contact - Validates robustness against human-body-model electrostatic discharge in end-user handling. |
Pinout & Package
Package: SlimSMA (DO-221AC), ultra-low-profile surface-mount case with 0.95 mm typical height, matte tin-plated leads, cathode indicated by color band. Complies with UL 94 V-0, MSL level 1, and JESD201 class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction; connected to lower-potential side of protected line. | Provides low forward voltage drop (<1.2 V at 10 A) for bidirectional testing or fault-current path definition. |
| Cathode | Current exit terminal during reverse-biased clamping; connected to higher-potential side (e.g., VCC or signal line). | Color band identifies polarity; critical for correct orientation in unidirectional TVS placement to avoid open-circuit failure mode. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping performance | VC = 28.3 V @ 21.2 A (10/1000 μs) - Limits voltage overshoot to safe levels for 3.3 V/5 V/12 V logic and power rails. |
| Thermal robustness | RθJA = 120–150 °C/W on FR4 - Enables reliable power dissipation without heatsink in space-constrained layouts. |
| Automated assembly support | MSL level 1, 260 °C peak reflow, J-STD-002 solderability - Eliminates pre-baking and supports high-yield SMT line integration. |
| Environmental compliance | Halogen-free, RoHS-compliant, UL 94 V-0 molding compound - Meets global safety and sustainability requirements for industrial end equipment. |
| ESD hardening | 15 kV air / 8 kV contact per IEC 61000-4-2 - Protects interface ports (USB, RS-485, CAN) from user-induced static discharge. |
Applications
| Industrial Sensor Interface | Power Supply Input Protection |
|---|---|
Use Scenario: Protecting analog output lines (4–20 mA, 0–10 V) of temperature/pressure sensors in factory automation cabinets exposed to relay switching noise. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between signal line and ground to clamp inductive kickback transients. Use Value: Prevents sensor IC latch-up or ADC input damage by limiting transient voltage to ≤28.3 V while maintaining <0.2 μA leakage at 18 V operating point. |
Use Scenario: Safeguarding 24 V DC input stage of PLC I/O modules against load dump and inductive switching surges from solenoid valves. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power rail upstream of DC-DC converter input. Use Value: Absorbs 600 W (10/1000 μs) surge energy without degradation, preserving downstream regulator reliability and reducing need for bulk capacitance. |
| Automotive Body Control Module | Telecom Line Card Protection |
Use Scenario: Shielding LIN bus transceivers and microcontroller GPIOs from battery line transients during jump-start or alternator load dump. IC Role / Device Role / Timing Role: Localized TVS at connector entry point, oriented cathode-to-VBAT for unidirectional suppression. Use Value: Withstands 175 °C junction temperature and meets AEC-Q200-relevant thermal cycling stability, ensuring long-term field reliability. |
Use Scenario: Guarding Ethernet PHY or PoE controller inputs on network switch line cards against lightning-induced surges on RJ45 ports. IC Role / Device Role / Timing Role: First-stage protection device on differential pair, coordinated with GDT or secondary TVS for multi-level defense. Use Value: Delivers 4 kW (8/20 μs) peak pulse power handling and 33.2 V clamping at 102 A, meeting ITU-T K.21 basic protection requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6F18A-M3/6A | Identical electrical specs and SlimSMA package; differs only in tape-and-reel packaging (3500 pcs vs. 14000 pcs per reel). | No functional difference; suitable for same PCB layouts and protection circuits. | Select SMA6F18A-M3/6A for smaller batch prototyping or low-volume production where reel size impacts inventory turnover. |
| SMAJ18A | Same VWM (18 V) and VBR range but lower PPPM (400 W vs. 600 W), higher RθJA (150 °C/W), and larger SMA (DO-214AC) package (2.3 mm height). | Less effective for high-energy transients; requires more board area and may need derating above 70 °C ambient. | Choose SMAJ18A only if legacy footprint compatibility is required and surge energy remains within 400 W limit. |
Compared with SMA6F18A-M3/6B, SMA6F18A-M3/6A offers identical protection performance in a smaller reel format, while SMAJ18A trades off surge capacity and thermal efficiency for backward-compatible packaging-making SMA6F18A-M3/6B optimal for new designs prioritizing compactness, high-energy clamping, and automated assembly yield.
Availability
SMA6F18A-M3/6B is available at Aetrix Electronics and suitable for industrial sensor interfaces, power supply input protection, and automotive body control modules requiring stable component supply, consistent MSL level 1 compliance, and verified TVS clamping performance across production lots.
Supply support for SMA6F18A-M3/6B 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, TVS devices, and optoelectronics with emphasis on reliability, precision, and application-specific optimization.
The SMA6FxxA series is part of Vishay's TRANSZORB® TVS platform, engineered for high-energy transient suppression in space-constrained, high-reliability applications including industrial automation, automotive electronics, and telecom infrastructure.
FAQ
What is the maximum clamping voltage of the SMA6F18A-M3/6B under a 10/1000 μs surge?
The SMA6F18A-M3/6B has a maximum clamping voltage (VC) of 28.3 V when subjected to a 10/1000 μs waveform at its rated peak pulse current of 21.2 A. This value is measured per the conditions specified in the Vishay datasheet document 89458 and reflects worst-case clamping performance across process and temperature variation. The SMA6F18A-M3/6B maintains this clamping level while delivering 600 W peak pulse power, making it suitable for protecting 24 V systems where voltage excursions must remain below 30 V.
Is the SMA6F18A-M3/6B unidirectional or bidirectional?
The SMA6F18A-M3/6B is a unidirectional transient voltage suppressor, meaning it conducts only in reverse bias above its breakdown voltage (VBR = 20.0–22.1 V) and blocks current in forward bias like a standard diode. Its polarity is marked by a cathode band, and it must be installed with the cathode toward the higher-potential side of the protected line. The SMA6F18A-M3/6B is not rated for bidirectional operation; using it in AC or bipolar signal paths without external circuitry will result in improper clamping behavior.
Does the SMA6F18A-M3/6B meet lead-free and RoHS requirements?
Yes, the SMA6F18A-M3/6B is halogen-free, RoHS-compliant, and qualified to JESD201 class 2 for tin whisker resistance. Its "M3" suffix explicitly denotes industrial-grade, lead-free construction with matte tin-plated terminals that comply with J-STD-002 solderability standards. The device also meets UL 94 V-0 flammability rating and J-STD-020 MSL level 1, confirming full suitability for modern lead-free reflow processes up to 260 °C peak temperature.
What is the thermal resistance junction-to-ambient (RθJA) for the SMA6F18A-M3/6B?
The SMA6F18A-M3/6B has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and a maximum of 150 °C/W when mounted on a standard FR4 PCB with 2 oz copper and the recommended pad layout. This value is measured per JEDEC 51-2A and directly impacts power derating: at 70 °C ambient, the device can safely dissipate ~0.7 W continuously. The SMA6F18A-M3/6B's low RθJA supports reliable operation in thermally dense industrial PCBs without additional heatsinking.
Can the SMA6F18A-M3/6B be used in automotive applications?
Yes, the SMA6F18A-M3/6B is suitable for non-safety-critical automotive applications such as body control modules, LIN bus protection, and lighting driver inputs. It operates across –55 °C to +175 °C junction temperature, withstands MSL level 1 reflow, and delivers robust ESD immunity (IEC 61000-4-2 level 4). While not AEC-Q200 certified as a complete device, its construction and characterization align with automotive environmental stress requirements-and the SMA6F18A-M3/6B is widely deployed in Tier-1 subsystems where qualification is performed at the module level.
SMA6F18A-M3/6B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- TransZorb®
- 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:
- 33.2V
- Current - Peak Pulse (10/1000µs):
- 102A (8/20µs)
- Power - Peak Pulse:
- 4000W (4kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-221AC (SlimSMA)
SMA6F18A-M3/6B FAQ
1.How can I place an order for SMA6F18A-M3/6B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6F18A-M3/6B 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 SMA6F18A-M3/6B reliable?
The price and inventory of SMA6F18A-M3/6B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6F18A-M3/6B is usually 5 days.
3.What payment methods are accepted for SMA6F18A-M3/6B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6F18A-M3/6B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6F18A-M3/6B?
SMA6F18A-M3/6B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6F18A-M3/6B 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 SMA6F18A-M3/6B?
For technical support, including SMA6F18A-M3/6B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6F18A-M3/6B requirements.
6.How does Aetrix verify that SMA6F18A-M3/6B is sourced from the original manufacturer or authorized distributors?
All SMA6F18A-M3/6B 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 SMA6F18A-M3/6B meets industry standards.
7.What is the process for return or replacement of SMA6F18A-M3/6B?
All SMA6F18A-M3/6B units undergo pre-shipment inspection (PSI). If there is an issue with SMA6F18A-M3/6B, 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 SMA6F18A-M3/6B part is unused and in its original packaging.
Return procedure for SMA6F18A-M3/6B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMA6F18A-M3/6B Tags
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