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Vishay General Semiconductor - Diodes Division SMF18A-M3-18
- Part No.:
- SMF18A-M3-18
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-219AB
- Datasheet:
-
SMF18A-M3-18.pdf
- Description:
- TVS DIODE 18VWM 29.2VC SMF
- Quantity:
- Payment:
- Shipping:
Inventory:3,814
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Product details
Overview
SMF18A-M3-18 from Vishay Semiconductors is a unidirectional surface-mount ESD protection diode in the SMF (DO-219AB) package, designed for clamping transient overvoltages on signal or power lines. It features a 18 V stand-off voltage (VRWM), 20–22.3 V reverse breakdown range (VBR), 29.2 V maximum clamping voltage at 6.8 A peak pulse current, 320 pF typical capacitance at 0 V, and ±30 kV IEC 61000-4-2 ESD immunity - used in USB 2.0 data line protection.
For engineers reviewing the SMF18A-M3-18 datasheet, SMF18A-M3-18 pinout, SMF18A-M3-18 application, or SMF18A-M3-18 equivalent, this device is selected for high-reliability ESD suppression in automotive infotainment interfaces, industrial sensor I/O, and portable medical device ports where low clamping voltage and sub-1 ns response time are critical.
Technical Context
The SMF18A-M3-18 operates as a single-channel unidirectional TVS diode with avalanche breakdown behavior, optimized for fast transient response under IEC 61000-4-2 and IEC 61000-4-5 surge conditions. Its junction design enables low incremental surge resistance and stable clamping performance across -65 °C to +175 °C operating temperature.
It delivers 200 W peak pulse power (10/1000 μs waveform) and 1000 W (8/20 μs), with thermal resistance RthJA = 180 K/W on standard epoxy-glass PCB pads. The device meets AEC-Q101 qualification for automotive-grade reliability and supports wave/reflow soldering per J-STD-020 MSL level 1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRWM) | 18 V - maximum continuous reverse working voltage before leakage exceeds 0.1 µA; defines safe operating margin below clamping threshold. |
| Reverse Breakdown (VBR) | 20–22.3 V at 1 mA - onset of avalanche conduction; ensures predictable turn-on during transients without premature conduction. |
| Clamping Voltage (VC) | 29.2 V at 6.8 A (10/1000 μs) - limits downstream IC voltage stress during ESD events; enables robust protection of 24 V logic interfaces. |
| Capacitance (CD) | 320 pF at 0 V, 1 MHz - impacts signal integrity on high-speed lines; suitable for ≤12 Mbps interfaces like RS-485 or CAN FD physical layer. |
| ESD Immunity | ±30 kV contact / ±30 kV air (IEC 61000-4-2) - exceeds Level 4 requirements; eliminates need for secondary ESD stages in end-equipment certification. |
| Peak Pulse Power | 200 W (10/1000 μs), 1000 W (8/20 μs) - sustains multi-pulse surges in industrial power supply rails and automotive load-dump scenarios. |
| AEC-Q101 Qualified | Yes - validated for automotive applications including infotainment, body control modules, and ADAS sensor interfaces per H3B HBM (>8 kV). |
Pinout & Package
Package: DO-219AB (SMF), low-profile SMD case with cathode marking bar; dimensions 3.9 mm × 1.9 mm × 1.08 mm; compatible with SOD-123W footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/line side connection | Connected to protected signal or power line; conducts surge current toward ground when cathode is held at reference potential. |
| Cathode | Ground/reference connection | Must be tied to low-impedance system ground plane; determines unidirectional clamping polarity and defines VRWM rating direction. |
Key Features
| Feature | Design Value |
|---|---|
| Low clamping voltage | 29.2 V at 6.8 A ensures protected ICs remain within absolute maximum ratings during 30 kV ESD strikes. |
| "Low Noise" fast response | Sub-1 ns turn-on time minimizes voltage overshoot on high-speed data lines such as USB 2.0 or HDMI DDC channels. |
| AEC-Q101 qualification | Validated for automotive underhood and cabin environments with full temperature cycling, humidity bias, and mechanical shock testing. |
| Solder compatibility | Wave and reflow process capable up to 260 °C peak; MSL level 1 handling eliminates bake requirements prior to assembly. |
| Single-channel unidirectional topology | Optimized for DC-biased lines (e.g., 12 V sensor supply, CAN_H); avoids capacitance doubling and leakage issues of bidirectional variants. |
Applications
| Automotive Infotainment USB Port | Industrial RS-485 Transceiver Protection |
|---|---|
Use Scenario: Protecting USB 2.0 D+ and D- lines in head unit docking connectors exposed to repeated ESD events during plug/unplug cycles. IC Role / Device Role / Timing Role: Unidirectional clamping diode placed between data line and chassis ground, with cathode grounded. Use Value: 320 pF capacitance maintains signal rise/fall times < 1 ns; 29.2 V clamping prevents damage to USB PHY transceivers rated for 3.3 V I/O. |
Use Scenario: Safeguarding RS-485 transceiver inputs against induced surges in factory automation cabling routed near motor drives. IC Role / Device Role / Timing Role: Line-to-ground TVS on A/B differential pair, leveraging 18 V VRWM to match common-mode voltage range of isolated RS-485 receivers. Use Value: 200 W pulse rating handles repetitive 1 kV/1 Ω surge tests per IEC 61000-4-4; AEC-Q101 grade ensures longevity in harsh plant-floor thermal cycling. |
| Medical Patient Monitor Sensor Interface | Smart Building PoE-Powered Node |
Use Scenario: Shielding analog front-end inputs (ECG, SpO₂) from ESD during clinical staff handling of reusable sensor cables. IC Role / Device Role / Timing Role: Low-leakage (0.1 µA max at 18 V) unidirectional clamp on signal path to precision ADC, minimizing offset drift. Use Value: 20–22.3 V VBR range provides tight tolerance window for accurate trigger threshold setting; 175 °C max junction temp supports sterilization reflow profiles. |
Use Scenario: Protecting 24 V auxiliary power input on PoE-powered lighting controllers subjected to lightning-induced surges on building wiring. IC Role / Device Role / Timing Role: Primary clamping device on DC input rail upstream of DC/DC converter, with cathode tied to local ground plane. Use Value: 1000 W 8/20 μs rating absorbs IEC 61000-4-5 Combination Wave surges; DO-219AB package withstands mechanical vibration in ceiling-mounted fixtures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ESD protection diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/57T | Higher clamping voltage (32.4 V at 6.4 A), larger SMA (DO-214AC) package (4.5 mm × 2.7 mm), 500 pF capacitance. | Less suitable for high-speed data lines due to higher CD; better for 24–48 V power rail protection where capacitance is non-critical. | Select SMAJ18A-E3/57T when board space allows larger footprint and lower-cost procurement is prioritized over signal integrity. |
| TPD2E001DRYR | Bi-directional dual-channel array (2 lines), 12 pF capacitance, 14 V VRWM, integrated ESD protection only (no surge rating beyond IEC 61000-4-2). | Designed exclusively for ultra-high-speed digital interfaces (USB 3.0, HDMI); lacks 1000 W IEC 61000-4-5 capability. | Choose TPD2E001DRYR for compact dual-line protection on high-frequency serial buses where surge robustness is secondary to capacitance. |
Compared with SMAJ18A-E3/57T and TPD2E001DRYR, the SMF18A-M3-18 uniquely balances low clamping (29.2 V), moderate capacitance (320 pF), and full IEC 61000-4-5 surge compliance in a compact DO-219AB package - making it optimal for cost-sensitive, space-constrained industrial and automotive signal-line protection.
Availability
SMF18A-M3-18 is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial RS-485 networks, and medical sensor interfaces requiring stable component supply and long-term lifecycle support.
Supply support for SMF18A-M3-18 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 Semiconductors is a global leader in discrete semiconductors, specializing in high-reliability diodes, MOSFETs, optoelectronics, and passive components for automotive, industrial, and computing markets.
The SMF series targets ESD and surge protection in space-constrained, thermally demanding applications - engineered for AEC-Q101 compliance, low-profile mounting, and consistent clamping performance across extended temperature ranges.
FAQ
What is the maximum clamping voltage of the SMF18A-M3-18 under standard test conditions?
The SMF18A-M3-18 has a maximum clamping voltage (VC) of 29.2 V when subjected to a 10/1000 μs surge current pulse of 6.8 A. This value is measured per IEC 61000-4-5 standards and reflects the peak voltage seen across the device during transient suppression - critical for ensuring downstream ICs remain within their absolute maximum ratings. The SMF18A-M3-18 achieves this while maintaining low incremental resistance and stable performance across its full operating temperature range.
Is the SMF18A-M3-18 qualified for automotive applications?
Yes, the SMF18A-M3-18 is AEC-Q101 qualified and rated for H3B human body model (HBM) ESD > 8 kV. It undergoes rigorous stress testing including temperature cycling, humidity bias, and mechanical shock per automotive reliability standards. This qualification makes the SMF18A-M3-18 suitable for use in automotive infotainment, body control modules, and ADAS sensor interfaces where long-term reliability under thermal and mechanical stress is mandatory.
What is the capacitance of the SMF18A-M3-18 and how does it affect high-speed signal lines?
The SMF18A-M3-18 exhibits 320 pF typical capacitance at 0 V and 1 MHz. This value directly impacts signal integrity on high-speed lines: it limits usable bandwidth and may degrade edge rates on interfaces exceeding ~12 Mbps. For USB 2.0 (480 Mbps), the SMF18A-M3-18 remains viable due to its low clamping and fast response, but designers should verify eye diagram margins. The SMF18A-M3-18 is not recommended for USB 3.0 or HDMI without additional signal conditioning.
Does the SMF18A-M3-18 support automated PCB assembly processes?
Yes, the SMF18A-M3-18 is fully compatible with both wave and reflow soldering per J-STD-020. Its DO-219AB package is rated for peak reflow temperatures up to 260 °C and classified as MSL level 1 - meaning no dry-pack or baking is required prior to assembly. The device's low-profile geometry (1.08 mm height) also supports low-clearance board stacking, and its cathode-bar marking enables reliable optical inspection during AOI.
How does the SMF18A-M3-18 compare to bidirectional TVS diodes in ESD protection design?
The SMF18A-M3-18 is unidirectional, meaning it clamps only when the anode is driven positive relative to the cathode - ideal for DC-biased lines like 12 V sensor supplies or CAN_H. Unlike bidirectional variants, it avoids doubled capacitance and higher leakage at zero bias. This gives the SMF18A-M3-18 superior signal fidelity on single-ended, biased interfaces and eliminates false triggering in asymmetric voltage environments - a key advantage in automotive and industrial power-rail protection.
SMF18A-M3-18 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-219AB
- Series:
- eSMP®
- 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):
- 6.8A
- Power - Peak Pulse:
- 200W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 320pF @ 1MHz
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AB (SMF)
SMF18A-M3-18 FAQ
1.How can I place an order for SMF18A-M3-18 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF18A-M3-18 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 SMF18A-M3-18 reliable?
The price and inventory of SMF18A-M3-18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF18A-M3-18 is usually 5 days.
3.What payment methods are accepted for SMF18A-M3-18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF18A-M3-18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF18A-M3-18?
SMF18A-M3-18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF18A-M3-18 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 SMF18A-M3-18?
For technical support, including SMF18A-M3-18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF18A-M3-18 requirements.
6.How does Aetrix verify that SMF18A-M3-18 is sourced from the original manufacturer or authorized distributors?
All SMF18A-M3-18 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 SMF18A-M3-18 meets industry standards.
7.What is the process for return or replacement of SMF18A-M3-18?
All SMF18A-M3-18 units undergo pre-shipment inspection (PSI). If there is an issue with SMF18A-M3-18, 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 SMF18A-M3-18 part is unused and in its original packaging.
Return procedure for SMF18A-M3-18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF18A-M3-18 Tags
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