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Vishay General Semiconductor - Diodes Division SMF18A-HM3-18
- Part No.:
- SMF18A-HM3-18
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-219AB
- Datasheet:
-
SMF18A-HM3-18.pdf
- Description:
- TVS DIODE 18VWM 29.2VC SMF
- Quantity:
- Payment:
- Shipping:
Inventory:4,750
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Product details
Overview
SMF18A-HM3-18 from Vishay Semiconductors is a unidirectional surface-mount ESD protection diode in DO-219AB (SOD-123W) package, designed for I/O line protection in high-speed digital interfaces. It features a 18 V stand-off voltage (VRWM), 20–22.3 V reverse breakdown range (VBR), 6.8 A peak pulse current (IPPM), 29.2 V maximum clamping voltage (VC) at IPPM, and 320 pF typical junction capacitance at 0 V.
For engineers reviewing the SMF18A-HM3-18 datasheet, SMF18A-HM3-18 pinout, SMF18A-HM3-18 application, or SMF18A-HM3-18 equivalent, this device is selected for robust ±30 kV IEC 61000-4-2 ESD protection in automotive infotainment ports, USB 2.0 data lines, and industrial sensor interfaces where low clamping voltage and AEC-Q101 qualification are required.
Technical Context
This diode operates as a unidirectional transient voltage suppressor (TVS), leveraging silicon avalanche technology to clamp fast-rising ESD transients before they damage downstream ICs. Its low incremental surge resistance ensures minimal voltage overshoot during 10/1000 μs surges, while its "Low Noise" design enables sub-nanosecond response time critical for protecting high-bandwidth signal paths.
The SMF18A-HM3-18 is rated for 200 W peak pulse power (10/1000 μs), supports ±30 kV contact/air discharge per IEC 61000-4-2, and meets AEC-Q101 stress requirements including H3B-class human body model (>8 kV). Its operating temperature range spans –65 °C to +175 °C, enabling deployment in under-hood automotive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRWM) | 18 V - Maximum continuous reverse voltage before significant leakage; sets minimum system operating margin for protected line. |
| Breakdown Voltage (VBR) | 20–22.3 V at 1 mA - Confirmed avalanche onset range; ensures reliable triggering above normal signal swing. |
| Clamping Voltage (VC) | 29.2 V max at 6.8 A - Peak voltage seen by protected IC during worst-case 10/1000 μs surge; defines safe voltage ceiling. |
| Junction Capacitance (CD) | 320 pF at 0 V, 1 MHz - Signal-line loading impact on USB 2.0 or CAN FD timing; requires layout compensation for >480 Mbps links. |
| ESD Rating | ±30 kV contact / ±30 kV air (IEC 61000-4-2) - Full immunity to worst-case handheld ESD events without degradation. |
| Package | DO-219AB (SOD-123W) - 3.9 × 1.9 × 1.08 mm low-profile outline compatible with automated SMT assembly and reflow profiles up to 260 °C. |
| AEC-Q101 Qualified | Yes - Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock per AEC standard. |
Pinout & Package
SMF18A-HM3-18 uses the DO-219AB (SOD-123W) surface-mount package: 3.9 mm length, 1.9 mm width, 1.08 mm height, cathode-bar marked end, and MSL level 1 moisture sensitivity rating. The device has two terminals in a single-diode configuration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Signal return path for protected line | Connected to ground or low-impedance reference; completes clamping loop during ESD event. |
| Cathode | Protected line input terminal | Connected directly to I/O trace (e.g., USB D+); blocks reverse leakage below VRWM and avalanches above VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 200 W peak pulse power (10/1000 μs) | Enables single-device protection against multiple IEC 61000-4-5 surge events without derating in compact layouts. |
| Low clamping voltage (29.2 V @ 6.8 A) | Reduces stress on 3.3 V or 5 V interface ICs by limiting transient overvoltage within safe SOA limits. |
| 320 pF junction capacitance | Permits use on USB 2.0 full-speed (12 Mbps) and low-speed (1.5 Mbps) lines without signal integrity loss. |
| AEC-Q101 qualified | Validates suitability for automotive applications including infotainment, body control modules, and ADAS sensor interfaces. |
| Wave and reflow solderable | Supports standard Pb-free reflow profiles (peak 260 °C) and wave soldering without parametric shift or delamination. |
Applications
| Automotive Infotainment USB Port | Industrial RS-485 Transceiver Line |
|---|---|
Use Scenario: Protecting USB 2.0 D+/D− lines in head-unit docking connectors exposed to repeated ESD events during vehicle entry/exit. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed in series with each data line, referenced to chassis ground, clamping transients before reaching USB PHY. Use Value: Maintains signal integrity at 480 Mbps while surviving >10,000 ±30 kV contact discharges per AEC-Q101 lifecycle testing. | Use Scenario: Safeguarding RS-485 differential pair (A/B) in factory automation PLC I/O modules subjected to cable-induced surges and operator ESD. IC Role / Device Role / Timing Role: Dual unidirectional clamping devices (one per line) referenced to local ground, absorbing common-mode transients up to 200 W. Use Value: Prevents transceiver latch-up and data corruption during 2 kV EFT bursts and 4 kV surge tests per IEC 61000-4-4/5. |
| Medical Patient Monitor Sensor Interface | Automotive Body Control Module LIN Bus |
Use Scenario: Shielding analog sensor inputs (ECG, SpO₂) from ESD coupling via patient cables and touch panels in Class II medical equipment. IC Role / Device Role / Timing Role: Low-leakage (0.1 μA @ 18 V) unidirectional TVS placed at connector entry point, minimizing DC offset error in precision front-end amplifiers. Use Value: Ensures <1 LSB error contribution in 24-bit ADC systems while meeting IEC 61000-4-2 Level 4 compliance. | Use Scenario: Protecting LIN bus transceiver pins in door module ECUs where harness routing increases susceptibility to battery dump and load-switch transients. IC Role / Device Role / Timing Role: Stand-off-rated TVS (18 V) placed between LIN pin and ground, clamping spikes above 20 V without interfering with 12 V nominal bus signaling. Use Value: Eliminates false wake-ups and communication dropouts during 12 V–24 V supply transitions and ISO 7637-2 pulse 1/2a events. |
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 | DO-214AC (SMA) package; 1.5× larger footprint; 35.5 V VC @ 6.5 A; 350 pF capacitance | Higher clamping voltage reduces margin for 3.3 V ICs; better thermal dissipation for repetitive surges | Select when board space allows larger package and higher surge repetition rate is required. |
| TPD2E001DRYR | 2-channel, 15 pF dual-channel ESD array in SOT-553; 12 V VRWM; not AEC-Q101 qualified | Lower capacitance suits USB 2.0 high-speed; lacks automotive qualification and single-line surge rating | Select for space-constrained consumer USB ports where AEC-Q101 is not mandated. |
Compared with SMAJ18A-E3/57T and TPD2E001DRYR, the SMF18A-HM3-18 delivers optimal balance of low-profile packaging, AEC-Q101 compliance, and 29.2 V clamping-making it preferred for automotive and industrial applications requiring both miniaturization and ruggedness.
Availability
SMF18A-HM3-18 is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial RS-485 networks, and medical sensor interfaces requiring stable component supply across extended production lifecycles.
Supply support for SMF18A-HM3-18 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 board-level ESD protection in space-constrained, high-reliability applications-designed specifically to meet AEC-Q101 and IEC 61000-4-2 requirements without sacrificing clamping performance or manufacturability.
FAQ
What is the maximum clamping voltage of the SMF18A-HM3-18 under a 10/1000 μs surge?
The SMF18A-HM3-18 has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current of 6.8 A using a 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and defines the upper voltage limit imposed on protected circuitry during transient events. The SMF18A-HM3-18 maintains this clamping performance across its full operating temperature range of –65 °C to +175 °C.
Is the SMF18A-HM3-18 qualified to AEC-Q101 standards?
Yes, the SMF18A-HM3-18 is AEC-Q101 qualified and certified for automotive applications. It passes all required stress tests including human body model (HBM) >8 kV (Class H3B), temperature cycling, high-temperature operating life, and unbiased highly accelerated stress testing. This qualification confirms its suitability for under-hood and cabin-mounted ECUs where long-term reliability under thermal and mechanical stress is mandatory. The SMF18A-HM3-18 documentation explicitly states AEC-Q101 qualification in its ordering information and features sections.
What is the junction capacitance of the SMF18A-HM3-18 and how does it affect high-speed signal lines?
The SMF18A-HM3-18 exhibits a typical junction capacitance of 320 pF at 0 V and 1 MHz. This value directly impacts signal integrity on high-speed lines: it is appropriate for USB 2.0 full-speed (12 Mbps) and low-speed (1.5 Mbps) but may cause measurable rise-time degradation on high-speed USB 2.0 (480 Mbps) or CAN FD links unless compensated with careful PCB layout and termination. The SMF18A-HM3-18 datasheet provides capacitance vs. voltage curves confirming stable behavior down to 18 V reverse bias.
Does the SMF18A-HM3-18 have polarity marking, and how is it identified on the package?
Yes, the SMF18A-HM3-18 features a cathode bar marking on the package body, consistent with DO-219AB (SOD-123W) industry convention. The marking appears as a distinct band near one end of the molded case, identifying the cathode terminal. This polarity indicator aligns with tape-and-reel orientation diagrams in the Vishay datasheet and ensures correct placement during automated pick-and-place assembly. The SMF18A-HM3-18's cathode must be connected to the protected line, and the anode to ground for proper unidirectional clamping operation.
What is the peak pulse power rating of the SMF18A-HM3-18 and under which waveform is it specified?
The SMF18A-HM3-18 is rated for 200 W peak pulse power under the 10/1000 μs double-exponential waveform, per IEC 61000-4-5. It also supports 1000 W under the shorter 8/20 μs waveform used in lightning surge testing. These ratings reflect non-repetitive surge capability and assume proper PCB thermal management (e.g., ≥3 mm × 3 mm copper pads). The SMF18A-HM3-18 datasheet specifies both values in its Absolute Maximum Ratings table, with derating applied above 25 °C ambient per its 180 K/W junction-to-ambient thermal resistance.
SMF18A-HM3-18 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:
- -
- Capacitance @ Frequency:
- 320pF @ 1MHz
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AB (SMF)
SMF18A-HM3-18 FAQ
1.How can I place an order for SMF18A-HM3-18 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF18A-HM3-18 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-HM3-18 reliable?
The price and inventory of SMF18A-HM3-18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF18A-HM3-18 is usually 5 days.
3.What payment methods are accepted for SMF18A-HM3-18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF18A-HM3-18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF18A-HM3-18?
SMF18A-HM3-18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF18A-HM3-18 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-HM3-18?
For technical support, including SMF18A-HM3-18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF18A-HM3-18 requirements.
6.How does Aetrix verify that SMF18A-HM3-18 is sourced from the original manufacturer or authorized distributors?
All SMF18A-HM3-18 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-HM3-18 meets industry standards.
7.What is the process for return or replacement of SMF18A-HM3-18?
All SMF18A-HM3-18 units undergo pre-shipment inspection (PSI). If there is an issue with SMF18A-HM3-18, 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-HM3-18 part is unused and in its original packaging.
Return procedure for SMF18A-HM3-18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF18A-HM3-18 Tags
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