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Vishay SMF18A-HE3_A18
- Part No.:
- SMF18A-HE3_A18
- Manufacturer:
- Vishay
- Category:
- TVS Diodes
- Package:
- DO-219AB
- Datasheet:
-
SMF18A-HE3_A18.pdf
- Description:
- ESD PROTECTION DIODE SMF DO219AB
- Quantity:
- Payment:
- Shipping:
Inventory:3,739
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Product details
Overview
SMF18A-HE3_A18 from Vishay Semiconductors is a unidirectional surface-mount ESD protection diode in the SMF (DO-219AB) package, designed for transient voltage suppression in high-speed data lines. It features a 18 V stand-off voltage (VRWM), 20 V minimum breakdown voltage (VBR), 29.2 V maximum clamping voltage at 6.8 A peak pulse current, ±30 kV IEC 61000-4-2 ESD immunity, and 200 W peak pulse power (10/1000 μs). It is used to safeguard USB 2.0, HDMI, and industrial sensor interfaces against electrostatic discharge.
For engineers reviewing the SMF18A-HE3_A18 datasheet, SMF18A-HE3_A18 pinout, SMF18A-HE3_A18 application, or SMF18A-HE3_A18 equivalent, key selection criteria include clamping voltage margin relative to IC I/O rails, capacitance impact on signal integrity (320 pF at 0 V), AEC-Q101 qualification status, and SOD-123W-compatible footprint compatibility with automated assembly processes.
Technical Context
This device operates as a single-channel unidirectional TVS diode, leveraging silicon avalanche technology to clamp transient overvoltages before they reach downstream circuitry. Its low incremental surge resistance ensures rapid energy diversion during ESD events, while its "Low Noise" design enables sub-nanosecond response time critical for protecting high-bandwidth interfaces.
The SMF18A-HE3_A18 is rated for continuous operation from –65 °C to +175 °C, with thermal resistance (RthJA) of 180 K/W on standard epoxy-glass PCBs using 3 mm × 3 mm copper pads. It meets IEC 61000-4-2 (±30 kV contact/air), IEC 61000-4-5 (1000 W, 8/20 μs), and AEC-Q101 Class H3B (>8 kV HBM) standards - confirming suitability for automotive and harsh-environment industrial applications.
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; sets upper limit for protected line voltage. |
| Breakdown Voltage (VBR) | 20–22.3 V at 1 mA - defines onset of avalanche conduction; ensures reliable triggering above normal operating voltage. |
| Clamping Voltage (VC) | 29.2 V max at 6.8 A (10/1000 μs) - limits peak voltage seen by protected IC; critical for 3.3 V or 5 V logic rail safety margin. |
| Peak Pulse Power | 200 W (10/1000 μs) - sustains short-duration transients without failure; supports repeated ESD strikes in production test environments. |
| Capacitance (CD) | 320 pF at 0 V, 1 MHz - impacts high-frequency signal integrity; suitable for ≤10 Mbps digital lines but not USB 3.0 or PCIe. |
| ESD Rating | ±30 kV contact / ±30 kV air per IEC 61000-4-2 - exceeds Level 4 immunity requirements for consumer and automotive electronics. |
| Package | DO-219AB (SOD-123W compatible) - low-profile (1.08 mm height), reflow-solderable, MSL level 1, RoHS-compliant. |
Pinout & Package
SMF18A-HE3_A18 uses the DO-219AB (SOD-123W) surface-mount package: cathode-marked anode-cathode configuration in a 3.9 mm × 1.9 mm × 1.08 mm low-profile molded case. The package is wave and reflow solderable, with MSL level 1 rating and peak reflow temperature up to 260 °C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (cathode-bar side) | Input terminal for transient energy | Connected to protected line; conducts during reverse-biased ESD event to shunt current to ground. |
| Cathode (marked end) | Reference/ground return path | Typically tied to system ground plane; establishes clamping reference and completes transient current loop. |
Key Features
| Feature | Design Value |
|---|---|
| 200 W peak pulse power (10/1000 μs) | Enables robust protection against multiple ESD events without degradation in compact PCB layouts. |
| ±30 kV IEC 61000-4-2 ESD immunity | Meets highest industrial and automotive ESD stress levels without external shielding or layout reinforcement. |
| AEC-Q101 qualified | Validated for automotive under-hood and infotainment applications requiring extended temperature reliability and lifetime validation. |
| Low-profile DO-219AB package | Reduces board space and profile vs. SMA/SMB; compatible with SOD-123W pick-and-place tooling and reflow profiles. |
| "Low Noise" fast-response technology | Sub-nanosecond turn-on minimizes voltage overshoot during ESD transients, preserving signal fidelity on sensitive analog/digital lines. |
Applications
| Industrial Sensor Interface | Automotive Infotainment Port |
|---|---|
Use Scenario: Protecting RS-485 transceivers and analog sensor outputs in factory automation PLCs exposed to cable-induced surges and operator ESD. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between signal line and chassis ground to clamp transients before reaching the transceiver's input pins. Use Value: Maintains 18 V VRWM margin above 12 V supply rails while limiting clamped voltage to ≤29.2 V, preventing latch-up or permanent damage to 3.3 V/5 V interface ICs. | Use Scenario: Safeguarding HDMI and USB 2.0 ports on head-unit displays subject to repeated plug/unplug and user-handling ESD. IC Role / Device Role / Timing Role: Standoff-clamp TVS positioned inline with differential data pairs to suppress common-mode ESD without distorting signal edges. Use Value: 320 pF capacitance preserves signal rise/fall times for USB 2.0 (480 Mbps) compliance; ±30 kV rating eliminates need for secondary ESD filters in cost-sensitive designs. |
| Medical Diagnostic Equipment | Smart Building Control Panel |
Use Scenario: Shielding UART and CAN FD lines in portable ultrasound devices where ESD must not disrupt real-time data acquisition or trigger false alarms. IC Role / Device Role / Timing Role: Primary ESD suppressor on serial communication lines connecting microcontroller to external sensors and displays. Use Value: AEC-Q101 qualification ensures stable performance across –40 °C to +85 °C operating range; 175 °C junction rating supports sterilization cycle survivability. | Use Scenario: Securing touch-screen controller I/O and Ethernet PHY lines in wall-mounted HVAC controllers installed in public areas with high human interaction. IC Role / Device Role / Timing Role: Bidirectional-capable unidirectional TVS used in conjunction with series resistors to limit current into sensitive capacitive touch inputs. Use Value: Low 0.1 μA leakage at 18 V prevents DC loading of high-impedance touch sense nodes; 200 W pulse rating handles repeated maintenance technician ESD events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar ESD protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/57T | Higher clamping voltage (32.4 V), larger SMA package (4.5 mm × 2.7 mm), 400 W peak power (8/20 μs). | Less suitable for space-constrained layouts; better for higher-energy surges like lightning-induced coupling. | Select when board area allows larger footprint and higher 8/20 μs surge immunity is required over ESD-only protection. |
| TPD2E001DRYR | 2-channel, 15 pF per line, 5.5 V VRWM, integrated ESD array in USON-6 package; not AEC-Q101 qualified. | Designed for ultra-low-capacitance high-speed interfaces (USB 2.0, HDMI); lacks automotive qualification and 18 V standoff capability. | Prefer for multi-line, high-frequency applications where capacitance <20 pF is mandatory and automotive qualification is not required. |
Compared with SMAJ18A-E3/57T and TPD2E001DRYR, SMF18A-HE3_A18 delivers optimal balance of 18 V standoff, 29.2 V clamping, AEC-Q101 qualification, and compact DO-219AB packaging - making it ideal for automotive and industrial single-line ESD protection where board space and reliability are prioritized over ultra-low capacitance or multi-channel integration.
Availability
SMF18A-HE3_A18 is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive infotainment ports, and medical diagnostic equipment requiring stable component supply across long product lifecycles.
Supply support for SMF18A-HE3_A18 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 high-volume ESD protection in space-constrained, thermally demanding applications - engineered specifically for AEC-Q101 compliance, low-profile mounting, and consistent clamping performance across temperature extremes.
FAQ
What is the maximum clamping voltage of the SMF18A-HE3_A18 under standard test conditions?
The SMF18A-HE3_A18 has a maximum clamping voltage (VC) of 29.2 V when subjected to a 10/1000 μs waveform at 6.8 A peak pulse current. This value is measured per IEC 61000-4-5 test methodology and ensures downstream ICs remain within safe voltage limits during ESD events. The clamping performance is guaranteed across the full operating temperature range of –65 °C to +175 °C.
Is SMF18A-HE3_A18 qualified to AEC-Q101, and what does that mean for automotive use?
Yes, SMF18A-HE3_A18 is AEC-Q101 qualified, specifically meeting Class H3B human body model (HBM) requirements (>8 kV). This qualification confirms rigorous testing for temperature cycling, humidity bias, mechanical shock, and ESD robustness - validating its suitability for automotive applications including infotainment, body control modules, and ADAS sensor interfaces where reliability under thermal and electrical stress is mandatory.
What is the capacitance of SMF18A-HE3_A18, and how does it affect high-speed signal lines?
The SMF18A-HE3_A18 exhibits 320 pF typical capacitance at 0 V and 1 MHz. This value makes it appropriate for low-to-moderate speed interfaces such as RS-485, UART, CAN, and USB 2.0 (up to 480 Mbps), but unsuitable for USB 3.0, HDMI 2.0, or PCIe Gen3+ where sub-2 pF capacitance is required. Designers must verify eye diagram integrity and jitter budgets when integrating SMF18A-HE3_A18 into high-speed paths.
Can SMF18A-HE3_A18 be used in bidirectional configurations?
No - SMF18A-HE3_A18 is a unidirectional TVS diode, intended for use with a defined polarity (anode to signal, cathode to ground). For bidirectional protection, two SMF18A-HE3_A18 devices may be connected in series opposing configuration, or a dedicated bidirectional part such as SMBJ18CA should be selected. Using SMF18A-HE3_A18 in reverse bias beyond its VRWM risks premature conduction and increased leakage.
What is the recommended PCB footprint and soldering profile for SMF18A-HE3_A18?
The SMF18A-HE3_A18 uses the DO-219AB (SOD-123W) package with recommended footprint dimensions of 2.9 mm × 1.4 mm pad length/width and 1.3 mm spacing. Reflow soldering follows J-STD-020 MSL level 1 guidelines: peak temperature ≤260 °C, with ramp rates and soak times aligned to standard lead-free profiles. Vishay provides detailed land pattern drawings in document S8-V-3915.01-001.
SMF18A-HE3_A18 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay
- 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 (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AB (SMF)
SMF18A-HE3_A18 FAQ
1.How can I place an order for SMF18A-HE3_A18 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF18A-HE3_A18 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-HE3_A18 reliable?
The price and inventory of SMF18A-HE3_A18 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF18A-HE3_A18 is usually 5 days.
3.What payment methods are accepted for SMF18A-HE3_A18?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF18A-HE3_A18 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF18A-HE3_A18?
SMF18A-HE3_A18 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF18A-HE3_A18 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-HE3_A18?
For technical support, including SMF18A-HE3_A18 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF18A-HE3_A18 requirements.
6.How does Aetrix verify that SMF18A-HE3_A18 is sourced from the original manufacturer or authorized distributors?
All SMF18A-HE3_A18 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-HE3_A18 meets industry standards.
7.What is the process for return or replacement of SMF18A-HE3_A18?
All SMF18A-HE3_A18 units undergo pre-shipment inspection (PSI). If there is an issue with SMF18A-HE3_A18, 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-HE3_A18 part is unused and in its original packaging.
Return procedure for SMF18A-HE3_A18:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF18A-HE3_A18 Tags
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