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Vishay General Semiconductor - Diodes Division SM5S18ATHE3/I
- Part No.:
- SM5S18ATHE3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AC
- Datasheet:
-
SM5S18ATHE3/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO218AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,578
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Product details
Overview
SM5S18ATHE3/I from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor in DO-218AC package, rated for 18 V stand-off voltage (VWM), 21.1 V nominal breakdown (VBR), 123 V clamping voltage at 150 A peak pulse current, 3600 W peak pulse power (10/1000 µs), and 175 °C junction temperature - designed for automotive load dump protection in engine control units and body electronics.
For engineers reviewing the SM5S18ATHE3/I datasheet, SM5S18ATHE3/I pinout, SM5S18ATHE3/I application, or SM5S18ATHE3/I equivalent, key selection criteria include unidirectional polarity, DO-218AC thermal performance (RθJC = 1.0 °C/W), AEC-Q101 qualification, ISO7637-2 compliance, and 10 µA max reverse leakage at VWM.
Technical Context
This TVS diode uses passivated anisotropic rectifier technology to deliver high-temperature stability up to TJ = 175 °C and low forward voltage drop (<2.0 V at 100 A). Its DO-218AC case provides direct metal heatsink mounting with anode-connected heatsink terminal.
The device meets MSL Level 1 per J-STD-020 (245 °C peak reflow), supports 500 A non-repetitive surge current (IFSM), and exhibits +0.083 %/°C temperature coefficient of VBR - enabling predictable clamping behavior across automotive thermal ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18.0 V - maximum continuous reverse operating voltage before conduction begins |
| VBR (nom) | 21.1 V at 5 mA - precise breakdown threshold for reliable transient triggering |
| VC @ IPPM | 123 V at 150 A (10/1000 µs) - clamping voltage limiting downstream circuit stress |
| PPPM | 3600 W (10/1000 µs) - peak surge energy handling for load dump transients |
| TJ max | 175 °C - enables under-hood deployment without derating in automotive environments |
| RθJC | 1.0 °C/W - low thermal resistance supports direct heatsink coupling for sustained power dissipation |
| Polarity | Unidirectional - anode connected to heatsink; cathode as signal terminal |
Pinout & Package
Package: DO-218AC - surface-mount, anode-integrated metal heatsink case with matte tin-plated leads; RoHS-compliant and AEC-Q101 qualified (HE3 suffix); meets UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Heatsink | Primary current return path and thermal interface | Electrically and thermally coupled to PCB copper pour or external heatsink; must be routed as low-impedance ground path |
| Cathode | Transient voltage sensing and clamping node | Connected to protected line (e.g., 12 V battery rail); conducts surge current to anode during overvoltage events |
Key Features
| Feature | Design Value |
|---|---|
| Junction passivation optimized design | Enables stable VBR and low leakage (<10 µA at VWM, 175 °C) under high-temperature automotive operation |
| TJ = 175 °C capability | Supports placement near heat sources (e.g., power modules) without thermal derating penalties |
| Meets ISO7637-2 surge specification | Validated for automotive load dump waveforms (e.g., Pulse 5a), ensuring system-level EMC robustness |
| AEC-Q101 qualified (HE3 suffix) | Qualified for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| MSL Level 1 rating | Allows standard SMT reflow (peak 245 °C) without moisture sensitivity concerns or baking requirements |
Applications
| Engine Control Unit (ECU) Power Rail Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protects 12 V supply input of microcontroller-based ECUs against alternator load dump transients up to 35 V. IC Role / Device Role / Timing Role: Unidirectional TVS clamps overvoltage spikes to <123 V within nanoseconds, diverting >150 A surge current to chassis ground. Use Value: Prevents latch-up or permanent damage to MCU, CAN transceivers, and analog sensors during cold-crank or battery-disconnect events. | Use Scenario: Shields BCM power inputs from switching noise and inductive kickback generated by door lock actuators and window motors. IC Role / Device Role / Timing Role: Acts as primary overvoltage clamp on fused 12 V distribution lines, responding faster than fuses or polymeric PTCs. Use Value: Maintains functional safety integrity by limiting transient-induced resets or communication errors in LIN/CAN networks. |
| Start-Stop System Battery Interface | LED Headlamp Driver Input Stage |
Use Scenario: Safeguards start-stop controller ICs during repeated battery voltage reversals and regenerative braking surges. IC Role / Device Role / Timing Role: Provides bidirectional-like protection via unidirectional configuration with robust 500 A IFSM surge rating. Use Value: Extends controller lifetime by absorbing repetitive 10–100 ms exponential surges without parameter drift or degradation. | Use Scenario: Clamps transients induced by PWM dimming circuits and relay switching in adaptive LED headlamps. IC Role / Device Role / Timing Role: Placed upstream of buck/boost LED drivers to limit input voltage excursions beyond 123 V. Use Value: Eliminates need for secondary filtering stages while maintaining ASIL-B compliance for optical output stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SM5S18AHM3 | Same electrical specs; HM3 suffix indicates halogen-free, lead-free, and enhanced whisker resistance (JESD 201 Class 2) | No change in load dump or ISO7637-2 performance; preferred for new designs requiring updated material compliance | Select SM5S18AHM3 for new automotive programs where HE3 is marked "Not For New Designs" |
| SMAJ18A | Lower PPPM (400 W vs. 3600 W), DO-214AC package, RθJC ≈ 50 °C/W, no AEC-Q101 qualification | Only suitable for low-energy transients (e.g., ESD); insufficient for load dump or ISO7637-2 Pulse 5 | Use SMAJ18A only in non-automotive, low-surge consumer applications with space constraints |
Compared with SM5S18ATHE3/I, SM5S18AHM3 offers identical protection performance with upgraded environmental compliance, while SMAJ18A provides cost-effective ESD-level clamping but lacks the thermal robustness and surge capacity required for automotive power rail protection.
Availability
SM5S18ATHE3/I is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, and start-stop system interfaces requiring stable component supply and long-term lifecycle support.
Supply support for SM5S18ATHE3/I 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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and high-temperature performance.
The SM5SxxAT family was engineered specifically for automotive-grade transient suppression - delivering high-power clamping, AEC-Q101 qualification, and DO-218AC thermal efficiency to meet ISO7637-2 load dump requirements.
FAQ
Is SM5S18ATHE3/I AEC-Q101 qualified?
Yes, SM5S18ATHE3/I is AEC-Q101 qualified. The HE3 suffix explicitly denotes RoHS compliance and full AEC-Q101 qualification, including stress tests for temperature cycling, highly accelerated life testing (HALT), and electrostatic discharge. This qualification confirms suitability for automotive powertrain and chassis applications where reliability under thermal and mechanical stress is critical. SM5S18ATHE3/I maintains its 175 °C junction rating and 3600 W surge capability throughout AEC-Q101 validation.
What is the clamping voltage of SM5S18ATHE3/I at rated surge current?
The clamping voltage (VC) of SM5S18ATHE3/I is 123 V when subjected to a 150 A peak pulse current with a 10/1000 µs waveform. This value is measured under standardized test conditions (TA = 25 °C) and defines the maximum voltage seen by downstream circuitry during a worst-case transient. At higher temperatures or longer pulse durations (e.g., 10/10,000 µs), VC remains stable due to the device's low RθJC (1.0 °C/W) and robust silicon design.
Can SM5S18ATHE3/I replace SM5S18AHM3 in existing designs?
SM5S18ATHE3/I and SM5S18AHM3 share identical electrical specifications, package (DO-218AC), pinout, and thermal performance. However, HM3 denotes halogen-free, enhanced whisker resistance (JESD 201 Class 2), and updated material compliance. While functionally interchangeable in legacy systems, SM5S18ATHE3/I is marked "Not For New Designs" per Vishay documentation, so new designs should use SM5S18AHM3. No PCB changes are needed for replacement.
What does the "HE3" suffix mean in SM5S18ATHE3/I?
The "HE3" suffix in SM5S18ATHE3/I indicates RoHS-compliant construction, AEC-Q101 qualification, matte tin-plated leads compliant with J-STD-002 and JESD 22-B102, and passing JESD 201 Class 2 whisker testing. It also specifies packaging in 13" plastic tape-and-reel (750 units per reel), with anode oriented toward sprocket holes. This suffix distinguishes it from non-automotive variants and confirms suitability for high-reliability automotive applications.
Does SM5S18ATHE3/I meet ISO7637-2 requirements?
Yes, SM5S18ATHE3/I meets ISO7637-2 surge test requirements, specifically Pulse 5a (load dump) under defined test conditions. Its 3600 W peak pulse power rating (10/1000 µs), 175 °C junction capability, and low clamping voltage (123 V) enable compliance with the 35 V/100 ms minimum clamping threshold specified for 12 V systems. Validation data is documented in Vishay's application notes and curve Fig. 2 ("Load Dump Power Characteristics").
SM5S18ATHE3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-218AC
- Series:
- PAR®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 123A
- Power - Peak Pulse:
- 3600W (3.6kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-218AC
SM5S18ATHE3/I FAQ
1.How can I place an order for SM5S18ATHE3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM5S18ATHE3/I 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 SM5S18ATHE3/I reliable?
The price and inventory of SM5S18ATHE3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM5S18ATHE3/I is usually 5 days.
3.What payment methods are accepted for SM5S18ATHE3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM5S18ATHE3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM5S18ATHE3/I?
SM5S18ATHE3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM5S18ATHE3/I 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 SM5S18ATHE3/I?
For technical support, including SM5S18ATHE3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM5S18ATHE3/I requirements.
6.How does Aetrix verify that SM5S18ATHE3/I is sourced from the original manufacturer or authorized distributors?
All SM5S18ATHE3/I 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 SM5S18ATHE3/I meets industry standards.
7.What is the process for return or replacement of SM5S18ATHE3/I?
All SM5S18ATHE3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM5S18ATHE3/I, 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 SM5S18ATHE3/I part is unused and in its original packaging.
Return procedure for SM5S18ATHE3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM5S18ATHE3/I Tags
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