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Vishay General Semiconductor - Diodes Division SM5S18-E3/2D
- Part No.:
- SM5S18-E3/2D
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM5S18-E3/2D.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,241
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Product details
Overview
SM5S18-E3/2D from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor (TVS) diode in DO-218AB package, rated for 18 V stand-off voltage (VWM), 32.2 V clamping voltage (VC) at 112 A peak pulse current (IPPM), and 3600 W peak pulse power (10/1000 µs). It delivers AEC-Q101 qualification, 175 °C junction capability, and automotive load dump protection.
For engineers reviewing the SM5S18-E3/2D datasheet, SM5S18-E3/2D pinout, SM5S18-E3/2D application, or SM5S18-E3/2D equivalent, this page provides verified electrical parameters, thermal resistance (RθJC = 1.0 °C/W), polarity configuration (heatsink = anode), ISO7637-2 compliance, and real-world design context for automotive power rail protection.
Technical Context
The SM5S18-E3/2D operates as a unidirectional avalanche diode with passivated anisotropic rectifier technology, enabling stable clamping under high-energy transients. Its 18.0 V stand-off voltage and 20.0–24.4 V breakdown range (VBR) define precise overvoltage threshold behavior in 12 V automotive systems.
Designed for direct placement on power rails, it handles 500 A non-repetitive forward surge (IFSM) and dissipates 5 W continuously on infinite heatsink. Thermal resistance of 1.0 °C/W (junction-to-case) supports robust thermal management when mounted to PCB copper planes or metal chassis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18.0 V - Maximum continuous reverse operating voltage before clamping begins |
| VC @ IPPM | 32.2 V - Clamped voltage at 112 A (10/1000 µs), limiting downstream IC stress during load dump |
| PPPM (10/1000 µs) | 3600 W - Peak transient energy absorption capacity for short-duration surges |
| TJ max. | +175 °C - Enables operation in under-hood environments without derating |
| RθJC | 1.0 °C/W - Confirmed thermal path efficiency from junction to case for heatsink-coupled mounting |
| AEC-Q101 | Qualified - Validated reliability for automotive electronics per stress test requirements |
| MSL Level | Level 1 (245 °C peak) - Supports standard SMT reflow without moisture sensitivity concerns |
Pinout & Package
Package: DO-218AB - Surface-mount molded case with integral metal heatsink tab (anode), UL 94 V-0 rated molding compound, matte tin-plated leads compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Lead 1 | Cathode | Connected to protected circuit node; carries transient current into device during clamping |
| Lead 2 / Metal Heatsink | Anode | Primary thermal and electrical connection point; must be soldered to large copper area or chassis for optimal power dissipation and low-inductance grounding |
Key Features
| Feature | Design Value |
|---|---|
| Junction passivation | Optimized anisotropic rectifier structure ensures stable VBR and low leakage (<10 µA at VWM) across temperature and life |
| High-temperature operation | Rated for continuous use up to +175 °C junction temperature-no derating required in engine bay applications |
| Automotive surge compliance | Validated against ISO7637-2 load dump waveforms, supporting 12 V system robustness without external filtering |
| Low clamping ratio | VC/VWM = 1.79 (32.2 V / 18.0 V) enables tighter voltage margin for 24 V tolerant downstream components |
| Whisker-resistant plating | HE3 suffix meets JESD201 Class 2, eliminating tin whisker risk in long-life automotive deployments |
Applications
| Automotive Load Dump Protection | 12 V Power Rail Transient Suppression |
|---|---|
Use Scenario: Protecting ECUs, body control modules, and infotainment systems from alternator-induced load dump spikes (up to ±120 V, 400 ms). IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between battery rail and input filter capacitor, clamping excess energy to ground via heatsink. Use Value: Limits peak voltage to ≤32.2 V during 3600 W transients, preventing damage to 36 V-rated DC-DC converters and microcontrollers. | Use Scenario: Safeguarding CAN/LIN transceivers and sensor interfaces connected to vehicle battery lines exposed to switching noise and relay bounce. IC Role / Device Role / Timing Role: Standoff-clamp protector on main 12 V supply line upstream of LDOs and PMICs, responding within nanoseconds to fast-rising edges. Use Value: Maintains <10 µA leakage at 18 V, minimizing quiescent current impact on always-on domains while clamping sub-100 ns spikes. |
| Industrial Motor Drive Input Protection | Commercial Vehicle Battery Management |
Use Scenario: Shielding PLC I/O power inputs from inductive kickback generated by solenoid valves and contactors in factory automation. IC Role / Device Role / Timing Role: Primary surge arrestor on 24 V DC input stage, absorbing repetitive 2800 W (10/10,000 µs) surges without degradation. Use Value: Withstands 500 A IFSM and 175 °C TJ, enabling reliable operation in enclosed cabinets with ambient temperatures up to +105 °C. | Use Scenario: Securing BMS front-end monitoring circuits in heavy-duty trucks where battery voltage can swing from -18 V to +40 V during cranking and regeneration. IC Role / Device Role / Timing Role: Bidirectional protection not required-unidirectional SM5S18-E3/2D used with series diode to block negative transients while clamping positive overvoltage. Use Value: RθJC = 1.0 °C/W allows direct thermal coupling to aluminum chassis, reducing thermal impedance by >60% versus SMC packages in space-constrained modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-E3/5AT | Lower PPPM (400 W vs. 3600 W); SMA package (RθJC ≈ 35 °C/W); bidirectional variant available | Not suitable for load dump; limited to ESD and low-energy switching transients | Select only for cost-sensitive consumer-grade 12 V inputs where surge energy <500 W |
| TPSMD18A | Same DO-218AB package; 3000 W PPPM (10/1000 µs); VC = 30.0 V at 120 A; RoHS but not AEC-Q101 qualified | Lacks automotive qualification; requires additional reliability validation for OEM programs | Acceptable for industrial transport or aftermarket modules where AEC-Q101 is not mandated |
Compared with SMAJ18A-E3/5AT and TPSMD18A, the SM5S18-E3/2D uniquely combines AEC-Q101 qualification, 3600 W surge rating, and 1.0 °C/W thermal resistance in DO-218AB-making it the only option validated for under-hood load dump protection without derating or supplemental cooling.
Availability
SM5S18-E3/2D is available at Aetrix Electronics and suitable for automotive electronic control units, industrial motor drives, commercial vehicle battery management systems, and 12 V power rail transient suppression requiring stable component supply and full AEC-Q101 traceability.
Supply support for SM5S18-E3/2D 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 high-reliability diodes, MOSFETs, optoelectronics, and passive components for automotive, industrial, and computing markets.
The SM5Sxx family was engineered specifically for automotive load dump and ISO7637-2 compliance, leveraging passivated anisotropic rectifier technology to deliver stable clamping performance at 175 °C junction temperature in surface-mount form.
FAQ
What is the maximum clamping voltage of the SM5S18-E3/2D at its rated peak pulse current?
The SM5S18-E3/2D has a maximum clamping voltage (VC) of 32.2 V when subjected to its rated peak pulse current (IPPM) of 112 A using the 10/1000 µs waveform. This value is measured at TA = 25 °C and defines the upper voltage limit imposed on protected circuitry during worst-case transient events. The SM5S18-E3/2D maintains this clamping performance across its full operating temperature range due to its passivated junction design.
Is the SM5S18-E3/2D suitable for bidirectional transient protection?
No, the SM5S18-E3/2D is unidirectional only, with the metal heatsink terminal designated as the anode. It protects against positive-going transients on a DC line referenced to ground. For bidirectional protection, a separate device such as the SM5S18A-E3/2D (which has symmetrical breakdown) would be required. The SM5S18-E3/2D datasheet explicitly states "Available in uni-directional polarity only" and specifies polarity as "Heatsink is anode."
Does the SM5S18-E3/2D meet automotive qualification standards?
Yes, the SM5S18-E3/2D is AEC-Q101 qualified, as confirmed in the Vishay document 88382 revision 14-Sep-11. This qualification covers stress tests including high-temperature operating life, temperature cycling, and humidity bias HAST, validating its suitability for automotive under-hood applications. The HE3 suffix further indicates compliance with JESD201 Class 2 whisker testing and RoHS Directive 2002/95/EC.
What is the thermal resistance from junction to case (RθJC) for the SM5S18-E3/2D?
The SM5S18-E3/2D has a typical thermal resistance of 1.0 °C/W from junction to case (RθJC), as specified in the Thermal Characteristics table of the Vishay datasheet. This low value is enabled by the DO-218AB package's integral metal heatsink and direct thermal path to the PCB copper or chassis. Proper mounting to ≥100 mm² of 2 oz copper is required to realize this performance in actual designs.
Can the SM5S18-E3/2D be used in place of the SM5S18A-E3/2D?
No-the SM5S18-E3/2D and SM5S18A-E3/2D are functionally distinct: the former is unidirectional (anode = heatsink), while the latter is bidirectional with symmetrical breakdown (VBR min/max = 20.0/22.1 V). Substituting them without circuit review risks failure during negative transients. The SM5S18-E3/2D datasheet confirms "Available in uni-directional polarity only," and its VBR range (20.0–24.4 V) reflects asymmetric avalanche behavior unlike the SM5S18A-E3/2D.
SM5S18-E3/2D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-218AB
- 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:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 112A
- Power - Peak Pulse:
- 3600W (3.6kW)
- 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-218AB
SM5S18-E3/2D FAQ
1.How can I place an order for SM5S18-E3/2D through Aetrix?
Please submit a Request for Quotation (RFQ) for SM5S18-E3/2D 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 SM5S18-E3/2D reliable?
The price and inventory of SM5S18-E3/2D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM5S18-E3/2D is usually 5 days.
3.What payment methods are accepted for SM5S18-E3/2D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM5S18-E3/2D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM5S18-E3/2D?
SM5S18-E3/2D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM5S18-E3/2D 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 SM5S18-E3/2D?
For technical support, including SM5S18-E3/2D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM5S18-E3/2D requirements.
6.How does Aetrix verify that SM5S18-E3/2D is sourced from the original manufacturer or authorized distributors?
All SM5S18-E3/2D 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 SM5S18-E3/2D meets industry standards.
7.What is the process for return or replacement of SM5S18-E3/2D?
All SM5S18-E3/2D units undergo pre-shipment inspection (PSI). If there is an issue with SM5S18-E3/2D, 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 SM5S18-E3/2D part is unused and in its original packaging.
Return procedure for SM5S18-E3/2D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM5S18-E3/2D Tags
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