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Vishay General Semiconductor - Diodes Division SM8S40-E3/2D
- Part No.:
- SM8S40-E3/2D
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S40-E3/2D.pdf
- Description:
- TVS DIODE 40VWM 71.4VC DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:8,179
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Product details
Overview
SM8S40-E3/2D from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor (TVS) designed for automotive load dump protection. It features a 40 V stand-off voltage (VWM), 71.4 V maximum clamping voltage (VC) at 92.4 A peak pulse current (IPPM), and 6600 W peak pulse power (10/1000 μs), operating up to TJ = 175 °C in the DO-218AB package.
For engineers reviewing the SM8S40-E3/2D datasheet, SM8S40-E3/2D pinout, SM8S40-E3/2D application, or SM8S40-E3/2D equivalent, key selection considerations include its AEC-Q101 qualification, ISO7637-2 compliance for load dump transients, low leakage (<10 μA at VWM), and thermal resistance of 0.90 °C/W (junction-to-case).
Technical Context
This TVS diode uses passivated anisotropic rectifier technology with junction passivation optimized for high-reliability operation. Its unidirectional polarity and heatsink-anode configuration enable robust clamping during positive-going transients, while the DO-218AB package provides low thermal resistance (0.90 °C/W) for efficient heat dissipation under sustained surge conditions.
The device meets MSL Level 1 per J-STD-020 (peak reflow ≤245 °C) and delivers stable performance across -55 °C to +175 °C junction temperature range. Its 6600 W (10/1000 μs) and 5200 W (10/10000 μs) surge ratings support demanding automotive electrical system protection requirements including battery line transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC operating margin in 12 V/24 V automotive systems. |
| VC @ IPPM | 71.4 V - Clamped voltage at 92.4 A peak pulse current; ensures downstream ICs see <72 V during ISO7637-2 load dump events. |
| PPPM (10/1000 μs) | 6600 W - Peak surge power handling capability; enables single-event protection against high-energy transients without failure. |
| TJ max. | +175 °C - Maximum junction temperature rating; supports under-hood placement and long-term reliability in automotive environments. |
| RθJC | 0.90 °C/W - Junction-to-case thermal resistance; allows direct heatsinking to PCB copper or metal chassis for thermal management. |
| AEC-Q101 | Qualified - Certified for automotive-grade reliability per stress test standard; required for engine control, body electronics, and ADAS modules. |
Pinout & Package
Package: DO-218AB - Surface-mount, thermally enhanced case with metal heatsink terminal (anode) and molded plastic body meeting UL 94 V-0 flammability rating. Matte tin-plated leads comply with J-STD-002 solderability and JESD 22-B102 whisker testing (Class 2).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Lead 1 | Cathode | Connected to protected circuit node; carries transient current into the device during overvoltage events. |
| Lead 2 / Metal Heatsink | Anode | Primary thermal path and electrical return; must be soldered to large copper pour or heatsink for effective power dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Unidirectional polarity | Enables precise clamping only on positive transients; avoids unnecessary conduction during normal reverse-biased operation in DC systems. |
| Low leakage current | <10 μA at 40 V (TA = 25 °C) and <150 μA at 40 V (TJ = 175 °C); minimizes standby power loss and prevents false triggering in battery-sensitive applications. |
| High surge capability | 92.4 A IPPM (10/1000 μs) and 700 A IFSM (8.3 ms half-sine); withstands repeated load dump and jump-start surges without degradation. |
| Automotive qualification | AEC-Q101 qualified and ISO7637-2 compliant; validated for use in engine control units, infotainment head units, and lighting modules. |
Applications
| Engine Control Unit (ECU) Power Protection | Automotive Lighting Module Protection |
|---|---|
|
Use Scenario: Protects microcontroller power rails and sensor interfaces in gasoline/diesel ECUs exposed to alternator load dump transients. IC Role / Device Role / Timing Role: Transient voltage suppressor placed between battery input and LDO/regulator input; clamps spikes within nanoseconds. Use Value: Limits voltage to ≤71.4 V during 12 V system load dump events, preventing latch-up or permanent damage to 5 V/3.3 V logic ICs. |
Use Scenario: Shields LED driver ICs and CAN transceivers in headlamp/tail lamp assemblies from switching-induced transients. IC Role / Device Role / Timing Role: Unidirectional TVS connected across input terminals; conducts only during positive overvoltage, preserving signal integrity. Use Value: Withstands repetitive 10/1000 μs surges up to 6600 W without parameter shift, ensuring >15-year field life in exterior lighting. |
| Body Control Module (BCM) Input Protection | Start-Stop System Battery Interface |
|
Use Scenario: Guards LIN bus transceivers and power switches in BCMs against relay coil flyback and ESD events. IC Role / Device Role / Timing Role: Fast-response clamping device mounted at connector entry point; shunts energy before reaching sensitive analog front-ends. Use Value: Delivers <10 μA leakage at 40 V, avoiding current drain on always-on vehicle networks while maintaining fast response time. |
Use Scenario: Safeguards bidirectional DC-DC converters and battery monitoring ICs in 12 V start-stop systems during cranking and regenerative braking. IC Role / Device Role / Timing Role: High-energy TVS integrated into main battery feed; handles combined load dump and reverse-polarity surge stress. Use Value: Operates reliably from -55 °C to +175 °C and maintains clamping performance after 1000+ thermal cycles, critical for under-hood deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A-E3/5AT | Lower PPPM (400 W vs. 6600 W), SMA package (RθJC ≈ 40 °C/W), bidirectional option available | Targeted at low-energy ESD/surge; unsuitable for load dump due to power limitation | Select SM8S40-E3/2D when protecting 12 V/24 V automotive power rails against ISO7637-2 load dump; SMAJ40A-E3/5AT fits board-level ESD-only scenarios. |
| TPSMA6L40A-Q1 | AEC-Q101 qualified, same VWM/VC specs, but lower IPPM (64.5 A) and PPPM (400 W), DO-214AC package | Limited to lower-energy transients; not rated for full load dump waveform per ISO7637-2 | Choose SM8S40-E3/2D for applications requiring verified 6600 W surge handling and DO-218AB thermal performance; TPSMA6L40A-Q1 suits cost-sensitive non-load-dump designs. |
Compared with SMAJ40A-E3/5AT and TPSMA6L40A-Q1, SM8S40-E3/2D delivers 16× higher peak pulse power and 0.90 °C/W thermal resistance-enabling direct heatsink mounting and reliable operation in high-temperature automotive power domains where lower-power alternatives would fail catastrophically.
Availability
SM8S40-E3/2D is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, and start-stop system battery interfaces requiring stable component supply across extended production lifecycles.
Supply support for SM8S40-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, and passive components for automotive, industrial, and computing markets.
The SM8S series is engineered specifically for automotive-grade transient suppression, with emphasis on AEC-Q101 qualification, high-temperature stability (TJ = 175 °C), and ISO7637-2 compliance for load dump protection in modern vehicle electrical architectures.
FAQ
What is the clamping voltage of the SM8S40-E3/2D at its rated peak pulse current?
The SM8S40-E3/2D has a maximum clamping voltage (VC) of 71.4 V at its specified peak pulse current (IPPM) of 92.4 A under a 10/1000 μs waveform. This value is measured per the conditions defined in the Vishay datasheet (Document Number: 88387) and ensures downstream circuitry remains within safe operating limits during automotive load dump events. The SM8S40-E3/2D maintains this clamping performance across its full temperature range.
Is the SM8S40-E3/2D suitable for bidirectional transient protection?
No, the SM8S40-E3/2D is a unidirectional TVS diode, meaning it clamps only positive-going transients relative to its anode (heatsink terminal). It is not designed for bidirectional protection like AC line or data-line applications. For bidirectional needs, engineers must select an explicitly labeled "A" variant (e.g., SM8S40A-E3/2D) or alternate series. The SM8S40-E3/2D polarity is fixed and clearly indicated in the DO-218AB mechanical drawing.
Does the SM8S40-E3/2D meet AEC-Q101 qualification requirements?
Yes, the SM8S40-E3/2D is AEC-Q101 qualified, as confirmed in the Vishay datasheet (Revision: 14-Sep-11, Document Number: 88387). This qualification covers stress tests including high-temperature operating life, temperature cycling, and unbiased highly accelerated stress testing-ensuring suitability for automotive under-hood and chassis-mounted applications. The SM8S40-E3/2D carries the HE3 suffix denoting RoHS compliance and AEC-Q101 qualification.
What is the thermal resistance from junction to case for the SM8S40-E3/2D?
The SM8S40-E3/2D has a typical thermal resistance (RθJC) of 0.90 °C/W, measured from junction to case (metal heatsink terminal) at TC = 25 °C. This low value enables efficient heat transfer to external heatsinks or large PCB copper areas, supporting sustained surge duty cycles. The RθJC value is specified in the Thermal Characteristics table of the official Vishay datasheet and is integral to thermal design validation for the SM8S40-E3/2D.
Can the SM8S40-E3/2D be used in 24 V automotive systems?
Yes, the SM8S40-E3/2D is commonly deployed in 24 V commercial vehicle systems-including trucks, buses, and off-road equipment-where its 40 V stand-off voltage (VWM) provides adequate margin above nominal rail voltage while delivering 71.4 V clamping during load dump. Its 175 °C junction rating and ISO7637-2 compliance make it suitable for both 12 V and 24 V architectures, as validated in Vishay's load dump power characteristics (Fig. 2) for the SM8S40-E3/2D.
SM8S40-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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 71.4V
- Current - Peak Pulse (10/1000µs):
- 92.4A
- Power - Peak Pulse:
- 6600W (6.6kW)
- 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
SM8S40-E3/2D FAQ
1.How can I place an order for SM8S40-E3/2D through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S40-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 SM8S40-E3/2D reliable?
The price and inventory of SM8S40-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 SM8S40-E3/2D is usually 5 days.
3.What payment methods are accepted for SM8S40-E3/2D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S40-E3/2D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S40-E3/2D?
SM8S40-E3/2D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S40-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 SM8S40-E3/2D?
For technical support, including SM8S40-E3/2D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S40-E3/2D requirements.
6.How does Aetrix verify that SM8S40-E3/2D is sourced from the original manufacturer or authorized distributors?
All SM8S40-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 SM8S40-E3/2D meets industry standards.
7.What is the process for return or replacement of SM8S40-E3/2D?
All SM8S40-E3/2D units undergo pre-shipment inspection (PSI). If there is an issue with SM8S40-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 SM8S40-E3/2D part is unused and in its original packaging.
Return procedure for SM8S40-E3/2D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S40-E3/2D Tags
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