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Vishay General Semiconductor - Diodes Division SM8S40CAHM3/I
- Part No.:
- SM8S40CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S40CAHM3/I.pdf
- Description:
- 6600 W BI-DIRECTIONAL TVS IS DO-
- Quantity:
- Payment:
- Shipping:
Inventory:1,475
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Product details
Overview
SM8S40CAHM3/I from Vishay General Semiconductor is a bidirectional surface-mount PAR® transient voltage suppressor (TVS) designed for automotive load dump protection in 12 V/24 V systems. It features a 40 V stand-off voltage (VWM), 46.8 V nominal breakdown voltage (VBR), 64.5 V maximum clamping voltage at 102 A peak pulse current, and 6600 W peak pulse power rating with 10/1000 μs waveform.
For engineers reviewing the SM8S40CAHM3/I datasheet, SM8S40CAHM3/I pinout, SM8S40CAHM3/I application, or SM8S40CAHM3/I equivalent, this device is selected for high-reliability automotive electronics requiring AEC-Q101 qualification, TJ = 175 °C operation, ISO 7637-2/16750-2 compliance, and DO-218AC package thermal performance.
Technical Context
The SM8S40CAHM3/I employs an avalanche diode structure optimized for fast response (<1 ns) to transients induced by inductive load switching and battery load dump events. Its bidirectional configuration enables symmetrical clamping without polarity sensitivity, supporting dual-rail protection in unidirectional or floating bus architectures.
Thermal design leverages the DO-218AC package's low junction-to-mount thermal resistance (RθJM = 0.35 °C/W) and metal heatsink terminal, enabling high-power surge dissipation without external heatsinking under defined PCB layout conditions per JEDEC 51-14.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before clamping begins; defines system operating margin in 24 V automotive applications. |
| VBR (nom) | 46.8 V - Breakdown voltage at 5 mA test current; ensures reliable triggering above normal transients but below system overvoltage limits. |
| VC @ IPPM | 64.5 V - Clamping voltage at 102 A peak pulse current (10/1000 μs); determines maximum voltage seen by protected downstream ICs. |
| PPPM (10/1000 μs) | 6600 W - Peak pulse power handling capacity; supports robust protection against severe ISO 7637-2 Pulse 5a load dump events. |
| TJ max | 175 °C - Maximum junction temperature rating; enables operation in under-hood environments without derating penalties up to ambient 125 °C. |
| Leakage @ VWM | 10 μA - Reverse leakage at 40 V and 25 °C; ensures minimal standby power loss in always-on vehicle modules. |
| Package | DO-218AC - Surface-mount package with integrated metal heatsink terminal; provides superior thermal conduction vs. DO-214AB or SMA. |
Pinout & Package
DO-218AC package features two terminals: Terminal 1 (anode side marking) and Terminal 2 (metal heatsink/cathode side). The metal heatsink terminal serves as both cathode connection and primary thermal path to PCB copper.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Terminal 1 | Anode | Connected to protected line (e.g., battery rail); forms one side of bidirectional avalanche junction. |
| Terminal 2 | Cathode / Metal Heatsink | Connected to ground or chassis; provides low-inductance return path and primary thermal interface to PCB copper pour. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per JESD47; required for engine control, body electronics, and ADAS modules. |
| ISO 7637-2 & ISO 16750-2 compliant | Meets Pulse 1, 2a, 2b, 3a/b, and critical Pulse 5a (load dump) requirements when mounted per recommended footprint; eliminates need for additional validation testing. |
| MSL Level 1 (245 °C peak) | Compatible with standard lead-free reflow profiles without moisture sensitivity concerns; supports automated SMT assembly without baking. |
| Halogen-free, RoHS-compliant, Pb-free | Meets global environmental regulations (IEC 61249-2-21, J-STD-609); avoids restricted substances in soldering and end-of-life processing. |
| Junction temperature rating: -55 °C to +175 °C | Enables deployment in extreme environments such as powertrain ECUs, transmission controllers, and under-bonnet sensors without thermal derating. |
Applications
| Automotive Load Dump Protection | Engine Control Unit (ECU) Power Input |
|---|---|
Use Scenario: Protecting 12 V/24 V power inputs of automotive electronic control units during alternator load dump events (ISO 7637-2 Pulse 5a). IC Role / Device Role / Timing Role: Primary clamping device placed directly at power entry point to limit transient voltage to safe levels for downstream DC/DC converters and microcontrollers. Use Value: Withstands 6600 W surges and clamps to ≤64.5 V, preventing latch-up or permanent damage to 5 V/3.3 V logic rails powered from protected input. |
Use Scenario: Safeguarding power supply pins of engine management microcontrollers exposed to ignition coil switching noise and battery disconnection spikes. IC Role / Device Role / Timing Role: Fast-response TVS placed adjacent to ECU main power connector to absorb sub-microsecond transients before they propagate into regulator ICs. Use Value: 1 ns response time and 10 μA leakage ensure no interference with ECU sleep-mode current budgets while maintaining immunity to repetitive switching transients. |
| Body Control Module (BCM) Power Rail | Advanced Driver Assistance Systems (ADAS) Camera Power |
Use Scenario: Securing 12 V input to BCMs managing lighting, door locks, and HVAC functions in modern vehicles. IC Role / Device Role / Timing Role: Bidirectional clamping element on main power bus to handle both positive and negative transients from relay coil de-energization and LIN bus coupling. Use Value: Bidirectional symmetry eliminates polarity installation errors; DO-218AC thermal performance sustains repeated 5000 W surges per ISO 16750-2 without degradation. |
Use Scenario: Protecting 12 V power input of forward-facing ADAS cameras subject to vibration-induced harness arcing and ESD from nearby high-voltage components. IC Role / Device Role / Timing Role: First-line transient suppressor upstream of camera module DC/DC converter and image sensor power domain. Use Value: 175 °C junction rating ensures stable clamping performance during prolonged exposure to under-hood temperatures exceeding 105 °C ambient. |
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-E3/57T | DO-214AC package; lower PPPM (400 W); VWM = 40 V; VC = 64.5 V; not AEC-Q101 qualified. | Limited to industrial or non-safety-critical automotive accessories; lacks load dump capability and high-temperature reliability. | Select only for cost-sensitive, non-automotive applications where ISO 7637-2 compliance and 175 °C operation are not required. |
| TPSMD40CA | DO-218AC package; same VWM/VC specs; AEC-Q101 qualified; PPPM = 6600 W; slightly higher ID (25 μA @ VWM). | Functionally identical for load dump protection; validated for same automotive use cases but with different manufacturer qualification documentation. | Drop-in alternative if Vishay supply constraints exist; verify mechanical fit and traceability requirements match OEM program needs. |
Compared with SMAJ40A-E3/57T and TPSMD40CA, the SM8S40CAHM3/I delivers certified automotive reliability (AEC-Q101), full ISO 7637-2 Pulse 5a support, and guaranteed 175 °C operation-making it the preferred choice for safety-critical power rail protection where long-term field stability is mandatory.
Availability
SM8S40CAHM3/I is available at Aetrix Electronics and suitable for automotive electronics, engine control units, and body control modules requiring stable component supply across multi-year production cycles.
Supply support for SM8S40CAHM3/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 high-reliability diodes, MOSFETs, and passive components for automotive, industrial, and computing markets.
The SM8S series is part of Vishay's PAR® TVS platform engineered specifically for automotive-grade transient suppression, emphasizing AEC-Q101 qualification, high-temperature stability, and ISO 7637-2 compliance in harsh vehicle environments.
FAQ
What is the clamping voltage of the SM8S40CAHM3/I at its rated peak pulse current?
The SM8S40CAHM3/I has a maximum clamping voltage (VC) of 64.5 V at its rated peak pulse current (IPPM) of 102 A under the 10/1000 μs waveform condition. This value is measured per Figure 4 in the official Vishay datasheet (Document Number: 98229) and defines the upper voltage limit imposed on protected circuitry during worst-case transients. The SM8S40CAHM3/I maintains this clamping performance across its full operating temperature range.
Is the SM8S40CAHM3/I qualified for automotive applications?
Yes, the SM8S40CAHM3/I is AEC-Q101 qualified and explicitly designed for automotive use. It meets ISO 7637-2 and ISO 16750-2 surge test requirements-including Pulse 5a load dump-and operates reliably from -55 °C to +175 °C junction temperature. The HM3 suffix confirms halogen-free, RoHS-compliant, and whisker-resistant construction per JESD 201 Class 2, satisfying Tier 1 supplier requirements for engine bay and chassis-mounted modules.
What package does the SM8S40CAHM3/I use, and why is it significant?
The SM8S40CAHM3/I uses the DO-218AC surface-mount package, which integrates a metal heatsink terminal for direct thermal coupling to PCB copper. This design achieves a low junction-to-mount thermal resistance (RθJM = 0.35 °C/W), enabling efficient dissipation of 6600 W surge energy without external heatsinks. Unlike DO-214AB or SMA packages, DO-218AC supports higher power density and improved long-term reliability in thermally demanding automotive applications.
How does the SM8S40CAHM3/I differ from standard SMAJ-series TVS diodes?
The SM8S40CAHM3/I differs from SMAJ40A-type devices in three key ways: it uses the thermally superior DO-218AC package (vs. DO-214AC), delivers 6600 W peak pulse power (vs. 400 W), and is AEC-Q101 qualified (vs. commercial grade). These differences make the SM8S40CAHM3/I suitable for automotive load dump protection, whereas SMAJ40A is limited to lower-energy industrial transients and lacks automotive reliability certification.
What is the reverse leakage current specification for the SM8S40CAHM3/I at its stand-off voltage?
The SM8S40CAHM3/I specifies a maximum reverse leakage current (ID) of 10 μA at its 40 V stand-off voltage (VWM) and 25 °C ambient temperature. At elevated junction temperature (TJ = 175 °C), leakage increases to 150 μA - still within acceptable limits for automotive always-on modules. This low leakage ensures minimal impact on battery drain in vehicle sleep modes while maintaining effective transient suppression capability.
SM8S40CAHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-218AB
- Series:
- PAR®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 102A
- Power - Peak Pulse:
- 6600W (6.6kW)
- 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-218AB
SM8S40CAHM3/I FAQ
1.How can I place an order for SM8S40CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S40CAHM3/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 SM8S40CAHM3/I reliable?
The price and inventory of SM8S40CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S40CAHM3/I is usually 5 days.
3.What payment methods are accepted for SM8S40CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S40CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S40CAHM3/I?
SM8S40CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S40CAHM3/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 SM8S40CAHM3/I?
For technical support, including SM8S40CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S40CAHM3/I requirements.
6.How does Aetrix verify that SM8S40CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SM8S40CAHM3/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 SM8S40CAHM3/I meets industry standards.
7.What is the process for return or replacement of SM8S40CAHM3/I?
All SM8S40CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S40CAHM3/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 SM8S40CAHM3/I part is unused and in its original packaging.
Return procedure for SM8S40CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S40CAHM3/I Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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PESD2V0Y1BSFYL
Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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