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Vishay General Semiconductor - Diodes Division SM8S20AHM3/I
- Part No.:
- SM8S20AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AC
- Datasheet:
-
SM8S20AHM3/I.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO218AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,476
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Product details
Overview
SM8S20AHM3/I from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor in DO-218AB package, rated for 20 V stand-off voltage (VWM), 22.2–24.5 V breakdown (VBR), and 6600 W peak pulse power (10/1000 μs). It delivers AEC-Q101 qualification, 175 °C junction capability, and low leakage (<10 μA at VWM), designed specifically for automotive load dump protection.
For engineers reviewing the SM8S20AHM3/I datasheet, SM8S20AHM3/I pinout, SM8S20AHM3/I application, or SM8S20AHM3/I equivalent, this page provides verified electrical parameters, thermal performance data, DO-218AB mechanical interface details, and validated alternatives for high-reliability 12 V automotive power rail protection.
Technical Context
The SM8S20AHM3/I uses passivated anisotropic rectifier technology to achieve stable clamping under repetitive surge stress, with junction temperature operation up to +175 °C - enabling use in under-hood automotive environments. Its unidirectional polarity and heatsink-as-anode configuration support direct mounting to metal chassis for enhanced thermal dissipation.
It meets ISO 7637-2 load dump surge requirements and J-STD-020 MSL Level 1 (245 °C peak reflow), with RθJM = 0.35 °C/W confirming efficient heat transfer from junction to heatsink. The device exhibits αT = 0.085 %/°C temperature coefficient of VBR, ensuring predictable voltage drift across operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - maximum continuous reverse operating voltage before conduction begins; defines safe operating window for 12 V automotive systems. |
| VBR (min/typ/max) | 22.2 / 23.4 / 24.5 V - measured at 5 mA; ensures reliable triggering above normal transients while avoiding false activation. |
| VC @ IPPM | 32.4 V - clamping voltage at 204 A peak pulse (10/1000 μs); limits downstream voltage stress during load dump events. |
| PPPM (10/1000 μs) | 6600 W - peak pulse power handling capacity; supports high-energy ISO 7637-2 Test Pulse 5a without failure. |
| TJ max | +175 °C - maximum junction temperature; enables placement near hot engine components without derating. |
| ID @ VWM | <10 μA at 25 °C - ultra-low reverse leakage preserves battery life in always-on vehicle modules. |
| RθJM | 0.35 °C/W - thermal resistance from junction to heatsink; confirms effective thermal coupling when mounted to metal chassis. |
Pinout & Package
Package: DO-218AB - molded surface-mount case with integral metal heatsink; anode terminal is the metal base (heatsink), cathode is lead 1; UL 94 V-0 rated, RoHS-compliant, AEC-Q101 qualified.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Metal Heatsink) | Positive connection point and primary thermal path | Must be soldered to copper pour or chassis for RθJM = 0.35 °C/W; polarity-critical for unidirectional operation. |
| Cathode (Lead 1) | Transient current return path | Connected to protected line (e.g., battery feed); carries full surge current during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated reliability for automotive electronics per stress test requirements - eliminates need for additional qualification by end customer. |
| Junction passivation | Stable VBR over lifetime and temperature; prevents parameter drift due to moisture or bias stress in harsh environments. |
| MSL Level 1 rating | Compatible with standard SMT reflow profiles up to 245 °C peak - no special baking or handling required. |
| ISO 7637-2 compliance | Proven performance against load dump surges (Pulse 5a) - reduces need for system-level validation testing. |
| Low forward voltage drop | VF ≤ 1.8 V at 100 A (300 μs pulse) - minimizes conduction loss during bidirectional fault conditions. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) Battery Line |
|---|---|
Use Scenario: Protects ECU microcontroller and CAN transceivers from 12 V battery line transients caused by alternator load dump and inductive switching. IC Role / Device Role / Timing Role: Unidirectional TVS clamps surge energy before it reaches downstream LDOs, MCUs, and communication ICs. Use Value: Limits clamped voltage to 32.4 V at 204 A, preventing damage to 3.3 V/5 V logic rails and maintaining functional safety integrity. | Use Scenario: Shields BCM power supply from repeated low-energy transients generated by door lock actuators, window motors, and lighting loads. IC Role / Device Role / Timing Role: Fast-response transient suppressor placed at main 12 V input, upstream of DC-DC converters and power switches. Use Value: Delivers <10 μA leakage at 20 V, minimizing standby current drain critical for vehicle sleep-mode battery budgeting. |
| Advanced Driver Assistance Systems (ADAS) Camera Power | Electric Power Steering (EPS) Motor Driver Supply |
Use Scenario: Safeguards image sensor and ISP power rails in rear-view or surround-view cameras exposed to engine bay EMI and load dump. IC Role / Device Role / Timing Role: Primary overvoltage protection element on 12 V input stage, coordinated with ceramic filtering and local regulation. Use Value: Withstands 175 °C ambient and maintains VBR stability - essential for camera housings mounted near exhaust or radiator. | Use Scenario: Protects H-bridge gate drivers and current sense amplifiers in EPS motor control units subjected to high-current switching noise. IC Role / Device Role / Timing Role: High-surge-capability TVS absorbing commutation spikes and reverse EMF from brushed/BLDC motor windings. Use Value: 6600 W peak pulse rating handles worst-case motor stall surges without degradation, supporting ASIL-B functional safety goals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20AHE3/A | Lower PPPM (400 W vs. 6600 W), DO-214AC package, 200 A IPPM, RθJA = 50 °C/W | Intended for lower-energy board-level ESD/surge; not suitable for ISO 7637-2 load dump. | Select SMAJ20AHE3/A only for non-automotive, low-power signal-line protection where space is constrained. |
| SM8S20AHE3/A | Same electrical specs and DO-218AB package, but lacks H-grade AEC-Q101 qualification and HE3 whisker-resistant plating. | Acceptable for industrial or consumer applications where automotive reliability certification is not required. | Choose SM8S20AHE3/A for cost-sensitive designs outside automotive OEM/ODM supply chains. |
Compared with SMAJ20AHE3/A and SM8S20AHE3/A, the SM8S20AHM3/I provides 16.5× higher surge power handling and certified automotive qualification - making it the sole option for production-grade 12 V load dump protection in safety-critical vehicle systems.
Availability
SM8S20AHM3/I is available at Aetrix Electronics and suitable for automotive ECU power protection, ADAS camera supply conditioning, and electric power steering module design requiring stable component supply and long-term lifecycle assurance.
Supply support for SM8S20AHM3/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, rectifiers, TVS devices, and optoelectronics with emphasis on high-reliability and automotive-grade solutions.
The SM8S series is part of Vishay's PAR® (Protection Against Transients) platform, engineered specifically for robust, high-energy transient suppression in automotive power distribution networks.
FAQ
What is the clamping voltage of the SM8S20AHM3/I at its rated peak pulse current?
The SM8S20AHM3/I has a maximum clamping voltage (VC) of 32.4 V when subjected to its rated peak pulse current of 204 A under the 10/1000 μs waveform. This value is guaranteed per the Vishay datasheet (Document Number 88387, page 2) and defines the upper voltage limit imposed on protected circuitry during surge events. The SM8S20AHM3/I maintains this clamping performance across its full operating temperature range.
Is the SM8S20AHM3/I suitable for ISO 7637-2 load dump protection?
Yes, the SM8S20AHM3/I is explicitly rated to meet ISO 7637-2 surge requirements, including Load Dump Pulse 5a, as confirmed in the Vishay datasheet (page 1, FEATURES section). Its 6600 W peak pulse power rating, 175 °C junction capability, and low clamping voltage ensure compliance with automotive OEM specifications for 12 V system protection. The SM8S20AHM3/I is widely deployed in production ECUs and body control modules for this purpose.
What does the "H" in SM8S20AHM3/I signify?
The "H" in SM8S20AHM3/I denotes AEC-Q101 qualification, confirming that the device has passed the full suite of stress tests defined by the Automotive Electronics Council for discrete semiconductors. This includes HTOL, TC, UHAST, and mechanical shock testing. The "H" grade distinguishes it from non-automotive variants like SM8S20AHE3/A and is mandatory for Tier 1 automotive supply chain acceptance. The SM8S20AHM3/I carries this designation per Vishay's ordering information table (page 3).
Does the SM8S20AHM3/I require a heatsink for operation?
The SM8S20AHM3/I integrates a metal heatsink as its anode terminal and is designed for direct thermal mounting to a PCB copper pour or chassis - no external heatsink is needed. Its RθJM = 0.35 °C/W (per datasheet page 3) assumes proper soldering to ≥1 in² of 2 oz. copper. Without such thermal coupling, junction temperature rise would exceed safe limits under sustained surge conditions. The SM8S20AHM3/I's DO-218AB package relies on this integrated heatsink for rated performance.
What is the reverse leakage current specification for the SM8S20AHM3/I at 25 °C?
The SM8S20AHM3/I specifies a maximum reverse leakage current (ID) of 10 μA at its 20 V stand-off voltage (VWM) and 25 °C ambient temperature, as listed in the Electrical Characteristics table (page 2 of datasheet 88387). At elevated temperatures (e.g., 175 °C), leakage increases to ≤250 μA - still within acceptable limits for automotive always-on modules. This low leakage directly supports stringent vehicle battery drain budgets.
SM8S20AHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-218AC
- Series:
- PAR®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 204A
- 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-218AC
SM8S20AHM3/I FAQ
1.How can I place an order for SM8S20AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S20AHM3/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 SM8S20AHM3/I reliable?
The price and inventory of SM8S20AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S20AHM3/I is usually 5 days.
3.What payment methods are accepted for SM8S20AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S20AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S20AHM3/I?
SM8S20AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S20AHM3/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 SM8S20AHM3/I?
For technical support, including SM8S20AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S20AHM3/I requirements.
6.How does Aetrix verify that SM8S20AHM3/I is sourced from the original manufacturer or authorized distributors?
All SM8S20AHM3/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 SM8S20AHM3/I meets industry standards.
7.What is the process for return or replacement of SM8S20AHM3/I?
All SM8S20AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S20AHM3/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 SM8S20AHM3/I part is unused and in its original packaging.
Return procedure for SM8S20AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S20AHM3/I Tags
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