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Vishay General Semiconductor - Diodes Division SM8S20CAHM3/I
- Part No.:
- SM8S20CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S20CAHM3/I.pdf
- Description:
- 6600 W BI-DIRECTIONAL TVS IS DO-
- Quantity:
- Payment:
- Shipping:
Inventory:2,934
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Product details
Overview
SM8S20CAHM3/I from Vishay General Semiconductor is a bidirectional surface-mount PAR® transient voltage suppressor (TVS) in DO-218AC package, with 20 V stand-off voltage (VWM), 22.2–24.5 V breakdown voltage (VBR), and 6600 W peak pulse power (10/1000 μs). It delivers 204 A peak pulse current and clamps to ≤32.4 V under surge, meeting AEC-Q101 qualification and ISO 7637-2 for automotive load dump protection.
For engineers reviewing the SM8S20CAHM3/I datasheet, SM8S20CAHM3/I pinout, SM8S20CAHM3/I application, or SM8S20CAHM3/I equivalent, this device is selected for high-reliability 12 V/24 V automotive power rail protection where TJ = 175 °C operation, low leakage (<10 μA at VWM), and MSL Level 1 reflow compatibility are required.
Technical Context
This TVS diode operates as a bidirectional clamping device across power rails, triggered when transient voltage exceeds its VBR range (22.2–24.5 V at IT = 5 mA). Its DO-218AC package integrates a metal heatsink terminal for low RθJM (0.35 °C/W), enabling robust thermal performance under repetitive surge stress.
It meets ISO 7637-2 Pulse 5a (load dump) and ISO 16750-2 surge immunity requirements when applied with appropriate PCB layout and series impedance. The device sustains 175 °C junction temperature and exhibits <15 μA reverse leakage at VWM up to 175 °C - critical for under-hood electronics reliability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 12 V/24 V systems |
| VBR (min–max) | 22.2–24.5 V at 5 mA - precise breakdown threshold ensuring predictable turn-on during transients |
| VC @ IPPM | ≤32.4 V at 204 A - clamping voltage limits downstream IC stress during 10/1000 μs surges |
| PPPM (10/1000 μs) | 6600 W - peak surge energy handling capacity for automotive load dump events |
| TJ max | 175 °C - enables placement near hot engine compartments without derating penalties |
| Leakage @ VWM | ≤10 μA at 25 °C; ≤15 μA at 175 °C - preserves battery life and signal integrity in always-on modules |
| Package | DO-218AC - surface-mount package with integrated metal heatsink terminal for low thermal resistance (RθJM = 0.35 °C/W) |
Pinout & Package
SM8S20CAHM3/I uses the DO-218AC package: a 2-terminal surface-mount device with asymmetrical leads - Lead 1 (anode side) and Lead 2 (metal heatsink/cathode side). The metal heatsink terminal serves as the primary thermal path and electrical return, requiring direct connection to a large copper pour for optimal power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Lead 1 | Anode | Connected to protected line (e.g., battery+); polarity-agnostic due to bidirectional operation |
| Lead 2 / Metal Heatsink | Cathode / Thermal Pad | Must be soldered to ≥100 mm² copper area for RθJM = 0.35 °C/W; forms low-inductance return path |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per JESD47 |
| Bidirectional clamping | Protects against both positive and negative transients without polarity marking or orientation constraints |
| MSL Level 1 (245 °C peak) | Compatible with standard lead-free reflow profiles without moisture sensitivity concerns |
| ISO 7637-2 compliance | Withstands 12 V system load dump pulses (Pulse 5a) up to 35 V/350 ms without degradation |
| Halogen-free & RoHS-compliant (M3) | Meets automotive environmental standards and UL 94 V-0 flammability rating for molding compound |
Applications
| Automotive Body Control Module (BCM) | Engine Control Unit (ECU) Power Input |
|---|---|
Use Scenario: Protecting 12 V supply inputs of BCMs from alternator load dump and inductive switching spikes. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed directly at connector entry point before input filter capacitors. Use Value: Limits transient voltage to ≤32.4 V, preventing damage to MCU, CAN transceivers, and power management ICs rated for 36 V absolute max. |
Use Scenario: Safeguarding main 12 V rail of diesel/gasoline ECUs exposed to cranking dips and load dump surges. IC Role / Device Role / Timing Role: Primary overvoltage clamp on battery feed, coordinated with upstream fuse and downstream DC-DC converter. Use Value: Enables reliable operation at TJ = 175 °C ambient, sustaining 6600 W surge without parametric shift or failure. |
| ADAS Camera Power Supply | Electric Power Steering (EPS) ECU |
Use Scenario: Shielding 12 V input of rear-view or surround-view cameras mounted near engine bay or chassis. IC Role / Device Role / Timing Role: First-line transient suppression before LDO regulators powering image sensors and SerDes links. Use Value: Low leakage (<10 μA) prevents standby current accumulation; DO-218AC metal pad ensures thermal stability during repeated surges. |
Use Scenario: Protecting high-current 12 V input of EPS motor drivers from battery transients during regenerative braking or fault conditions. IC Role / Device Role / Timing Role: High-power TVS placed between main fuse and H-bridge gate driver power stage. Use Value: 204 A peak pulse current rating handles worst-case ISO 16750-2 Class IV surges while maintaining clamping below MOSFET VDS(max). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20CA | DO-214AC package; lower PPPM (400 W), lower IPPM (22.5 A), no AEC-Q101 qualification | Rated for commercial/industrial use only; unsuitable for automotive under-hood deployment | Select SMAJ20CA only for cost-sensitive non-automotive applications with <500 W surge exposure |
| TPSMD20CA | DO-218AC package; same VWM/VBR; lower PPPM (5000 W at 10/10k μs), not ISO 7637-2 tested | Lacks documented compliance with automotive surge standards; limited thermal data at TJ = 175 °C | Use TPSMD20CA where ISO 7637-2 validation is not required and 5000 W surge margin suffices |
Compared with SMAJ20CA and TPSMD20CA, SM8S20CAHM3/I uniquely combines AEC-Q101 qualification, 6600 W surge rating, ISO 7637-2 compliance, and 175 °C operation - making it the only option qualified for front-end protection in safety-critical automotive power domains.
Availability
SM8S20CAHM3/I is available at Aetrix Electronics and suitable for automotive body control modules, engine control units, ADAS camera systems, and electric power steering ECUs requiring stable component supply across extended temperature and surge stress conditions.
Supply support for SM8S20CAHM3/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 designs and manufactures discrete semiconductors including diodes, rectifiers, and TVS devices for automotive, industrial, and computing applications.
SM8S20CAHM3/I belongs to the SM8SxxCA PAR® TVS family engineered specifically for high-energy automotive load dump protection, emphasizing AEC-Q101 reliability, DO-218AC thermal performance, and ISO-standard surge immunity.
FAQ
What is the clamping voltage of SM8S20CAHM3/I at its rated peak pulse current?
The SM8S20CAHM3/I has a maximum clamping voltage (VC) of 32.4 V when subjected to its rated peak pulse current (IPPM) of 204 A under the standard 10/1000 μs waveform. This value is measured per Figure 4 in the Vishay datasheet (Doc. #98229) and ensures downstream components see voltage limited well below typical 36 V absolute maximum ratings. The SM8S20CAHM3/I maintains this clamping performance across its full operating temperature range.
Is SM8S20CAHM3/I suitable for 24 V automotive systems?
Yes, SM8S20CAHM3/I is explicitly designed for 24 V nominal automotive systems. Its 20 V stand-off voltage (VWM) provides adequate margin above regulated 24 V rail tolerances, while its 22.2–24.5 V breakdown range ensures reliable triggering during load dump events that can exceed 35 V. The device's AEC-Q101 qualification and 175 °C junction rating confirm suitability for under-hood deployment in heavy-duty and commercial vehicle applications using SM8S20CAHM3/I.
Does SM8S20CAHM3/I require a specific PCB layout for thermal performance?
Yes - the DO-218AC package of SM8S20CAHM3/I relies on its metal heatsink terminal (Lead 2) for thermal conduction. Vishay specifies mounting on an FR-4 board with ≥100 mm² copper area connected directly to this terminal to achieve the published RθJM of 0.35 °C/W. Failure to implement this layout results in elevated junction temperature, reduced surge endurance, and potential premature failure during repetitive transients. The SM8S20CAHM3/I datasheet provides exact pad dimensions in inches and millimeters.
How does SM8S20CAHM3/I differ from standard SMAJ-series TVS diodes?
SM8S20CAHM3/I differs from SMAJ20CA 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 (SMAJ20CA is not). These differences make SM8S20CAHM3/I capable of surviving automotive load dump events where SMAJ20CA would fail catastrophically. The SM8S20CAHM3/I also features halogen-free construction (M3 suffix) and MSL Level 1 reflow compatibility.
What surge test standards does SM8S20CAHM3/I meet?
SM8S20CAHM3/I meets ISO 7637-2 (Pulse 5a for load dump) and ISO 16750-2 surge immunity requirements, as verified by Vishay's internal testing under defined conditions. Compliance is documented in the "Features" section of the datasheet (Doc. #98229, Rev. 23-Jan-2026). It is not certified to IEC 61000-4-5, as that standard applies to AC mains equipment - SM8S20CAHM3/I is specified exclusively for 12 V/24 V DC automotive power networks.
SM8S20CAHM3/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):
- 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-218AB
SM8S20CAHM3/I FAQ
1.How can I place an order for SM8S20CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S20CAHM3/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 SM8S20CAHM3/I reliable?
The price and inventory of SM8S20CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S20CAHM3/I is usually 5 days.
3.What payment methods are accepted for SM8S20CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S20CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S20CAHM3/I?
SM8S20CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S20CAHM3/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 SM8S20CAHM3/I?
For technical support, including SM8S20CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S20CAHM3/I requirements.
6.How does Aetrix verify that SM8S20CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SM8S20CAHM3/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 SM8S20CAHM3/I meets industry standards.
7.What is the process for return or replacement of SM8S20CAHM3/I?
All SM8S20CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S20CAHM3/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 SM8S20CAHM3/I part is unused and in its original packaging.
Return procedure for SM8S20CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S20CAHM3/I Tags
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