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Vishay General Semiconductor - Diodes Division SM8S45CAHM3/I
- Part No.:
- SM8S45CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S45CAHM3/I.pdf
- Description:
- 6600 W BI-DIRECTIONAL TVS IS DO-
- Quantity:
- Payment:
- Shipping:
Inventory:2,979
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Product details
Overview
SM8S45CAHM3/I from Vishay General Semiconductor is a bidirectional surface-mount PAR® transient voltage suppressor (TVS) designed for automotive load dump protection. It features a 45 V stand-off voltage (VWM), 52.7 V nominal breakdown voltage (VBR), 72.7 V maximum clamping voltage (VC) at 90.8 A peak pulse current (IPPM), and 6600 W peak pulse power (10/1000 μs). It operates from −55 °C to +175 °C and is AEC-Q101 qualified for under-hood electronics.
For engineers reviewing the SM8S45CAHM3/I datasheet, SM8S45CAHM3/I pinout, SM8S45CAHM3/I application, or SM8S45CAHM3/I equivalent, this device is selected for high-reliability 12 V/24 V automotive power rail protection where ISO 7637-2 and ISO 16750-2 surge compliance, low leakage (<10 μA at VWM), and DO-218AC thermal performance are critical.
Technical Context
This TVS diode uses an avalanche-based silicon junction optimized for fast response (<1 ns) to transients induced by inductive load switching and alternator load dump events. Its bidirectional architecture enables symmetrical clamping without polarity constraints, and its DO-218AC package provides low thermal resistance (RθJM = 0.35 °C/W) for direct metal heatsink coupling.
The device delivers 6600 W peak pulse power with 10/1000 μs waveform and sustains 5200 W with 10/10 000 μs waveform - meeting stringent automotive surge test profiles. Its TJ = 175 °C rating supports operation in high-temperature engine compartments without derating penalties up to ambient 150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45.0 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin for 12 V/24 V systems. |
| VBR (nom) | 52.7 V - Breakdown voltage at 5 mA test current; ensures reliable turn-on before downstream IC damage thresholds. |
| VC @ IPPM | 72.7 V - Clamping voltage at 90.8 A peak pulse current; limits transient overvoltage seen by protected ECUs. |
| PPPM (10/1000 μs) | 6600 W - Peak pulse power handling capacity; enables survival of ISO 7637-2 Pulse 5a (load dump) surges. |
| TJ max | +175 °C - Maximum junction temperature; supports under-hood placement without external cooling or layout derating. |
| Leakage @ VWM | <10 μA at 25 °C - Ultra-low reverse leakage preserves battery life and avoids false triggering in always-on circuits. |
| Package | DO-218AC - Surface-mount case with integral metal heatsink tab; enables direct PCB thermal conduction and meets MSL Level 1. |
Pinout & Package
SM8S45CAHM3/I is housed in a DO-218AC package with two terminals: Terminal 1 (anode) and Terminal 2 (cathode/metal heatsink tab). The device is bidirectional - no cathode band marking - and the metal tab serves as both mechanical heatsink and electrical terminal (common to both polarities).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Terminal 1 | Anode (bidirectional) | Primary connection point for line-side protection; symmetric with Terminal 2 due to bidirectional structure. |
| Terminal 2 / Metal Tab | Cathode / Heatsink Interface | Electrically common to both polarities; must be soldered to large copper pour for thermal management and surge current return path. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including HTOL, TC, HAST, and bond wire strength per JESD22 standards. |
| ISO 7637-2 & ISO 16750-2 compliance | Tested to Pulse 5a (load dump), Pulse 1, Pulse 2a, and Pulse 3a waveforms - enabling drop-in use in OEM ECU designs. |
| DO-218AC thermal performance | RθJM = 0.35 °C/W enables >8 W steady-state dissipation when mounted on ≥2 oz. copper with thermal pad - exceeds standard SMA/SMB limits. |
| Halogen-free, RoHS-compliant, whisker-resistant | HM3 suffix confirms JESD201 Class 2 whisker resistance and material compliance for long-life automotive deployments. |
| Bidirectional symmetry | No polarity marking required; simplifies PCB layout and eliminates orientation errors during automated assembly. |
Applications
| Engine Control Unit (ECU) Power Input Protection | Body Control Module (BCM) CAN Bus Power Rail |
|---|---|
Use Scenario: Protects 12 V supply input of engine control units against alternator load dump transients up to 35 V for 400 ms. IC Role / Device Role / Timing Role: Primary clamping element on main power rail; responds within <1 ns to limit voltage excursion below 75 V. Use Value: Prevents latch-up or permanent damage to MCU, power management ICs, and analog front-ends during cold-crank and load dump events. |
Use Scenario: Shields 12 V power feeding isolated CAN transceivers and microcontrollers in body electronics modules. IC Role / Device Role / Timing Role: Standoff protector upstream of DC/DC converter; clamps ISO 7637-2 Pulse 1 (inductive switch-off) spikes. Use Value: Maintains CAN bus communication integrity by preventing power rail collapse or reset during door lock actuator switching. |
| Advanced Driver Assistance Systems (ADAS) Camera Power Supply | Electric Power Steering (EPS) Motor Driver Board |
Use Scenario: Secures 12 V input to image sensor and ISP power rails in rear-view or surround-view camera modules. IC Role / Device Role / Timing Role: First-line transient suppressor before LDO regulators; handles repetitive surges from nearby solenoid activation. Use Value: Eliminates video artifacts and sensor resets caused by sub-100 ns transients from adjacent actuators or harness coupling. |
Use Scenario: Guards gate driver and MCU power supplies on EPS motor control boards exposed to high-current motor commutation noise. IC Role / Device Role / Timing Role: High-energy clamping device across H-bridge DC bus; absorbs regenerative energy spikes during rapid deceleration. Use Value: Extends lifetime of MOSFET drivers and prevents false fault reporting by maintaining stable logic supply during torque transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ45CA | Same VWM (45 V) and VC (73.0 V), but lower PPPM (400 W vs. 6600 W); DO-214AC package with higher RθJA (65 °C/W). | Suitable for low-energy consumer or industrial I/O protection; insufficient for automotive load dump per ISO 7637-2 Pulse 5a. | Select SM8S45CAHM3/I when full automotive surge compliance and thermal robustness are required. |
| ON Semiconductor SMCJ45CA | Identical VWM (45 V), VC (73.0 V), and PPPM (6600 W); DO-214AB package with RθJM = 0.45 °C/W (vs. 0.35 °C/W). | Valid for ISO 7637-2, but requires larger thermal pad area to match SM8S45CAHM3/I's junction-to-mount performance. | Choose SM8S45CAHM3/I for space-constrained layouts needing superior thermal conduction via metal tab. |
Compared with SMAJ45CA and SMCJ45CA, SM8S45CAHM3/I delivers 16× higher peak power capability than SMAJ45CA and 29% lower junction-to-mount thermal resistance than SMCJ45CA - directly enabling smaller heatsinking and higher reliability in under-hood automotive placements.
Availability
SM8S45CAHM3/I is available at Aetrix Electronics and suitable for automotive ECU design, ADAS camera module development, and electric power steering system production requiring stable component supply with AEC-Q101 traceability and long-term lifecycle support.
Supply support for SM8S45CAHM3/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 SM8SxxCA family was engineered specifically for automotive power rail transient suppression, combining AEC-Q101 qualification, DO-218AC thermal efficiency, and ISO 7637-2 compliance in a single surface-mount solution.
FAQ
What is the maximum clamping voltage of the SM8S45CAHM3/I at its rated peak pulse current?
The SM8S45CAHM3/I has a maximum clamping voltage (VC) of 72.7 V at its rated peak pulse current (IPPM) of 90.8 A with a 10/1000 μs waveform. This value is measured per Figure 4 in the Vishay datasheet and ensures protected downstream circuitry remains below critical overvoltage thresholds during ISO 7637-2 load dump events. The SM8S45CAHM3/I maintains this clamping performance across its full operating temperature range.
Is the SM8S45CAHM3/I suitable for 24 V commercial vehicle applications?
Yes, the SM8S45CAHM3/I is explicitly rated for 24 V systems: its 45 V stand-off voltage (VWM) provides adequate margin above nominal 24 V rails, and its 72.7 V clamping voltage aligns with 24 V ECU voltage tolerances. It meets ISO 16750-2 requirements for commercial vehicles and supports junction temperatures up to +175 °C - essential for under-hood environments in trucks and buses. The SM8S45CAHM3/I is validated for both 12 V and 24 V automotive architectures.
Does the SM8S45CAHM3/I require a specific PCB footprint or thermal pad design?
Yes, the SM8S45CAHM3/I uses the DO-218AC package and requires adherence to Vishay's recommended mounting pad layout (Document 98229, page 5), including a minimum 3.5 mm × 3.5 mm copper pour connected to Terminal 2 (metal tab) for optimal thermal conduction. Deviating from this footprint increases RθJM and risks thermal runaway during repeated surges. The SM8S45CAHM3/I's performance depends critically on correct thermal pad implementation.
How does the HM3 suffix impact the reliability of the SM8S45CAHM3/I?
The HM3 suffix on SM8S45CAHM3/I indicates halogen-free construction, RoHS compliance, and JESD201 Class 2 whisker resistance - all verified per AEC-Q101 stress testing. This ensures long-term interconnect integrity in high-humidity, high-temperature automotive environments and eliminates tin whisker risk in solder joints. The HM3 designation is mandatory for Tier 1 automotive supply chain acceptance, and SM8S45CAHM3/I carries full documentation traceability for these qualifications.
Can the SM8S45CAHM3/I replace older SM8S45A or SMAJ45CA devices in existing designs?
No - the SM8S45CAHM3/I is not a direct replacement for SM8S45A (which lacks HM3 and AEC-Q101 validation) or SMAJ45CA (DO-214AC, 400 W rating). Its DO-218AC package differs mechanically and thermally, and its 6600 W surge rating exceeds those parts by over 16×. Retrofitting SM8S45CAHM3/I requires PCB footprint revision and thermal validation. For legacy compatibility, SM8S45CAHM3/I must be treated as a new design-in component, not a drop-in upgrade.
SM8S45CAHM3/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):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.7V
- Current - Peak Pulse (10/1000µs):
- 90.8A
- 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
SM8S45CAHM3/I FAQ
1.How can I place an order for SM8S45CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S45CAHM3/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 SM8S45CAHM3/I reliable?
The price and inventory of SM8S45CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S45CAHM3/I is usually 5 days.
3.What payment methods are accepted for SM8S45CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S45CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S45CAHM3/I?
SM8S45CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S45CAHM3/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 SM8S45CAHM3/I?
For technical support, including SM8S45CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S45CAHM3/I requirements.
6.How does Aetrix verify that SM8S45CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SM8S45CAHM3/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 SM8S45CAHM3/I meets industry standards.
7.What is the process for return or replacement of SM8S45CAHM3/I?
All SM8S45CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S45CAHM3/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 SM8S45CAHM3/I part is unused and in its original packaging.
Return procedure for SM8S45CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S45CAHM3/I Tags
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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