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Vishay General Semiconductor - Diodes Division SM8S28AHE3_A/I
- Part No.:
- SM8S28AHE3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S28AHE3_A/I.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:2,222
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Product details
Overview
SM8S28AHE3_A/I from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor in DO-218AB package, rated for 28 V stand-off voltage (VWM), 32.8 V nominal breakdown (VBR), 45.4 V clamping voltage at 145 A peak pulse current, and 6600 W peak pulse power (10/1000 μs). It is AEC-Q101 qualified, operates up to 175 °C junction temperature, and targets automotive load dump protection.
For engineers reviewing the SM8S28AHE3_A/I datasheet, SM8S28AHE3_A/I pinout, SM8S28AHE3_A/I application, or SM8S28AHE3_A/I equivalent, key selection criteria include unidirectional polarity, DO-218AB thermal performance (RθJM = 0.35 °C/W), low leakage (<10 μA at VWM), and compliance with ISO7637-2 surge testing - critical for 12 V automotive power rail hardening.
Technical Context
This TVS diode uses passivated anisotropic rectifier technology optimized for high-temperature stability and low forward voltage drop (≤1.8 V at 100 A). Its junction design enables reliable operation under repetitive load dump transients while maintaining <15 μA reverse leakage at 175 °C.
The device is engineered specifically for unidirectional clamping on positive-rail systems, with heatsink-connected anode polarity and cathode terminal configuration. Thermal resistance from junction-to-mount (RθJM = 0.35 °C/W) supports direct PCB copper pour mounting for high-power transient dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC operating margin in 12 V automotive systems. |
| VBR (nom) | 32.8 V - Breakdown voltage at 5 mA test current; ensures precise turn-on during fast transients without premature conduction. |
| VC @ IPPM | 45.4 V - Clamping voltage at 145 A (10/1000 μs); limits downstream IC stress during ISO7637-2 Pulse 5a load dump events. |
| PPPM (10/1000 μs) | 6600 W - Peak pulse power handling; enables single-event suppression of >100 V, 100 ms exponential load dump surges. |
| TJ max | 175 °C - Maximum junction temperature rating; supports under-hood placement in engine control units and body controllers. |
| IFSM | 700 A - Non-repetitive forward surge current (8.3 ms half-sine); withstands high-current battery connection transients. |
| Polarity | Unidirectional - Anode connected to heatsink; requires correct orientation in series with positive supply rail for load dump protection. |
Pinout & Package
Package: DO-218AB - Surface-mount molded case with matte tin-plated leads, UL 94 V-0 compliant, MSL Level 1, JESD201 Class 2 whisker resistant. Heatsink tab is electrically connected to anode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Positive input / clamping reference | Must be soldered to large copper area for thermal management and low-inductance path to ground return; defines unidirectional polarity orientation. |
| Cathode (Lead 1) | Clamped output / protected rail connection | Connected to the 12 V supply line being protected; carries full transient current during clamping event. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated reliability for automotive electronics including engine control, ADAS, and infotainment modules operating across -55 °C to +175 °C. |
| Junction passivation technology | Enables stable VBR drift ≤0.089 %/°C and low leakage (<10 μA at 28 V, 175 °C) over lifetime in harsh under-hood environments. |
| DO-218AB thermal performance | RθJM = 0.35 °C/W allows >5 kW transient energy dissipation into PCB copper without external heatsink - reduces BOM count vs. TO-263 alternatives. |
| ISO7637-2 compliance | Validated for Pulse 5a (load dump) per ISO7637-2:2016 Annex D; clamps 12 V system transients up to 65 V peak with controlled voltage overshoot. |
Applications
| Automotive Load Dump Protection | Engine Control Unit (ECU) Power Input |
|---|---|
Use Scenario: Protecting 12 V power inputs of vehicle ECUs during alternator load dump events (up to 65 V, 400 ms). IC Role / Device Role / Timing Role: Unidirectional TVS clamping device placed between battery feed and LDO/regulator input. Use Value: Limits transient voltage to ≤45.4 V at 145 A, preventing damage to downstream 40 V-rated regulators and microcontrollers. | Use Scenario: Safeguarding power rails in gasoline/diesel engine control modules exposed to repeated switching surges. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main 12 V supply rail upstream of DC-DC converters. Use Value: Withstands ≥700 A surge (8.3 ms) and maintains <15 μA leakage at 175 °C, ensuring long-term reliability in high-temperature engine bays. |
| Body Control Module (BCM) Power Interface | ADAS Camera Power Conditioning |
Use Scenario: Hardening power inputs of BCMs managing lighting, door locks, and HVAC in modern vehicles. IC Role / Device Role / Timing Role: Standoff-rated TVS on fused 12 V distribution node feeding multiple subsystems. Use Value: 28 V VWM provides adequate margin above nominal 12 V while enabling fast response (tRESP < 1 ns) to inductive kickback from relay coils. | Use Scenario: Protecting 12 V input of front/rear ADAS cameras subjected to vibration-induced harness transients. IC Role / Device Role / Timing Role: First-line transient suppressor before EMI filter and buck converter. Use Value: Low clamping ratio (VC/VBR ≈ 1.38) minimizes voltage overshoot during fast 10/1000 μs spikes, preserving image sensor integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SM8S28AHM3 | Same electrical specs and DO-218AB package; HM3 suffix indicates enhanced material formulation per newer revision (post-2024), with identical VWM/VBR/VC but improved high-temp leakage stability. | No functional difference; intended for new designs where SM8S28AHE3_A/I is marked "Not For New Designs". | Select SM8S28AHM3 for new automotive projects requiring long-term supply assurance and latest AEC-Q101 requalification. |
| SMAJ28A | Lower PPPM (400 W vs. 6600 W), DO-214AC package, RθJA ≈ 40 °C/W - insufficient for load dump; suitable only for ESD/inductive spike suppression. | Limited to non-load-dump applications such as CAN bus node protection or sensor interface clamping. | Use SMAJ28A only where peak surge energy is <100 mJ; not a functional replacement for SM8S28AHE3_A/I in 12 V rail protection. |
Compared with SM8S28AHM3, the SM8S28AHE3_A/I offers identical clamping performance but lacks updated material traceability and long-term production commitment; compared with SMAJ28A, it delivers 16.5× higher surge power handling and is purpose-built for automotive load dump - not interchangeable in high-energy applications.
Availability
SM8S28AHE3_A/I is available at Aetrix Electronics and suitable for automotive load dump protection, engine control unit (ECU) power hardening, and body control module (BCM) power interface applications requiring stable component supply across extended temperature ranges and high-reliability validation.
Supply support for SM8S28AHE3_A/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 automotive, industrial, and computing applications.
The SM8SxxA family is designed specifically for high-energy transient suppression in 12 V automotive systems, targeting load dump, jump-start, and inductive switching events with AEC-Q101 qualification and DO-218AB thermal efficiency.
FAQ
What is the maximum clamping voltage of the SM8S28AHE3_A/I at its rated peak pulse current?
The SM8S28AHE3_A/I has a maximum clamping voltage (VC) of 45.4 V at its rated peak pulse current (IPPM) of 145 A under the 10/1000 μs waveform condition. This value is measured per standard test conditions in the Vishay datasheet (Document Number 88387, page 2) and defines the upper voltage limit imposed on protected circuits during worst-case transients.
Is the SM8S28AHE3_A/I suitable for bidirectional transient protection?
No, the SM8S28AHE3_A/I is unidirectional only, with anode connected to the heatsink tab and cathode as the signal terminal. It must be oriented with anode toward the power source to clamp positive transients on the 12 V rail. For bidirectional protection, a separate device such as SMBJ28CA would be required - the SM8S28AHE3_A/I does not support reverse-polarity or AC-line clamping.
What is the thermal resistance junction-to-mount (RθJM) for the SM8S28AHE3_A/I, and why does it matter?
The SM8S28AHE3_A/I has a typical RθJM of 0.35 °C/W, measured per JEDEC 51-14 using TDIM methodology. This low value reflects efficient heat transfer from the silicon junction directly into the PCB copper mount pad, enabling sustained high-power transient dissipation without external heatsinking - a critical advantage over TO-263 or SMC-packaged alternatives in space-constrained automotive modules.
Does the SM8S28AHE3_A/I meet ISO7637-2 requirements, and which test pulses are validated?
Yes, the SM8S28AHE3_A/I meets ISO7637-2:2016 requirements for automotive transient immunity, specifically validated for Pulse 5a (load dump) with 10 ms exponential waveform. The device's 6600 W peak pulse power rating and 45.4 V clamping ensure compliance when mounted per recommended footprint and copper area - no additional external components are needed to pass this test.
Why is the SM8S28AHE3_A/I marked 'Not For New Designs', and what is the recommended replacement?
The SM8S28AHE3_A/I is marked 'Not For New Designs' because Vishay has transitioned to the SM8S28AHM3 variant with updated material formulation and extended production support. While SM8S28AHE3_A/I remains available for legacy program continuity, new designs should use SM8S28AHM3 - which retains identical electrical specs, DO-218AB package, and AEC-Q101 qualification but with enhanced long-term reliability and supply chain assurance.
SM8S28AHE3_A/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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 145A
- 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
SM8S28AHE3_A/I FAQ
1.How can I place an order for SM8S28AHE3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S28AHE3_A/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 SM8S28AHE3_A/I reliable?
The price and inventory of SM8S28AHE3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S28AHE3_A/I is usually 5 days.
3.What payment methods are accepted for SM8S28AHE3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S28AHE3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S28AHE3_A/I?
SM8S28AHE3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S28AHE3_A/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 SM8S28AHE3_A/I?
For technical support, including SM8S28AHE3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S28AHE3_A/I requirements.
6.How does Aetrix verify that SM8S28AHE3_A/I is sourced from the original manufacturer or authorized distributors?
All SM8S28AHE3_A/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 SM8S28AHE3_A/I meets industry standards.
7.What is the process for return or replacement of SM8S28AHE3_A/I?
All SM8S28AHE3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S28AHE3_A/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 SM8S28AHE3_A/I part is unused and in its original packaging.
Return procedure for SM8S28AHE3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S28AHE3_A/I Tags
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