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Vishay General Semiconductor - Diodes Division SM8S28ATHE3/I
- Part No.:
- SM8S28ATHE3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AC
- Datasheet:
-
SM8S28ATHE3/I.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO218AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,746
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Product details
Overview
SM8S28ATHE3/I from Vishay General Semiconductor is a unidirectional surface-mount PAR® Transient Voltage Suppressor designed for automotive load dump protection. It features a breakdown voltage of 31.1–34.4 V at 5 mA, 6600 W peak pulse power (10/1000 μs), 45.4 V clamping voltage at 145 A, and AEC-Q101 qualification for under-hood applications up to 175 °C junction temperature.
For engineers reviewing the SM8S28ATHE3/I datasheet, SM8S28ATHE3/I pinout, SM8S28ATHE3/I application, or SM8S28ATHE3/I equivalent, this device is selected for high-reliability 24 V automotive power rail protection where low leakage (<10 μA at 28 V), low forward voltage drop (<1.8 V at 100 A), and ISO7637-2 compliance are critical design requirements.
Technical Context
This TVS diode uses passivated anisotropic rectifier technology with junction passivation optimized for stable operation at TJ = 175 °C. Its DO-218AC package integrates a metal heatsink as the anode terminal, enabling direct thermal coupling to PCB copper for high-power transient dissipation.
The device delivers 6600 W surge capability under 10/1000 μs waveform and 5200 W under 10/10 000 μs, meeting automotive load dump requirements per ISO7637-2. It exhibits a positive temperature coefficient of VBR (0.089 %/°C) and thermal resistance RθJC = 0.90 °C/W.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 31.1 / 32.8 / 34.4 V at IT = 5 mA - defines precise clamping onset threshold for 24 V system overvoltage events |
| VWM | 28.0 V - maximum continuous reverse operating voltage before significant leakage begins |
| VC @ IPPM | 45.4 V at 145 A - clamped voltage during 6600 W transient, limiting downstream IC stress |
| PPPM (10/1000 μs) | 6600 W - peak surge power handling capacity compatible with ISO7637-2 load dump test profiles |
| IFSM | 700 A - single half-sine surge current rating (8.3 ms), supporting high-energy inductive switch-off events |
| TJ max | 175 °C - enables placement near hot engine control units without derating concerns |
| RθJC | 0.90 °C/W - low thermal resistance from junction to case supports efficient heat transfer to heatsink or PCB copper |
Pinout & Package
Package: DO-218AC - surface-mount, anode-heatsink configuration with matte tin-plated leads, MSL Level 1 (245 °C peak reflow), UL 94 V-0 molding compound, JESD201 Class 2 whisker resistant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Lead 1 | Cathode | Connected to protected circuit node; carries full transient current into the device |
| Lead 2 / Metal Heatsink | Anode | Primary thermal path and electrical return; must be soldered to large copper area for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per JEDEC standards |
| Junction passivation optimized design | Reduces parameter drift and leakage increase over lifetime in high-temperature under-hood environments |
| Meets ISO7637-2 surge specification | Guarantees performance against standardized automotive load dump transients without external filtering |
| Low leakage current | <10 μA at VWM = 28 V ensures minimal standby power loss in always-on vehicle modules |
| Unidirectional polarity only | Simplifies layout and eliminates need for reverse-bias protection in DC power rail applications |
Applications
| Automotive Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
Use Scenario: Protection of 24 V supply input against alternator load dump transients during battery disconnection. IC Role / Device Role / Timing Role: Primary clamping device on main power rail, placed upstream of DC/DC converters and microcontrollers. Use Value: Limits voltage to ≤45.4 V during 6600 W surges, preventing latch-up or permanent damage to downstream ASICs and regulators. |
Use Scenario: Safeguarding LIN bus power supply and internal MCU rails from switching noise and relay-induced spikes. IC Role / Device Role / Timing Role: Standby-mode TVS on fused 24 V feed, activated only during >28 V overvoltage events. Use Value: Maintains <10 μA leakage at 28 V, preserving battery life in parked vehicle state while responding within nanoseconds to transients. |
| Commercial Vehicle Telematics Unit | Truck HVAC Control System |
Use Scenario: Securing GPS/GSM module power input exposed to long harness runs susceptible to inductive kickback. IC Role / Device Role / Timing Role: First-line transient suppressor at board edge connector, paired with ceramic capacitor for fast response. Use Value: Withstands repeated 10/1000 μs surges up to 145 A without degradation, ensuring field reliability over 15-year vehicle lifecycle. |
Use Scenario: Protecting motor driver ICs and position sensors in high-temperature cabin environments (>105 °C ambient). IC Role / Device Role / Timing Role: Thermally anchored TVS on heatsink pad, leveraging 175 °C TJ rating for sustained operation. Use Value: Delivers stable VBR with 0.089 %/°C tempco and RθJC = 0.90 °C/W, minimizing thermal runaway risk during continuous duty cycles. |
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 VBR, VC, and PPPM; HM3 suffix indicates halogen-free, RoHS-compliant variant with identical DO-218AC package and AEC-Q101 qualification. | No functional difference; intended as direct replacement for new designs where halogen-free compliance is mandated. | Select SM8S28AHM3 for new designs requiring halogen-free materials; SM8S28ATHE3/I remains valid for legacy production and repair. |
| SMAJ28A | Lower PPPM = 400 W (10/1000 μs), VC = 45.4 V, DO-214AC package, AEC-Q101 qualified but not ISO7637-2 tested. | Not suitable for load dump; limited to lower-energy ESD and switching transients in non-critical 24 V subsystems. | Use SMAJ28A only in cost-sensitive, low-surge applications where 6600 W capability is unnecessary and space constraints favor smaller footprint. |
Compared with SM8S28ATHE3/I, SM8S28AHM3 offers identical electrical and thermal performance with halogen-free construction, while SMAJ28A provides a lower-cost, lower-power alternative unsuitable for ISO7637-2 load dump protection but viable for general-purpose 24 V rail clamping where surge energy is below 400 W.
Availability
SM8S28ATHE3/I is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, commercial vehicle telematics, and truck HVAC systems requiring stable component supply across extended production lifecycles.
Supply support for SM8S28ATHE3/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 SM8SxxAT family was engineered specifically for automotive load dump protection, combining high surge power, AEC-Q101 qualification, and DO-218AC thermal efficiency to replace older axial-leaded TVS solutions in modern ECUs and power modules.
FAQ
What is the primary function of the SM8S28ATHE3/I in automotive circuits?
The SM8S28ATHE3/I functions as a unidirectional transient voltage suppressor that clamps load dump surges on 24 V automotive power rails. It activates above 31.1 V to limit voltage to 45.4 V at 145 A, protecting downstream ICs like MCUs and DC/DC controllers. Its DO-218AC package with anode-heatsink construction enables direct thermal coupling to PCB copper, making SM8S28ATHE3/I ideal for under-hood ECU and BCM applications where sustained 175 °C operation is required.
Is the SM8S28ATHE3/I compliant with automotive reliability standards?
Yes, the SM8S28ATHE3/I is AEC-Q101 qualified and meets ISO7637-2 surge test requirements for automotive load dump protection. It is rated for operation from -55 °C to +175 °C junction temperature and passes JESD201 Class 2 whisker testing. The HE3 suffix confirms RoHS compliance and matte tin plating per J-STD-002, making SM8S28ATHE3/I suitable for production in automotive modules requiring long-term field reliability and thermal stability.
What does the "HE3" suffix indicate in SM8S28ATHE3/I?
The "HE3" suffix in SM8S28ATHE3/I denotes a RoHS-compliant, AEC-Q101-qualified version with matte tin-plated leads and JESD201 Class 2 whisker resistance. It specifies packaging in 13-inch plastic tape and reel (750 units per reel), with anode oriented toward sprocket holes. This suffix distinguishes SM8S28ATHE3/I from non-automotive variants and confirms its suitability for high-reliability automotive manufacturing processes.
How does the SM8S28ATHE3/I compare to standard SMAJ-series TVS diodes?
The SM8S28ATHE3/I delivers 6600 W peak pulse power (10/1000 μs), over 16× higher than the 400 W rating of SMAJ28A. It uses the DO-218AC package with integrated metal heatsink for superior thermal performance (RθJC = 0.90 °C/W), whereas SMAJ28A uses DO-214AC. SM8S28ATHE3/I is ISO7637-2 validated and rated for 175 °C operation, making it appropriate for engine bay deployment-unlike SMAJ28A, which is intended for lower-energy transients in less demanding locations.
Can the SM8S28ATHE3/I be used in 12 V automotive systems?
No, the SM8S28ATHE3/I is specified for 24 V nominal systems, with VWM = 28.0 V and VBR starting at 31.1 V. Using it in a 12 V system would leave insufficient margin between normal operating voltage and clamping threshold, risking premature conduction and thermal overstress. For 12 V applications, Vishay recommends SM8S12ATHE3/I or SM8S15ATHE3/I-models with lower VBR and VWM matched to that voltage class. SM8S28ATHE3/I is engineered exclusively for 24 V commercial and heavy-duty vehicle platforms.
SM8S28ATHE3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-218AC
- Series:
- PAR®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-218AC
SM8S28ATHE3/I FAQ
1.How can I place an order for SM8S28ATHE3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S28ATHE3/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 SM8S28ATHE3/I reliable?
The price and inventory of SM8S28ATHE3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S28ATHE3/I is usually 5 days.
3.What payment methods are accepted for SM8S28ATHE3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S28ATHE3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S28ATHE3/I?
SM8S28ATHE3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S28ATHE3/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 SM8S28ATHE3/I?
For technical support, including SM8S28ATHE3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S28ATHE3/I requirements.
6.How does Aetrix verify that SM8S28ATHE3/I is sourced from the original manufacturer or authorized distributors?
All SM8S28ATHE3/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 SM8S28ATHE3/I meets industry standards.
7.What is the process for return or replacement of SM8S28ATHE3/I?
All SM8S28ATHE3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S28ATHE3/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 SM8S28ATHE3/I part is unused and in its original packaging.
Return procedure for SM8S28ATHE3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S28ATHE3/I Tags
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