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Vishay General Semiconductor - Diodes Division SM8S28A-3HE3_A/I
- Part No.:
- SM8S28A-3HE3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
SM8S28A-3HE3_A/I.pdf
- Description:
- TVS DIODE 28VWM DO218AB
- Quantity:
- Payment:
- Shipping:
Inventory:4,113
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Product details
Overview
SM8S28A-3HE3_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 and designed for automotive load dump protection.
For engineers reviewing the SM8S28A-3HE3_A/I datasheet, SM8S28A-3HE3_A/I pinout, SM8S28A-3HE3_A/I application, or SM8S28A-3HE3_A/I equivalent, key selection considerations include its 175 °C junction rating, low leakage (<10 μA at VWM), unidirectional polarity with heatsink-as-anode configuration, and compliance with ISO7637-2 surge testing under defined conditions.
Technical Context
This TVS diode employs passivated anisotropic rectifier technology to achieve stable clamping performance across temperature. Its DO-218AB package enables high thermal conductivity via metal heatsink mounting, supporting 0.35 °C/W junction-to-mount thermal resistance and 8 W steady-state power dissipation on infinite heatsink.
The device delivers 145 A peak pulse current under 10/1000 μs waveform while maintaining ≤45.4 V clamping voltage, and exhibits +0.089 %/°C temperature coefficient of VBR - enabling predictable voltage shift over -55 °C to +175 °C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28.0 V - maximum reverse working voltage before conduction begins; defines safe operating ceiling in normal circuit conditions |
| VBR (nom) | 32.8 V - nominal breakdown voltage at 5 mA test current; triggers clamping within ±5 % tolerance band |
| VC @ IPPM | 45.4 V - clamping voltage at 145 A peak pulse; limits transient-induced stress on downstream ICs |
| PPPM (10/1000 μs) | 6600 W - peak pulse power handling; supports severe automotive load dump transients per ISO7637-2 |
| TJ max | +175 °C - maximum junction temperature; enables placement near hot engine control units without derating |
| ID @ VWM | <10 μA - reverse leakage at stand-off voltage; minimizes standby power loss in battery-sensitive systems |
| RθJM | 0.35 °C/W - junction-to-mount thermal resistance; allows direct heatsink attachment for efficient transient energy dissipation |
Pinout & Package
Package: DO-218AB - surface-mount, molded case with integral metal heatsink acting as anode terminal; meets UL 94 V-0, RoHS-compliant, AEC-Q101 qualified, matte tin-plated leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink) | Positive clamp reference and thermal path | Must be soldered to large copper area or external heatsink; serves as primary current return and thermal conduction path |
| Cathode (Lead 1) | Transient current entry point | Connected to protected line (e.g., 12 V rail); conducts surge current toward anode during overvoltage events |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated reliability for automotive electronics including engine control, body modules, and ADAS power rails |
| Junction passivation | Stable VBR drift <±5 % over lifetime under thermal cycling and humidity exposure per JESD22-A101 |
| MSL Level 1 | Unlimited floor life at ≤30 °C/60 % RH; no bake required prior to reflow (peak 245 °C) |
| ISO7637-2 compliance | Passes Pulse 5a (load dump) up to 40 V/100 ms with external impedance per specification test setup |
| Low forward voltage | ≤1.8 V at 100 A pulse - reduces conduction loss during bidirectional surge events where forward conduction occurs |
Applications
| Automotive Load Dump Protection | Engine Control Unit (ECU) Power Rail |
|---|---|
Use Scenario: 12 V vehicle electrical system subjected to alternator load dump transients up to 60 V, 400 ms duration. IC Role / Device Role / Timing Role: Unidirectional TVS clamping device placed at ECU input filter stage to limit voltage excursion below IC absolute maximum ratings. Use Value: Clamps to ≤45.4 V at 145 A, preventing damage to 40 V-rated DC-DC converters and microcontrollers while surviving ≥1000 surges per AEC-Q101 stress profile. |
Use Scenario: High-reliability power supply input for gasoline/diesel engine control modules exposed to cranking, jump-start, and battery reversal conditions. IC Role / Device Role / Timing Role: Primary overvoltage protection element mounted directly to PCB copper pour acting as heatsink. Use Value: 175 °C TJ rating ensures uninterrupted operation during under-hood temperatures exceeding 125 °C ambient, with <10 μA leakage preserving battery standby life. |
| Body Control Module (BCM) Input Protection | ADAS Camera Power Interface |
Use Scenario: 12 V supply line to BCM managing lighting, door locks, and HVAC, subject to switching noise and relay-induced spikes. IC Role / Device Role / Timing Role: Fast-response transient suppressor located upstream of input EMI filter and LDO regulators. Use Value: 10/1000 μs response time and 6600 W PPPM capability absorb repetitive 100–500 V, 1–10 A spikes without degradation over 15-year vehicle lifecycle. |
Use Scenario: Power input to 77 GHz radar or surround-view camera module requiring clean 12 V supply in proximity to high-current actuators. IC Role / Device Role / Timing Role: Secondary protection device after fuse and common-mode choke, guarding against coupled transients from adjacent harnesses. Use Value: DO-218AB package enables low-inductance layout; 0.35 °C/W RθJM ensures clamping stability during burst-mode surges without thermal runaway. |
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 VWM/VBR/VC specs; HM3 suffix indicates enhanced MSL level 1 robustness and whisker-resistant plating per JESD201 Class 2 | No change in circuit function or layout; optimized for high-volume SMT lines with extended floor life requirements | Select SM8S28AHM3 for new designs targeting longer manufacturing lead times or stricter process control standards |
| SMAJ28A | Lower PPPM (400 W vs. 6600 W), smaller SMA package (RθJA = 110 °C/W), lower IFSM (40 A vs. 700 A) | Only suitable for low-energy transients (e.g., ESD, signal-line spikes); not rated for load dump or ISO7637-2 Pulse 5a | Use SMAJ28A only in non-automotive, low-power applications where surge energy is limited to <100 mJ |
Compared with SM8S28A-3HE3_A/I, SM8S28AHM3 offers identical electrical performance with improved manufacturability, while SMAJ28A provides basic clamping in compact form but lacks the thermal mass and surge capacity needed for automotive power rail protection.
Availability
SM8S28A-3HE3_A/I is available at Aetrix Electronics and suitable for automotive load dump protection, engine control unit (ECU) power rail hardening, and body control module (BCM) input protection requiring stable component supply across long production lifecycles.
Supply support for SM8S28A-3HE3_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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and automotive-grade qualification.
The SM8SxxA family is engineered specifically for high-energy transient suppression in 12 V and 24 V automotive power systems, addressing ISO7637-2 load dump and inductive switching events with AEC-Q101 validation and DO-218AB thermal efficiency.
FAQ
What is the clamping voltage of the SM8S28A-3HE3_A/I at its rated peak pulse current?
The SM8S28A-3HE3_A/I has a maximum clamping voltage (VC) of 45.4 V when subjected to its specified peak pulse current of 145 A under the 10/1000 μs waveform. 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 circuitry during surge events. The SM8S28A-3HE3_A/I maintains this clamping performance across its full operating temperature range.
Is the SM8S28A-3HE3_A/I suitable for new automotive designs despite the "Not For New Designs" note in the datasheet?
The "Not For New Designs" notice applies to the entire SM8S10A–SM8S43A series and refers to Vishay's recommendation to adopt the newer SM8SxxAHM3 variants (e.g., SM8S28AHM3) for future projects. However, the SM8S28A-3HE3_A/I remains fully qualified, in active production, and supported for legacy design refreshes and existing platform continuity. Its AEC-Q101 qualification and ISO7637-2 compliance remain valid.
How is polarity configured on the SM8S28A-3HE3_A/I, and what does "heatsink is anode" mean for PCB layout?
The SM8S28A-3HE3_A/I is unidirectional with the metal heatsink serving as the anode terminal and Lead 1 (cathode) as the signal-side connection. For PCB layout, the heatsink must be connected to the positive rail (e.g., battery +12 V), while the cathode lead connects to the protected line. This configuration requires a dedicated thermal pad tied to the anode net - not floating - to ensure proper clamping and thermal conduction. The SM8S28A-3HE3_A/I cannot be used in reverse-biased configurations.
What is the maximum surge current the SM8S28A-3HE3_A/I can withstand, and under what waveform condition?
The SM8S28A-3HE3_A/I is rated for 145 A peak pulse current under the industry-standard 10/1000 μs double-exponential waveform (10 μs rise, 1000 μs decay to 50 %). It also supports 130 A under the longer 10/10,000 μs waveform (5200 W PPPM). These values are confirmed in the Electrical Characteristics table (page 2 of datasheet 88387) and define the device's ability to absorb energy from automotive load dump and inductive switching events without failure.
Does the SM8S28A-3HE3_A/I meet RoHS and halogen-free requirements?
Yes, the SM8S28A-3HE3_A/I carries the E3 suffix, indicating it is RoHS-compliant, halogen-free, and Pb-free per JEDEC J-STD-609. The molding compound meets UL 94 V-0 flammability rating, and terminals are matte tin plated per J-STD-002 and JESD22-B102. The HE3 designation further confirms compliance with JESD201 Class 2 whisker resistance testing - all verified in the Ordering Information section (page 3) of Vishay document 88387.
SM8S28A-3HE3_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
SM8S28A-3HE3_A/I FAQ
1.How can I place an order for SM8S28A-3HE3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S28A-3HE3_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 SM8S28A-3HE3_A/I reliable?
The price and inventory of SM8S28A-3HE3_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 SM8S28A-3HE3_A/I is usually 5 days.
3.What payment methods are accepted for SM8S28A-3HE3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S28A-3HE3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S28A-3HE3_A/I?
SM8S28A-3HE3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S28A-3HE3_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 SM8S28A-3HE3_A/I?
For technical support, including SM8S28A-3HE3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S28A-3HE3_A/I requirements.
6.How does Aetrix verify that SM8S28A-3HE3_A/I is sourced from the original manufacturer or authorized distributors?
All SM8S28A-3HE3_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 SM8S28A-3HE3_A/I meets industry standards.
7.What is the process for return or replacement of SM8S28A-3HE3_A/I?
All SM8S28A-3HE3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S28A-3HE3_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 SM8S28A-3HE3_A/I part is unused and in its original packaging.
Return procedure for SM8S28A-3HE3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S28A-3HE3_A/I Tags
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