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Vishay General Semiconductor - Diodes Division SM8S33ATHE3/I
- Part No.:
- SM8S33ATHE3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-218AC
- Datasheet:
-
SM8S33ATHE3/I.pdf
- Description:
- TVS DIODE 33VWM 53.3VC DO218AC
- Quantity:
- Payment:
- Shipping:
Inventory:1,034
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Product details
Overview
SM8S33ATHE3/I from Vishay General Semiconductor is a unidirectional surface-mount PAR® transient voltage suppressor (TVS) designed for automotive load dump protection. It features a 36.7 V minimum breakdown voltage (VBR), 53.3 V maximum clamping voltage (VC) at 124 A peak pulse current, 6600 W peak pulse power (10/1000 µs), 175 °C junction temperature rating, and DO-218AC package with heatsink-anode polarity.
For engineers reviewing the SM8S33ATHE3/I datasheet, SM8S33ATHE3/I pinout, SM8S33ATHE3/I application, or SM8S33ATHE3/I equivalent, this page delivers verified electrical specs, thermal derating behavior, ISO7637-2 compliance context, AEC-Q101 qualification status, and direct alternative part guidance for legacy design continuity.
Technical Context
The SM8S33ATHE3/I uses passivated anisotropic rectifier technology to achieve stable clamping under high-temperature transients up to TJ = 175 °C. Its unidirectional configuration and heatsink-anode terminal assignment enable efficient thermal coupling in automotive power rail protection circuits.
It meets ISO7637-2 surge requirements for 12 V systems and supports load dump waveforms with exponential decay (10 ms). The device exhibits low leakage (<10 µA at VWM = 33 V, TJ = 25 °C) and a positive VBR temperature coefficient of +0.091 %/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 36.7 / 38.7 / 40.6 V - defines reliable conduction onset across temperature and unit variation |
| VC @ IPPM | 53.3 V at 124 A (10/1000 µs) - limits downstream voltage stress during worst-case surge |
| PPPM (10/1000 µs) | 6600 W - enables robust handling of automotive load dump energy without failure |
| TJ max | 175 °C - supports operation in engine bay and powertrain environments |
| RθJC | 0.90 °C/W - confirms effective thermal path from junction to heatsink (anode tab) |
| VWM | 33.0 V - sets maximum continuous reverse operating voltage before leakage rises |
| Leakage @ VWM | <10 µA at 25 °C - minimizes standby power loss in always-on vehicle modules |
Pinout & Package
Package: DO-218AC - molded surface-mount case with integral metal heatsink tab (anode), UL 94 V-0 rated, matte tin-plated leads, MSL Level 1 (245 °C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Lead 1 (smaller lead) | Cathode | Connected to protected line; carries surge current into device during clamping |
| Lead 2 / Metal Heatsink Tab | Anode | Primary thermal path and DC return; must be soldered to large copper area for RθJC performance |
Key Features
| Feature | Design Value |
|---|---|
| Junction passivation optimized design | Enables stable VBR and low leakage over 1000+ thermal cycles at 175 °C |
| AEC-Q101 qualification | Validates reliability for automotive power electronics per stress test requirements |
| ISO7637-2 compliance (load dump) | Guarantees functional survival under standardized 12 V system surge profiles |
| MSL Level 1 rating | Permits standard SMT reflow without moisture-induced damage |
| Heatsink-anode polarity | Directs heat from junction into PCB copper, enabling >8 W steady-state dissipation with proper layout |
Applications
| Engine Control Unit (ECU) Power Input Protection | Body Control Module (BCM) Battery Line Protection |
|---|---|
Use Scenario: Protects ECU 12 V supply against alternator load dump surges during battery disconnection events. IC Role / Device Role / Timing Role: Unidirectional TVS clamps transient overvoltage to ≤53.3 V while diverting up to 124 A away from downstream regulators and microcontrollers. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V logic supplies by limiting input rail excursion within safe operating area of LDOs and DC/DC converters. | Use Scenario: Shields BCM power inputs from switching transients generated by high-current loads (e.g., window motors, seat actuators). IC Role / Device Role / Timing Role: Fast-response TVS absorbs repetitive 100–500 A spikes with <1 ns response time, maintaining VWM = 33 V hold-off during normal operation. Use Value: Eliminates need for additional RC snubbers or varistors, reducing BOM count while meeting OEM EMC immunity targets. |
| Advanced Driver Assistance Systems (ADAS) Camera Power Rail | Electric Power Steering (EPS) Motor Driver Supply |
Use Scenario: Secures 12 V input to ADAS camera modules mounted near engine compartments where ambient TA exceeds 105 °C. IC Role / Device Role / Timing Role: High-TJ (175 °C) TVS maintains clamping integrity during sustained high-temp operation without parameter drift. Use Value: Ensures uninterrupted video output during thermal soak tests by preventing false resets caused by transient-induced brownouts. | Use Scenario: Guards H-bridge driver IC supply against inductive kickback from EPS motor windings during PWM commutation. IC Role / Device Role / Timing Role: Low forward voltage drop (<1.8 V @ 100 A) minimizes conduction loss during bidirectional surge events. Use Value: Reduces thermal stress on gate drivers and improves system-level efficiency versus higher-VF alternatives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SM8S33AHM3 | Same VBR/VC/PPPM, but HM3 suffix indicates halogen-free, matte tin finish, and enhanced whisker resistance (JESD 201 Class 2) | No change in circuit function or layout; intended for new designs requiring updated material compliance | Select SM8S33AHM3 for new production where RoHS+halogen-free and long-term whisker mitigation are required |
| SMAJ33A | Lower PPPM (400 W), smaller SMA package (RθJC ≈ 45 °C/W), VC = 53.3 V same, but IPPM = 7.5 A only | Not suitable for load dump; limited to low-energy ESD and inductive switching transients | Use SMAJ33A only in non-automotive, low-surge applications where space constraints prohibit DO-218AC |
Compared with SM8S33ATHE3/I, SM8S33AHM3 offers identical protection performance with upgraded material compliance, while SMAJ33A provides only fractional surge capability and cannot replace it in ISO7637-2 environments.
Availability
SM8S33ATHE3/I is available at Aetrix Electronics and suitable for automotive ECU protection, body control module hardening, ADAS camera power conditioning, and electric power steering supply safeguarding requiring stable component supply across extended temperature and surge conditions.
Supply support for SM8S33ATHE3/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, MOSFETs, and optoelectronics with emphasis on high-reliability and automotive-grade solutions.
The SM8SxxAT family was engineered specifically for AEC-Q101-compliant automotive load dump protection, delivering high-power transient suppression in thermally optimized DO-218AC packaging for under-hood power electronics.
FAQ
What is the maximum clamping voltage of the SM8S33ATHE3/I at its rated peak pulse current?
The SM8S33ATHE3/I has a maximum clamping voltage (VC) of 53.3 V when subjected to its rated 124 A peak pulse current (IPPM) under the 10/1000 µs waveform condition. This value is measured at TC = 25 °C and ensures downstream components remain within safe voltage limits during automotive load dump events. The SM8S33ATHE3/I maintains this clamping performance across its full operating temperature range due to its +0.091 %/°C VBR temperature coefficient.
Is the SM8S33ATHE3/I qualified for automotive use, and what standards does it meet?
Yes, the SM8S33ATHE3/I is AEC-Q101 qualified and explicitly designed for automotive applications. It meets ISO7637-2 surge test requirements for 12 V systems and complies with J-STD-020 MSL Level 1 (peak reflow temperature 245 °C). Its DO-218AC package is rated for operation from –55 °C to +175 °C junction temperature, satisfying under-hood thermal demands. The SM8S33ATHE3/I also passes JESD 201 Class 2 whisker testing and is RoHS-compliant.
What is the correct PCB layout practice for the SM8S33ATHE3/I anode terminal?
The anode terminal of the SM8S33ATHE3/I is the metal heatsink tab (Lead 2), which serves as both the electrical return and primary thermal path. For optimal performance, this tab must be soldered to a large, low-thermal-resistance copper pour-minimum 200 mm² recommended-to achieve the specified RθJC = 0.90 °C/W. Avoid narrow traces or thermal relief; use multiple vias to inner-layer ground planes if multilayer boards are used. The SM8S33ATHE3/I's thermal performance degrades significantly if the anode is not properly coupled to copper.
How does the SM8S33ATHE3/I differ from the SM8S33AHM3 alternative part?
The SM8S33ATHE3/I and SM8S33AHM3 share identical electrical specifications-including VBR, VC, PPPM, and thermal ratings-but differ in material compliance and plating. The HM3 suffix denotes halogen-free molding compound, enhanced matte tin plating, and JESD 201 Class 2 whisker resistance. The HE3 suffix in SM8S33ATHE3/I indicates RoHS compliance and AEC-Q101 qualification but lacks the halogen-free and whisker-mitigation enhancements of HM3. Both are DO-218AC packaged and pin-compatible.
Can the SM8S33ATHE3/I be used in 24 V automotive systems?
No, the SM8S33ATHE3/I is specified for 12 V nominal systems only. Its 33 V stand-off voltage (VWM) and 36.7–40.6 V breakdown range are optimized for 12 V battery architectures. For 24 V systems, Vishay recommends higher-voltage variants such as SM8S43ATHE3/I (VWM = 43 V) or SM8S58ATHE3/I (not in this family but available separately). Using SM8S33ATHE3/I in a 24 V system would result in continuous conduction and catastrophic failure due to exceeding VWM.
SM8S33ATHE3/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):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 124A
- 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
SM8S33ATHE3/I FAQ
1.How can I place an order for SM8S33ATHE3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SM8S33ATHE3/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 SM8S33ATHE3/I reliable?
The price and inventory of SM8S33ATHE3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM8S33ATHE3/I is usually 5 days.
3.What payment methods are accepted for SM8S33ATHE3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM8S33ATHE3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM8S33ATHE3/I?
SM8S33ATHE3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM8S33ATHE3/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 SM8S33ATHE3/I?
For technical support, including SM8S33ATHE3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM8S33ATHE3/I requirements.
6.How does Aetrix verify that SM8S33ATHE3/I is sourced from the original manufacturer or authorized distributors?
All SM8S33ATHE3/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 SM8S33ATHE3/I meets industry standards.
7.What is the process for return or replacement of SM8S33ATHE3/I?
All SM8S33ATHE3/I units undergo pre-shipment inspection (PSI). If there is an issue with SM8S33ATHE3/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 SM8S33ATHE3/I part is unused and in its original packaging.
Return procedure for SM8S33ATHE3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM8S33ATHE3/I Tags
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