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Diodes Incorporated ALS8W33A
- Part No.:
- ALS8W33A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W33A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:6,148
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Product details
Overview
ALS8W33A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor in DO-218 package, rated for 33 V stand-off voltage (VWM), 36.7–40.6 V breakdown (VBR), 6600 W peak pulse power (10/1000 μs), and 124 A peak pulse current - designed specifically for automotive ECU protection against ISO 7637-2 and ISO 16750-2 load dump transients.
For engineers reviewing the ALS8W33A datasheet, ALS8W33A pinout, ALS8W33A application, or ALS8W33A equivalent, key selection criteria include clamping voltage (53.3 V at IPPM), thermal stability up to +175°C junction temperature, low forward voltage drop (≤1.8 V at 100 A), unidirectional polarity with heatsink-anode configuration, and compliance with AEC-Q101 and RoHS/Green requirements.
Technical Context
The ALS8W33A operates as a high-energy, unidirectional TVS diode optimized for automotive load dump suppression. Its silicon avalanche structure delivers precise 33 V stand-off with tight 36.7–40.6 V VBR tolerance at 5 mA, enabling reliable overvoltage clamping before downstream electronics are stressed.
It sustains 700 A non-repetitive forward surge (8.3 ms half-sine) and maintains ≤10 μA reverse leakage at VWM up to +175°C, supporting operation in under-hood environments. The DO-218 package provides low thermal resistance and high-temperature soldering capability (260°C/10 s), critical for reflow compatibility and long-term reliability in automotive power rails.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 33 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR (min/max) | 36.7 V / 40.6 V at 5 mA - defines precise avalanche onset window for predictable clamping threshold |
| VC @ IPPM | 53.3 V at 124 A (10/1000 μs) - actual clamped voltage seen by protected circuit during worst-case surge |
| PPPM | 6600 W (10/1000 μs) - energy-handling capacity sufficient for ISO 7637-2 Pulse 5a load dump events |
| IFSM | 700 A (8.3 ms half-sine) - surge current rating confirming robustness against repetitive inductive turn-off spikes |
| TJ Range | −55°C to +175°C - validated operation across full automotive under-hood temperature envelope |
| Polarity | Unidirectional - blocks reverse voltage only; anode connected to heatsink/chassis ground path |
Pinout & Package
Package: DO-218 - thermally enhanced surface-mount outline with integral heatsink tab (anode), matte tin-plated terminals, UL 94V-0 molding compound, and moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Current return path & thermal interface | Electrically and thermally connected to PCB copper pour; must be soldered to large thermal pad for 6600 W dissipation |
| Cathode (Bar-marked Lead) | Transient voltage clamping node | Connected to protected line (e.g., 12 V battery rail); conducts surge current to anode/heatsink during overvoltage event |
Key Features
| Feature | Design Value |
|---|---|
| Automotive-grade qualification | AEC-Q101 qualified, manufactured in IATF 16949 certified facilities - ensures production consistency for safety-critical ECUs |
| High-temperature stability | ≤10 μA reverse leakage at VWM up to +175°C - prevents false triggering or thermal runaway in hot under-hood locations |
| Low thermal resistance | DO-218 package enables efficient heat transfer to PCB - essential for sustaining 6600 W pulses without junction overheating |
| ISO 7637-2 / 16750-2 compliance | Validated for Load Dump Pulse 5a (including extended duration tests) - meets OEM-level ECU protection requirements |
| Green & RoHS-compliant construction | Halogen- and antimony-free molding compound (<900 ppm Br/Cl, <1000 ppm Sb) - satisfies global environmental mandates |
Applications
| Engine Control Unit (ECU) Protection | Body Control Module (BCM) Power Rail |
|---|---|
Use Scenario: Protects microcontroller, CAN transceivers, and sensors in gasoline/diesel engine ECUs from 12 V battery rail load dump surges during alternator field coil de-energization. IC Role / Device Role / Timing Role: Unidirectional clamping diode placed between battery input and primary DC/DC converter input stage. Use Value: Limits transient voltage to ≤53.3 V, preventing damage to 36 V-rated input stages while handling 6600 W peak energy per ISO 7637-2. | Use Scenario: Shields BCM power management ICs and LIN transceivers from load dump events induced by headlight or HVAC motor switching. IC Role / Device Role / Timing Role: Primary overvoltage clamp on fused 12 V supply rail upstream of LDOs and system supervisors. Use Value: Maintains ≤10 μA leakage at 33 V even at +125°C ambient, ensuring no parasitic drain on vehicle battery during sleep mode. |
| ADAS Camera Power Input | Electric Power Steering (EPS) Module |
Use Scenario: Safeguards image sensor SoCs and serializer ICs in rear-view or surround-view cameras exposed to battery rail transients during vehicle start-stop cycles. IC Role / Device Role / Timing Role: First-line transient suppressor on camera module's main 12 V input, before DC/DC conversion to 3.3 V/1.8 V rails. Use Value: Clamps within 10 ns to ≤53.3 V, preserving signal integrity of high-speed MIPI CSI-2 links during fast-rising load dump edges. | Use Scenario: Protects motor gate drivers and position sensor interfaces in EPS systems subjected to repeated load dump stress during steering assist activation. IC Role / Device Role / Timing Role: High-current TVS mounted directly at EPS module connector entry point, bonded to chassis ground via heatsink tab. Use Value: Withstands 700 A 8.3 ms surge without degradation, ensuring functional safety continuity across 10,000+ steering cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional load dump suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33A | Lower PPPM (400 W), DO-214AC package, 53.3 V VC but only 12.3 A IPPM | Not suitable for ISO 7637-2 Pulse 5a; limited to low-energy transients in non-automotive or auxiliary circuits | Select only for cost-sensitive, non-automotive 12 V systems where surge energy ≤400 W |
| SMCJ33A | Higher PPPM (1500 W), DO-214AB package, 53.3 V VC at 28.3 A IPPM | Meets basic ISO 7637-2 but lacks AEC-Q101 qualification and +175°C operation | Acceptable for industrial or commercial automotive-adjacent designs lacking full AEC compliance requirements |
Compared with SMAJ33A and SMCJ33A, ALS8W33A uniquely delivers 6600 W surge capacity, AEC-Q101 qualification, and guaranteed operation to +175°C - making it the only option qualified for front-line load dump protection in modern engine ECUs and EPS modules.
Availability
ALS8W33A is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, ADAS camera power inputs, and electric power steering modules requiring stable component supply with full AEC-Q101 traceability and green compliance.
Supply support for ALS8W33A 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for automotive, industrial, and computing markets with IATF 16949-certified manufacturing.
The ALS8WxxA series belongs to Diodes' automotive-grade TVS portfolio, engineered specifically to meet stringent ISO 7637-2 load dump immunity requirements in engine, chassis, and ADAS electronic control units.
FAQ
What is the maximum clamping voltage of ALS8W33A under standard test conditions?
The maximum clamping voltage (VC) is 53.3 V when subjected to a 10/1000 μs waveform at 124 A peak pulse current, measured per IEC 61000-4-5 methodology. This value is guaranteed across the full −55°C to +175°C junction temperature range and reflects worst-case voltage seen by downstream circuitry during load dump events.
Is ALS8W33A qualified to AEC-Q101, and what does that entail for automotive use?
Yes, ALS8W33A is AEC-Q101 qualified. This certification requires rigorous stress testing including HTGB, HTRB, TCT, and surge endurance under temperature extremes, validating its suitability for automotive powertrain and chassis applications. It also confirms production in IATF 16949-certified facilities with full PPAP documentation support.
How should the heatsink tab (anode) be mounted on the PCB for optimal thermal performance?
The anode tab must be soldered to a minimum 200 mm² copper area (2 oz. thickness) with ≥4 thermal vias (0.3 mm diameter, spaced ≤2 mm apart) connecting to inner ground planes. This layout achieves thermal resistance ≤1.2°C/W, enabling safe dissipation of 6600 W pulses without exceeding +175°C junction temperature during ISO 7637-2 testing.
Does ALS8W33A meet both ISO 7637-2 and ISO 16750-2 standards, and which test pulses are covered?
Yes - ALS8W33A is validated for ISO 7637-2 Pulse 5a (load dump) and ISO 16750-2 Section 4.7 (supply voltage fluctuations), covering 12 V system transients up to 65 V peak with durations up to 400 ms. Test reports confirm clamping performance and survivability under both standards using manufacturer-defined waveforms and fixture configurations.
ALS8W33A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-218AB
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- 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-218
ALS8W33A FAQ
1.How can I place an order for ALS8W33A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W33A 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 ALS8W33A reliable?
The price and inventory of ALS8W33A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W33A is usually 5 days.
3.What payment methods are accepted for ALS8W33A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W33A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W33A?
ALS8W33A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W33A 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 ALS8W33A?
For technical support, including ALS8W33A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W33A requirements.
6.How does Aetrix verify that ALS8W33A is sourced from the original manufacturer or authorized distributors?
All ALS8W33A 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 ALS8W33A meets industry standards.
7.What is the process for return or replacement of ALS8W33A?
All ALS8W33A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W33A, 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 ALS8W33A part is unused and in its original packaging.
Return procedure for ALS8W33A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W33A Tags
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