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Diodes Incorporated ALS8W28A
- Part No.:
- ALS8W28A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W28A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:6,978
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Product details
Overview
ALS8W28A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor in DO-218 package, rated for 28 V stand-off voltage (VWM), 31.1–34.4 V breakdown (VBR), 6600 W peak pulse power (10/1000 µs), and 145 A peak pulse current-designed specifically for automotive ECU-level load dump protection per ISO7637-2 and ISO16750-2.
For engineers reviewing the ALS8W28A datasheet, ALS8W28A pinout, ALS8W28A application, or ALS8W28A equivalent, key selection criteria include clamping voltage (45.4 V at IPPM), low thermal resistance, high-temperature operation up to +175°C junction, and compliance with AEC-Q101, RoHS, and halogen-free requirements.
Technical Context
This TVS diode operates as a unidirectional clamping device with anode-connected heatsink configuration, enabling robust energy absorption during automotive load dump events. Its 6600 W (10/1000 µs) rating and 45.4 V clamping voltage ensure reliable protection of downstream DC-DC converters and microcontrollers against high-energy transients.
Designed for direct integration into 12 V/24 V automotive power rails, it sustains 700 A forward surge current (8.3 ms half-sine) and exhibits <10 µA reverse leakage at 28 V and +25°C, dropping to <150 µA at +175°C-critical for long-term reliability in under-hood environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28.0 V - Maximum continuous reverse operating voltage before clamping initiates; sets system rail compatibility with 24 V automotive architectures. |
| VBR (min/max) | 31.1 V / 34.4 V - Breakdown voltage range at 5 mA test current; defines turn-on threshold consistency across temperature and unit variation. |
| VC @ IPPM | 45.4 V - Clamping voltage at 145 A peak pulse current; determines maximum stress imposed on protected ICs during worst-case load dump. |
| PPPM (10/1000 µs) | 6600 W - Peak pulse power handling capability; enables survival of ISO7637-2 Pulse 5a (load dump) waveforms without degradation. |
| IFSM | 700 A - Non-repetitive forward surge current (8.3 ms half-sine); supports high-current inrush during system startup or fault recovery. |
| TJ Range | −55°C to +175°C - Extended junction temperature range; ensures functionality in engine bay and powertrain control modules. |
| Leakage @ VWM | 10 µA @ +25°C, ≤150 µA @ +175°C - Low reverse leakage preserves battery drain budgets and signal integrity in always-on circuits. |
Pinout & Package
Package: DO-218 plastic outline with heatsink-anode polarity; molded "Green" compound (UL 94V-0), matte tin-plated terminals, moisture sensitivity level 1, weight ≈2.74 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink) | Main current path input terminal | Electrically connected to metal heatsink base; must be mounted to PCB copper pour for thermal management and low-inductance grounding. |
| Cathode (Bar-marked lead) | Clamping output terminal | Connected to protected circuit rail; reverse-biased during normal operation; conducts only during overvoltage events to clamp voltage. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive-grade qualification | AEC-Q101 qualified, manufactured in IATF 16949 certified facilities-ensures production consistency and failure rate compliance for safety-critical ECUs. |
| High-temperature stability | Stable clamping performance up to +175°C junction temperature-enables placement near heat sources without derating loss. |
| Low thermal resistance | Optimized DO-218 thermal path from junction to heatsink-anode mounting delivers efficient heat dissipation during repetitive surge events. |
| ISO7637-2 & ISO16750-2 compliance | Validated against Pulse 5a (load dump) and other automotive transient standards-reduces need for additional validation testing in Tier-1 designs. |
| Halogen- and antimony-free | <900 ppm Br, <900 ppm Cl, <1000 ppm Sb-meets global environmental regulations and OEM green material requirements. |
Applications
| Engine Control Unit Protection | Body Control Module Power Rail |
|---|---|
|
Use Scenario: Protecting MCU, CAN transceivers, and analog sensors in engine bay ECUs exposed to alternator load dump transients. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between battery rail and LDO input, absorbing >6 kW surges within microseconds. Use Value: Limits voltage seen by downstream 5 V/3.3 V regulators to ≤45.4 V, preventing latch-up or permanent damage during ISO7637-2 Pulse 5a events. |
Use Scenario: Safeguarding power inputs to BCMs managing lighting, door locks, and HVAC controls in 12 V vehicle platforms. IC Role / Device Role / Timing Role: Primary overvoltage suppression element on main 12 V supply line, coordinated with fuses and upstream filters. Use Value: Maintains system uptime by surviving repeated 10/1000 µs surges up to 145 A without parameter shift-critical for field reliability. |
| ADAS Camera Power Input | Electric Power Steering (EPS) Module |
|
Use Scenario: Securing 12 V input to image sensor SoCs and ISP processors in front/rear-view cameras subject to battery transients. IC Role / Device Role / Timing Role: Fast-response clamping device placed immediately after connector entry point, minimizing trace inductance. Use Value: Achieves sub-100 ns response time and 45.4 V clamping-prevents pixel corruption, frame loss, or sensor reset during ignition cycling. |
Use Scenario: Protecting motor driver ICs and position feedback circuits in EPS systems where load dump can induce torque anomalies. IC Role / Device Role / Timing Role: High-energy TVS integrated into main power stage PCB layout, thermally coupled to heatsink plane. Use Value: Withstands 700 A surge current and operates continuously at +150°C ambient-ensures fail-safe steering function integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A (Diodes Inc.) | Lower PPPM (400 W), SMA package, 30.8–34.0 V VBR, 45.4 V VC @ 8.8 A | Targeted at lower-energy transients (e.g., ISO16750-2 Pulse 1/2); unsuitable for full load dump duty. | Select when cost-sensitive, space-constrained designs require basic surge immunity-not for primary load dump protection. |
| SMCJ28A (Diodes Inc.) | Higher PPPM (1500 W), SMC package, 31.1–34.4 V VBR, 45.4 V VC @ 33.0 A | Valid for moderate load dump; lacks 6600 W rating and AEC-Q101 requalification for extended life at +175°C. | Use where DO-218 footprint is unavailable but higher surge margin than SMAJ is needed-verify thermal design for repeated pulses. |
Compared with SMAJ28A and SMCJ28A, ALS8W28A delivers 4.4× and 4.4× higher peak pulse power respectively, maintains stable leakage at +175°C, and is explicitly validated for automotive load dump-making it the only option among the three qualified for primary ECU protection in modern ICE and hybrid platforms.
Availability
ALS8W28A is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, ADAS camera power supplies, and electric power steering systems requiring stable component supply, AEC-Q101 compliance, and guaranteed long-term availability.
Supply support for ALS8W28A 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 and AEC-Q qualified product lines.
ALS8W28A belongs to Diodes' automotive-grade TVS portfolio engineered specifically for load dump protection in 12 V/24 V vehicle electrical systems-emphasizing high pulse power, thermal resilience, and regulatory compliance.
FAQ
What is the recommended PCB layout for optimal thermal performance of ALS8W28A?
Mount the anode (heatsink) directly to a minimum 200 mm² copper pour ≥2 oz thick, connected via ≥8 thermal vias (0.3 mm diameter) to inner ground planes. Keep cathode trace short (<5 mm) and wide (>1.5 mm) to minimize inductance. Avoid solder mask over heatsink pad to maximize thermal transfer.
Does ALS8W28A meet AEC-Q101 requirements out-of-the-box?
Yes-ALS8W28A is fully AEC-Q101 qualified per Rev. 9 of DS43856, including stress testing for temperature cycling, HTRB, HTGB, and surge robustness. No additional qualification is required for automotive production use, provided assembly follows Diodes' recommended solder profile (+260°C/10 s).
How does ALS8W28A's clamping behavior compare to bidirectional TVS devices in load dump scenarios?
ALS8W28A's unidirectional architecture provides lower clamping voltage (45.4 V) than equivalent bidirectional parts (typically >55 V), reducing stress on downstream 24 V-rated components. It also avoids false triggering from normal negative transients, making it ideal for DC-biased automotive rails.
Can ALS8W28A be used in 48 V mild-hybrid systems?
No-its 28 V stand-off and 34.4 V max breakdown are optimized for 12 V/24 V systems. For 48 V architectures, Diodes offers ALS8W58A (VWM = 58 V) with matching DO-218 packaging, 6600 W rating, and AEC-Q101 qualification-verified for 48 V load dump per ISO16750-2 Annex D.
ALS8W28A 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):
- 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-218
ALS8W28A FAQ
1.How can I place an order for ALS8W28A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W28A 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 ALS8W28A reliable?
The price and inventory of ALS8W28A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W28A is usually 5 days.
3.What payment methods are accepted for ALS8W28A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W28A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W28A?
ALS8W28A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W28A 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 ALS8W28A?
For technical support, including ALS8W28A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W28A requirements.
6.How does Aetrix verify that ALS8W28A is sourced from the original manufacturer or authorized distributors?
All ALS8W28A 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 ALS8W28A meets industry standards.
7.What is the process for return or replacement of ALS8W28A?
All ALS8W28A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W28A, 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 ALS8W28A part is unused and in its original packaging.
Return procedure for ALS8W28A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W28A Tags
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