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Diodes Incorporated ALS8W18A
- Part No.:
- ALS8W18A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W18A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:3,055
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Product details
Overview
ALS8W18A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor in DO-218 package, rated for 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown (VBR), 6600 W peak pulse power (10/1000 μs), and 226 A peak pulse current, designed for automotive ECU protection against ISO 7637-2 load dump transients.
For engineers reviewing the ALS8W18A datasheet, ALS8W18A pinout, ALS8W18A application, or ALS8W18A equivalent, this device delivers high-temperature-stable clamping with low thermal resistance, low forward voltage (≤1.8 V @ 100 A), and AEC-Q101 qualification - critical for under-hood power rail protection in 12 V automotive systems.
Technical Context
The ALS8W18A operates as a unidirectional avalanche diode optimized for load dump suppression in automotive 12 V battery systems. Its 18 V stand-off voltage ensures stable blocking during normal operation, while its 29.2 V maximum clamping voltage at 226 A (10/1000 μs) limits downstream voltage stress.
It meets ISO 7637-2 and ISO 16750-2 surge test requirements across defined test conditions, supports continuous operation up to +175 °C junction temperature, and features low reverse leakage (≤10 μA at VWM, ≤150 μA at TJ = +175 °C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18.0 V - Stable reverse blocking voltage during nominal 12 V system operation |
| VBR (min/max) | 20.0–22.1 V - Confirmed avalanche onset range at 5 mA test current |
| VC (at IPPM) | 29.2 V - Maximum clamped voltage at 226 A peak pulse, limiting IC stress |
| PPPM (10/1000 μs) | 6600 W - Sustains high-energy load dump surges without failure |
| IFSM | 700 A - Withstands 8.3 ms half-sine surge without bond wire fusing |
| TJ Range | −55 to +175 °C - Enables placement near hot engine compartments |
| VF (max) | 1.8 V @ 100 A - Minimizes conduction loss and self-heating during surge |
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.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink) | Current entry point during clamping | Electrically connected to metal heatsink tab - must be mounted to PCB copper pour for thermal management |
| Cathode (Bar-marked lead) | Current exit point during clamping | Marked with cathode band; connects to protected circuit rail (e.g., ECU VDD input) |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature stability | Junction operation up to +175 °C enables under-hood deployment without derating |
| Low thermal resistance | DO-218 package with heatsink-anode reduces θJC, improving surge energy dissipation |
| Automotive qualification | AEC-Q101 qualified and manufactured in IATF 16949 certified facilities |
| Low forward voltage | ≤1.8 V at 100 A minimizes power loss and localized heating during surge conduction |
| RoHS & Halogen-free | Compliant with RoHS 3 (2015/863/EU); <900 ppm Br/Cl, <1000 ppm Sb - meets automotive environmental mandates |
Applications
| Engine Control Unit (ECU) Protection | Body Control Module (BCM) Power Rail |
|---|---|
Use Scenario: Protecting microcontroller power inputs from 12 V battery line transients during alternator load dump events. IC Role / Device Role / Timing Role: Unidirectional TVS clamping diode placed between battery rail and LDO/regulator input. Use Value: Limits voltage to ≤29.2 V at 226 A, preventing overvoltage damage to 3.3 V/5 V logic supplies and analog front-ends. | Use Scenario: Safeguarding BCM power distribution networks handling lighting, window, and door actuator loads. IC Role / Device Role / Timing Role: Primary load dump suppressor on main 12 V input before DC-DC converters and power switches. Use Value: Absorbs 6600 W surge energy without degradation, maintaining system uptime during repeated ignition cycles. |
| Advanced Driver Assistance Systems (ADAS) Camera Module | Electric Power Steering (EPS) Control Unit |
Use Scenario: Shielding image sensor and ISP power rails in rear-view or surround-view cameras exposed to vehicle-level transients. IC Role / Device Role / Timing Role: Front-end transient suppressor on camera module's 12 V input, upstream of buck converters. Use Value: Clamps within 10 ns response time, preserving signal integrity and preventing reset or latch-up in vision processors. | Use Scenario: Protecting motor driver ICs and position sensors in EPS systems subject to high-current switching noise and load dump. IC Role / Device Role / Timing Role: High-current TVS on EPS H-bridge supply rail, co-located with bulk capacitance. Use Value: Withstands 700 A non-repetitive surge (IFSM), ensuring reliability during steering assist activation under fault conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load dump suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Lower PPPM (400 W), DO-214AC package, 28.2 V VC at 12.9 A | Not suitable for full ISO 7637-2 load dump; limited to lower-energy transients | Select only for non-automotive or low-risk 12 V subsystems with <500 W surge exposure |
| SMCJ18A | PPPM = 1500 W, DO-214AB package, 29.2 V VC at 51.7 A | Lacks AEC-Q101 qualification and high-temp capability (TJ max = +150 °C) | Acceptable for industrial control where automotive qualification and +175 °C operation are not required |
Compared with SMAJ18A and SMCJ18A, ALS8W18A provides 4.4× and 4.4× higher peak pulse power respectively, full AEC-Q101 compliance, and extended +175 °C operation - making it the only option qualified for primary load dump protection in modern automotive ECUs.
Availability
ALS8W18A is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, and ADAS camera power systems requiring stable component supply with full AEC-Q101 traceability and IATF 16949 manufacturing assurance.
Supply support for ALS8W18A 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.
The ALS8WxxA series belongs to Diodes' automotive-grade transient voltage suppressor product line, engineered specifically for robust load dump protection in 12 V vehicle electrical architectures per ISO 7637-2.
FAQ
What is the polarity configuration of ALS8W18A?
The ALS8W18A is a unidirectional TVS diode with anode connected to the heatsink tab and cathode marked by a band on the lead. During normal operation, it blocks reverse voltage up to 18 V; during a positive-going load dump transient, it conducts from anode to cathode to clamp the rail. Mounting the heatsink tab to a large copper area is mandatory for thermal performance.
Does ALS8W18A meet AEC-Q101 stress testing requirements?
Yes - ALS8W18A is AEC-Q101 qualified and manufactured in IATF 16949 certified facilities. It passes stress tests including high-temperature operating life (HTOL), temperature cycling, and surge robustness per AEC-Q101 Rev D. Full qualification documentation is available upon request through Diodes' automotive support team.
How does ALS8W18A compare to standard SMA/SMC TVS diodes in surge handling?
ALS8W18A delivers 6600 W peak pulse power (10/1000 μs), versus 400 W for SMAJ18A and 1500 W for SMCJ18A. Its DO-218 package features a heatsink-anode structure that lowers thermal impedance, enabling sustained energy absorption without thermal runaway - a key differentiator for automotive load dump compliance.
Can ALS8W18A be used in 24 V commercial vehicle systems?
No - ALS8W18A is specified for 12 V automotive systems with 18 V stand-off. For 24 V systems, Diodes offers ALS8W36A (36 V VWM) and ALS8W43A (43 V VWM) in the same DO-218 package and qualification grade. Using ALS8W18A on a 24 V rail would cause continuous conduction and catastrophic failure due to exceeding VWM.
ALS8W18A 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 226A
- 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
ALS8W18A FAQ
1.How can I place an order for ALS8W18A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W18A 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 ALS8W18A reliable?
The price and inventory of ALS8W18A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W18A is usually 5 days.
3.What payment methods are accepted for ALS8W18A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W18A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W18A?
ALS8W18A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W18A 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 ALS8W18A?
For technical support, including ALS8W18A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W18A requirements.
6.How does Aetrix verify that ALS8W18A is sourced from the original manufacturer or authorized distributors?
All ALS8W18A 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 ALS8W18A meets industry standards.
7.What is the process for return or replacement of ALS8W18A?
All ALS8W18A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W18A, 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 ALS8W18A part is unused and in its original packaging.
Return procedure for ALS8W18A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W18A Tags
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