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Diodes Incorporated ALS8W12A
- Part No.:
- ALS8W12A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W12A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:7,200
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Product details
Overview
ALS8W12A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor in DO-218 package, designed for automotive ECU protection against ISO7637-2/ISO16750-2 load dump surges. It features 13.3–14.7 V breakdown voltage (VBR), 12.0 V stand-off voltage (VWM), 6600 W peak pulse power (10/1000 µs), 332 A peak pulse current, and clamps to ≤19.9 V at rated surge - deployed as a primary clamping diode in 12 V automotive power rails.
For engineers reviewing the ALS8W12A datasheet, ALS8W12A pinout, ALS8W12A application, or ALS8W12A equivalent, key selection criteria include its 12 V system compatibility, DO-218 thermal performance (TJ up to +175°C), low 1.8 V forward voltage at 100 A, AEC-Q101 qualification readiness, and compliance with automotive surge immunity standards.
Technical Context
The ALS8W12A operates as a unidirectional avalanche diode optimized for high-energy transient suppression in 12 V automotive electrical systems. Its DO-218 package provides low thermal resistance and heatsink-anode polarity, enabling direct mounting to metal chassis for efficient heat dissipation during 10 ms exponential load dump events.
It meets ISO7637-2 Pulse 5a/b and ISO16750-2 load dump test conditions with verified clamping behavior up to 6600 W (10/1000 µs) and 5200 W (10/10000 µs), while maintaining <10 µA reverse leakage at VWM and stable operation from −55°C to +175°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/max) | 13.3 V / 14.7 V - defines guaranteed avalanche onset range under 5 mA test current; ensures robust turn-on before downstream IC damage. |
| VWM | 12.0 V - maximum continuous reverse operating voltage; matches nominal 12 V automotive battery rail with safety margin. |
| VC @ IPPM | ≤19.9 V - clamping voltage at 332 A peak pulse; limits protected circuit stress during worst-case load dump. |
| PPPM (10/1000 µs) | 6600 W - peak surge power handling; enables single-device protection for high-power ECUs without parallel staging. |
| IFSM | 700 A - 8.3 ms half-sine surge current rating; supports repeated high-current transients without bond wire failure. |
| TJ Range | −55°C to +175°C - extended junction temperature capability; sustains reliability in under-hood environments near engines or power modules. |
Pinout & Package
Package: DO-218 - molded plastic case with heatsink-anode polarity; anode terminal forms integral metal tab for direct thermal mounting; cathode marked by bar; RoHS-compliant matte tin plating; moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Power Input / Thermal Path | Electrically connected to anode; serves as primary thermal interface to PCB copper pour or chassis; must be soldered to ≥200 mm² copper area for rated power derating. |
| Cathode (Lead) | Clamped Output / Surge Return | Connected to protected 12 V rail ground reference; conducts surge current from battery line to ground during avalanche conduction. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive-grade surge immunity | Validated per ISO7637-2 Pulse 5 and ISO16750-2 load dump protocols - eliminates need for external test validation in Tier 1 designs. |
| High-temperature stability | Rated for continuous operation up to +175°C junction temperature - enables placement near power converters or engine control units without thermal derating. |
| Low forward voltage | Max 1.8 V at 100 A (8.3 ms sine wave) - minimizes conduction loss and self-heating during sustained overvoltage events. |
| Green compound packaging | Halogen- and antimony-free molding compound (UL 94V-0) - satisfies OEM environmental requirements without compromising flame resistance or mechanical integrity. |
Applications
| Engine Control Unit (ECU) Protection | Body Control Module (BCM) Power Rail |
|---|---|
Use Scenario: Protects microcontroller, CAN transceivers, and sensor interfaces in gasoline/diesel engine ECUs from alternator load dump transients during battery disconnect. IC Role / Device Role / Timing Role: Primary clamping diode placed between battery input and main DC/DC converter input stage. Use Value: Limits rail voltage to ≤19.9 V during 6600 W surges, preventing latch-up or gate oxide damage in 3.3 V/5 V logic and analog front-ends. | Use Scenario: Shields BCM power distribution network from load dump events induced by high-current loads (e.g., headlamps, HVAC blower) switching on/off. IC Role / Device Role / Timing Role: Unidirectional TVS mounted directly at BCM main power entry point, upstream of fuse and pre-regulator. Use Value: Maintains VWM = 12.0 V compatibility with 12 V nominal architecture while surviving repeated 10 ms exponential surges per ISO16750-2. |
| ADAS Camera Power Supply | Electric Power Steering (EPS) Module |
Use Scenario: Safeguards image sensor, ISP, and serializer ICs in rear-view or surround-view cameras exposed to vehicle-level transients. IC Role / Device Role / Timing Role: Standoff-rated clamping device on 12 V camera module input, co-located with input filter capacitor. Use Value: Delivers <10 µA leakage at 12 V to preserve low-quiescent current design; clamps within 100 ns to protect fast-switching MIPI CSI-2 interfaces. | Use Scenario: Protects motor driver ICs, position sensors, and MCU in EPS systems where high inductive kickback occurs during assist torque modulation. IC Role / Device Role / Timing Role: High-current transient suppressor integrated into EPS main power board, thermally coupled to aluminum housing. Use Value: Handles 700 A non-repetitive surge (8.3 ms) without degradation, ensuring functional safety continuity during steering assist transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load dump suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A | Lower PPPM (400 W), SMA package, VC = 19.9 V at 21.2 A - insufficient for ISO7637-2 Pulse 5. | Rated for consumer/industrial use only; not qualified for automotive under-hood temperature or surge profiles. | Select only for non-automotive 12 V systems with sub-1 kA surge exposure. |
| SMCJ12A | PPPM = 1500 W, SMC package, VC = 19.9 V at 75 A - lacks thermal mass for sustained 10 ms load dump. | Meets ISO7637-2 Pulse 5a but fails Pulse 5b due to lower energy rating; limited to lower-power ECUs. | Acceptable for cost-sensitive body electronics with derated surge margin; not recommended for powertrain or ADAS. |
Compared with SMAJ12A and SMCJ12A, ALS8W12A delivers 4.4× and 4.4× higher peak pulse power respectively, enables direct heatsink mounting for +175°C operation, and is engineered specifically for full compliance with automotive load dump standards - making it the only option among the three qualified for high-reliability powertrain and ADAS applications.
Availability
ALS8W12A is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, ADAS camera power supplies, and electric power steering modules requiring stable component supply across long production lifecycles.
Supply support for ALS8W12A 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 facilities.
The ALS8WxxA series belongs to Diodes' automotive-grade transient voltage suppressor product line, developed specifically to meet stringent ISO7637-2 and ISO16750-2 load dump requirements in 12 V and 24 V vehicle electrical architectures.
FAQ
What is the polarity configuration of ALS8W12A?
The ALS8W12A is a unidirectional TVS diode with anode connected to the heatsink tab and cathode on the lead. This configuration requires the anode to be tied to the protected power rail (e.g., battery+) and cathode to system ground - reverse connection will prevent clamping function and may cause catastrophic failure during surge events.
Does ALS8W12A require external heat sinking beyond PCB copper?
Yes - the DO-218 package relies on the anode tab as the primary thermal path. For full 6600 W rating, the tab must be soldered to ≥200 mm² of 2 oz copper on inner or outer PCB layers, or directly mounted to a metal chassis. Without this, derating to ≤3000 W is required above +100°C ambient per Figure 1 in DS43856.
Is ALS8W12A AEC-Q101 qualified?
ALS8W12A is designed and manufactured in IATF 16949-certified facilities and meets all electrical, thermal, and mechanical requirements of AEC-Q101. While the datasheet states "PPAP capable" and "AEC-Q101 qualified upon request", formal qualification documentation is provided per customer PPAP submission - not pre-certified out-of-box.
Can ALS8W12A be used in 24 V systems?
No - ALS8W12A is specified for 12 V nominal systems with VWM = 12.0 V and VBR = 13.3–14.7 V. For 24 V applications, Diodes offers ALS8W24A (VWM = 24.0 V, VBR = 26.7–29.5 V), which shares identical DO-218 package, thermal performance, and surge ratings.
ALS8W12A 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):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 332A
- 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
ALS8W12A FAQ
1.How can I place an order for ALS8W12A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W12A 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 ALS8W12A reliable?
The price and inventory of ALS8W12A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W12A is usually 5 days.
3.What payment methods are accepted for ALS8W12A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W12A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W12A?
ALS8W12A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W12A 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 ALS8W12A?
For technical support, including ALS8W12A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W12A requirements.
6.How does Aetrix verify that ALS8W12A is sourced from the original manufacturer or authorized distributors?
All ALS8W12A 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 ALS8W12A meets industry standards.
7.What is the process for return or replacement of ALS8W12A?
All ALS8W12A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W12A, 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 ALS8W12A part is unused and in its original packaging.
Return procedure for ALS8W12A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W12A Tags
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