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Diodes Incorporated ALS5W40A
- Part No.:
- ALS5W40A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS5W40A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:5,524
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Product details
Overview
ALS5W40A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor (TVS) diode in DO-218 package, designed for automotive ECU protection against ISO 7637-2/16750-2 load dump transients. It features 40 V stand-off voltage (VWM), 44.4–49.1 V breakdown (VBR), 3600 W peak pulse power (10/1000 µs), 56 A peak pulse current, and clamps to 64.5 V at rated surge.
For engineers reviewing the ALS5W40A datasheet, ALS5W40A pinout, ALS5W40A application, or ALS5W40A equivalent, key selection criteria include its 40 V operating threshold, 64.5 V clamping performance under 10/1000 µs surge, AEC-Q101 qualification, DO-218 thermal robustness, and suitability for high-temperature (>150 °C junction) automotive load switching and lighting circuits.
Technical Context
The ALS5W40A operates as a unidirectional clamping diode with anode-connected heatsink configuration, enabling direct mounting to PCB copper for low thermal resistance. Its 3600 W peak pulse rating applies to standardized 10/1000 µs waveform, while derating to 2800 W for 10/10,000 µs exponential load dump events per ISO 16750-2.
It delivers 500 A forward surge capability (8.3 ms half-sine), maintains <2.0 V forward voltage at 100 A, and exhibits <10 µA reverse leakage at VWM and <150 µA at 175 °C - confirming stable operation across full automotive temperature range (−55 °C to +175 °C).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 40 V - Maximum continuous reverse operating voltage before clamping begins; sets system-level overvoltage trip threshold. |
| VBR (min/max) | 44.4 V / 49.1 V - Breakdown occurs within this band at 5 mA test current; ensures predictable turn-on margin above VWM. |
| VC @ IPPM | 64.5 V - Clamping voltage at 56 A peak pulse (10/1000 µs); defines maximum voltage seen by protected downstream ICs. |
| PPPM (10/1000 µs) | 3600 W - Peak transient energy absorption capacity; enables single-device protection against severe load dump events. |
| IFSM | 500 A - Forward surge rating (8.3 ms half-sine); supports high-current inrush during load switching without degradation. |
| TJ Range | −55 °C to +175 °C - Full automotive junction temperature range; validated for under-hood ECU environments. |
| Leakage @ 175 °C | 150 µA - Confirmed reverse leakage at max operating temperature; ensures minimal standby power loss in hot-cranking conditions. |
Pinout & Package
ALS5W40A uses the DO-218 plastic package with integrated heatsink terminal. The anode is connected to the metal heatsink base (exposed tab), and the cathode is marked by a bar on the molded body. This configuration enables low-thermal-resistance mounting directly to PCB copper pour.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Power return path & thermal interface | Electrically connects to system ground or chassis; primary heat dissipation path to PCB copper. |
| Cathode (Marked Lead) | Transient voltage sensing & clamping node | Connected to protected line (e.g., battery rail); conducts surge current to anode when VIN exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress-test requirements including HTGB, HTRB, TCT, and surge cycling. |
| ISO 7637-2 & ISO 16750-2 compliant | Meets Pulse 5a/b load dump immunity standards for 12 V and 24 V systems up to 100 V peak. |
| DO-218 thermal design | Low RθJC enables >2800 W dissipation at 125 °C case temperature; supports compact under-hood layouts. |
| Lead-free & halogen-free | RoHS 3 compliant (2015/863/EU); <900 ppm Br/Cl, <1000 ppm Sb; meets automotive environmental mandates. |
| MSL Level 1 | Unlimited floor life at ≤30 °C/60% RH; no bake required prior to reflow soldering at 260 °C/10 s. |
Applications
| Automotive Load Dump Protection | LED Headlamp Driver Protection |
|---|---|
Use Scenario: Protecting engine control unit (ECU) power input during alternator field-circuit disconnection. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between battery rail and ECU input filter capacitor. Use Value: Limits transient voltage to ≤64.5 V, preventing damage to 40 V-rated DC/DC converters and microcontrollers. | Use Scenario: Safeguarding constant-current LED driver ICs in adaptive front-lighting systems (AFS) during cold-crank and load dump events. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12 V supply rail upstream of buck controller and gate drivers. Use Value: Maintains <10 µA leakage at 40 V, minimizing quiescent current draw in always-on lighting modules. |
| Start-Stop System Battery Rail | Body Control Module (BCM) Power Input |
Use Scenario: Securing power management ICs in vehicles with regenerative braking and frequent engine restart cycles. IC Role / Device Role / Timing Role: High-reliability surge suppressor on main 12 V distribution bus feeding PMICs and CAN transceivers. Use Value: Withstands ≥500 surge cycles at 175 °C junction temperature, ensuring longevity in thermally stressed start-stop environments. | Use Scenario: Protecting BCM microcontroller and LIN transceiver inputs from induced transients in door module wiring harnesses. IC Role / Device Role / Timing Role: Low-leakage clamping device mounted near connector entry point on BCM PCB. Use Value: Delivers 64.5 V clamping at 56 A with <2.0 V forward drop at 100 A, preserving voltage headroom for 5 V LDOs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load dump suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A | Lower PPPM (400 W), SMA package, 64.5 V clamping at 6.4 A (not 56 A) | Not suitable for ISO 16750-2 Pulse 5; limited to low-energy transients | Select only for non-automotive, low-power 12 V systems where 3600 W capability is unnecessary. |
| SMCJ40A | Same VWM/VC, but 3000 W PPPM (10/1000 µs), SMC package, 47 A IPPM | Marginally meets ISO 16750-2; lacks AEC-Q101 and MSL Level 1 certification | Acceptable for industrial-grade 12 V systems requiring cost-sensitive TVS, but not for automotive PPAP programs. |
Compared with SMAJ40A and SMCJ40A, ALS5W40A provides 9× higher surge power handling, AEC-Q101 validation, and DO-218 thermal performance-making it the only option qualified for production automotive load dump protection where reliability, thermal margin, and compliance are mandatory.
Availability
ALS5W40A is available at Aetrix Electronics and suitable for automotive ECU protection, LED headlamp driver circuits, and start-stop system battery rails requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for ALS5W40A 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 ALS5WxxA series belongs to Diodes' AEC-Q101-qualified automotive TVS portfolio, engineered specifically for robust load dump suppression in 12 V and 24 V vehicle electrical systems with stringent thermal and surge endurance requirements.
FAQ
What is the polarity configuration of ALS5W40A, and how must it be mounted?
The ALS5W40A is unidirectional with the anode connected to the exposed metal heatsink tab and the cathode identified by a bar marking on the molded body. It must be mounted with the tab soldered to a large PCB copper area serving as both electrical ground return and thermal sink. Reverse installation will prevent clamping and cause catastrophic failure during surge events.
Does ALS5W40A meet ISO 16750-2 Pulse 5 requirements for 12 V systems?
Yes - ALS5W40A is explicitly tested and rated for ISO 16750-2 Pulse 5 (load dump) with 3600 W (10/1000 µs) and 2800 W (10/10,000 µs exponential) capability. Its 64.5 V clamping voltage at 56 A ensures compliance with the 12 V system limit of ≤70 V peak, verified across −40 °C to +125 °C ambient conditions.
How does the DO-218 package improve thermal performance versus SMC or SMA packages?
The DO-218's integral metal heatsink tab provides direct thermal conduction to PCB copper, achieving significantly lower junction-to-case thermal resistance (RθJC) than SMC/SMA. This allows sustained 2800 W dissipation at 125 °C case temperature - a 40% power advantage over SMCJ40A under identical thermal conditions - critical for under-hood ECU designs.
Is ALS5W40A compatible with lead-free reflow processes, and what is its moisture sensitivity level?
Yes - ALS5W40A has a matte tin finish and is rated MSL Level 1 per J-STD-020, meaning unlimited floor life at ≤30 °C/60% RH and full compatibility with standard lead-free reflow profiles up to 260 °C peak for 10 seconds. No pre-bake is required, simplifying manufacturing for automotive Tier 1 suppliers.
ALS5W40A 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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 56A
- Power - Peak Pulse:
- 3600W (3.6kW)
- 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
ALS5W40A FAQ
1.How can I place an order for ALS5W40A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS5W40A 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 ALS5W40A reliable?
The price and inventory of ALS5W40A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS5W40A is usually 5 days.
3.What payment methods are accepted for ALS5W40A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS5W40A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS5W40A?
ALS5W40A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS5W40A 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 ALS5W40A?
For technical support, including ALS5W40A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS5W40A requirements.
6.How does Aetrix verify that ALS5W40A is sourced from the original manufacturer or authorized distributors?
All ALS5W40A 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 ALS5W40A meets industry standards.
7.What is the process for return or replacement of ALS5W40A?
All ALS5W40A units undergo pre-shipment inspection (PSI). If there is an issue with ALS5W40A, 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 ALS5W40A part is unused and in its original packaging.
Return procedure for ALS5W40A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS5W40A Tags
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ESD9B5.0ST5G
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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