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Diodes Incorporated ALS8W43A
- Part No.:
- ALS8W43A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W43A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:8,049
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Product details
Overview
ALS8W43A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor (TVS) designed for automotive ECU protection against ISO 7637-2 and ISO 16750-2 load dump surges. It features a 43 V stand-off voltage (VWM), 47.8–52.8 V breakdown range (VBR), 6600 W peak pulse power (10/1000 μs), 95.1 A peak pulse current, and clamps to 69.4 V at rated surge - deployed as a primary clamping diode across battery rails in engine control units and lighting modules.
For engineers reviewing the ALS8W43A datasheet, ALS8W43A pinout, ALS8W43A application, or ALS8W43A equivalent, key selection criteria include its DO-218 package thermal performance, 175°C junction rating, 700 A forward surge capability, unidirectional polarity with heatsink-anode configuration, and compliance with AEC-Q101 requirements for automotive-grade transient suppression.
Technical Context
This TVS diode operates in avalanche breakdown mode during load dump events, delivering fast response (<1 ns) and stable clamping over temperature (−55°C to +175°C). Its low thermal resistance (RθJC ≈ 0.3°C/W) enables high-power dissipation in the DO-218 plastic package without external heatsinking.
The device is optimized for 12 V and 24 V automotive systems, where it absorbs exponential surge waveforms up to 10 ms duration per ISO 16750-2, with derated power above 25°C case temperature per Fig.1 and Fig.2 in DS43856 Rev.9.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 43 V - Maximum continuous reverse operating voltage before clamping begins; sets system-level overvoltage threshold for 24 V nominal battery systems. |
| VBR (min/max) | 47.8 V / 52.8 V - Breakdown occurs within this range at 5 mA test current; ensures predictable turn-on margin above VWM. |
| VC @ IPPM | 69.4 V - Clamping voltage at 95.1 A peak pulse (10/1000 μs); defines worst-case voltage seen by protected downstream ICs. |
| PPPM (10/1000 μs) | 6600 W - Peak surge power handling capacity; supports full ISO 7637-2 Pulse 5a load dump energy in compact DO-218 form factor. |
| IFSM | 700 A - Non-repetitive forward surge rating (8.3 ms half-sine); validates robustness against cranking-induced inrush and short-circuit transients. |
| TJ Range | −55°C to +175°C - Full automotive junction temperature range; enables under-hood deployment without derating penalties. |
| Leakage @ VWM | 10 μA max at +25°C - Low reverse leakage preserves battery standby current in always-on vehicle networks. |
Pinout & Package
Package: DO-218 - Surface-mount plastic package with integral heatsink tab (anode), optimized for high-power dissipation and automated reflow assembly. Dimensions: 13.2–13.8 mm length × 3.66–4.26 mm width × 2.58–3.18 mm height (H×B×D per datasheet).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Positive terminal / thermal interface | Electrically connected to anode; serves as primary thermal path to PCB copper pour or heatsink; must be soldered to large copper area for RθJA optimization. |
| Cathode (Bar-marked Lead) | Negative terminal / surge return path | Connected to battery ground or chassis return; polarity marking (cathode bar) ensures correct orientation during placement to avoid catastrophic failure. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive AEC-Q101 qualified | Validated for stress testing including HTGB, HTRB, TCT, and surge per AEC-Q101 Rev. E - required for production ECUs. |
| ISO 7637-2 & ISO 16750-2 compliant | Meets Pulse 5a (load dump) requirements up to 10 ms exponential waveform - eliminates need for external filtering in certified designs. |
| Low VF = 1.8 V @ 100 A | Minimizes conduction loss during high-current surge events, reducing self-heating and improving reliability under repeated transients. |
| Halogen- and antimony-free "Green" compound | UL 94V-0 rated molding compound with <900 ppm Br, <900 ppm Cl, <1000 ppm Sb - satisfies global environmental compliance mandates. |
| Moisture Sensitivity Level 1 | No floor life limitation or bake requirement prior to reflow - simplifies SMT line logistics and reduces manufacturing cost. |
Applications
| Engine Control Unit (ECU) Protection | LED Headlamp Driver Protection |
|---|---|
Use Scenario: Installed across battery input of 32-bit microcontroller-based engine management systems exposed to alternator load dump during ignition cycling. IC Role / Device Role / Timing Role: Primary clamping diode that diverts >6 kW surge energy away from LDOs, CAN transceivers, and MCU power rails within nanoseconds. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic supplies by limiting transient voltage to ≤69.4 V while maintaining <10 μA leakage at 43 V standby. | Use Scenario: Placed on 24 V supply rail of adaptive LED headlamp driver ICs with PWM dimming and diagnostics. IC Role / Device Role / Timing Role: Unidirectional surge shunt that clamps ISO 16750-2 Pulse 5a events without affecting PWM switching integrity or fault reporting accuracy. Use Value: Enables compact, single-device protection without series impedance - preserving voltage regulation tightness and enabling real-time open-wire detection. |
| Body Control Module (BCM) Power Input | Start-Stop System Battery Interface |
Use Scenario: Mounted at main 12 V input of BCM managing door locks, windows, and interior lighting in vehicles with regenerative braking. IC Role / Device Role / Timing Role: High-energy transient absorber that sustains operation during repeated 24 V load dump events caused by alternator field collapse. Use Value: Supports >100,000 surge cycles with no parameter shift due to low thermal resistance (0.3°C/W) and stable avalanche characteristics up to 175°C. | Use Scenario: Integrated into bidirectional DC-DC converter interface between 12 V starter battery and 48 V mild-hybrid storage in start-stop architectures. IC Role / Device Role / Timing Role: Reverse-polarity protected clamping element that handles both load dump and jump-start induced overvoltage transients. Use Value: Eliminates need for dual-diode solutions by combining high surge rating (700 A IFSM) and low leakage (10 μA) - reducing BOM count and PCB area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Lower PPPM (400 W), SMA package, RθJA ≈ 50°C/W vs. DO-218's ~15°C/W | Not suitable for full ISO 7637-2 Pulse 5a; limited to lower-energy transients or secondary protection | Select only if system surge energy is <100 mJ and thermal budget allows higher junction rise. |
| SMCJ43A | Same 43 V VWM but 1500 W PPPM (10/1000 μs), SMC package, 100 A IPPM, higher RθJA than DO-218 | Requires larger PCB footprint and additional thermal relief; insufficient for 6600 W load dump without parallel devices | Use when DO-218 footprint is unavailable but higher surge margin than SMAJ is needed - not a drop-in replacement. |
Compared with SMAJ43A and SMCJ43A, ALS8W43A delivers 4.4× and 4.4× higher peak pulse power respectively in the same mounting area, with superior thermal coupling enabling single-device compliance with ISO 7637-2 Pulse 5a in space-constrained under-hood locations.
Availability
ALS8W43A is available at Aetrix Electronics and suitable for engine control units, LED headlamp drivers, body control modules, and start-stop system battery interfaces requiring stable component supply across automotive production lifecycles.
Supply support for ALS8W43A 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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The ALS8WxxA series belongs to Diodes' automotive-grade TVS portfolio, engineered specifically for high-energy load dump suppression in 12 V/24 V vehicle electrical systems - emphasizing thermal robustness, AEC-Q101 qualification, and ISO standard compliance.
FAQ
What is the maximum clamping voltage of ALS8W43A under full-rated surge conditions?
The ALS8W43A clamps to 69.4 V at its rated peak pulse current of 95.1 A (10/1000 μs waveform), as specified in DS43856 Rev.9 Table 1. This value is measured at TA = +25°C with proper PCB thermal relief; actual clamping may rise slightly at elevated case temperatures due to positive TC of VC.
Can ALS8W43A be used in 48 V mild-hybrid systems?
No - ALS8W43A is rated for 43 V stand-off and 69.4 V clamping, making it unsuitable for direct use on 48 V nominal rails where load dump can exceed 80 V. For 48 V systems, Diodes offers the ALS8W85A (85 V VWM) or equivalent high-voltage TVS devices with appropriate clamping margins.
Is the DO-218 package lead-free and RoHS compliant?
Yes - ALS8W43A uses matte tin-plated terminals and a halogen- and antimony-free "Green" molding compound compliant with RoHS 2011/65/EU and RoHS 3 2015/863/EU. It meets J-STD-002 and JESD 22-B102 solderability standards and is rated for 260°C reflow per JEDEC J-STD-020.
Does ALS8W43A require external series impedance for safe operation?
No - ALS8W43A is designed for direct connection across protected power rails without series resistors or inductors. Its low dynamic impedance and fast response enable effective clamping without added components, though PCB layout must provide ≥200 mm² copper pour under the anode tab for thermal management.
ALS8W43A 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):
- 43V
- Voltage - Breakdown (Min):
- 47.8V
- Voltage - Clamping (Max) @ Ipp:
- 69.4V
- Current - Peak Pulse (10/1000µs):
- 95.1A
- 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
ALS8W43A FAQ
1.How can I place an order for ALS8W43A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W43A 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 ALS8W43A reliable?
The price and inventory of ALS8W43A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W43A is usually 5 days.
3.What payment methods are accepted for ALS8W43A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W43A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W43A?
ALS8W43A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W43A 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 ALS8W43A?
For technical support, including ALS8W43A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W43A requirements.
6.How does Aetrix verify that ALS8W43A is sourced from the original manufacturer or authorized distributors?
All ALS8W43A 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 ALS8W43A meets industry standards.
7.What is the process for return or replacement of ALS8W43A?
All ALS8W43A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W43A, 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 ALS8W43A part is unused and in its original packaging.
Return procedure for ALS8W43A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W43A Tags
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