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Diodes Incorporated ALS8W22A
- Part No.:
- ALS8W22A
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-218AB
- Datasheet:
-
ALS8W22A.pdf
- Description:
- Transient Voltage Suppressor PP
- Quantity:
- Payment:
- Shipping:
Inventory:6,472
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Product details
Overview
ALS8W22A 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 22.0 V stand-off voltage (VWM), 24.4–26.9 V breakdown voltage (VBR), 6600 W peak pulse power (10/1000 µs), 186 A peak pulse current, and clamps to 35.5 V at rated surge. Used as a clamping diode across battery rails in engine control units and lighting modules.
For engineers reviewing the ALS8W22A datasheet, ALS8W22A pinout, ALS8W22A application, or ALS8W22A equivalent, key selection criteria include its DO-218 package thermal performance, 175°C junction rating, unidirectional polarity with heatsink-anode configuration, and compliance with automotive-grade surge standards under high-temperature operation.
Technical Context
This TVS diode operates in avalanche breakdown mode during transients, providing low-clamp-voltage protection by diverting surge current away from sensitive downstream circuitry. Its unidirectional structure enables forward conduction only when anode-to-cathode voltage exceeds ~1.8 V (at 100 A), while blocking reverse leakage ≤10 µA at 22.0 V and ≤150 µA at 175°C.
The device is optimized for exponential 10 ms load dump waveforms per ISO 16750-2, delivering 5200 W capability at 10/10000 µs and maintaining stable clamping up to +175°C junction temperature. Thermal resistance is minimized via the DO-218 plastic package's low RθJC, enabling high-power dissipation without external heatsinking in constrained automotive layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 22.0 V - Maximum continuous reverse operating voltage before significant leakage begins; sets system rail margin for 24 V automotive systems. |
| VBR min/max | 24.4 V / 26.9 V - Breakdown onset range at 5 mA test current; defines minimum clamping threshold under surge conditions. |
| VC @ IPPM | 35.5 V - Clamping voltage at 186 A peak pulse; limits maximum voltage seen by protected ICs during load dump events. |
| PPPM (10/1000 µs) | 6600 W - Peak surge power handling capacity; supports robust protection against worst-case ISO 7637-2 Pulse 5a transients. |
| IFSM | 700 A - Non-repetitive forward surge current rating (8.3 ms half-sine); ensures survivability during repeated ignition cycles. |
| Junction Temp Range | −55°C to +175°C - Enables operation in under-hood environments without derating; critical for engine bay ECU placement. |
Pinout & Package
Package: DO-218 - Surface-mount plastic case with integral heatsink tab (anode), optimized for high thermal conductivity and automated reflow assembly. Dimensions: 13.2–13.8 mm length × 3.66–4.26 mm width × 2.58–3.18 mm height (L×W×H). Polarity marked by cathode bar on top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Heatsink Tab) | Positive terminal / thermal path | Electrically connected to anode; serves as primary heat sink interface; must be soldered to copper pour for thermal management. |
| Cathode (Top Lead) | Surge current return path | Connected to vehicle chassis or ground plane; carries full transient current during clamping; marked by cathode band. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | Designed and manufactured in IATF 16949 certified facilities; meets AEC-Q101 stress test requirements for discrete semiconductors. |
| High-temperature stability | Leakage remains ≤150 µA at VWM and +175°C junction temperature-ensures reliable blocking in hot under-hood locations. |
| Low thermal resistance | DO-218 package achieves low RθJC, enabling >5 kW dissipation without external heatsink in typical PCB layouts. |
| ISO-compliant surge handling | Validated to withstand ISO 7637-2 Pulse 5a (load dump) and ISO 16750-2 transient profiles without degradation. |
Applications
| Engine Control Unit Protection | LED Headlamp Driver Protection |
|---|---|
Use Scenario: Installed across battery input of 32-bit MCU-based ECU to absorb load dump energy during alternator field collapse. IC Role / Device Role / Timing Role: Unidirectional clamping diode that conducts only during overvoltage events, limiting rail voltage to ≤35.5 V for <100 ms. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V power management ICs and CAN transceivers exposed to 120 V/350 ms transients. | Use Scenario: Placed at input of buck-boost LED driver powering adaptive front lighting systems (AFS) in 24 V commercial vehicles. IC Role / Device Role / Timing Role: Fast-response transient suppressor that activates within nanoseconds to clamp voltage spikes induced by relay switching or motor load shedding. Use Value: Maintains LED driver IC functionality during repeated 60 V/100 ms surges, eliminating need for oversized input capacitors or redundant protection stages. |
| Body Control Module Power Rail | Start-Stop System Battery Interface |
Use Scenario: Mounted on BCM main PCB near fuse box connection to protect LIN transceivers, EEPROM, and microcontroller power domains. IC Role / Device Role / Timing Role: Standby-mode protector with <10 µA leakage at 22 V, minimizing quiescent current draw during vehicle sleep mode. Use Value: Ensures <30 µA total system leakage in ISO 8820-compliant sleep state, extending battery life during extended parking periods. | 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: Bidirectional surge shunt (via series configuration or complementary pairing) managing regenerative braking transients and cold-crank recovery spikes. Use Value: Supports 175°C operation during repeated thermal cycling, avoiding derating or failure during high-frequency stop-start cycles in urban driving. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar load dump protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ22A | Lower PPPM (400 W), SMA package, 35.5 V clamping at 11.9 A - insufficient for ISO 7637-2 Pulse 5a. | Limited to low-energy surges in non-automotive industrial controls; not qualified to AEC-Q101. | Select only for cost-sensitive 24 V systems with <500 W surge exposure and no automotive qualification requirement. |
| SMCJ22A | Higher VC (35.5 V same), but lower IPPM (100 A), SMC package, 1500 W PPPM - fails 6600 W load dump test. | Suitable for secondary protection or board-level ESD; lacks thermal mass for sustained 10 ms surges. | Use where space constraints prevent DO-218 mounting, but accept reduced surge margin and require supplemental thermal design. |
Compared with SMAJ22A and SMCJ22A, ALS8W22A delivers 4.4× and 4.4× higher peak pulse power respectively, maintains identical clamping voltage while supporting 186 A surge current, and is qualified for automotive under-hood use-making it the only option meeting full ISO 7637-2 Pulse 5a compliance in a single-device solution.
Availability
ALS8W22A 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 ALS8W22A 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 TVS portfolio, engineered specifically for load dump suppression in 12 V/24 V vehicle electrical systems-prioritizing high-temperature stability, low clamping voltage, and IATF 16949 manufacturing compliance.
FAQ
What is the anode-cathode polarity configuration of ALS8W22A?
The ALS8W22A uses a unidirectional configuration where the metal heatsink tab is the anode and the top lead (marked with a cathode bar) is the cathode. This arrangement allows forward conduction during load dump events while blocking reverse leakage under normal operation. Mounting requires the anode tab to be soldered to the positive rail or heatsink plane.
Does ALS8W22A meet AEC-Q101 qualification requirements?
Yes, ALS8W22A is designed and manufactured in IATF 16949 certified facilities and qualified to AEC-Q101 for discrete semiconductors. It passes stress tests including high-temperature reverse bias, temperature cycling, and humidity testing-ensuring reliability in automotive under-hood environments up to +175°C junction temperature.
How does ALS8W22A perform under extended high-temperature operation?
At +175°C junction temperature, ALS8W22A maintains ≤150 µA reverse leakage at 22.0 V stand-off voltage and retains full 6600 W peak pulse power capability for 10/1000 µs waveforms. Its DO-218 package provides low thermal resistance, enabling stable clamping performance without derating in continuous high-temperature environments like engine compartments.
Can ALS8W22A be used in bidirectional surge protection circuits?
No-ALS8W22A is strictly unidirectional. For bidirectional protection, two devices must be connected in series opposition (anode-to-anode or cathode-to-cathode), or a dedicated bidirectional TVS such as the P6SMB22CA must be selected. Using a single ALS8W22A in reverse-biased configuration will not provide clamping during negative transients.
ALS8W22A 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):
- 22V
- Voltage - Breakdown (Min):
- 24.4V
- Voltage - Clamping (Max) @ Ipp:
- 35.5V
- Current - Peak Pulse (10/1000µs):
- 186A
- 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
ALS8W22A FAQ
1.How can I place an order for ALS8W22A through Aetrix?
Please submit a Request for Quotation (RFQ) for ALS8W22A 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 ALS8W22A reliable?
The price and inventory of ALS8W22A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ALS8W22A is usually 5 days.
3.What payment methods are accepted for ALS8W22A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ALS8W22A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ALS8W22A?
ALS8W22A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ALS8W22A 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 ALS8W22A?
For technical support, including ALS8W22A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ALS8W22A requirements.
6.How does Aetrix verify that ALS8W22A is sourced from the original manufacturer or authorized distributors?
All ALS8W22A 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 ALS8W22A meets industry standards.
7.What is the process for return or replacement of ALS8W22A?
All ALS8W22A units undergo pre-shipment inspection (PSI). If there is an issue with ALS8W22A, 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 ALS8W22A part is unused and in its original packaging.
Return procedure for ALS8W22A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ALS8W22A Tags
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