Diodes Incorporated ALS8W17A

Overview

ALS8W17A from Diodes Incorporated is a unidirectional surface-mount load dump transient voltage suppressor in DO-218 package, rated for 17 V stand-off voltage (VWM), 18.9–20.9 V breakdown voltage (VBR), 6600 W peak pulse power (10/1000 µs), and 239 A peak pulse current. It serves as a clamping diode for automotive electronic control units to protect sensitive downstream circuitry against ISO 7637-2 and ISO 16750-2 load dump transients.

For engineers reviewing the ALS8W17A datasheet, ALS8W17A pinout, ALS8W17A application, or ALS8W17A equivalent, key selection criteria include clamping voltage (27.6 V at 239 A), thermal stability up to +175 °C junction temperature, low forward voltage drop (≤1.8 V at 100 A), and compliance with AEC-Q101 for automotive-grade reliability.

Technical Context

The ALS8W17A operates as a unidirectional TVS diode optimized for high-energy automotive load dump suppression. Its silicon avalanche structure delivers precise 17 V stand-off with tight 18.9–20.9 V breakdown tolerance and clamps at 27.6 V under 239 A surge, limiting voltage overshoot to <62% above VWM. The device uses a thermally efficient DO-218 package with heatsink-anode polarity to maximize power dissipation during 10 ms exponential surges.

It meets ISO 7637-2 Level 5 and ISO 16750-2 load dump test conditions with guaranteed operation from –55 °C to +175 °C. Reverse leakage remains ≤10 µA at VWM and ≤150 µA at +175 °C, ensuring low standby power loss in always-on vehicle modules such as body control units and lighting drivers.

Key Specifications

Pinout & Package

Package: DO-218 plastic outline with heatsink-anode configuration; cathode marked by bar; 2.74 g mass; UL 94V-0 flammability rating; matte tin-plated terminals; moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar load dump suppression applications.

Compared with SMAJ17A and SMCJ17A, ALS8W17A delivers 4.4× and 2.2× higher peak pulse power respectively, enabling single-device compliance with stringent ISO 7637-2 Level 5 load dump testing-critical for next-generation ADAS and electrified powertrain ECUs.

Availability

ALS8W17A is available at Aetrix Electronics and suitable for engine control units, LED lighting drivers, body control modules, and infotainment power rails requiring stable component supply across automotive production lifecycles.

Supply support for ALS8W17A 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 protection in 12 V vehicle electrical systems with emphasis on thermal robustness, AEC-Q101 compliance, and ISO standard conformance.

FAQ

What is the maximum clamping voltage of ALS8W17A under full-rated surge current?

The ALS8W17A clamps at 27.6 V when subjected to its rated peak pulse current of 239 A using the 10/1000 µs waveform. This value is measured per JEDEC standards and confirmed in the DS43856 datasheet Table 1. It represents the upper voltage limit imposed on protected circuitry during worst-case load dump events.

Is ALS8W17A suitable for 24 V commercial vehicle applications?

No-ALS8W17A is specified for 12 V nominal systems with 17 V stand-off voltage. For 24 V vehicles, Diodes recommends ALS8W33A (33 V VWM) or ALS8W36A (36 V VWM), which provide appropriate margin above 28 V regulated bus voltage while maintaining identical DO-218 packaging and 6600 W surge capability.

How does the DO-218 package improve thermal performance versus DO-214AB?

The DO-218 package features an integrated metal heatsink tab electrically tied to the anode, enabling direct thermal coupling to PCB copper planes. This reduces junction-to-board thermal resistance by ~40% compared to DO-214AB, allowing sustained 6600 W pulse handling without external heatsinking-critical for compact ECU layouts.

Does ALS8W17A require derating at elevated ambient temperatures?

Yes-power derating begins at +25 °C case temperature per Figure 1 in DS43856. At +100 °C case, maximum PPPM drops to ~3000 W (45% of rated 6600 W). Designers must calculate board-level thermal resistance and ensure heatsink-anode mounting achieves ≤+100 °C case temp during worst-case surge to maintain specification compliance.