New range of load dump varistors for automotive applications

Kyocera AVX offers a new range of load dump varistors as an extension of its trusted TransGuard Automotive Series.

This series of varistors are innovative, zinc-oxide-based ceramic semiconductor devices that deliver bidirectional overvoltage protection and EMI/RFI attenuation in a single, space-saving SMT package qualified to AEC-Q200 and backed by over 20 years of proven performance in an array of automotive electronics. Key features include a unique monolithic multilayer construction, nonlinear, bidirectional voltage-current characteristics, high-current and energy-handling capabilities, multi-strike capabilities, and extremely fast, sub-nanosecond response times. They are also available with glass encapsulation for enhanced resistance against harsh environmental hazards, including acids, salts, and chlorite flux. Combined, these features allow the varistor series to provide reliable, state-of-the-art circuit protection from voltage transients caused by ESD, induction motor loads, module load dump, and other disruptions, which is increasingly vital as the number of electronic systems deployed in automotive applications grows.

The new load dump varistors are characterised by higher peak current ratings than the rest of the series (2,000A), making them even more effective at providing reliable protection against high-energy automotive load dump transients. Load dump pulses simulate a sudden battery disconnection from the alternator and cause the alternator to generate an overvoltage impulse that can damage sensitive ICs, which are also increasingly common in today's automotive designs.

These varistors, including the new load dump varistors, are ideal for use in internal combustion engines, HEVs, and PHEVs, including commercial vehicles, and are suitable for use in CAN, LIN, and FlexRay modules, sensors, and induction motors. They are compact and lightweight, rated for operating temperatures extending from -55C to +125C with no derating, and compliant with JASO D001 1994 and ISO 7637-2-2004 standards for protection against transient surges in the automotive industry. They are also RoHS-compliant, lead-free compatible, and free of other substances of very high concern.

"When compared to similar competing parts, the new TransGuard Automotive Series load dump varistors outperform in energy handling while utilising a smaller footprint and maintaining all necessary parameters," said Tyler Lagnese, product marketing manager, Kyocera AVX. "This allows design engineers to achieve significant performance improvements with the added benefit of space and weight savings, which is especially valuable considering the growing number of electronic systems deployed in automotive applications."

The new TransGuard Automotive Series load dump varistors' initial release consists of three standard part numbers (VCAS222016W400, VCAS222016Y390, and VCAS222016Z400) and their glass-encapsulated counterparts (VGAS222016W400, VGAS222016Y390, and VGAS222016Z400), but further codes are currently in development.