Improved circuit protection with glass-encapsulated varistors

June 20, 2013 // By Graham Prophet
The latest additions to AVX’s TransGuard & Automotive TransGuard Series varistors extend bi-directional over-voltage protection and EMI/RFI attenuation benefits to high energy and harsh environment applications

These multilayer varistors include glass-encapsulated, acid-resistant parts for use in high energy and harsh environment commercial, industrial, and automotive applications. Exhibiting non-linear, bi-directional, V-I characteristics, both zinc-oxide-based ceramic semiconductor device series provide bi-directional over-voltage protection and EMI/RFI attenuation in a single SMT package. The series also feature multi-strike capability, sub 1-nsec response to ESD strikes, and excellent solderability.

The TransGuard and Automotive TransGuard varistor series feature a high-energy, monolithic multilayer construction that provides circuit protection from voltage transients caused by ESD, lightning, inductive switching, automotive related transients, and other disruptions, the company says; with the addition of the high energy, glass-encapsulated options, an even broader range of applications can take advantage of the series’ advanced, high-reliability circuit protection capabilities.

For use in harsh environments – such as those with acid, salt, or chlorite flux – glass-encapsulated TransGuard and Automotive TransGuard Series varistors are available in three case sizes (1210, 1812, and 2220), four energy ratings (spanning 2-12J) and feature a peak current rating of up to 2000A. Both series also have Ni/Sn-plated terminations, are RoHS compliant, and are rated for use in temperatures spanning -55°C to +125°C.

TransGuard Series varistors are available in four working voltages (16, 22, 28, and 65 VDC), four clamping voltages (42, 44, 77, and 135V), and can be employed in a range of professional, industrial, and commercial applications, including: IC protection, DC motor protection, relays, controllers, sensors, smart grids, and alarms, among others.

Available in four working voltages (16, 34, and 65 VDC) and three clamping voltages (42, 77, and 135V), Automotive TransGuard Series varistors exhibit high current and energy handling capabilities, are AEC-Q200-qualified, and are suited for use in a variety of automotive applications typical of internal combustion, hybrid electric, plug-in hybrid electric, and commercial vehicles. The series can also provide advanced circuit protection in sensor, relay, LIN BUS, ECU, and DC motor applications.

AVX, www.avx.com