Multilayer varistors boast high surge current capability

2nd July 2015

Barney Scott

0 0

TDK presents its high-surge series of EPCOS multilayer varistors, characterised by their high surge current capability, ranging from one surge of up to 5000A to ten surges of up to 3500A, with a pulse of 8/20µs and an operating voltage of up to 65VDC. The SMD components are available in case sizes EIA1210 through EIA2220 and require less space than wired types or semiconductor-based solutions, while offering the same performance and reliability.

A high-performance ceramic material set and an improved component design have made the further miniaturisation possible. This means that, in comparison with conventional technologies, current densities of three times higher can be achieved. On this basis, TDK now manufactures protection components in the EIA 1210 case size that offer the same performance as existing EIA 2220 types, which are three times larger. Despite their compact design, the maximum energy absorption for EIA 2220 components is about 15J for a pulse of 2ms.

In addition, the rugged varistors are resistant to thermo-mechanical stress, offering a high surge current capability even at 125°C, a temperature at which other technologies can only be operated with derating. The protection components are designed for a lead-free reflow soldering process. Applications for the varistors include power supplies for telecomms and PoE systems.