Varistors with higher operating temperature for overvoltage protection

August 08, 2017 // By Nick Flaherty
TDK has launched leaded metal oxide disk varistors that have been approved for an increased operating temperature of 105 °C, up from 85 °C.

The recertification of the EPCOS B722 series of varistors is in accordance with UL 1449, 4th Edition, and IEC 61051. Raising the permissible operating temperature to 105 °C also changes the climate category from 40/85/56 to 40/105/56. The flammability of the epoxy enclosure complies with UL 94 V-0.

The monolithic EPCOS varistors are available with rated voltages of between 11 VRMS and 1100 VRMS and, depending on type, can withstand surge currents of up to 20 kA (8/20 µs). To assist in the design process, PSpice libraries are available at

The varistors are aimed at the protection of power supply and converter inputs for industrial electronics applications, as well as household appliances and telecommunication devices.

Further information is at