Compact overvoltage protection with an integrated fuse

TDK Corporation has extended its EPCOS ThermoFuse family of fuse protected varistors with the new compact NT14 and NT20 series. The new components offer a footprint that fits into existing circuit board layouts. The NT14 series (disk diameter 14mm) is intended to absorb maximum surge currents with an 8/20µs pulse of 6kA at rated voltages of between 130VRMS and 680VRMS, while the NT20 series (disk diameter 20mm) has a surge current capability with an 8/20µs pulse of 10kA at rated voltages of between 130VRMS and 750VRMS. The series offers a maximum energy absorption of up to 220J and 480J for 2ms, respectively. Both series are available in two-leaded and three-leaded types, with the third lead used to monitor whether the fuse has been activated. With their compact dimensions and superior surge current ability over a broad range of voltages, the NT types are ideal for use in a wide range of applications, such as ballasts for lighting, home appliances, power supplies, inverters for solar installations, frequency converters for drives, and smart meters. They can also be utilised for the general protection of electrical wiring and installations.