TDK ThermoFuse Thermally Protected Varistor: Provides Compact Overvoltage Protection with Integrated Fuses

Thursday, October 18, 2018

TDK Corporation (Tokyo Stock Exchange: 6762) has recently expanded its EPCOS ThermoFuseTM product family with the introduction of the new compact NT14 and NT20 series of thermal fuse-protected varistors. The new ThermoFuseTM components take up little space to meet the layout requirements of today's boards. The NT14 series (disc diameter 14mm) is designed to absorb surge current pulses of 8/20-μs and up to 6 kA at 130 VRMS to 680 VRMS rated voltage, while the NT20 series (20 mm disc diameter) Surge current pulses of 8/20-μs and up to 10 kA at 130 VRMS to 750 VRMS rated. The NT14 and NT20 series varistors have a maximum energy absorption capacity of 220 J and 480 J in 2 ms, respectively, and both series are available in 2-pin and 3-pin types, the third of which is used to monitor the fuse. Whether it is activated.

The ThermoFuseTM Thermally Protected Varistor is a specially designed disc-shaped varistor in series with a thermally coupled fuse that is inherently safe. Once the varistor is overheated, the thermal fuse (patented) is disconnected, which isolates the varistor from the grid for unmatched reliability. This prevents any potential damage to the PCB or components in the vicinity of the varistor and improves the reliability of the protected device. Thanks to thermistors and flame retardant epoxy coatings, the ThermoFuseTM NT series is UL 94 V-0 compliant and UL 1449 (4th Edition) 4CA certified.

With its compact size and excellent surge current capability over a wide voltage range, NT series varistors are suitable for a wide range of applications, such as lighting ballasts, household appliances, power supplies, inverters for solar installations, and inverters for drives. Smart meters, etc. In addition, they can also be used for general protection of electrical wiring and electrical equipment.


Author:Brittany Antonia (The author of article owns the copyright.)