The HMOV varistor series from Littelfuse can operate at ambient temperatures up to 125°C with 2500 V isolation voltage, an advance made possible through the use of a new silicone coating technology. Competitive epoxy-coated varistor designs are typically limited to maximum temperatures of just 85°C while similar phenolic coating designs have limited isolation voltages. This high operating temperature makes it possible to reduce end-product production costs by eliminating the need for an additional heat sink or potting process. The combination of high operating temperature, high surge current absorption of up to 10 kA (8/20 µs), reliability confirmed by a 1000-cycle thermal shock test, and high (2500 V) isolation voltage make it the highest performance radial-leaded varistor currently on the market.

Applications include industrial automation controls, solar power inverters, security systems, fire alarm and smoke detectors, smart meters, LED lighting base transceiver station (BTS) power supplies, and harsh environment/outdoor power supplies.

Video: HMOV Series - High Operating Temperature Varistors