Littelfuse Inc., a manufacturer circuit protection, power control and sensing technology solutions, has unveiled the LST varistor series. Constructed with a proprietary thermally protected varistor technology (TMOV) developed by Littelfuse, this new varistor incorporates both a built-in thermal disconnect function and electric arc shield. This combination provides additional robust protection to prevent catastrophic failure and fire hazard even under the extreme circumstances of abnormal overvoltage conditions or varistor end-of-life.
It is specifically designed for Type 1 and Type 2 surge protective devices (SPDs) used in markets and 
Source: Littelfuse Inc.applications including:
- Residential, commercial and Industrial buildings
- Uninterruptable power supply (UPS)
- Industrial motor control
- Renewable energy
- HVAC systems
The LST varistor series facilitates meeting UL1449 listed Type 1 or Type 2 standards by incorporating 200 kA short circuit current rating, 20 kA In, UL1449 Type 4 recognized component assembly. These varistors offer the flexibility of using 50 kA and 75 kA Imax rated devices with the same footprint on printed circuit boards. More options are also available for designing remote indication/monitoring of SPD product or system via mechanically triggered AC and DC rated microswitch (normally open/normally closed, pin length, two pin/three pin/without pin).
The series offers operating voltage ranges up to 690 V AC for the 50 kA version and up to 550 V AC for the 75 kA version and is available in three trays containing 24 pieces each.
