LST Series - SPD Thermally Protected Varistor

Littelfuse Varistor LST image
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Disclaimer Notice

Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

The LST Varistor Series is constructed with Littelfuse’s renowned thermally protected varistor technology (TMOV). The built-in thermal disconnecting function and electric arc shield provides additional protection to prevent catastrophic failure and fire hazard even under the extreme circumstances of varistor end-of-life or abnormal overvoltage conditions. It is specifically designed for Type 1 and Type 2 Surge Protective Devices (SPDs).


  • 200 kA SCCR, 20 kA In, UL1449 Type 4 recognized component assembly 
  • Same footprint and PCB layout for Imax 50 kA and 75 kA options 
  • Mechanically triggered AC and DC rated micro-switch with Normally Open or Normally Closed options for remote indication/monitoring circuit 
  • Visual tab option to display LST working status 
  • RoHS compliant, Lead-free, and Halogen-free


  • Facilitate meeting UL1449 listed Type 1 or Type 2 standards 
  • Same PCB layout/design for 50 kA and 75 kA Imax rated SPDs 
  • More flexibilities/options for designing an isolated remote indication/monitoring circuit 
  • Clear indication for technician/engineer to replace EOL product to continue surge protection for the end product 
  • Environment-friendly

Access specifications, certifications, check availability and order parts below

Catalog #VMAX AC (V)VMAX DC (V)(ITM 1xAmps (A)Vc (V)PolarityLead FormOperating TemperaturePartner ECAD ModelsStockSamplesCompare
LST1505VL2NT115020050000600Bi-directionalTerminal-40° to 85°CLST1505VL2NT1CheckOrder
LST1507VL2NT115020075000600Bi-directionalTerminal-40° to 85°CLST1507VL2NT1CheckOrder
LST1805VL2NT118024050000800Bi-directionalTerminal-40° to 85°CLST1805VL2NT1CheckOrder
LST1807VL2NT118024075000800Bi-directionalTerminal-40° to 85°CLST1807VL2NT1CheckOrder
LST2755VL2NT127535050000900Bi-directionalTerminal-40° to 85°CLST2755VL2NT1CheckOrder
LST2757VL2NT127535075000900Bi-directionalTerminal-40° to 85°CLST2757VL2NT1CheckOrder
LST3205VL2NT1320420500001000Bi-directionalTerminal-40° to 85°CLST3205VL2NT1CheckOrder
LST3207VL2NT1320420750001000Bi-directionalTerminal-40° to 85°CLST3207VL2NT1CheckOrder
LST3855VL2NT1385510500001500Bi-directionalTerminal-40° to 85°CLST3855VL2NT1Check
LST3857VL2NT1385510750001500Bi-directionalTerminal-40° to 85°CLST3857VL2NT1Check
LST4205VL2NT1420560500001500Bi-directionalTerminal-40° to 85°CLST4205VL2NT1CheckOrder
LST4207VL2NT1420560750001500Bi-directionalTerminal-40° to 85°CLST4207VL2NT1CheckOrder
LST5105VL2NT1510675500001500Bi-directionalTerminal-40° to 85°CLST5105VL2NT1CheckOrder
LST5107VL2NT1510675750001500Bi-directionalTerminal-40° to 85°CLST5107VL2NT1CheckOrder
LST5505VL2NT1550710500001500Bi-directionalTerminal-40° to 85°CLST5505VL2NT1CheckOrder
LST5507VL2NT1550710750001500Bi-directionalTerminal-40° to 85°CLST5507VL2NT1CheckOrder
LST6905VL2NT1690890500002000Bi-directionalTerminal-40° to 85°CLST6905VL2NT1CheckOrder
Part # Part Description RoHS Pb-free RoHS (2015/ 863/EU) Certificate REACH (SVHC’s) Declaration Halogen Free REACH (SVHC’s) IPC-Material Declaration
LST3205VL2NT1 Thermally Protected MOV RoHS No 10/06/2020 PbFree No 10/06/2020 CoC_RoHS10_LST3205VL2NT1 REACH209_Declaration_LST3205VL2NT1 Yes
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