SM20 Series 20mm SMD Varistors

Littelfuse latest development in overvoltage circuit protection and transient suppression

The Littelfuse SM20 series devices are surface-mount metal oxide varistors that are used in applications requiring hi-energy and transient current capability. The AC rated parts are designed to operate continuously across AC power lines. The DC rated parts are suitable for automotive applications, and the series comprises a Nylon molded package with folded tin plated metal leads for soldering to a PCB. The SM20 series is based on a radial 20mm internal varistor element with similar characteristics to the Littelfuse LA / ZA series of varistors.   SM20 Series Datasheet
Littelfuse SM20 Series 20mm SMD Varistors

  Features   Applications
  • DC voltage rating: 26VDC
  • AC voltage rating: 175 - 320VAC
  • No de-rating up to 85°C ambient
  • Lead- and halogen-free, RoHS compliant
  • Low voltage devices specified for automotive load dump energy
  • Available in "waffle" tray packaging
RoHS Compliant
  • Load management equipment
  • Automotive load dump devices
  • Electronic/AC power meter
  • Valves used in automatic car wash systems
  • Plug-in cards
  • Remote controls
  • GFCIs (ground fault circuit interrupters)
  • Motor compressors
  • Drive and control electronics
  • Switch mode power supplies and UPS

Part Number
Part Number
Varistor Voltage Current-
Maximum AC Voltage Maximum DC Voltage Energy  
F3543-ND V26SM20 40V 2kA 20VAC 26VDC 20J SM20 Series Datasheet
F3544-ND V175SM20 303V 6.5kA 175VAC 225VDC 90J
F3545-ND V230SM20 396V 6.5kA 230VAC 300VDC 122J
F3546-ND V250SM20 429V 6.5kA 250VAC 330VDC 130J
F3547-ND V275SM20 473V 6.5kA 275VAC 369VDC 140J
F3548-ND V300SM20 517V 6.5kA 300VAC 405VDC 165J
F3549-ND V320SM20 540V 6.5kA 320VAC 420VDC 150J