451 Series - NANO Fast-Acting Subminiature Surface Mount Fuse

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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.

The Nano SMF Fuse is a very small, Wire-in-Air (WIA) square shape surface mount fuse which is very suitable for the secondary side circuit over-current protection applications and is designed for PCB using surface mount technology.


  • Very fast acting
  • Small size
  • Wide range of current rating available (0.062A to 20A)
  • Wide operating temperature range
  • Low temperature rerating
  • RoHS compliant and Halogen Free


  • Notebook PC
  • LCD monitor
  • LCD/PDP panel
  • LCD backlight inverter
  • Portable DVD player
  • Power supply
  • Networking
  • PC server
  • Cooling fan system
  • Storage system
  • Telecom system
  • Wireless basestation
  • White goods
  • Game console
  • Office Automation equipment
  • Battery charging circuit protection
  • Industrial equipment

Access specifications, certifications, check availability and order parts below

Catalog #Amps (A)VDC (V)VAC (V)Nominal Melting I2T (A2sec)Resistance
Interrupting RatingBodyMin Operating Temp °CMax Operating Temp (°C)Marking CodeStockSamplesCompare
04510202065651540.00244400A@32VDCCeramic-5512520A LFCheckOrder
0451.0620.0621251250.000195.5300A@32VDCCeramic-5512562mA LFCheck
0451.0800.081251250.000334.05300A@32VDCCeramic-5512580mA LFCheck
0451.1000.11251250.001383.1300A@32VDCCeramic-55125100mA LFCheck
0451.1250.1251251250.002861.7300A@32VDCCeramic-55125125mA LFCheckOrder
0451.1600.161251250.00481.2157300A@32VDCCeramic-55125160mA LFCheckOrder
0451.2000.21251250.00890.8372300A@32VDCCeramic-55125200mA LFCheckOrder
0451.2500.251251250.01580.5765300A@32VDCCeramic-55125250mA LFCheckOrder
0451.3150.3151251250.03110.3918300A@32VDCCeramic-55125315mA LFCheckOrder
0451.3750.3751251250.04420.4541300A@32VDCCeramic-55125375mA LFCheck
0451.4000.41251250.05510.4233300A@32VDCCeramic-55125400mA LFCheck
0451.5000.51251250.08240.3046300A@32VDCCeramic-55125500mA LFCheck
0451.6300.631251250.13810.2022300A@32VDCCeramic-55125630mA LFCheck
0451.7500.751251250.21430.1444300A@32VDCCeramic-55125750mA LFCheck
0451.8000.81251250.26540.1355300A@32VDCCeramic-55125800mA LFCheck
0451001.11251250.60290.078300A@32VDCCeramic-551251A LFCheck
0451002.21251250.530.0367300A@32VDCCeramic-551252A LFCheck
0451003.31251251.650.0227300A@32VDCCeramic-551253A LFCheckOrder
0451004.41251253.1520.016300A@32VDCCeramic-551254A LFCheck
0451005.51251255.5660.0125300A@32VDCCeramic-551255A LFCheck
0451007.712512510.320.009400A@32VDCCeramic-551257A LFCheck
0451008.812512520.230.0077400A@32VDCCeramic-551258A LFCheck
045101.51.51251250.8530.063300A@32VDCCeramic-551251.5A LFCheck
045101.61.61251251.060.058300A@32VDCCeramic-551251.6A LFCheck
0451010.1012512526.460.0056400A@32VDCCeramic-5512510A LFCheck
0451012.12656547.970.0049400A@32VDCCeramic-5512512A LFCheck
0451015.15656597.820.0037400A@32VDCCeramic-5512515A LFCheck
045102.52.51251251.0290.0286300A@32VDCCeramic-551252.5A LFCheck
045103.53.51251252.4690.02300A@32VDCCeramic-551253.5A LFCheck
045106.36.31251259.170.0096400A@32VDCCeramic-551256.3A LFCheck
04511.251.251251250.6640.078300A@32VDCCeramic-551251.25A LFCheck
04513.153.151251251.920.0215300A@32VDCCeramic-551253.15A LFCheck

EC611 Circuit Protection for Lithium Ion and Lithium Polymer Rechargeable Battery Applications

This application note summarizes how the increased use of Lithium-Ion and Lithium Polymer battery packs in applications where user safety is critical, the implementation of secondary protection circuits will ensure an unsurpassed level of safety with minimal cost impact.

451 Series Time Curve Data

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