278 Series - MICRO™ Very Fast-Acting Subminiature Radial Leaded Fuse

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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.

Developed originally for the U.S. Space Program, MICRO™ fuse provides reliability in a compact design. The MICRO™ fuse is available in plug–in or radial lead styles and a complete range of ampere ratings from 0.002A to 5A to suit a wide variety of design needs.


  • Military grade available
  • High breaking capacity
  • Clear cover option to view fuse element status
  • Available from very low ampere of 0.002A to 5A
  • Plug-in with short or long leads option


  • Printed circuit boards and similar equipment
  • Electronic components

Access specifications, certifications, check availability and order parts below

Catalog #VDC (V)VAC (V)Resistance
Nominal Melting I2T (A2sec)OpeningMax Operating Temp (°C)Min Operating TemperatureInterupt Voltage (V) -1Interupt Voltage (V) -2Partner ECAD ModelsStockSamplesCompare
0278.00212512522008.45E-09Very Fast-Acting (FF)125-551251250278.002CheckOrder
0278.0051251252807.66E-08Very Fast-Acting (FF)125-551251250278.005CheckOrder
0278.010125125804.62E-07Very Fast-Acting (FF)125-551251250278.010CheckOrder
0278.015125125441.23E-06Very Fast-Acting (FF)125-55125125CheckOrder
0278.031125125168.1E-06Very Fast-Acting (FF)125-551251250278.031CheckOrder
0278.0501251253.526.66E-05Very Fast-Acting (FF)125-551251250278.050CheckOrder
0278.0621251252.550.000115Very Fast-Acting (FF)125-551251250278.062CheckOrder
0278.1001251251.380.000385Very Fast-Acting (FF)125-551251250278.100CheckOrder
0278.12512512510.000691Very Fast-Acting (FF)125-551251250278.125CheckOrder
0278.2001251252.30.00409Very Fast-Acting (FF)125-551251250278.200CheckOrder
0278.2501251251.750.0064Very Fast-Acting (FF)125-551251250278.250CheckOrder
0278.3001251251.250.00945Very Fast-Acting (FF)125-551251250278.300CheckOrder
0278.4001251250.2270.0251Very Fast-Acting (FF)125-551251250278.400CheckOrder
0278.5001251250.1670.0716Very Fast-Acting (FF)125-551251250278.500CheckOrder
0278.6001251250.430.0411Very Fast-Acting (FF)125-551251250278.600CheckOrder
0278.7001251250.3240.071Very Fast-Acting (FF)125-551251250278.700CheckOrder
0278.7501251250.2930.0563Very Fast-Acting (FF)125-551251250278.750CheckOrder
0278.8001251250.2710.113Very Fast-Acting (FF)125-551251250278.800CheckOrder
0278001.1251250.0880.0648Very Fast-Acting (FF)125-551251250278001.CheckOrder
0278002.1251250.04250.3Very Fast-Acting (FF)125-551251250278002.CheckOrder
0278003.1251250.02750.759Very Fast-Acting (FF)125-551251250278003.CheckOrder
027801.51251250.05780.16Very Fast-Acting (FF)125-55125125027801.5CheckOrder
Obsolete: 2015 -01-28
1251250.02021.38Very Fast-Acting (FF)125-551251250278004.
Obsolete: 2015 -01-28
1251250.01562.21Very Fast-Acting (FF)125-551251250278005.
Part # Part Description RoHS Pb-free RoHS (2015/ 863/EU) Certificate REACH (SVHC’s) Declaration Halogen Free REACH (SVHC’s) IPC-Material Declaration
0278.050V FUSE 125V V/FA MICRO FUSE RAD .050A RoHS No 02/27/2002 PbFree No 02/27/2002 CoC_RoHS10_0278.050V REACH191_Declaration_0278.050V No
Does not Contain IPC_0278.050V
0278004.V FUSE 125V V/FA MICRO FUSE RAD 4A RoHS No 02/27/2002 PbFree No 02/27/2002
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