Radial Lead Fuses MICRO > Very Fast-Acting Fuse > 272/273/274/278/279 Series QPL 272/273/274/278/279 Series, MICRO Very Fast-Acting Fuse Description Developed originally for the U.S. Space Program, MICRO fuse provides reliability in a compact design. The MICRO fuse is available in plugin or radial lead styles and a complete range of ampere ratings from 0.002A to 5A to suit a wide variety of design needs. Features Military grade available Available from very low ampere of 0.002A to 5A High breaking capacity Plug-in with short or long Clear cover option to view leads option fuse element status Agency Approvals Agency Agency File Number Ampere Range Applications E10480 Printed circuit boards Electronic components 0.002A - 5A and similar equipment 29862 0.002A - 5A Electrical Characteristics FM02 0.002A - 5A QPL % of Ampere Ampere Rating Opening Time Rating 100% 0.002 5 4 Hours, Min. 0.002 0.3 5 Seconds, Max. 200% 0.4 - 5 2 Seconds, Max. Electrical Characteristics Agency Approvals Amp Code Max Nominal Ampere Nominal (for all Voltage Interrupting Cold Rating Melting above Rating Rating Resistance 2 2 QPL (A) I t (A sec) series) (V) (Ohms) X X X .002 .002 125 2200 0.00000000845 X X X .005 .005 125 280 0.0000000766 .010 .010 125 80.0 0.000000462 X X X .015 .015 125 44.0 0.00000123 X X X X X X .031 .031 125 16.0 0.00000810 X X X .050 .050 125 3.52 0.0000666 .062 .062 125 2.55 0.000115 X X X .100 .100 125 1.38 0.000385 X X X X X X .125 .125 125 1.0 0.000691 X X X .200 .200 125 2.30 0.00409 .250 .250 125 1.75 0.00640 X X X .300 .300 125 1.25 0.00945 X X X 10,000A 125VAC/VDC .400 .400 125 0.227 0.0251 X X X X X X .500 .500 125 0.167 0.0716 .600 .600 125 0.430 0.0411 X X X .700 .700 125 0.324 0.0710 X X X .750 .750 125 0.293 0.0563 X X X X X X .800 .800 125 0.271 0.113 1.00 001. 125 0.0880 0.0648 X X X 01.5 01.5 125 0.0578 0.160 X X X X X X 2.00 002. 125 0.0425 0.300 X X X 3.00 003. 125 0.0275 0.759 *4.00 004. 125 0.0202 1.38 X X X *5.00 005. 125 0.0156 2.21 X X X * The fuses of 4A and 5A for 272 and 278 Series are obsolete. 2015 Littelfuse, Inc. Specifications are subject to change without notice. Specifications are subject to change without notice. Application testing is strongly recommended. Revised: 07/29/15Radial Lead Fuses MICRO > Very Fast-Acting Fuse > 272/273/274/278/279 Series Temperature Re-rating Curve Average Time Current Curves 100 10 1 0.1 Note: 1. Rerating depicted in this curve is in addition to the standard derating of 25% for 0.01 continuous operation. 0.001 0.005 0.01 0.1 1 10 100 CURRENT IN AMPERES Soldering Parameters - Wave Soldering 300 Recommended Process Parameters: 280 260 Wave Parameter Lead-Free Recommendation 240 220 Preheat: 200 (Depends on Flux Activation Temperature) (Typical Industry Recommendation) 180 Temperature Minimum: 100 C 160 Temperature Maximum: 150 C 140 120 Preheat Time: 60-180 seconds 100 Solder Pot Temperature: 80 260 C Maximum 60 Solder Dwell Time: 2-5 seconds 40 20 0 Recommended Hand-Solder Parameters: Time (Seconds) Solder Iron Temperature: 350 C +/- 5C Preheat Time Cooling Time Heating Time: 5 seconds max. Dwell Time Note: These devices are not recommended for IR or Convection Reflow process. 2015 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 07/29/15 Temperature (C) - Measured on bottom side of board 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 TIME IN SECONDS 1/200 A 1/100 A 1/64 A 1/32 A 1/16 A 1/8 A 1/4 A 1/2 A 3/4 A 1 A 1 1/2 A 2 A 3 A 4 A 5 A