Radial Lead Fuses MICRO > Very Fast-Acting > 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 1/500 to 5A to suit a wide variety of design needs. Features t Military grade available t Available from very low ampere of 2mA to 5A t High breaking capacity t Plug-in with short or long t Clear cover option to view leads option fuse element status Agency Approvals Applications Agency Agency File Number Ampere Range t Printed circuit boards t Electronic components E10480 2mA - 5A and similar equipment LR 29862 2mA - 5A Electrical Characteristics FM02 2mA - 5A QPL % of Ampere Ampere Rating Opening Time Rating 100% 1/5005 4 Hours, Min. 1/5003/10 5 Seconds, Max. 200% 4/10-5 2 Seconds, Max. Electrical Characteristics Amp Code Max Nominal Agency Approvals Ampere Nominal (for all Voltage Interrupting Cold Rating Melting above Rating Rating Resistance 2 2 QPL (A) I t (A sec) series) (V) (Ohms) .002 .002 125 2200 0.00000000845 XXX XXX .005 .005 125 280 0.00000000810 .010 .010 125 80.0 0.000000462 XXX .015 .015 125 44.0 0.00000123 XXX .031 .031 125 16.0 0.00000810 XXX XXX .050 .050 125 3.20 0.0000666 .062 .062 125 2.32 0.000115 XXX .100 .100 125 1.25 0.000385 XXX .125 .125 125 1.0 0.000691 XXX XXX .200 .200 125 2.30 0.00409 .250 .250 125 1.75 0.00640 XXX 10,000 amperes at .300 .300 125 1.25 0.00945 XXX 125 VAC/VDC400 .400 125 0.227 0.0251 XXX XXX .500 .500 125 0.167 0.0716 XXX .600 .600 125 0.430 0.0411 .700 .700 125 0.324 0.0710 XXX .750 .750 125 0.293 0.0900 XXX XXX .800 .800 125 0.271 0.113 XXX 1.00 001. 125 0.0880 0.0648 01.5 01.5 125 0.0578 0.160 XXX XXX 2.00 002. 125 0.0425 0.300 3.00 003. 125 0.0275 0.759 XXX 4.00 004. 125 0.0202 1.38 XXX 5.00 005. 125 0.0156 2.21 XXX 2009 Littelfuse, Inc. 272/273/274/278/279 Series 131 Specications are subject to change without notice. Revised: January 7, 2009 Please refer to www.littelfuse.com/series/272.html, /273.html, /274.html, /278.html or /279.html for current information. 272-4/278-9Radial Lead Fuses IntrIntroduction toduction too Cir Circuit Prcuit Prototectionection Transientology MICRO > Very Fast-Acting > 272/273/274/278/279 Series Temperature Rerating Curve Average Time Current Curves 100 10 1 0.1 0.01 0.001 0.005 0.01 1 10 100 0.1 CURRENT IN AMPERES Soldering Parameters - Wave Soldering 300 Recommended Process Parameters: 280 260 Wave Parameter Lead-Free Recommendation 240 220 Preheat: (Typical Industry Recommendation) 200 (Depends on Flux Activation Temperature) 180 Temperature Minimum: 100 C 160 Temperature Maximum: 150 C 140 120 Preheat Time: 60-180 seconds 100 Solder Pot Temperature: 260 C Maximum 80 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 Dwell Time Heating Time: 5 seconds max. Note: These devices are not recommended for IR or Convection Reow process. 2009 Littelfuse, Inc. 272/273/274/278/279 Series 132 Specications are subject to change without notice. Revised: January 7, 2009 Please refer to www.littelfuse.com/series/272.html, /273.html, /274.html, /278.html or /279.html for current information. 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