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 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. Features • Military grade available • High breaking capacity • Clear cover option to view • Plug-in with short or long leads option fuse element status Agency Approvals Agency QPL • Available from very low ampere of 0.002A to 5A Agency File Number Ampere Range E10480 0.002A - 5A 29862 0.002A - 5A FM02 0.002A - 5A Applications • Printed circuit boards and similar equipment • Electronic components Electrical Characteristics % of Ampere Rating Ampere Rating Opening Time 100% 0.002 – 5 4 Hours, Min. 0.002 – 0.3 5 Seconds, Max. 0.4 - 5 2 Seconds, Max. 200% Electrical Characteristics Ampere Rating (A) .002 .005 .010 .015 .031 .050 .062 .100 .125 .200 .250 .300 .400 .500 .600 .700 .750 .800 1.00 01.5 2.00 3.00 *4.00 *5.00 Amp Code (for all above series) .002 .005 .010 .015 .031 .050 .062 .100 .125 .200 .250 .300 .400 .500 .600 .700 .750 .800 001. 01.5 002. 003. 004. 005. Max Voltage Rating (V) 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 125 Interrupting Rating 10,000A@125VAC/VDC Nominal Cold Resistance (Ohms) 2200 280 80.0 44.0 16.0 3.52 2.55 1.38 1.0 2.30 1.75 1.25 0.227 0.167 0.430 0.324 0.293 0.271 0.0880 0.0578 0.0425 0.0275 0.0202 0.0156 Agency Approvals Nominal Melting I2t (A2 sec) 0.00000000845 0.0000000766 0.000000462 0.00000123 0.00000810 0.0000666 0.000115 0.000385 0.000691 0.00409 0.00640 0.00945 0.0251 0.0716 0.0411 0.0710 0.0563 0.113 0.0648 0.160 0.300 0.759 1.38 2.21 QPL X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X * The fuses of 4A and 5A for 272 and 278 Series are obsolete. © 2015 Littelfuse, Inc. Specifications are subject to strongly change without notice. Specifications are subject to change without notice. Application testing is recommended. Revised: 07/29/15 Radial Lead Fuses MICRO™ > Very Fast-Acting Fuse > 272/273/274/278/279 Series 1/2 A 3/4 A 1A 1 1/2 A 2A 3A 4A 5A 1/4 A 1/8 A 1/16 A 1/32 A 100 1/100 A 1/64 A Average Time Current Curves 1/200 A Temperature Re-rating Curve TIME IN SECONDS 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 CURRENT IN AMPERES 10 100 Soldering Parameters - Wave Soldering Recommended Process Parameters: 280 260 Wave Parameter 240 220 Preheat: 200 (Depends on Flux Activation Temperature) 180 160 140 120 100 80 60 40 Lead-Free Recommendation (Typical Industry Recommendation) Temperature Minimum: 100° C Temperature Maximum: Preheat Time: 150° C 60-180 seconds Solder Pot Temperature: 260° C Maximum Solder Dwell Time: 2-5 seconds Time (Seconds) Cooling Time Preheat Time Dwell Time 240 230 220 210 200 190 180 170 160 150 140 130 120 110 90 100 80 70 60 50 40 30 0 0 20 20 10 Temperature (°C) - Measured on bottom side of board 300 Recommended Hand-Solder Parameters: Solder Iron Temperature: 350° C +/- 5°C Heating Time: 5 seconds max. 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 Radial Lead Fuses MICRO™ > Very Fast-Acting Fuse > 272/273/274/278/279 Series Dimensions Product Characteristics Operating Temperature: 273 and 279: –55ºC to +85ºC; 272 and 278: –55ºC to +125ºC Fuses to MIL SPEC Military QPL type (FM02). To order, change 273 to 274. Materials 272 and 278 series cap: Nickel Plated Brass 273, 274 and 279 series cap: Mirror polished Polycarbonate Base: R-4 Ryton Pins: Tin Plated Copper Current and voltage ratings stamped on cap Product Marking 272 000 Series (Short Lead, Metal Cap) 5.97 (.235") 7.30 (.29") 4.32 (.17") 2.54 (.10") 278 000 Series (Long Lead, Metal Cap) 5.97 (.235") 7.30 (.29") 25.4 (1.0") 2.54 (.10") Part Numbering System 273 000 and 274 000 Series (Short Lead, Clear Plastic Cap) 0273 xxxx V 6.35 (.25") 8.89 (.35") Series 4.32 (.17") 2.54 (.10") Amp. Code Refer to Amp Code column of Electrical Characteristics Table 279 000 Series Packaging Code (Long Lead, Clear Plastic Cap) 6.35 (.25") V=5 H = 100 8.89 (.35") 25.4 (1.0") 2.54 (.10") Additional Information NOTE: Amperage and voltage rating stamped on cap. Leads are tin plated copper; .025" diameter. Datasheet 272 Series Datasheet 273 Series Resources 272 Series Resources 273 Series Samples 272 Series Samples 273 Series Datasheet 274 Series Resources 274 Series Samples 274 Series Datasheet 278 Series Resources 278 Series Samples 278 Series Datasheet 279 Series Resources 279 Series Samples 279 Series Packaging Packaging Option Packaging Specification Quantity Quantity & Packaging Code Bulk N/A 5 V Bulk N/A 100 H © 2015 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 07/29/15