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Axial Lead & Cartridge Fuses
QPL
QPL
QPL
MICRO™ > Very Fast-Acting Fuse > 272/273/274/278/279 Series
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
fuse element status
• Available from very low
ampere of 0.002A to 5A
• Plug-in with short or long
leads option
• Recognized to UL/CSA/
NMX 248-1 and UL/CSA/
NMX 248-14
Agency Approvals
Agency Agency File Number Ampere Range
E10480 0.002A - 5A
29862 0.002A - 5A
QPL-23419 0.002A - 5A
Applications
• Printed circuit boards
• Electronic components
and similar equipment
Electrical Characteristics
% of Ampere Rating Ampere Rating Opening Time
100 % 0.002 – 5 4 Hours, Min.
200%
0.002 – 0.3 5 Seconds, Max.
0.4 - 5 2 Seconds, Max.
Electrical Characteristics
Ampere
Rating
(A)
0.002 0.002 125
0.005 0.005 125 280 0.0000000766 X X X
0.010 0.010 125 80.0 0.000000462 X X X
0.015 0.015 125 44.0 0.00000123 X X X
0.031 0.031 125 16.0 0.00000810 X X X
0.050 0.050 125 3.52 0.0000666 X X X
0.062 0.062 125 2.55 0.000115 X X X
0.100 0.100 125 1.38 0.000385 X X X
0.125 0.125 125 1.0 0.000691 X X X
0.200 0.200 125 2.30 0.00409 X X X
0.250 0.250 125 1.75 0.00640 X X X
0.300 0.300 125 1.25 0.00945 X X X
0.400 0.400 125 0.227 0.0251 X X X
0.500 0.500 125 0.167 0.0716 X X X
0.600 0.600 125 0.430 0.0411 X X X
0.700 0.700 125 0.324 0.0710 X X X
0.750 0.750 125 0.293 0.0563 X X X
0.800 0.800 125 0.271 0.113 X X X
1.00 0 01.0 125 0.0880 0.0648 X X X
01. 5 01. 5 125 0.0578 0.160 X X X
2.00 002.0 125 0.0425 0.300 X X X
3.00 003.0 125 0.0275 0.759 X X X
*4.00 004.0 125 0.0202 1.38 X X X
*5.00 005.0 125 0.0156 2.21 X X X
* The fuses of 4A and 5A for 272 and 278 Series are obsolete.
Amp Code
(for all above
series)
Max
Voltage
Rating (V)
Interrupting
Rating
10,000A@125VAC/VDC
Nominal Cold
Resistance
(Ohms)
2200 0.00000000845 X X X
Specifications are subject to change without notice. Application testing is strongly recommended.
Nominal Melting
I2t (A2 sec)
Agency Approvals
Specifications are subject to change without notice.
© 2019 Littelfuse, Inc.
Revised: 11/14/19
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Axial Lead & Cartridge Fuses
MICRO™ > Very Fast-Acting Fuse > 272/273/274/278/279 Series
Temperature Re-rating Curve
Note:
1. Rerating depicted in this curve is in addition to the standard derating of 25% for
continuous operation.
Average Time Current Curves
1/64 A
1/100 A
1/200 A
100
10
1
TIME IN SECONDS
0.1
0.01
0.001
0.005
0.01
1/32 A
1/16 A
1/8 A
1/4 A
0.1
CURRENT IN AMPERES
1/2 A
1
3/4 A
1 A
1 1/2 A
2 A
3 A
4 A
5 A
10
100
Soldering Parameters - Wave Soldering
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
Temperature (°C) - Measured on bottom side of board
0
102030405060708090
Time (Seconds)
Preheat Time
100
110
120
130
140
150
Dwell Time
160
170
Cooling Time
Recommended Process Parameters:
Wave Parameter Lead-Free Recommendation
Preheat:
(Depends on Flux Activation Temperature) (Typical Industry Recommendation)
Temperature Minimum: 10 0° C
Temperature Maximum: 150° C
Preheat Time: 60-180 seconds
Solder Pot Temperature: 260° C Maximum
Solder Dwell Time: 2-5 seconds
Recommended Hand-Solder Parameters:
Solder Iron Temperature: 350° C +/- 5°C
180
190
200
210
220
230
Heating Time: 5 seconds max.
240
Note: These devices are not recommended for IR or Convection Reflow process.
Specifications are subject to change without notice.
© 2019 Littelfuse, Inc.
Revised: 11/14/19
Page 3
Axial Lead & Cartridge Fuses
2.54 (.10")
272 000 Series
(Short Lead, Metal Cap)
NOTE:
Leads are tin plated copper; .025" diameter.
MICRO™ > Very Fast-Acting Fuse > 272/273/274/278/279 Series
Product Characteristics
Operating Temperature:
Fuses to MIL SPEC
Materials
Product Marking Current and voltage ratings stamped on cap
273 and 279: –55ºC to +85ºC;
272 and 278: –55ºC to +125ºC
Military QPL type (FM02).
To order, change 273 to 274.
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
Part Numbering System
0273 xxxx V
Series
Amp. Code
Refer to Amp Code column of
Electrical Characteristics Table
Packaging Code
V = 5
H = 100
Additional Information
Dimensions
5.97
(.235")
7.30
(.29")
4.32
(.17")
278 000 Series
(Long Lead, Metal Cap)
5.97
(.235")
7.30
(.29")
273 000 and 274 000 Series
(Short Lead, Clear Plastic Cap)
6.35
(.25")
8.89
(.35")
4.32
(.17")
279 000 Series
(Long Lead, Clear Plastic Cap)
6.35
(.25")
8.89
(.35")
2.54 (.10")
25.4 (1.0")
2.54 (.10")
2.54 (.10")
25.4 (1.0")
Datasheet
272 Series
Datasheet
273 Series
Datasheet
274 Series
Datasheet
278 Series
Datasheet
279 Series
Disclaimer Notice - Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and test each product selected for their own applications. Littelfuse products are
not designed for, and may not be used in, all applications. Read complete Disclaimer Notice at: www.littelfuse.com/disclaimer-electronics.
Resources
272 Series
Resources
273 Series
Resources
274 Series
Resources
278 Series
Resources
279 Series
Samples
272 Series
Samples
273 Series
Samples
274 Series
Samples
278 Series
Samples
279 Series
Amperage and voltage rating stamped on cap.
Packaging
Packaging
Option
Bulk N / A 5 V
Bulk N / A 100 H
*Only V-pack version for low current rating from 0.002 - 0.062 (A) and for 274, 278, 279 Series
Packaging
Specification
Quantity
Specifications are subject to change without notice.
Quantity &
Packaging Code
© 2019 Littelfuse, Inc.
Revised: 11/14/19
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