Radial Lead Fuses
MICRO™ > Very Fast-Acting > 272/273/274/278/279 Series
272/273/274/278/279 Series, MICRO™ Very Fast-Acting Fuse
Description
QPL
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
1/500 to 5A to suit a wide variety of design needs.
Features
• Military grade available
• High breaking capacity
Agency Approvals
Agency
Agency File Number
Ampere Range
• Available from very low
ampere of 2mA to 5A
• Clear cover option to view • Plug-in with short or long
leads option
fuse element status
Applications
• Printed circuit boards
and similar equipment
Electrical Characteristics
% of Ampere
Rating
100%
200%
Ampere Rating
1/500–5
1/500–3/10
4/10-5
Opening Time
4 Hours,
Min.
5 Seconds,
Max.
2 Seconds,
Max.
E10480
LR 29862
2mA - 5A
2mA - 5A
2mA - 5A
• Electronic components
QPL
FM02
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
Nominal
Cold
Resistance
(Ohms)
2200
280
80.0
44.0
16.0
3.20
2.32
1.25
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
Nominal
melting
I
2
t (A
2
sec)
0.00000000845
0.00000000810
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
0.0900
0.113
0.0648
0.160
0.300
0.759
1.38
2.21
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Agency Approvals
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
10,000 amperes at
125 VAC/VDC.
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/19/13
Radial Lead Fuses
MICRO™ > Very Fast-Acting > 272/273/274/278/279 Series
Temperature Rerating Curve
Average Time Current Curves
1/200 A
1/100 A
1/64 A
100
10
TIME IN SECONDS
1
0.1
0.01
0.001
0.005
1/2 A
3/4 A
1A
1 1/2 A
2A
3A
4A
5A
1/32 A
1/16 A
1/8 A
1/4 A
0.01
0.1
1
CURRENT IN AMPERES
10
100
Soldering Parameters - Wave Soldering
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
10
20
30
40
50
60
70
80
90
0
0
Recommended Process Parameters:
Wave parameter
preheat:
(Depends on Flux Activation Temperature)
(Typical Industry Recommendation)
Temperature (°C) - Measured on bottom side of board
lead-Free Recommendation
Temperature Minimum:
Temperature Maximum:
Preheat Time:
Solder pot Temperature:
Solder Dwell Time:
100
°
C
150
°
C
60-180 seconds
260
°
C Maximum
2-5 seconds
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.
Time (Seconds)
Preheat Time
Dwell Time
Cooling Time
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/19/13
Radial Lead Fuses
MICRO™ > Very Fast-Acting > 272/273/274/278/279 Series
Product Characteristics
273 and 279: –55ºC to +85ºC;
272 and 278: –55ºC to +125ºC
273 Series is available in CSA LR
29862. 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
Current and voltage ratings stamped
on cap
Dimensions
272 000 Series
(Short lead, metal Cap)
5.97
(.235")
7.30
(.29")
(.17")
Operating Temperature:
4.32
Fuses to MIL SPEC
2.54 (.10")
278 000 Series
(long lead, metal Cap)
5.97
(.235")
7.30
(.29")
25.4 (1.0")
2.54 (.10")
Materials
Product Marking
Part Numbering System
273 000 and 274 000 Series
(Short lead, Clear plastic Cap)
6.35
(.25")
8.89
(.35")
(.17")
0273 xxxx V
Series
Amp. Code
Refer to Amp Code column of
Electrical Characteristics Table
4.32
2.54 (.10")
279 000 Series
(long lead, Clear plastic Cap)
6.35
(.25")
8.89
(.35")
25.4 (1.0")
2.54 (.10")
Packaging Code
V=5
H = 100
Additional Information
NOTe: Amperage and voltage rating stamped on cap.
leads are tin plated copper; .025" diameter.
Datasheet
272 Series
Resources
272 Series
Samples
272 Series
Packaging
packaging
Option
packaging
Specification
N/A
N/A
Quantity &
packaging
Code
V
H
Quantity
Datasheet
273 Series
Resources
273 Series
Samples
273 Series
Bulk
Bulk
5
100
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
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/19/13