Axial Lead & Cartridge Fuses
PICO
®
ll > Very Fast-Acting > 251/253 Series
251/253 Series,
PICO
®
II, Very Fast-Acting Fuse
PS
E
TUV
QPL
Description
The PICO
®
II Very Fast-Acting Fuse is designed to meet an
extensive array of performance characteristics in a
space-saving subminiature package.
Features
temperature range
range (62mA- 15A)
rerating
Agency Approvals
Agency
Agency File Number
Ampere Range
Applications
E10480
LR 29862
PS
E
62mA - 15A
62mA - 15A
1A - 5A
500mA - 10A
62mA - 15A
500mA, 1A, 2A, 2.5A,
3A, 4A, 5A, 7A, 10A
JET 1896-31007-1001
J50158379
FM10
2009010207366577 –
500mA to 5A
Pending – 7A, 10A
TUV
Electrical Characteristics for Series
% of Ampere
Rating
100%
200%
Ampere Rating
62mA - 15A
62mA - 7A
10A
12 - 15A
275%
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
Opening Time
4 Hours, Min.
1 Second, Max.
3 Seconds, Max.
10 Seconds, Max.
300 msecs., Max.
QPL
400%
30 msecs., Max.
1000%
4 msecs., Max.
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
199
Revised: July 27, 2011
251/253 Series
251/253 Series
Introduction to & Cartridge Fuses
Axial Lead Circuit Protection
Transientology
PICO
®
ll > Very Fast-Acting > 251/253 Series
Electrical Specifications by Item
Nom
Max
Nominal
Ampere
Nominal
Ordering Ordering
Voltage
Amp
Voltage Interrupting
Cold
Rating
Melting
Number Number
Drop
Code
Rating
Rating
Resistance
2
(A)
I t (A
2
sec)
(Std.)
(Mil.)
(V)
(V)
(Ohms)
.062
.125
.250
.375
.500
.630
.750
1.00
1.25
1.50
2.00
2.50
3.00
3.50
4.00
5.00
7
.00
10.0
12.0
15.0
Note:
P = Pending
Agency Approvals
PS
E
TUV
QPL
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
.062
.125
.250
.375
.500
.630
.750
001.
1.25
01.5
002.
02.5
003.
03.5
004.
005.
007
.
010.
012.
015.
251.062
251.125
251.250
251.375
251.500
251.630
251.750
251001.
2511.25
25101.5
251002.
25102.5
251003.
25103.5
251004.
251005.
251007
.
251010.
251012.
251015.
253.062
253.125
253.250
253.375
253.500
253.750
253001.
25301.5
253002.
253003.
253004.
253005.
253007
.
253010.
253015.
125
125
125
125
125
125
125
125
125
125
125
125
125
125
125
125
125
125
32
32
300 A @ rated
50 A @ rated
For CCC 7A:
70 A @ rated
For CCC 10A:
100 A @ rated
7
.000
1.700
0.665
0.395
0.280
0.205
0.175
0.128
0.100
0.0823
0.0473
0.0360
0.0290
0.0240
0.0204
0.0155
0.0105
0.00705
0.0055
0.00446
0.000113
0.00174
0.0116
0.0296
0.0598
0.094
0.153
0.256
0.390
0.587
0.405
0.721
1.19
1.58
2.45
4.14
10.4
25.5
45.2
68.8
1.4
0.285
0.24
0.215
0.2165
0.188
0.176
0.194
0.2
0.21
0.141
0.132
0.131
0.1205
0.114
0.11
0.102
0.1
0.0878
0.071
x
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P
P
251/253 Series
200
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
Axial Lead & Cartridge Fuses
PICO
®
ll > Very Fast-Acting > 251/253 Series
Temperature Rerating Curve
Average Time Current Curves
.250A
.375A
.500A
.630A
.750A
1A
1.25A
1.5A
2A
2.5A
3A
3.5A
4A
5A
7A
10A
12A
15A
1
10
CURRENT IN AMPERES
100
.062A
100
10
TIME IN SECONDS
1
0.1
.125A
Note:
1. Rerating depicted in this curve is in addition to the standard rerating of 25% for
continuous operation.
0.01
Soldering Parameters
Recommended Process Parameters:
Wave Parameter
Preheat:
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
Lead-Free Recommendation
0.001
0.05 0.1
1000
Recommended Hand-Solder Parameters:
Heating Time: 5 seconds max.
Note: These devices are not recommended for IR or
Convection Reflow process.
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
201
251/253 Series
251/253 Series
Introduction to & Cartridge Fuses
Axial Lead Circuit Protection
Transientology
PICO
®
ll > Very Fast-Acting > 251/253 Series
Product Characteristics
Materials
Solderability
Lead Pull Force
Vibration
Fuses To MIL SPEC
QPL for MIL-PRF-23419. To order, change
251 to 253
Moisture Resistance
Resistance to Soldering
Heat
Flammability Rating
O
Body:
Operating Temperature
Shock
Condition I (100 G’s peak for 6
msecs.)
C
and up to 260ºC, maximum
UL 94V–0
Dimensions
251 Series (RoHS Version) Markings
(T1 lead length)
62.7 (2.468")
52.4 (2.062")*
7.11 (.280")
Part Numbering System
0251 xxxx N R T1 L
Series
251
= Standard type
253
= Military type
6.35 (.25")
tape
27.78
(1.094")
27.78
(1.094")
1A
6.35 (.25")
tape
5.0 (.197")
F
L
2.80
(.11")
MAX
Current Rating
Refer to Amp Code column of
Electrical Specifications Table
1A
F
L
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 12-15 amp
Quantity
N
= 5000
P
= 2000
M
= 1000
H
= 100
251 Series (RoHS and Halogen-free Version) Markings
(T1 lead length)
62.7 (2.468")
52.4 (2.062")*
7.11 (.280")
27.78
(1.094")
27.78
(1.094")
F
L
6.35 (.25")
tape
5.0 (.197")
1A
2.80
(.11")
MAX
6.35 (.25")
tape
Type of Packaging
R = Reel
A = Ammo Pack
X = Loose Pack
1A
F
L
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 12-15 amp
Lead Length
The default lead length for Ammo pack and
Loose pack is now T1 for 251 series, and
remains T3 for 253 series, therefore:
T1
= 52.4mm (2.062”), 251 series only*
Blank
= 52.4mm (2.062”) for 251 series*
or 73mm (2.874”) for 253 series**
6.35 (.25")
tape
253 Series (RoHS Version) Markings
(T3 lead length)
83.31 (3.28")
38.1
(1.5")
73.0 (2.874")**
7.11 (.280")
38.1
(1.5")
F
L
6.35 (.25")
tape
5.0 (.197")
1A
2.61 (.103")
MAX
Option Codes
L
= RoHS + HF
F
L
1A
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 15 amp
Packaging
Packaging Option
Packaging Specification
EIA 296
EIA 296
above in "Part Numbering System”
Quantity &
Packaging Code
T1 length is for 251 series only.
T3 length is for 253 series only.
251/253 Series
202
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
