199
© 2009 Littelfuse, Inc.
Specications are subject to change without notice.
Axial Lead & Cartridge Fuses
251/253 Series
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
PICO® ll > Very Fast-Acting > 251/253 Series
251/253 Series
Revised: July 27, 2011
251/253 Series, PICO® II, Very Fast-Acting Fuse
Description
The PICO® II Very Fast-Acting Fuse is designed to meet an
extensive array of performance characteristics in a
space-saving subminiature package.
Agency Approvals
Agency Agency File Number Ampere Range
E10480 62mA - 15A
LR 29862 62mA - 15A
PS
EJET 1896-31007-1001 1A - 5A
TUV J50158379 500mA - 10A
QP
L
FM10 62mA - 15A
2009010207366577 –
500mA to 5A
Pending – 7A, 10A
500mA, 1A, 2A, 2.5A,
3A, 4A, 5A, 7A, 10A
Features
Electrical Characteristics for Series
% of Ampere
Rating Ampere Rating Opening Time
100% 62mA - 15A 4 Hours, Min.
200%
62mA - 7A 1 Second, Max.
10A 3 Seconds, Max.
12 - 15A 10 Seconds, Max.
275%
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
300 msecs., Max.
400%
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
30 msecs., Max.
1000%
500mA, 1A, 2A,
2.5A, 3A, 4A, 5A,
7A, 10A
4 msecs., Max.
Applications
PS
E
t 'MBUoQBOFMEJTQMBZ57
t -$%NPOJUPS
t -$%CBDLMJHIUJOWFSUFS
t 0GåDFNBDIJOFT
t 1PXFSTVQQMZ
t "VEJP7JEFPTZTUFN
t -JHIUJOHTZTUFN
t .FEJDBMFRVJQNFOU
4FDPOEBSZQSPUFDUJPOGPSTQBDFDPOTUSBJOFEBQQMJDBUJPOT
TUV QP
L
t 7FSZGBTUBDUJOH
t 4NBMMTJ[F
t 8JEFDVSSFOUSBUJOH
range (62mA- 15A)
t 3P)4DPNQMJBOU
t )BMPHFOGSFFBWBJMBCMF
t 8JEFPQFSBUJOH
temperature range
t -PXUFNQFSBUVSF
rerating
Introduction to Circuit Protection
Introduction to Circuit Protection
Transientology
200 © 2009 Littelfuse, Inc.
Specications are subject to change without notice.
Axial Lead & Cartridge Fuses
251/253 Series
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
PICO® ll > Very Fast-Acting > 251/253 Series
Ampere
Rating
(A)
Amp
Code
Ordering
Number
(Std.)
Ordering
Number
(Mil.)
Max
Voltage
Rating
(V)
Interrupting
Rating
Nominal
Cold
Resistance
(Ohms)
Nominal
Melting
I2t (A2 sec)
Nom
Voltage
Drop
(V)
Agency Approvals
PS
ETUV QP
L
.062 .062 251.062 253.062 125
300 A @ rated
WPMUBHF%$
50 A @ rated
WPMUBHF"$
For CCC 7A:
70 A @ rated
WPMUBHF"$
For CCC 10A:
100 A @ rated
WPMUBHF"$
7.000 0.000113 1.4 x x x
.125 .125 251.125 253.125 125 1.700 0.00174 0.285 x x x
.250 .250 251.250 253.250 125 0.665 0.0116 0.24 x x x
.375 .375 251.375 253.375 125 0.395 0.0296 0.215 x x x
.500 .500 251.500 253.500 125 0.280 0.0598 0.2165 x x x x x
.630 .630 251.630 125 0.205 0.094 0.188 x x
.750 .750 251.750 253.750 125 0.175 0.153 0.176 x x x x
1.00 001. 251001. 253001. 125 0.128 0.256 0.194 xxxxxx
1.25 1.25 2511.25 125 0.100 0.390 0.2 x x x
1.50 01.5 25101.5 25301.5 125 0.0823 0.587 0.21 xxxxx
2.00 002. 251002. 253002. 125 0.0473 0.405 0.141 xxxxxx
2.50 02.5 25102.5 125 0.0360 0.721 0.132 xxxx x
3.00 003. 251003. 253003. 125 0.0290 1.19 0.131 xxxxxx
3.50 03.5 25103.5 125 0.0240 1.58 0.1205 xxxx
4.00 004. 251004. 253004. 125 0.0204 2.45 0.114 xxxxxx
5.00 005. 251005. 253005. 125 0.0155 4.14 0.11 xxxxxx
7.00 007. 251007. 253007. 125 0.0105 10.4 0.102 x x x x P
10.0 010. 251010. 253010. 125 0.00705 25.5 0.1 x x x x P
12.0 012. 251012. 32 0.0055 45.2 0.0878 x x
15.0 015. 251015. 253015. 32 0.00446 68.8 0.071 x x x
Electrical Specications by Item
Note: )JHIFSBNQFSFSBUJOHTBSFBWBJMBCMF1MFBTFDPOUBDU-JUUFMGVTF5FDIOJDBM4VQQPSUPSZPVS-JUUFMGVTFQSPEVDUTSFQSFTFOUBUJWFGPSBTTJTUBODF
P = Pending
201
© 2009 Littelfuse, Inc.
Specications are subject to change without notice.
Axial Lead & Cartridge Fuses
251/253 Series
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
PICO® ll > Very Fast-Acting > 251/253 Series
251/253 Series
Average Time Current CurvesTemperature Rerating Curve
Soldering Parameters
100
10
1
0.1
0.01
0.001
.062A
0.05 0.1 1 10 100 1000
.125A
.250A
.375A
.500A
.750A
.630A
1A
1.5A
2A
2.5A
3A
3.5A
4A
5A
7A
10A
12A
15A
TIME IN SECONDS
CURRENT IN AMPERES
1.25A
Wave Parameter Lead-Free Recommendation
Preheat:
%FQFOETPO'MVY"DUJWBUJPO5FNQFSBUVSF 5ZQJDBM*OEVTUSZ3FDPNNFOEBUJPO
Temperature Minimum: 100° 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:
4PMEFS*SPO5FNQFSBUVSF¡$¡$
Heating Time: 5 seconds max.
Note: These devices are not recommended for IR or
Convection Reow process.
Recommended Process Parameters:
Note:
1. Rerating depicted in this curve is in addition to the standard rerating of 25% for
continuous operation.
Introduction to Circuit Protection
Introduction to Circuit Protection
Transientology
202 © 2009 Littelfuse, Inc.
Specications are subject to change without notice.
Axial Lead & Cartridge Fuses
251/253 Series
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
PICO® ll > Very Fast-Acting > 251/253 Series
Materials &ODBQTVMBUFE&QPYZ$PBUFE
Body:1VSF5JODPBUFE$PQQFSXJSFMFBET
Solderability .*-45%.FUIPE
Lead Pull Force .*-45%.FUIPE5FTU$POEJUJPO
"XJMMXJUITUBOEBMCTBYJBMQVMMUFTU
Fuses To MIL SPEC
4FSJFTJTBWBJMBCMFJO'.PO
QPL for MIL-PRF-23419. To order, change
251 to 253
Product Characteristics
Operating Temperature o$UP$
Shock
.*-45%.FUIPE5FTU
Condition I (100 G’s peak for 6
msecs.)
Vibration
.*-45%.FUIPEo
)[.FUIPE5FTU$POEJUJPO$
o)[BU(T1FBL
Moisture Resistance .*-45%.FUIPE
Resistance to Soldering
Heat
8JUITUBOETTFDPOETBCPWFOC
and up to 260ºC, maximum
Flammability Rating UL 94V–0
Dimensions
Packaging
Part Numbering System
Packaging Option Packaging Specication Quantity &
Packaging Code
5NN5BQFBOE3FFM EIA 296
1MFBTFSFGFSUPBWBJMBCMFRVBOUJUJFT
above in "Part Numbering System”
5NNh5BQFBOE3FFM EIA 296
0251 xxxx N R T1 L
Lead Length
Type of Packaging
Quantity
Current Rating
Series
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**
R = Reel
A = Ammo Pack
X = Loose Pack
N = 5000
P = 2000
M = 1000
H = 100
Refer to Amp Code column of
Electrical Specifications Table
251
= Standard type
253
= Military type
Option Codes
L = RoHS + HF
5IFEFGBVMUMFBEMFOHUIGPSCPUIBNNPQBDLBOEMPPTFQBDLJT5GPSBOEJT5GPS
/PUFT 5EJNFOTJPOJTEFåOFEBTUIFMFOHUIPGUIFDPNQPOFOUCFUXFFOUIFUXPUBQFT5IFGVMMDPNQPOFOUMFOHUIJTNN T1 length is for 251 series only.
5EJNFOTJPOJTEFåOFEBTUIFMFOHUIPGUIFDPNQPOFOUCFUXFFOUIFUXPUBQFT5IFGVMMDPNQPOFOUMFOHUIJTNNwT3 length is for 253 series only.
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 15 amp
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 12-15 amp
2.61 (.103")
MAX 6.35 (.25")
tape
5.0 (.197")
6.35 (.25")
tape
38.1
(1.5")
38.1
(1.5")
7.11 (.280")
83.31 (3.28")
253 Series (RoHS Version) Markings
(T3 lead length)
L1 A
L1 A
73.0 (2.874")**
L1 A
F
L
1 A
27.78
(1.094")
27.78
(1.094")
7.11 (.280")
62.7 (2.468")
52.4 (2.062")*
2.80
(.11")
MAX 6.35 (.25")
tape
5.0 (.197")
6.35 (.25")
tape
251 Series (RoHS and Halogen-free Version) Markings
(T1 lead length)
Wire Diameter:
0.64 (.025") for 0.62-10.0 amp,
0.81 (.032") for 12-15 amp
F
L
1 A
F
L
1 A
27.78
(1.094")
27.78
(1.094")
7.11 (.280")
62.7 (2.468")
52.4 (2.062")*
2.80
(.11")
MAX 6.35 (.25")
tape
5.0 (.197")
6.35 (.25")
tape
251 Series (RoHS Version) Markings
(T1 lead length)
F
F
F