1
Cartridge and Axial Lead Fuses
©2008 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com for current information.
Revised: August 14, 2008
251/253 Series
PICO® II > Very Fast-Acting > 251/253 Series
Cartridge and Axial Lead Fuses
PICO® II > Very Fast-Acting > 251/253 Series
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 J02037794 500mA - 10A
QP
L
FM10 62mA - 15A
Features
Electrical Characteristics
t 7FSZGBTUBDUJOH
t 4NBMMTJ[F
t 8JEFDVSSFOUSBUJOHSBOHF
(62mA- 15A)
t 3P)4DPNQMJBOU
t 8JEFPQFSBUJOH
temperature range
t -PXUFNQFSBUVSFEFSBUJOH
% of Ampere
Rating Ampere Rating Opening Time
100% 1/16–15 )PVSTMin.
200%
1/16–7 4FDPOETMax.
10 4FDPOET Max.
12-15 4FDPOETMax.
Applications
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
(mV)
Agency Approvals
®
®
PS
ETUV QPL
.062 .062 251.062 253.062 125
300 amperes
at rated
WPMUBHF7%$
50 amperes at
SBUFEWPMUBHF
VAC
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
.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 x x x x x
1.25 1.25 2511.25 125 0.100 0.390 0.2 x x x x
1.50 01.5 25101.5 25301.5 125 0.0823 0.587 0.21 x x x x x
2.00 002. 251002. 253002. 125 0.0473 0.405 0.141 x x x x x
2.50 02.5 25102.5 125 0.0360 0.721 0.132 x x x x
3.00 003. 251003. 253003. 125 0.0290 1.19 0.131 x x x x x
3.50 03.5 25103.5 125 0.0240 1.58 0.1205 x x x x
4.00 004. 251004. 253004. 125 0.0204 2.45 0.114 x x x x x
5.00 005. 251005. 253005. 125 0.0155 4.14 0.11 x x x x x
7.00 007. 251007. 253007. 125 0.0105 10.4 0.102 x x x x
10.0 010. 251010. 253010. 125 0.00705 25.5 0.1 x x x x
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 Characteristics
Note: )JHIFSBNQFSFSBUJOHTBSFBWBJMBCMF1MFBTFDPOUBDU-JUUFMGVTF5FDIOJDBM4VQQPSUPSZPVS-JUUFMGVTFQSPEVDUTSFQSFTFOUBUJWFGPSBTTJTUBODF
RoHS
®
PS
E
t 'MBUoQBOFMEJTQMBZ57
t -$%NPOJUPS
t -$%CBDLMJHIUJOWFSUFS
t 0GmDFNBDIJOFT
t 1PXFSTVQQMZ
t "VEJP7JEFPTZTUFN
t -JHIUJOHTZTUFN
t .FEJDBMFRVJQNFOU
4FDPOEBSZQSPUFDUJPOGPSTQBDFDPOTUSBJOFEBQQMJDBUJPOT
TUV
®
QPL
2
Cartridge and Axial Lead Fuses
©2008 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com for current information.
Revised: August 14, 2008
251/253 Series
PICO® II > Very Fast-Acting > 251/253 Series
Cartridge and Axial Lead Fuses
PICO® II > Very Fast-Acting > 251/253 Series
Average Time Current CurvesTemperature Rerating Curve
Soldering Parameters
100
10
1
0.1
0.01
0.001
0.062A
0.05 0.1 1 10 100 1000
0.125A
0.250A
0.375A
0.50A
0.75A
1.00A
1.50A
2.0A
2.5A
3.0A
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¡$¡$
)FBUJOH5JNFTFDPOETNBY
Note: These devices are not recommended for IR or
Convection Reflow process.
Recommended Process Parameters:
3
Cartridge and Axial Lead Fuses
©2008 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com for current information.
Revised: August 14, 2008
251/253 Series
PICO® II > Very Fast-Acting > 251/253 Series
Cartridge and Axial Lead Fuses
PICO® II > Very Fast-Acting > 251/253 Series
Materials &ODBQTVMBUFE&QPYZ$PBUFE
#PEZ1VSF5JODPBUFE$PQQFSXJSFMFBET
Solderability .*-45%.FUIPE
Lead Pull Force .*-45%.FUIPE5FTU$POEJUJPO
"XJMMXJUITUBOEBMCTBYJBMQVMMUFTU
Fuses To MIL SPEC
4FSJFTJTBWBJMBCMFJO'.PO
21-GPS.*-13'5PPSEFSDIBOHF
251 to 253
Product Characteristics
Operating Temperature o$UP$
Shock
.*-45%.FUIPE5FTU
Condition I (100 G’s peak for 6
NJMMJTFDPOET
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 260º$NBYJNVN
Flammability Rating UL 94V–0
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
2.80 (.11")
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
(T3 lead length)
F
L1 A
F
L1 A
73.0 (2.874")**
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
(T1 lead length)
Dimensions
Packaging
Part Numbering System
Packaging Option Packaging Specification Quantity &
Packaging Code
5NN5BQFBOE3FFM EIA 296
1MFBTFSFGFSUPBWBJMBCMFRVBOUJUJFT
BCPWFJO1BSU/VNCFSJOH4ZTUFNw
5NNh5BQFBOE3FFM EIA 296
0251 xxxx N R T1 L
RoHS
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
V = 5
Refer to Amp Code column of
Electrical Characteristics Table
251
= Standard type
253
= Military type
5IFEFGBVMUMFBEMFOHUIGPSCPUIBNNPQBDLBOEMPPTFQBDLJT5GPSBOEJT5GPS
/PUFT 5EJNFOTJPOJTEFmOFE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EFmOFEBTUIFMFOHUIPGUIFDPNQPOFOUCFUXFFOUIFUXPUBQFT5IFGVMMDPNQPOFOUMFOHUIJTNNwT3 length is for 253 series only.