Axial Lead & Cartridge Fuses
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
above in "Part Numbering System”
EIA 296
Quantity &
Packaging Code
T1 length is for 251 series only.
T3 length is for 253 series only.
251/253 Series
© 2012 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/251.html
or /253.html for current information.
LITTELFUSE [ LITTELFUSE ]
