Introduction to Circuit Protection
Introduction to Circuit Protection
Transientology
202
2009 Littelfuse, Inc.
Specifications 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
Body:
Solderability
Lead Pull Force
Fuses To MIL SPEC
QPL for MIL-PRF-23419. To order, change
251 to 253
Product Characteristics
Operating Temperature
Shock
Condition I (100 G’s peak for 6
msecs.)
Vibration
Moisture Resistance
Resistance to Soldering
Heat
O
C
and up to 260C, maximum
Flammability Rating
UL 94V–0
Dimensions
Packaging
Part Numbering System
Packaging Option
Packaging Specification
Quantity &
Packaging Code
EIA 296
above in "Part Numbering System”
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 = RoHS and Halogen-free
(for 251 Series only)
T1 length is for 251 series only.
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)
L 1 A
73.0 (2.874")**
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 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