Surface Mount Fuses
Ceramic Fuse > 437 Series
437 Series – 1206 Fast-Acting Fuse
RoHS Pb
Description
This 100% Lead-free, RoHS compliant and Halogen-free
fuse series has been designed specifically to provide over
current protection to circuits might encounter high working
ambient temperatures (up to 150ºC).
The general design ensures excellent temperature stability
and performance reliability.
In addition to this, the high I²t values typical of the
Littelfuse Ceramic Fuse family ensure high inrush current
withstand capability.
Features
• Operating Temperature
from -55ºC to +150ºC
Agency Approvals
Agency
Agency File Number
Ampere Range
E10480
0.250A - 8A
29862
0.250A - 8A
• Suitable for both leaded
and lead-free reflow /
wave soldering
• 100% Lead-free, HalogenFree and RoHS compliant • UL Recognized to UL/
CSA/NMX 248-1 and UL/
CSA/NMX 248-14
Applications
Ampere Rating
• Scanners
• Servers
• Data Modems
• Printers
Electrical Characteristics for Series
% of Ampere
Rating
100%
• LCD Displays
Opening Time at 25ºC
250mA - 8A
4 hours, Minimum
250%
750mA - 8A
5 seconds, Maximum
350%
250mA -500mA
5 seconds, Maximum
350%
750mA - 8A
1 second, Maximum
Additional Information
Datasheet
Resources
Samples
Electrical Specifications by Item
Ampere
Rating
(A)
Amp
Code
Max.
Voltage
Rating (V)
0.25
0.375
0.5
0.75
1.0
1.25
1.5
1.75
2.0
2.5
3.0
3.5
4.0
5.0
7.0
8.0
.250
.375
.500
.750
001.
1.25
01.5
1.75
002.
02.5
003.
03.5
004.
005.
007.
008.
125
125
63
63
63
63
63
63
63
45
45
45
45
45
32
32
Interrupting Rating1
50 A @ 125 V AC/DC
50 A @ 63 V AC/DC
50A @ 45V AC/63V DC
50 A @ 32 V AC/35 V DC
Nominal
Resistance
(Ohms)2
Nominal
Melting I2t
(A2Sec.)3
Nominal Voltage
Drop At Rated
Current (V)4
Nominal Power
Dissipation At Rated
Current (W)
2.29
1.33
0.908
0.665
0.42
0.318
0.209
0.071
0.058
0.043
0.033
0.027
0.022
0.0159
0.01
0.008
0.003
0.01
0.018
0.064
0.1
0.256
0.324
0.075
0.225
0.441
0.506
0.777
1.024
2.3
5.02
7.23
0.78
0.6
0.52
0.45
0.41
0.4
0.39
0.27
0.2
0.15
0.14
0.13
0.13
0.13
0.13
0.13
0.195
0.225
0.26
0.338
0.41
0.5
0.585
0.473
0.4
0.375
0.42
0.455
0.52
0.65
0.91
1.04
Agency Approvals
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Notes:
1. AC Interrupting Rating tested at rated voltage with unity power factor. DC Interrupting Rating tested at rated voltage with time constant < 0.8 msec.
2. Nominal Resistance measured with < 10% rated current.
3. Contact Littelfuse if application transient surges are less than 1 ms.
4. Nominal Voltage Drop measured at rated current after temperature has stabilized.
Devices designed to carry rated current for 4 hours minimum. It is recommended that devices be operated continuously at no more than 80% rated current. See “Temperature Re-rating Curve”for additional re-rating information.
Devices designed to be mounted with marking code facing up.
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: GD. 10/19/20
Surface Mount Fuses
Ceramic Fuse > 437 Series
5A
7A
8A
2.5A
3A
3.5A
4A
1.25A
1.5A
1.75A
2A
120
100
1
80
60
40
-65
-45
-25
-5
15
35
55
75
95
115
135
155
TIME IN SECONDS
PERCENT OF RATING
10
.750A
1A
140
.250A
Average Time Current Curves
.375A
.500A
Temperature Re-rating Curve
0.1
TEMPERATURE (°C)
0.01
Note:
1. Re-rating depicted in this curve is in addition to the standard re-rating of 20% for continuous operation.
Example:
For continuous operation at 75 degrees celsius, the fuse should be rerated as follows:
I = (0.80)(0.85)IRAT = (0.68)IRAT
0.001
0.1
1
10
100
CURRENT IN AMPERES
Soldering Parameters
Pre Heat
Pb – free assembly
- Temperature Min (Ts(min))
150°C
- Temperature Max (Ts(max))
200°C
- Time (Min to Max) (ts)
60 – 180 seconds
Average Ramp-up Rate (Liquidus Temp (TL) to peak) 3°C/second max.
TS(max) to TL - Ramp-up Rate
Reflow
5°C/second max.
- Temperature (TL) (Liquidus)
217°C
- Temperature (tL)
60 – 150 seconds
Peak Temperature (TP)
260+0/-5 °C
Time within 5°C of actual peak Temperature (tp)
10 – 30 seconds
Ramp-down Rate
6°C/second max.
Time 25°C to peak Temperature (TP)
8 minutes max.
Do not exceed
260°C
Wave Soldering
tP
TP
Critical Zone
TL to TP
Ramp-up
TL
TS(max)
Temperature
Reflow Condition
tL
Ramp-down
TS(min)
25
Preheat
tS
time to peak temperature
(t 25ºC to peak)
Time
260°C, 10 seconds max.
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: GD. 10/19/20
Surface Mount Fuses
Ceramic Fuse > 437 Series
Product Characteristics
Body: Advanced Ceramic
Terminations: Ag / Ni / Sn (100% Lead-free)
Element Cover Coating: Ceramic/Lead-free Glass
Materials
Moisture Sensitivity
Level
Solderability
Humidity Test
Resistance to Solder
Heat
Moisture Resistance
Thermal Shock
MIL-STD-202, Method 107, Condition B
Mechanical Shock
MIL-STD-202, Method 213, Condition A
Vibration
MIL-STD-202, Method 201
Vibration, High Frequency
MIL-STD-202, Method 204, Condition D
IPC/EIC/JEDEC J-STD-002, Condition B
Dissolution of Metallization
IPC/EIC/JEDEC J-STD-002, Condition D
MIL-STD-202, Method 103, Condition D
Terminal Strength
IEC 60127-4
IPC/JEDEC J-STD-020, Level 1
MIL-STD-202, Method 210, Condition B
MIL-STD-202, Method 106
Dimensions
Part Marking System
3.200 ± 0.1778
[0.126 ± 0.007]
N
1.63 +0.10 / -0.2
[0.064 +0.004 / -0.008]
1.000
[0.039]
3.200 ± 0.1778
[0.126 ± 0.007]
H
1.63 +0.10 / -0.2
[0.064 +0.004 / -0.008]
Amp Code
Marking Code
Amp Code
Marking Code
0.25
D
2.0
N
0.375
E
2.5
O
0.5
F
3.0
P
0.75
G
3.5
R
1.0
H
4.0
S
1.25
J
5.0
T
1.5
K
7.0
W
1.75
L
8.0
X
Part Numbering System
0437
008. W R
Series
Packaging Code
R = Reel Pack
AMP Code
0.835 ± 0.15
[0.0329 ± 0.006]
Quantity Code
W = 3000 pcs
0.520 ± 0.200
[0.020 ± 0.008]
Packaging
1.000
[0.039]
1.500
[0.059]
1.800
[0.071]
Packaging
Option
8mm Tape
& Reel
Packaging
Specification
Quantity
Quantity & Packaging
Code
EIA-481, IEC 60286-3
3000
WR
3.500
[0.138]
Disclaimer Notice - Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications,
devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth
in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable
for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and
Conditions of Sale, unless otherwise agreed by Littelfuse. Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and test each product selected for their own
applications. Littelfuse products are not designed for, and may not be used in, all applications. Read complete Disclaimer Notice at www.littelfuse.com/disclaimer-electronics.
© 2020 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: GD. 10/19/20
