437 Series Datasheet by Littelfuse Inc.

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© 2018 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/13/18
Surface Mount Fuses
Ceramic Fuse > 437 Series
437 Series – 1206 Fast-Acting Fuse
Description
This 100% Lead-free, RoHS compliant and Halogen-free
fuse series has been designed specifically to provide over
current protection to circuits that see 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.
Agency Approvals
AGENCY AGENCY FILE NUMBER AMPERE RANGE
E10480 0.250A ~ 8A
29862 0.250A ~ 8A
Features
Electrical Characteristics for Series
Operating Temperature
from -55ºC to +150ºC
100% Lead-free, Halogen-
Free and RoHS compliant
Suitable for both leaded
and lead-free reflow /
wave soldering
% of Ampere
Rating Ampere Rating Opening Time at 25ºC
100% 250mA - 8A 4 hours, Minimum
250% 750mA - 8A 5 seconds, Maximum
350% 250mA -500mA 5 seconds, Maximum
350% 750mA - 8A 1 second, Maximum
Applications
Ampere
Rating
(A)
Amp
Code
Max.
Voltage
Rating (V) Interrupting Rating1
Nominal
Resistance
(Ohms)2
Nominal
Melting I2t
(A2Sec.)3
Nominal Voltage
Drop At Rated
Current (V)4
Nominal Power
Dissipation At
Rated Current (W)
Agency Approvals
0.250 .250 125 50 A @ 125 V AC/DC 2.290 0.003 0.78 0.195 x x
0.375 .375 125 1.330 0.010 0.60 0.225 x x
0.500 .500 63
50 A @ 63 V AC/DC
0.908 0.018 0.52 0.260 x x
0.750 .750 63 0.665 0.064 0.45 0.338 x x
1. 0 0 0 01. 63 0.420 0.100 0.41 0.410 x x
1.25 1.25 63 0.318 0.256 0.40 0.500 x x
1.50 01.5 63 0.209 0.324 0.39 0.585 x x
1.75 1.75 63 0.071 0.075 0.27 0.473 x x
2.00 002. 63 0.058 0.225 0.20 0.400 x x
2.50 02.5 32
50 A @ 32 V AC/35 V DC
0.043 0.441 0.15 0.375 x x
3.00 003. 32 0.033 0.506 0.14 0.420 x x
3.50 03.5 32 0.027 0.777 0.13 0.455 x x
4.00 004. 32 0.022 1.024 0.13 0.520 x x
5.00 005. 32 0.0159 2.30 0.13 0.650 x x
7. 0 0 0 0 7. 32 0.0100 5.02 0.13 0.910 x x
8.00 008. 32 0.008 7.23 0.13 1.040 x x
Electrical Specifications by Item
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.
RoHS
Pb
LCD Displays
• Servers
• Printers
• Scanners
Data Modems
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.
Application testing is strongly recommended.
Additional Information
Datasheet Samples
Resources
% Litteltuse” ExnevhxeADnlled \ AnswevxDelweved
© 2018 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/13/18
Surface Mount Fuses
Ceramic Fuse > 437 Series
Average Time Current Curves
.250A
4A
3.5A
3A
2.5A
2A
1.75A
1.5A
1.25A
1A
.500A
.375A
7A
5A
.750A
8A
0.001
0.01
0.1
1
10
TIME IN SECONDS
0.1110 100
CURRENT IN AMPERES
Reflow Condition Pb – free assembly
Pre Heat
- 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 5°C/second max.
Reflow - 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
Soldering Parameters
Temperature Re-rating Curve
40
60
80
100
120
140
-65 -45 -25 -5 15 35 55 75 95 115 135 15 5
TEMPERATURE C)
PERCENT OF RATING
Time
Temperature
TP
TL
TS(max)
TS(min)
25
tP
tL
tS
time to peak temperature
(t 25ºC to peak)
Ramp-down
Ramp-up
Preheat
Critical Zone
TL to TP
Example:
For continuous operation at 75 degrees celsius, the fuse should be rerated as follows:
I = (0.80)(0.85)IRAT = (0.68)IRAT
Note:
1. Re-rating depicted in this curve is in addition to the standard re-rating of 20% for
continuous operation.
Wave Soldering 260°C, 10 seconds max.
% Littelfuse" Expemsn mm \ Answcv: mums 0437 008. W R P x “I El
© 2018 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/13/18
Surface Mount Fuses
Ceramic Fuse > 437 Series
Materials
Body: Advanced Ceramic
Terminations: Ag / Ni / Sn (100% Lead-free)
Element Cover Coating: Ceramic/Lead-free
Glass
Moisture
Sensitivity Level IPC/JEDEC J-STD-020, Level 1
Solderability IPC/EIC/JEDEC J-STD-002, Condition B
Humidity Test MIL-STD-202, Method 103, Condition D
Resistance to
Solder Heat MIL-STD-202, Method 210, Condition B
Moisture
Resistance MIL-STD-202, Method 106
Product Characteristics
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
Dissolution of
Metallization IPC/EIC/JEDEC J-STD-002,
Condition D
Terminal Strength IEC 60127-4
Dimensions
0.520 ± 0.200
[0.020 ± 0.008]
3.200 ± 0.1778
[0.126 ± 0.007]
1. 000
[0.039]
1.63 +0.10 / -0.2
[0.064 +0.004 / -0.008]
1.500
[0.059]
1.800
[0.071]
3.500
[0.138]
1. 000
[0.039]
0.8179 +0.046 / -0.076
[0.0322 +0.0018 / -0.003]
3.200 ± 0.1778
[0.126 ± 0.007]
1.63 +0.10 / -0.2
[0.064 +0.004 / -0.008]
N
H
Packaging
Part Marking System
Packaging
Option Packaging
Specification Quantity Quantity &
Packaging Code
8mm Tape
and Reel EIA-481, IEC
60286-3 3000 WR
Part Numbering System
0437 008. W R
SERIES
AMP CODE
QUANTITY CODE
PACKING CODE
W = 3000 pcs
R = Reel Pack
Amp Code Marking Code
.250 D
.375 E
.500 F
.750 G
0 01. H
1.25 J
01.5 K
1.75 L
Amp Code Marking Code
002. N
02.5 O
003. P
03.5 R
004. S
005. T
0 0 7. W
008. X
O
N
P
R
S
T
W
X
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.

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