
Surface Mount Fuses
Thin Film > 1206 Size > Very Fast Acting > 433 Series
433 Series Fuse
Agency Approvals
Agency Agency File Number Ampere Range
®
Electrical Characteristics for Series
% of Ampere 
E10480 125mA - 5A
LR29862 125mA - 5A
®
Rating
100% 4 hours, Minimum
200% 5 sec., Maximum
300% 0.2 sec., Maximum
Opening Time at 25
®
®
Description
The 433 series fast-acting surface mount fuse series 
is a small (1206 size) thin-film device designed for 
secondary protection of circuits used in space constrained 
applications such as hand-held portable electronic devices. 
For RoHS compliant and lead-free design, please refer to 
the Littelfuse 466 series thin film fuse. For new designs of 
7 amp please refer to Littelfuse 429 series thin film fuse.
Features
t 5IF4MJN-JOF
fuse is an extremely 
small, low profile design 
(1206 chip size) utilizing 
thin-film technology to 
achieve precise control of 
electrical characteristics.
t 5IFMPXFSIFJHIUQSPmMF
produces a flat surface for 
improved performance in 
pick-and-place operations 
and an alternate solution 
for height critical 
application.
t .PVOUJOHQBEBOE
electrical specification are 
identical to the popular 
429 Series specifications.
Applications
O
C
Secondary protection for space constrained applications 
such as:
t $FMMQIPOFT
t #BUUFSZQBDLT
t %7%QMBZFST
t )BSEEJTLESJWFT
t %JHJUBMDBNFSBT
Electrical Specifications by Item
Ampere 
Rating
(A)
0.125 .125 125
0.200 .200 125 0.93800 0.00055 x x
0.250 .250 125 0.62500 0.00100 x x
0.375 .375 125 0.37500 0.00280 x x
0.50 .500 63
0.60 .600 63 0.21000 0.01310 x x
0.75 .750 63 0.13700 0.01700 x x
0.80 .800 63 0.12250 0.03050 x x
1.00 001. 63 0.09950 0.03500 x x
1.25 1.25 63 0.07475 0.06500 x x
1.50 01.5 63 0.06250 0.12500 x x
1.75 1.75 63 0.05000 0.15000 x x
2.00 02.0 63 0.03975 0.23000 x x
2.50 02.5 32
3.00 03.0 32 0.02625 0.70000 x x
4.00 04.0 24
5.00 05.0 24 0.01100 1.6000 x x
1. Measured at 10% of rated current, 25ºC.
2. Measured at rated voltage.
©2008 Littelfuse, Inc.
Specifications are subject to change without notice. 
Please refer to www.littelfuse.com for the most current information
Amp 
Code
Max
Voltage Rating 
(V)
Interrupting
Rating
50A @125 V AC/DC
50A @63 V AC/DC
50A @32 V AC/DC
50A @24 V AC/DC
Nominal Cold 
Resistance 
(Ohms)
3.45000 0.00040 x x
0.24050 0.00600 x x
0.03065 0.50000 x x
0.01400 1.0240 x x
7
Revision: February 13, 2008
Nominal 
Melting 
2
t (A2sec)
I
Agency Approvals
®
433 Series

Surface Mount Fuses
Thin Film > 1206 Size > Very Fast Acting > 433 Series
Temperature Rerating Curve
Average Time Current Curves
1.25A
1A
.8A
.75A
.6A
.5A
.375A
.25A
.200A
.125A
100
10
1
TIME IN SECONDS
0.1
0.01
0.001
0.1
1
CURRENT IN AMPERES
1.5A
1.75A
2A
2.5A
3A
5A
4A
10 10
Soldering Parameters - Wave Soldering
Reflow Condition Pb – Free assembly
- Temperature Min (T
Pre Heat
- Temperature Max (T
- Time (Min to Max) (ts) 60 – 180 secs
Average ramp up rate (Liquidus Temp 
(T
) to peak
L
 to TL - Ramp-up Rate 5°C/second max
T
S(max)
Reflow
- Temperature (T
- Temperature (t
L
) 60 – 150 seconds
L
Peak Temperature (TP) 250
Time within 5°C of actual peak 
Temperature (t
)
p
Ramp-down Rate 5°C/second max
Time 25°C to peak Temperature (T
Do not exceed 260°C
) 150°C 
s(min)
) 200°C
s(max)
5°C/second max
) (Liquidus) 217°C 
+0/-5
20 – 40 seconds
) 8 minutes Max.
P
 °C
433 Series
8
Revision: February 13, 2008
Please refer to www.littelfuse.com for the most current information
Specifications are subject to change without notice. 
©2008 Littelfuse, Inc.

Product Characteristics
Surface Mount Fuses
Thin Film > 1206 Size > Very Fast Acting > 433 Series
Body: Epoxy Substrate
Materials
Terminations: 95% Tin / 5% Lead over Nickel 
over Copper
Element Cover Coat: Conformal Coating
Operating 
Temperature
O
C to 90OC. Consult temperature rerating 
 – 55 
curve chart.
Thermal Shock Withstands 5 cycles of – 55
Dimensions
MARKING CODE VARIES 
WITH AMPERAGE RATING 
(SEE CHART)
Sn/Pb
3.18
(.125")
Cu
3.18
(.125")
1.65
(.065")
1.52
(.060")
2.03
(.080")
WAVE SOLDER REFLOW SOLDER
Sn/Pb
4.83
(.190")
Sn/Pb
1.52
(.060")
.56
(.022")
3.81
(.150")
O
C to 125OC
.66
(.026")
Coating
2.03
(.080")
(.023")
1.27
(.050")
1.14
(.045")
.58
Humidity
MIL-STD-202F Method 103B 
Condition D
Vibration Per MIL-STD-202F, Method 201A
Insulation Resistance 
(After Opening) 
Resistance to 
Soldering Heat
Greater than 10,000 ohms. 
Withstands 60 seconds above 200 
and up to 260OC, maximum
Part Marking System
Amp 
Code
.125 B
.200 C
.250  D
.375  E
.500  F
.600 .6
.750  G
.800 .8
001.  H
1.25  J
01.5  K
1.75  L
002.  N
02.5  O
003.  P
03.5  R
004.  S
005.  T
Marking 
Code
O
C 
Part Numbering System
0433 .125 NR
SERIES
AMP CODE
Packaging
Packaging Option Packaging Specification Quantity
Tape & Reel – 8mm tape EIA RS-481-1 (IEC 286, part 3) 5000 NR
©2008 Littelfuse, Inc.
Specifications are subject to change without notice. 
Please refer to www.littelfuse.com for the most current information
Revision: February 13, 2008
9
 Packaging Code
QUANTITY CODE
Quantity &
433 Series