© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 10/25/14
Surface Mount Fuses
Thin Film > 0603 Size > Fast-Acting > 494 Series
494 Series Fuse, NRA Special Series Integrated Circuit Protector
Description
Agency Approvals
AGENCY AGENCY FILE NUMBER AMPERE RANGE
®
E10480 250mA - 5A
LR29862 250mA - 5A
Electrical Characteristics for Series
Features
• Compatiblewithlead-
freesoldersandhigher
temperatureproles
• Highperformance
materialsprovide
improvedperformance
inelevatedambient
temperatureapplications
• Markedontopsurface
withcodetoallowampere
ratingidentication
withouttesting
• Lowproleforheight
sensitiveapplications
• Flattopsurfaceforpick-
and-placeoperations
• Element-coveringmaterial
isresistanttoindustry
standardcleaning
operations
• Mountingpadand
electricalperformanceare
identicaltoLittelfuse431
and434Seriesproducts
• Alloy-basedelement
constructionprovides
superiorinrushwithstand
characteristics(I2t)over
ceramicorglass-based
0603fuseproducts
% of Ampere
Rating Opening Time at 25OC
100% 4hours,Minimum
200% 5sec.,Maximum
300% 0.2sec.,Maximum
Applications
®
The494SeriesFast-ActingSMFisanultrasmall(0603
size)thin-lmdevicedesignedforsecondaryprotection
ofcircuitsusedinspaceconstrainedapplicationssuch
ashand-heldportableelectronicdevices.Thisseriesis
100%lead-freeandmeetstherequirementsoftheRoHS
directive.NewHalide-Free494Seriesfusesareavailable
toorderusingthe“HF”sufx.SeePartNumberingsection
foradditionalinformation.
• Cellphones
• Batterypacks
• Digitalcameras
• DVDplayers
• Harddisk
drives
Secondaryprotectionforspaceconstrainedapplications:
Ampere
Rating
(A)
Amp
Code
Max
Voltage
Rating
(V)
Interrupting
Rating
Nominal Cold
Resistance
(Ohms)
Nominal
Melting
I2t (A2sec)
Nom
Voltage
Drop
(mV)
Nom
Power
Dissipation
(W)
Agency Approvals
®
0.250 .250 32
50A@32VAC/DC
0.5450 0.0030 158.56 0.0396 x x
0.375 .375 32 0.2900 0.0053 128.03 0.0480 x x
0.500 .500 32 0.1870 0.0087 115.71 0.0579 x x
0.750 .750 32 0.1170 0.0171 107.33 0.0805 x x
1. 0 0 0 01. 32 0.0710 0.0212 89.10 0.0891 x x
1.25 1.25 32
35A@32VAC/DC
0.0530 0.0518 84.32 0.1054 x x
1.40 01. 4 32 0.049 0.05529 74.84 0.1048 x x
1.50 01.5 32 0.0410 0.0766 81.14 0.1217 x x
1.75 1.75 32 0.0320 0.0903 78.75 0.1378 x x
2.00 002. 32 0.0300 0.1103 78.22 0.1564 x x
2.50 02.5 32 0.0220 0.1440 76.10 0.1903 x x
3.00 003. 32 0.0180 0.2403 75.04 0.2251 x x
3.15 3.15 32 0.017 0.27405 63.78 0.2009 x x
3.50 03.5 32 0.0150 0.4306 74.25 0.2599 x x
4.00 004. 32 0.0130 0.5760 73.72 0.2949 x x
5.00 005. 32 0.0090 0.9000 72.71 0.3635 x x
Electrical Specifications by Item
1. Measured at 10% of rated current, 25ºC. 2. Measured at rated voltage.
RoHS
Pb
Additional Information
Datasheet Samples
Resources
© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 10/25/14
Surface Mount Fuses
Thin Film > 0603 Size > Fast-Acting > 494 Series
Average Time Current Curves
TIME IN SECONDS
CURRENT IN AMPERES
0.01
0.1
0.1
1
1
10
100
10 10
0
0.00
1
3.50 A
3.00 A
2.50 A
2.00 A
1.75 A
1.50 A
1.25 A
1.00 A
0.750
A
0.500
A
0.375
A
0.250
A
4.00 A
5.00 A
Temperature Rerating Curve
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) 5°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)250+0/-5°C
Time within 5°C of actual peak
Temperature (tp)20–40seconds
Ramp-down Rate 5°C/secondmax.
Time 25°C to peak Temperature (TP)8minutesmax.
Do not exceed 260°C
Soldering Parameters
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
© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 10/25/14
Surface Mount Fuses
Thin Film > 0603 Size > Fast-Acting > 494 Series
Materials
Body: AdvancedHighTemperatureSubstrate
Terminations:100%TinoverNickeloverCopper
Element Cover Coat: ConformalCoating
Operating
Temperature
–55°Cto90°C.Consulttemperaturererating
curvechart.Foroperationabove90°Ccontact
Littelfuse.
Humidity MIL-STD-202F,Method103B,ConditionD
Thermal Shock Withstands5cyclesof–55°Cto125°C
Vibration PerMIL-STD-202F
Insulation Resistance
(After Opening) Greaterthan10,000ohms
Resistance to
Soldering Heat
Withstands60secondsabove200°C
andupto260°C,maximum
Product Characteristics
Dimensions Part Marking System
1.09
(.043")
REFLOW SOLDER
1.60
(.063") .305
(.012")
.279
(.011")
.18
(.007")
.127
(.005")
MARKING CODE VARIES
WITH AMPERAGE RATING
(SEE CHART)
R
REF.
1.02
(.040")
.762
(.030")
2.54
(.100")
1.09
(.043")
WAVE SOLDER
3.20
(.126")
1.09
(.043")
1.02
(.040")
.813
(.032")
Sn
Sn
Cu
Sn
Coating
Amp
Code
Marking
Code
.250 D
.375 E
.500 F
.750 G
0 01. H
1.25 J
01. 4
01.5 K
1.75 L
002. N
02.5 O
003. P
3.15
03.5 R
004. S
005. T
Part Numbering System
Packaging
Packaging
Option
Packaging
Specification Quantity
Quantity &
Packaging
Code
8mmTape
andReel
EIARS-481-2(IEC
286,part3) 5000 NR
0494002.NRHF
SERIES
AMP Code
‘HF’ SUFFIX HALIDE
FREE ITEM
PACKAGING Code
RefertoAmpCodecolumninthe
ElectricalSpecicationstable.
NOTE:Thedotispoisitionedbefore
thePackagingSufxwithwhole
ratingsandwithinthenumbering
sequenceforfractionalratings.
NR=TapeandReel,5000pcs