Surface Mount Fuses Thin Film > 0603 Size > Fast-Acting > 494 Series 494 Series Fuse, NRA Special Series Integrated Circuit Protector RoHS Pb ® Description The 494 Series Fast-Acting SMF is an ultra small (0603 size) thin-film 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” suffix. See Part Numbering section for additional information. Features • Compatible with leadfree solders and higher temperature profiles Agency Approvals Agency Agency File Number Ampere Range E10480 250mA - 5A LR29862 250mA - 5A ® • High performance materials provide improved performance in elevated ambient temperature applications Electrical Characteristics for Series % of Ampere Rating 100% 4 hours, Minimum 5 sec., Maximum 300% 0.2 sec., Maximum • Mounting pad and electrical performance are identical to Littelfuse 431 and 434 Series products • Marked on top surface • Alloy-based element with code to allow ampere construction provides rating identification superior inrush withstand without testing characteristics (I2t) over ceramic or glass-based • Low profile for height 0603 fuse products sensitive applications Opening Time at 25OC 200% • Element-covering material is resistant to industry standard cleaning operations • Flat top surface for pickand-place operations Additional Information Applications Secondary protection for space constrained applications: Datasheet Samples Resources • Cell phones • Digital cameras • Battery packs • DVD players • Hard disk drives Electrical Specifications by Item Ampere Rating (A) Amp Code Max Voltage Rating (V) 0.250 0.375 0.500 0.750 1.00 1.25 1.40 1.50 1.75 2.00 2.50 3.00 3.15 3.50 4.00 5.00 .250 .375 .500 .750 001. 1.25 01.4 01.5 1.75 002. 02.5 003. 3.15 03.5 004. 005. 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 32 1. Measured at 10% of rated current, 25ºC. Interrupting Rating 50A @32V AC/DC 35A @32V AC/DC 2. Measured at rated voltage. © 2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 10/25/14 Nominal Cold Resistance (Ohms) Nominal Melting I2t (A2sec) Nom Voltage Drop (mV) 0.5450 0.2900 0.1870 0.1170 0.0710 0.0530 0.049 0.0410 0.0320 0.0300 0.0220 0.0180 0.017 0.0150 0.0130 0.0090 0.0030 0.0053 0.0087 0.0171 0.0212 0.0518 0.05529 0.0766 0.0903 0.1103 0.1440 0.2403 0.27405 0.4306 0.5760 0.9000 158.56 128.03 115.71 107.33 89.10 84.32 74.84 81.14 78.75 78.22 76.10 75.04 63.78 74.25 73.72 72.71 Agency Approvals Nom Power Dissipation ® (W) 0.0396 0.0480 0.0579 0.0805 0.0891 0.1054 0.1048 0.1217 0.1378 0.1564 0.1903 0.2251 0.2009 0.2599 0.2949 0.3635 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 Surface Mount Fuses Thin Film > 0603 Size > Fast-Acting > 494 Series 1.75 A 2.00 A 2.50 A 3.00 A 3.50 A 4.00 A 5.00 A 0.750 A 1.00 A 1.25 A 1.50 A 0.375 A 0.500 A Average Time Current Curves 0.250 A Temperature Rerating Curve 100 TIME IN SECONDS 10 1 0.1 0.01 0.001 0.1 1 10 CURRENT IN AMPERES 100 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) 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 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 © 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 Product Characteristics 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 Dimensions .305 (.012") Sn MARKING CODE VARIES WITH AMPERAGE RATING (SEE CHART) Cu Coating .279 (.011") .18 R (.007") REF. .813 (.032") 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 1.09 (.043") 3.20 (.126") 1.09 (.043") WAVE SOLDER Amp Code .250 Marking Code D .375 .500 .750 001. 1.25 E F G H J 01.4 Sn 1.02 (.040") Withstands 5 cycles of – 55°C to 125°C Part Marking System 1.60 (.063") .127 (.005") Sn Thermal Shock 2.54 (.100") 1.02 (.040") .762 (.030") 1.09 (.043") REFLOW SOLDER 01.5 1.75 002. 02.5 003. K L N O P 3.15 03.5 004. 005. R S 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 Refer to Amp Code column in the Electrical Specifications table. NOTE: The dot is poisitioned before the Packaging Suffix with whole ratings and within the numbering sequence for fractional ratings. packaging code NR = Tape and Reel, 5000 pcs ‘hf’ SUFFIX HALIDE FREE ITEM © 2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 10/25/14