494 LITTELFUSE | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 3

Technical content

Features

  • Compatible with lead- free solders and higher temperature profiles
  • High performance materials provide improved performance in elevated ambient temperature applications
  • Marked on top surface with code to allow ampere rating identification without testing
  • Low profile 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 (I 2t) 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-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.

  • 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 1.25 1.25 32 35A @32V AC/DC 0.0530 0.0518 84.32 0.1054 x x Electrical Specifications by Item 1. Measured at 10% of rated current, 25ºC. 2. Measured at rated voltage. RoHS Pb Additional Information Datasheet SamplesResources

© 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 0.1 100 10 100 0.001 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 T emperature 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) 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 T erminations: 100% Tin over Nickel over Copper Element Cover Coat: Conformal Coating Operating T emperature – 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 001. 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 SystemPackaging 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 Specifications table. NOTE: The dot is poisitioned before the Packaging Suffix with whole ratings and within the numbering sequence for fractional ratings. NR = Tape and Reel, 5000 pcs