Fuse Mounting Accessories Page 48 Fuse & Mounting Accessories

2017 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 03/03/17 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 1 10 100 10 100 0.001 3.15 A 3.00 A 2.50 A 2.00 A 1.75 A 1.40 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 1.50 A 3.50 A Temperature Re-rating Curve Reflow Condition Pb - free assembly Pre Heat - Temperature Min (T s(min) ) 150C - Temperature Max (T s(max) ) 200C - Time (Min to Max) (t s ) 60 - 180 seconds Average Ramp-up Rate (Liquidus Temp (T L ) to peak) 5C/second max. T S(max) to T L - Ramp-up Rate 5C/second max. Reflow - Temperature (T L ) (Liquidus) 217C - Temperature (t L ) 60 - 150 seconds Peak Temperature (T P ) 250 +0/-5 C Time within 5C of actual peak Temperature (t p ) 20 - 40 seconds Ramp-down Rate 5C/second max. Time 25C to peak Temperature (T P ) 8 minutes max. Do not exceed 260C Soldering Parameters Time Temperature T P T L T S(max) T S(min) 25 t P t L t S time to peak temperature (t 25C to peak) Ramp-down Ramp-up Preheat Critical Zone T L to T P Note: 1. Rerating depicted in th1s curve 1s in addition to the standard rerating of 20% for continuous operation. Example: For continuous operation at 75 degrees Celsius, the fuse should be rerated as follows I = (0.80)(0.85)IRAT = (0.68)IRAT

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