0437.375WR Littelfuse

Surface Mount Fuses Ceramic Fuse > 437 Series RoHS Pb 437 Series 1206 Fast-Acting Fuse Description This 100% Lead-free, RoHS compliant and Halogen-free fuse series has been designed specifically to provide over current protection to circuits might encounter high working ambient temperatures (up to 150C). The general design ensures excellent temperature stability and performance reliability. In addition to this, the high It values typical of the Littelfuse Ceramic Fuse family ensure high inrush current withstand capability. Features Operating Temperature Suitable for both leaded from -55C to +150C and lead-free reflow / Agency Approvals wave soldering 100% Lead-free, Halogen- Free and RoHS compliant UL Recognized to UL/ Agency Agency File Number Ampere Range CSA/NMX 248-1 and UL/ E10480 0.250A - 8A CSA/NMX 248-14 29862 0.250A - 8A Applications LCD Displays Scanners Servers Data Modems Printers Electrical Characteristics for Series % of Ampere Additional Information Ampere Rating Opening Time at 25C Rating 100% 250mA - 8A 4 hours, Minimum 250% 750mA - 8A 5 seconds, Maximum 350% 250mA -500mA 5 seconds, Maximum 350% 750mA - 8A 1 second, Maximum Datasheet Resources Samples Electrical Specifications by Item Agency Approvals Ampere Max. Nominal Nominal Nominal Voltage Nominal Power Amp 1 2 Rating Voltage Interrupting Rating Resistance Melting I t Drop At Rated Dissipation At Rated Code 2 2 3 4 (A) Rating (V) (Ohms) (A Sec.) Current (V) Current (W) 0.25 .250 125 2.29 0.003 0.78 0.195 x x 50 A 125 V AC/DC 0.375 .375 125 1.33 0.01 0.6 0.225 x x 0.5 .500 63 0.908 0.018 0.52 0.26 x x 0.75 .750 63 0.665 0.064 0.45 0.338 x x 1.0 001. 63 0.42 0.1 0.41 0.41 x x 1.25 1.25 63 50 A 63 V AC/DC 0.318 0.256 0.4 0.5 x x 1.5 01.5 63 0.209 0.324 0.39 0.585 x x 1.75 1.75 63 0.071 0.075 0.27 0.473 x x 2.0 002. 63 0.058 0.225 0.2 0.4 x x 2.5 02.5 45 0.043 0.441 0.15 0.375 x x 3.0 003. 45 0.033 0.506 0.14 0.42 x x 3.5 03.5 45 50A 45V AC/63V DC 0.027 0.777 0.13 0.455 x x 4.0 004. 45 0.022 1.024 0.13 0.52 x x 5.0 005. 45 0.0159 2.3 0.13 0.65 x x 7.0 007. 32 0.01 5.02 0.13 0.91 x x 50 A 32 V AC/35 V DC 8.0 008. 32 0.008 7.23 0.13 1.04 x x Notes: 1. AC Interrupting Rating tested at rated voltage with unity power factor. DC Interrupting Rating tested at rated voltage with time constant < 0.8 msec. 2. Nominal Resistance measured with < 10% rated current. 3. Contact Littelfuse if application transient surges are less than 1 ms. 4. Nominal Voltage Drop measured at rated current after temperature has stabilized. Devices designed to carry rated current for 4 hours minimum. It is recommended that devices be operated continuously at no more than 80% rated current. See Temperature Re-rating Curvefor additional re-rating information. Devices designed to be mounted with marking code facing up. 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/19/20Surface Mount Fuses Ceramic Fuse > 437 Series Temperature Re-rating Curve Average Time Current Curves 140 10 120 100 1 80 60 0.1 40 -65 -45 -25 -5 15 35 55 75 95 115 135 155 TEMPERATURE (C) 0.01 Note: 1. Re-rating depicted in this curve is in addition to the standard re-rating 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)I = (0.68)I RAT RAT 0.001 0.1 1 10 100 CURRENT IN AMPERES Soldering Parameters Reflow Condition Pb free assembly t P - Temperature Min (T ) 150C T s(min) P Critical Zone Ramp-up T to T L P Pre Heat - Temperature Max (T ) 200C s(max) T - Time (Min to Max) (t ) 60 180 seconds L s t L T Average Ramp-up Rate (Liquidus Temp (T ) to peak) 3C/second max. S(max) L T to T - Ramp-up Rate 5C/second max. S(max) L Ramp-down Preheat - Temperature (T ) (Liquidus) 217C L T Reflow S(min) - Temperature (t ) 60 150 seconds t L S +0/-5 Peak Temperature (T ) 260 C P 25 Time within 5C of actual peak Temperature (t ) 10 30 seconds p time to peak temperature Time Ramp-down Rate 6C/second max. (t 25C to peak) Time 25C to peak Temperature (T ) 8 minutes max. P Do not exceed 260C Wave Soldering 260C, 10 seconds max. 2020 Littelfuse, Inc. Specifications are subject to change without notice. Revised: GD. 10/19/20 PERCENT OF RATING TIME IN SECONDS .250A .375A .500A .750A 1A 1.25A 1.5A 1.75A 2A 2.5A 3A 3.5A 4A 5A 7A 8A Temperature