17 ? 2009 littelfuse, inc. specifcations are subject to change without notice. surface mount fuses please refer to www.littelfuse.com/series/437.html for current information. 437 series ceramic fuse > 437 series 437 series 437 series C 1206 fast-acting fuse description this 100% lead-free, rohs compliant and halogen-free fuse series has been designed specifcally to provide over current protection to circuits that see high working ambient temperatures (up to 150oc). the general design ensures excellent temperature stability and performance reliability. in addition to this, the high i2t values typical of the littelfuse ceramic fuse family ensure high inrush current withstand capability. agency approvals agency agency file number ampere range e 10480 0.250a ~ 8a lr29862 0.250a ~ 8a features electrical characteristics for series ? operating temperature from -55oc to +150oc ? 100% lead-free and rohs compliant ? suitable for both leaded and lead-free refow / wave soldering % of ampere r ating ampere r ating opening time at 25o c 100% 250ma - 8a 4 hours, minimum 250% 750ma - 8a 5 seconds, maximum 350% 250ma -500ma 5 seconds, maximum 350% 750ma - 8a 1 second, maximum applications ampere r ating (a) amp code max. voltage r ating (v) i nterrupting r ating nominal r esistance (ohms) 2 nominal melting i 2 t (a 2 sec.) 3 n ominal voltage drop at r ated c urrent (v) 4 nominal p ower dissipation at r ated c urrent (w) agency approvals 250ma .250 125 50 a @ 125 v ac/dc 2.290 0.003 0.78 0.195 x x 375ma .375 125 1.330 0.010 0.60 0.225 x x 500ma .500 63 50 a @ 63 v ac/dc 0.908 0.018 0.52 0.260 x x 750ma .750 63 0.665 0.064 0.45 0.335 x x 1a 0 01. 63 0.360 0.100 0.41 0.415 x x 1.25a 1.25 63 0.318 0.256 0.40 0.496 x x 1.5a 01.5 63 0.209 0.324 0.39 0.579 x x 1.75a 1.75 63 0.0703 0.075 0.27 0.474 x x 2a 002. 63 0.058 0.144 0.17 0.345 x x 2.5a 02.5 32 50 a @ 32 v ac/35 v dc 0.043 0.225 0.14 0.363 x x 3a 003. 32 0.033 0.400 0.15 0.462 x x 3.5a 03.5 32 0.027 0.576 0.16 0.560 x x 4a 004. 32 0.022 1.024 0.16 0.618 x x 5a 005. 32 0.016 1.936 0.09 0.484 x x 7a 007. 32 0.010 4.900 0.11 0.760 x x 8a 008. 32 0.0084 6.400 0.067 0.539 x x electrical specifcations by item 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. nominal melting i2t measured at 1 msecs. opening time. 4. nominal voltage drop measured at rated current after temperature has stabilized. ? automotive electronics ? lcd displays ? servers ? printers ? scanners ? data modems 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 rerating curvefor additional rerating information. devices designed to be mounted with marking code facing up. revised: june 23, 2011
introduction to circuit protection introduction to circuit protection transientology 18 ? 2009 littelfuse, inc. specifcations are subject to change without notice. surface mount fuses please refer to www.littelfuse.com/series/437.html for current information. 437 series ceramic fuse > 437 series average time current curves 0. 00 1 0.01 0. 1 1 10 10 0 0.1 1 10 10 0 cu rr en t in am peres time in se co nd s .2 50 a .3 75 a .50 0a .750a 1a 2a 7a 1 .25 1 .5a 1 .75 2.5a 3a 3.5a 4a 5a 8a r efow condition pb C free assembly p re heat - temperature min (t s(min) ) 150c - temperature max (t s(max) ) 200c - time ( min to max) (t s ) 60 C 180 seconds average r amp-up r ate (l iquidus temp (t l ) to peak) 3csecond max. t s(max) to t l - r amp-up r ate 5csecond max. r efow - temperature (t l ) (liquidus) 21c - temperature (t l ) 60 C 150 seconds p eak temperature (t p ) 260 0-5 c time within 5 c of actual peak temperature (t p ) 10 C 30 seconds r amp-down r ate 6csecond max. time 25 c to peak temperature (t p ) 8 minutes max. do not exceed 260c soldering parameters temperature rerating curve 40 60 80 10 0 12 0 14 0 -6 5 -45 -25 -5 15 35 55 75 95 115 135 15 5 te m per at ur e ( c) pe rc en t of ra ti ng ti me te mperature t p t l t s(max) t s(min) 25 t p t l t s time to peak temperature (t 25oc to peak) ramp-down ramp-up preheat critical zone t l to t p example: wave soldering 260c 10 seconds max.
19 ? 2009 littelfuse, inc. specifcations are subject to change without notice. surface mount fuses please refer to www.littelfuse.com/series/437.html for current information. 437 series ceramic fuse > 437 series 437 series materials body: advanced ceramic terminations: ag / ni / sn (100% lead-free) element cover coating: lead-free glass moisture sensitivity level ipc/jedec j-std-020c, level 1 solderability ipc/eic/jedec j-std-002b, condition b humidity test mil-std-202, method 103b, conditions d resistance to solder heat mil-std-202, method 210f, condition b product characteristics moisture resistance mil-std-202, method 106g thermal shock mil-std-202, method 107g, condition b mechanical shock mil-std-202, method 213b, condition a vibration mil-std-202, method 201a vibration, high frequency mil-std-202, method 204d, condition d dissolution of metallization ipc/eic/jedec j-std-002b, condition d terminal strength iec 60127-4 dimensions 0.520 0.200 [0.020 0.08] 2 3.200 0.1778 [0.126 0.007] 1.000 [0.039] 1.63 +0.10 / -0.2 [0.064 +0.004 / -0.008] n 1.500 [0.059] 1.800 [0.071] 3.500 [0.138] 1.000 [0.039] 0.8179 +0.046 / -0.076 [0.0332 +0.0018 / -0.003] packaging part marking system p ackaging option p ackaging specication quantity quantity p ackaging code 8mm tape and reel eia-481, iec 60286, part 3 3000 wr part numbering system 0437 008. w r series amp code qu antit y code pac king code w = 3000 pcs r = reel pack .250 d .375 e .500 f .750 g 0 01. h 1.25 j 01.5 k 1.75 l 002. n 02.5 o 003. p 03.5 r 004. s 005. t 007. w 008. x
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