12-28-98 sb98107 rev. a dimensional data .29" ( .015) (7.47 mm) ( .006) .05" (1.27 mm) buss sft 5a 125v a123 .17" ( .015) (4.32 mm) ( .006) .12" ( .015) (3.05 mm) ( .006) .09" ( .015) (2.29 mm) ( .006) typical voltage agency** rated interrupting pre-arcing typical total clearing 3 drop 2 volts at approvals rated voltage rating 1 i 2 t (a 2 sec) i 2 t (a 2 sec) 100% rated current 5 ac (max.) dc (max.) ac dc ac dc ac dc current 63ma 125v 125v 50a 300a 125ma 125v 125v 50a 300a 250ma 125v 125v 50a 300a 7.49 x 10 -5 5.1 x 10 -6 2.0 x 10 -4 6.29 x 10 -6 .8 375ma 125v 125v 50a 300a 3.17 x 10 -4 2.18 x 10 -5 4.18 x 10 -4 2.67 x 10 -5 .75 500ma 125v 125v 50a 300a 4.46 x 10 -4 3.8 x 10 -5 5.74 x 10 -4 4.63 x 10 -5 .66 750ma 125v 125v 50a 300a 1.72 x 10 -3 2.27 x 10 -4 2.59 x 10 -3 2.77 x 10 -4 .525 1 125v 125v 50a 300a .0099 .0069 .0114 .0076 .12 1.5 125v 125v 50a 300a .0302 .0204 .0345 .0246 .20 2 125v 125v 50a 300a .0784 .0651 .0891 .0811 .170 2.5 125v 125v 50a 300a .1775 .1390 .2383 .1574 .145 3 125v 125v 50a 300a .3355 .2419 .4359 .2664 .130 3.5 125v 125v 50a 300a .4980 .3812 .6355 .4696 .155 4 125v 125v 50a 300a .8855 .6785 1.0740 .7829 .135 5 125v 125v 50a 300a 1.7264 1.2912 2.3779 1.3556 .125 7.0a 60v 90v 50a 300a 1.64 .518 1.97 .573 .114 10.0a 60v 90v 50a 300a 3.79 1.06 3.92 1.67 .130 12.5a 48v 60v ? 50a 300a 15 4.04 20 4.28 .090 **approvals: ul recognition, std. 248-14, guide #jdyx2, file #e19180; csa certification, c22.2 no. 248.14, class #1422-01, file # 53787. ? note: sft 12.5a is ul recognized on ac only. 1. interrupting ratings were measured at 100% power factor on ac, and a time constant less than 1ms on dc. 2. voltage drop was measured at 25? 3? ambient temperature at rated current with device mounted on a circuit trace. 3. i 2 t measured at 50 amp, 125 vac, .95pf, random closing angle; 300 amps, 125 vdc, tc<1ms. 4. electrical characteristics for 12.5 amp to be determined. 5. device designed to carry 125% of rated current for one hour minimum. an operating current of 80% or less of rated current is recommended, with further derating required at elevated ambient temperatures. smd tron surface mount fuses sft for .170?x .294?(4.32mm x 7.47mm) fuses form no. sft page 1 of 2 bif doc #2005 bussmann *packaging & ordering information: product rated current symbol package code tr/ 500 pcs., on a 7?reel, 16mm tape width. tr1/ 2000 pcs., on a 13?reel, 16mm tape width. tr2/ 500 pcs., on a 7?reel, 12mm tape width. tr3/ 2500 pcs., on a 13?reel, 12mm tape width. weight = .6 lbs/500 (see table) sft catalog symbol: sft characteristics: fast-acting, current-limiting construction: solid matrix time in seconds 1 10 current in amperes 10 1 .01 .1 ampere rating 250ma 375ma 500ma 750ma 1a 1.5a 2a 2.5a 3a 3.5a 5a 7a 10a 12.5a time-current characteristic curveseaverage melt (full size curves available) u.r. csa electrical characteristics r time-current characteristics: rated percent of rating current 100% 250% 0-10 4 hrs. (min) 5 sec. (max) ce logo denotes compliance with european union low voltage directive (50-1000 vac, 75-1500 vdc). refer to bif document #8002 or contact bussmann application engineering at 314-527-1270 for more information. *see page 2.
12-28-98 sb98107 rev. a smd tron surface mount fuses sft for .170?x .294?(4.32mm x 7.47mm) fuses bussmann form no. sft page 2 of 2 bif doc #2005 the only controlled copy of this bif document is the electronic read-only version located on the bussmann network drive. all ot her copies of this bif document are by definition uncontrolled. this bulletin is intended to clearly present comprehensive product data and provide technical information that will help the end user with design applications. bussmann reserves the right, without no tice, to change design or construction of any products and to discontinue or limit distribution of any products. bussmann also reserv es the right to change or update, without notice, any technical information contained in this bulletin. once a product has been se lected, it should be tested by the user in all possible applications. r 1.0 materials body material: thermoplastic, with a rating of 94v-o as defined by u.l. standard 94. material has an oxygen index of 53% per astm d2863-77. lead material: base?opper. barrier?ickel (50-100 micro inches). finish?lectroplated tin (400-500 micro inches with a 2-10% lead content). 2.0 markings body shall be permanently and legibly marked with buss , catalog symbol, ampere rating, voltage rating and date code. markings will not become illegible or discolored when the parts are subjected to solvents normally used to remove solder/flux, fingerprints, and other contaminants from printed circuit boards, as tested per mil-std-202, method 215f. 3.0 trace geometry considerations trace geometry can affect fuse performance and should be considered when applying any subminiature fuse. figures 1 and 2 detail the trace geometry used in generating this specification. suitable trace geometry for a particular applica- tion depends on fuse rating, current flow, and ambient temperature. final deter- mination of suitability for a specific application should be based on empirical testing with all parameters involved. printed circuit board is .096 inches thick, epoxy glass with 1 ounce copper foil, coated with 300 micro inches of 60/40 tin lead solder. note: smaller than recommended trace width may affect the fuse performance by providing additional heat and reducing carrying capacity of the fuse. 4.0 thermal withstand capability infrared exposure. when the device is exposed to the time-temperature profile detailed in figure 3, the resistance of the device will not change by more than 5%, as measured after the device has dwelled at room temperature for at least one hour. i r time-temperature profile vapor phase exposure. when the device is exposed for ten minutes to the vapor produced by liquid fluorinert fc-5312 at 218?, the resistance of the device will not change by more than 5%, as measured after the device has dwelled at room temperature for at least one hour. resistance to soldering heat. mil-std-202f, method b. when device is immersed in a 260? soldering pot for 10 seconds, the resistance of the device will not change by more than 5% as measured after the device has dwelled at room temperature for at least one hour. 5.0 mechanical characteristics mechanical shock. fuse base shall not chip or crack when dropped from a height of 48" onto a concrete surface. vibration. the fuse resistance shall return to within 10% of the original value when the fuse is subjected to a frequency range cycle of one minute in each of the three mutually perpendicular directions having a vibration amplitude of .06 inches peak to peak at a frequency of 10-55hz. per mil-std-202f, method 204 condition a. terminal secureness. the fuse terminals shall not distort, and the fuse body will not chip or crack when the fuse is placed on a printed circuit board and a vertical downward force of 1/2 kilograms is applied to the top of the fuse for 10 seconds. 6.0 packaging all unit packaging material will be manufactured from static inhibiting materials. tape and reel packaging will comply with eia std 481-2. tape width shall be 16mm and reel diameter 7 inches or 13 inches. packaging code tr/ 500 on a 7" reel, 16mm tape width tr1/ 2000 on a 13" reel, 16mm tape width 7.0 load cycling load cycling of the smd tron was performed to observe the stability of the resistances and voltage drops for cycling applications. through measurement of initial and final resistances, an assessment of the reliability of the fuse can be predicted. test conditions. a duty cycle of 60 seconds on at rated current and 60 sec- onds off to make a total period of 120 seconds. other circuit parameters were: amplitude ?100% rated current rise time ?36.8 microseconds ripple average ?5.9ma system voltage ?55 volts test criteria. the fuse must complete 200,000 cycles without failure, then resistance and voltage drop measurements are compared to initial measure- ments, which cannot change by more than 5%. test data: average initial resistance: 21.11 milli ohms average final resistance: 20.57 milli ohms % change: ?.55% sft voltage drop as a percent of rated current (typical) 25 c25 c 175 c 230 c 250 c 2 min. 2 min. 3.5 min. .14" .06 " dia. .08" .16" .07" .32" .19" .01" a a .63" .3" .31" embossed carrier tape which conforms to the eia standards eia481-2. carrier material black conductive polystyr ene, non-conductive tape material. figure 3 4.800" 4.550" .250" 000 .350" .100" 000 detail a 2.550" 2.495" 2.305" 2.250" .055" .060" .114" figure 1 figure 2 detail a voltage drop .2 .18 .16 .14 .12 .1 .08 .06 .04 .02 0 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% percent of rated current sft-1.5 sft-2 sft-3.5 sft-2.5 sft-4 sft-3 sft-10 sft-5 sft-1 sft-7 voltage drop .8 .7 .6 .5 .4 .3 .2 .1 0 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% percent of rated current sft-.25 sft-.5 sft-.375 sft-.75 figure 4 *better solderability. to eliminate solder ball extrusion and to provide improved solderability in formed areas of leads, order part number sft-1j0367-amp. for 63ma - 10a fuses.
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