power metal oxide film resistors mo-s series small size for power rating can replace carbon composition in many pulse handling applications flameproof protection mo 1 / 2 s mo1s mo2s mo3s mo5s power rating at 70? watts 0.5 1.0 2.0 3.0 5.0 restance range ohms 10r - 50k 10r - 100k 10r - 100k limiting element voltage volts 250 350 500 tcr ppm/? 350 isolation voltage volts 350 500 700 resistance tolerance % 5, 10 standard values e24 preferred thermal impedance ?/watt 140 110 80 60 35 ambient temperature range ? -55 to +155 general note welwyn components reserves the right to make changes in product specification without notice or liability. all information is subject to welwyn s own data and is considered accurate at time of going to print. ?welwyn components limited ?bedlington, northumberland ne22 7aa, uk telephone: +44 (0) 1670 822181 ?facsimile: +44 (0) 1670 829465 ?email :info@welwyn-tt.com ?website: www.welwyn-tt.com electrical data issue c ?07.04 a subsidiary of tt electronics plc welwyn components 149 construction the tin oxide resistance element is deposited onto a high purity ceramic rod. end caps are force fitted and termination wires are welded to the end caps. the element is adjusted to the required resistance value by a helical cut; finally a cement protection is applied to the resistor body prior to marking with indelible ink. terminations material resistor sizes up to and including the mo3s use solder coated copper terminations. mo4s and mo5s use solder coated steel cored terminations. strength the terminations meet the requirements of iec 68.2.21. solderability the terminations meet the requirements of iec 115-1, clause 4.17.3.2. marking mo 1 / 2 s, mo1s, mo2s and mo3s resistors are colour coded with four bands. iec 62 colours are used. for larger sizes type reference, resistance value and tolerance are legend marked. the resistance value marking conforms to lec 62. solvent resistance the body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. flammability the resistor coating will not burn or emit incandescent particles under any condition of applied temperature or power overload. dimensions (mm) and weight (g) pcb min mounting bend wt. type l max. d max. f min. d nom. centres radius nom. mo 1 / 2 s 6.2 2.5 21.0 0.6 10.0 0.6 0.3 mo1s 9.0 3.6 19.6 0.8 12.5 1.2 0.5 mo2s 12.5 4.2 17.8 0.8 15.0 1.2 0.9 mo3s 14.5 5.3 23.8 0.8 20.0 1.2 1.1 mo5s 25.0 8.5 27.6 0.8 30.0 1.2 4.3 physical data l d f d mo-s_c.qxd 7/22/04 2:19 pm page 1
power metal oxide film resistors mo-s series ?welwyn components limited bedlington, northumberland ne22 7aa, uk telephone: +44 (0) 1670 822181 ?facsimile: +44 (0) 1670 829465 ?email: info@welwyn-tt.com ?website: www.welwyn-tt.com issue c ?07.04 welwyn components 150 b f 1 f 2 6 6 c body location f 1 ?f 2 1.4 mm application notes 1. if the resistors are to dissipate full rated power, it is recommended that the terminations should not be soldered closer than 4mm from the body. 2. due to operating temperature limitations imposed by some pcb materials, derating may be necessary. an estimate of the temperature rise to be expected can be calculated using the thermal impedance figures given under electrical data. 3. mo-s resistors can also be supplied pre-formed. see lead form section for details. packaging our standard packaging for mo 1 / 2 s, mo1s, mo2s and mo3s is taped and ammo packed, mo5s is taped and reeled. the critical dimensions are shown in figure 1. the component wires will not protrude beyond the outside edge of the tapes. pre-formed resistors are supplied loose packed in plastic bags or boxes. alternative packaging available by request. figure 1 60 80 100 120 140 160 180 200 220 240 100 90 80 70 60 50 40 30 20 10 0 ambient temp mo-s series derating curve % of rated power at 70 c maximum load at rated power: 1000 hrs at 70? ? r% 5 shelf life: 12 months at room temperature ? r% 2 derating see derating curve climatic ? r% 1 climatic category 40/125/56 temperature rapid change ? r% 0.5 resistance to solder heat ? r% 0.5 performance data type mo 1 / 2 s mo1s mo2s mo3s mo5s b5252526785 c 5 5 5 10 10 type mo 1 / 2 s mo1s mo2s mo3s mo5s reel 5000 2500 2500 1000 700 ammo pack 5000 2500 1500 1000 n/a standard quantities per package mo-s_c.qxd 7/22/04 2:19 pm page 2
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