14 ntc smd thermistors with nickel barrier termination nb 21 ty p e s nb 21 iec size : 0603 terminations nickel barrier marking on packaging only climatic category 40/125/56 operating temperature -55c to +150c tolerance on rn (25c) 5%, 10%, 20% maximum dissipation at 25c 0.07 w thermal dissipation factor 1 mw/c thermal time constant 4 s chip thermistors are high quality and low cost devices especially developed for surface mounting applications. they are widely used for temperature compensation but can also achieve temperature control of printed circuits. a nickel barrier metallization provides outstanding qualities of solderability and enables this chip to meet the requirements of the most severe soldering processes. applications ? lcd compensation ? battery packs ? mobile phones ? cd players ? heating systems ? air-conditioning systems ? temperature control of switch mode power supplies ? compensation of pressure sensors ? protection of power transistors in various electronic circuits 1.6 (.063) 0.2 (.008) 0.8 (.031) 0.2 (.008) 0.8 (.031) 0.2 (.008) 0.2 (.008) min 0.2 (.008) min resistance - temperature characteristics: pages 36 to 40. how to order nb 21 ty p e k 0 material code k (see tables page 15) 0103 resistance 10,000 m tolerance m (20%) j (5%) k (10%) bb suffix: packaging C C: bulk bb: cardboard tape (180mm diam. reel) bf: cardboard tape (1/2 reel) bd: cardboard tape (330mm diam. reel) dimensions: millimeters (inches)
15 ntc smd thermistors with nickel barrier termination nb 21 table of values nb 21 iec size : 0603 ty p e s rn at 25c material b (k) at 25c () code ( b/b ) (%/c) nb 21 kc 0 470 47 nb 21 kc 0 101 100 kc 3470 5% C 3.9 nb 21 kc 0 471 470 nb 21 mc 0 102 1,000 mc 3910 3% C 4.4 nb 21 j 0 0472 4,700 j 3480 3% C 3.9 nb 21 j 5 0682 6,800 j5 3480 3% C 3.9 nb 21 j 5 0103 10,000 3480 3% C 3.9 nb 21 k 0 0103 10,000 k 3630 3% C 4.0 nb 21 k 0 0153 15,000 nb 21 l 0 0223 22,000 l 3790 3% C 4.2 nb 21 m 0 0333 33,000 m 3950 3% C 4.4 nb 21 m 0 0473 47,000 nb 21 l 2 0683 68,000 l2 3805 3% C 4.1 nb 21 n 0 0683 68,000 n 4080 3% C 4.6 nb 21 n 5 0104 100,000 n5 4160 3% C 4.7 nb 21 p 0 0154 150,000 p 4220 3% C 4.7 nb 21 q 0 0334 330,000 q 4300 3% C 4.7 nb 21 q 0 0474 470,000 (1) 5% (2) 3%
16 packaging for automatic insertion ntc chip thermistors / nc/nb series automatic insertion super 8 plastic tape packaging: the mechanical and dimensional reel characteristics are in accordance with the iec publication 286-3. r = 0.3 (.012) max. max 3 max 3 max 3 max 3 cover tape 30 5 t k a1 b1 b0 d0 p2 p0 w hole f e a0 5.5 (.217) 0.2 (.008) direction of unreeling +0.2 (.008) -0 1 (.039) designation symbol value tolerance tape width w 8 0.2 tape thickness t 0.4 max. pitch of the sprocket holes p0 4 0.1 diameter of the sprocket holes d0 1.5 0.1 -0 distance e 1.75 0.1 distance (center to center) f 3.5 0.05 distance (center to center) p2 2 0.1 sizes of the nc 12 (0805) a0 1.5 0.1 cavities b0 2.4 0.1 k 1.4 max. k 0.1 (size is adjustable) (k = t1 +0.2) nc 20 (1206) a0 1.95 0.1 b0 3.55 0.1 k 1.5 max. k 0.1 (size is adjustable) (k = t1 +0.2) bottom side reel upper side direction of unreeling reel according to iso/dis 3639-2 ?12.75 (.502) + 0.15 (.006) - 0 ?80 (7.09) + 0 - 2 (.079) ?20.5 (.087) + 0.5 (.020) - 0 8.4 (.331) +0.15 (.006) 14.4 (.567) max. ?62 (2.44) 1.5 (.059) quantity per reel type suffix qty per reel nc - nb 12 ba 4000 be 2000 nc 20 - nb 20 ba 3000 be 1500
17 packaging for automatic insertion ntc chip thermistors / nc/nb series automatic insertion 8mm paper tape packaging: the mechanical and dimensional reel characteristics are in accordance with the iec publication 286-3. p 0 b 0 p 1 p 2 d 0 t top cover tape bottom cover tape center lines of cavity cavity size see note 1 10 pitches cumulative tolerance on tape 0.20mm (0.008) e 1 f g user direction of feed e 2 w t 1 t 1 a 0 designation symbol value tolerance tape width w 8 -.0.1/+0.3 tape thickness t 1.1 max. pitch of the sprocket holes p 0 40.1 diameter of the sprocket holes d 0 1.5 0.1 -0/+0.1 distance e 1 1.75 0.1 distance (center to center) f 3.5 0.05 distance (center to center) p 2 2 0.05 cover tape thickness t 1 0.10 max. distance e 2 6.25 min. distance g 0.75 min. component pitch 0805/0603 p 1 40.1 0402 2 0.1 bottom side reel upper side direction of unreeling reel according to iso/dis 3639-2 ?12.75 (.502) + 0.15 (.006) - 0 ?80 (7.09) + 0 - 2 (.079) ?20.5 (.087) + 0.5 (.020) - 0 8.4 (.331) +0.15 (.006) 14.4 (.567) max. ?62 (2.44) 1.5 (.059) quantity per reel type suffix qty per reel nb - nc 12 bb 4000 nb 21 bf 2000
storage good solderability is maintained for at least twelve months, provided the components are stored in their as received packaging at less than 40c and 70% rh. solderability / leaching terminations to be well soldered after immersion in a 60/40 tin/lead solder bath at 235 5c for 2 1 seconds. terminations will resist leaching for at least the immersion times and conditions recommendations shown below. nb products are compatible with a wide range of soldering conditions consistent with good manufacturing practice for surface mount components. this includes pb free reflow processes with peak temperatures up to 270oc. recommended profiles for reflow and wave soldering are shown below for reference. nc products are recommended for lead soldering application or gluing techniques. surface mounting guide chip thermistor C application notes reflow soldering wave soldering 18 p/n termination solder solder immersion type tin/lead temp oc time seconds nc agpdpt 60/40 260 5 15 max nb nickel barrier 60/40 260 5 30 1 case p/nd1d2d3d4d5 size 0402 nb23 1.70 0.60 0.50 0.60 0.50 (.067) (.024) (.020) (.024) (.020) 0603 NB21 2.30 0.80 0.70 0.80 0.75 (.091) (.031) (.028) (0.31) (.030) 0805 nb12 3.00 1.00 1.00 1.00 1.25 (.118) (.039) (.039) (.039) (.049) 1206 nb20 4.00 1.00 2.00 1.00 2.50 (.157) (.039) (.079) (.039) (.098) case p/nd1d2d3d4d5 size 0603 NB21 3.10 1.20 0.70 1.20 0.75 (.122) (.047) (.028) (.047) (.030) 0805 nb12 4.00 1.50 1.00 1.50 1.25 (.157) (.059) (.039) (.059) (.049) 1206 nb20 5.00 1.50 2.00 1.50 1.60 (.197) (.059) (.079) (.059) (.063) reflow 300 250 200 150 100 50 0 solder temp. 10 sec. max 1min 1min (minimize soldering time) natural cooling 220oc to 250oc preheat a) the visual standards used for evaluation of solder joints will need to be modified as lead free joints are not as bright as with tin-lead pastes and the fillet may not be as large. b) resin color may darken slightly due to the increase in temperature required for the new pastes. c) lead-free solder pastes do not allow the same self align- ment as lead containing systems. standard mounting pads are acceptable, but machine set up may need to be modified. 300 250 200 150 100 50 0 0 50 100 150 200 250 300 ? pre-heating: 150c 15c / 60-90s ? max. peak gradient: 2.5c/s ? peak temperature: 245c 5c ? time at >230c: 40s max. temperature c time (s) wave 300 250 200 150 100 50 0 solder temp. 3 sec. max 1 to 2 min (preheat chips before soldering) t/maximum 150c preheat natural cooling 230oc to 250oc t d1 d2 d3 d4 d5 recommended soldering pad layout dimensions in mm (inches)
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