3 surface mount varistors surface mount varistors 151 www.littelfuse.com multiline transient voltage surge suppressor MLN surgearray suppressor the MLN surgearray suppressor is designed to help protect compo- nents from transient voltages that exist at the circuit board level. this device provides four independent suppressors in a single 1206 leadless chip in order to reduce part count and placement time as well as save space on printed circuit boards. surgearray devices are intended to suppress esd, eft and other transients in order to protect integrated circuits or other sensitive components operating at any voltage up to 18v dc . surgearray devices are rated to the iec 61000-4-2 human body model esd to help products attain emc compliance. the array offers excellent isolation and low crosstalk between sections. the inherent capacitance of the surgearray suppressor permits it to function as a filter/suppressor, thereby replacing separate zener/ capacitor combinations. the MLN array is manufactured using the littelfuse multilayer technology process and is similar to the littelfuse ml and mle series of discrete leadless chips. the MLN can also be provided in a dual version. contact littelfuse for information. features four individual devices in one 1206 chip esd rated to iec 61000-4-2 (level 4) ac characterized for impedance and capacitance low adjacent channel crosstalk, -55db at 10mhz (typ) low leakage (6na at 5.5v, 30na at 15v) operating voltage up to 18v m(dc) -55 o c to 125 o c operating temperature range low-profile, pcmcia compatible applications data, diagnostic i/o ports analog signal/sensor lines portable/hand-held products mobile communications/cellular phones computer/dsp products industrial instruments including medical
multiline transient voltage surge suppressor MLN surgearray suppressor surface mount varistors 152 www.littelfuse.com absolute maximum ratings for ratings of individual members of a series, see device ratings and specifications table. continuous: steady state applied voltage: dc voltage range (v m(dc) ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 v operating ambient temperature range (t a ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 125 o c storage temperature range (t stg ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to 150 o c device ratings and specifications any single section temperature derating for applications exceeding 125 o c ambient temperature, the peak surge current and energy ratings must be reduced as shown in figure 1. MLN array units pa rt number max ratings (125 o c) performance specifications (25 o c) maximum continuous working voltage maximum non- repetitive surge current (8/20 s) maximum clamping voltage (at noted current 8/20 s) maximum non- repetitive surge energy (10/1000 s) typical esd suppression voltage (note 1) nominal voltage at 1ma dc current capacitance at 1mhz (1v p-p) v m(dc) i tm v c w tm (v) (a) (v) (j) (v) (v) (pf) v5.5MLN41206 v9MLN41206 v14MLN41206 v18MLN41206 v18MLN41206l 430 520 250 300 140 175 100 125 notes: 1. tested to iec61000-4-2 human body model (hbm) discharge test circuit. see explanation of terms on page 7. 2. direct discharge to device terminals (iec preffered test method). see figure 2. 3. corona discharge through air (represents actual esd event) 4. capacitance may be customized, contact sales. (see fig. 3) peak (note 2) 8kv contact (note 3) 15kv air clamp (v) peak (v) (v) v n(dc) min v n(dc) max (note 4) c typ max (pf) 45 75 5.5 9 14 18 18 30 30 30 30 20 7.1 11.0 15.9 22.0 25.0 9.3 16.0 20.3 28.0 35.0 60 95 110 165 200 35 50 55 60 95 45 75 85 100 130 0.1 0.1 0.1 0.1 0.05 15.5 at 2a 23 at 2a 30 at 2a 40 at 2a 50 at 1a 100 90 80 70 60 50 40 30 20 10 0 -55 50 60 70 80 90 100 110 120 130 140 150 percent of rated value ambient temperature ( o c) figure 1. peak current and energy derating curve t t 1 t 2 100 90 50 10 o 1 time percent of peak value o 1 = virtual origin of wave t 1 = virtual front time = 1.25 x t (impulse duration) t = time from 10% to 90% of peak t 2 = virtual time to half value example: for an 8/20 s current waveform: 8 s = t 1 = virtual front 20 s = t 2 = virtual time to half value time figure 2. peak pulse current test waveform for clamping voltage
typical performance curves any single section 40 30 20 10 0 1 10 100 1000 number of discharges v nom 10,000 figure 4. pr oduct distribution of capacitance (1mhz) 70 60 50 40 30 20 10 0 samples capacitance (pf) 70 60 50 40 30 35 45 55 65 typical performance curves any single section figure 5. v-i characteristics figure 6. pulse rating for long duration surges (any single section) 90 80 70 60 50 40 30 20 10 0 varistor voltage (v) 1.0e -07 current (a) 1.0e -06 1.0e -05 1.0e -04 1.0e -03 1.0e -02 1.0e -01 1.0e +00 1.0e +01 1.0e +02 maximum standby current (leakage) maximum clamp voltage typical 1 2 10 100 10 3 10 4 10 5 10 6 100 10 1 0.1 10 100 1000 10000 square wave pulse duration ( s) surge current (a) number of surges MLN surgearray suppressor surface mount varistors multiline transient voltage surge suppressor 153 www.littelfuse.com 3 surface mount varistors
multiline transient voltage surge suppressor MLN surgearray suppressor surface mount varistors 154 www.littelfuse.com typical performance curves any single section (continued) figure 7. standby current at normalized varistor voltage and temperature (any single section) figure 8. capacitance vs frequency figure 9. equivalent series resistance 100 10 0.1 a1 a10 a 100 a1ma current (a) normalized varistor voltage (%) -40 o c 25 o c 85 o c 125 o c 70 65 60 55 50 45 40 1ghz 100mhz 10mhz 1mhz frequency capacitance (pf) 1000 1mhz frequency ohms 100 10 1 0.1 10mhz 100mhz 1ghz 10ghz
soldering recommendations the principal techniques used for the soldering of components in surface mount technology are infrared (ir) reflow, vapour phase reflow, and wave soldering. typical profiles are shown in figures 12, 13 and 14. when wave soldering, the MLN suppressor is attached to the circuit board by means of an adhesive. the assembly is then placed on a con- veyor and run through the soldering process to contact the wave. with ir and vapour phase reflow, the device is placed in a solder paste on the substrate. as the solder paste is heated, it reflows and solders the unit to the board. the recommended solder for the MLN suppressor is a 62/36/2 (sn/pb/ag), 60/40 (sn/pb), or 63/37 (sn/pb). littelfuse also recommends an rma solder flux. wave soldering is the most strenuous of the processes. to avoid the possibility of generating stresses due to thermal shock, a preheat stage in the soldering process is recommended, and the peak temperature of the solder process should be rigidly controlled. typical performance curves any single section (continued) figure 10. impedance vs frequency figure 11. adjacent channel crosstalk 10000 1000 100 10 1 0.1 1mhz 10mhz 100mhz 1ghz 10ghz frequency impedance (z) 0 -20 -40 -60 -80 -100 -120 1khz 100khz 10khz 1mhz 10mhz 100mhz 1ghz frequency crosstalk (db) v in = 1v rms z = 50 ? when using a reflow process, care should be taken to ensure that the MLN chip is not subjected to a thermal gradient steeper than 4 degrees per second; the ideal gradient being 2 degrees per second. during the soldering process, preheating to within 100 degrees of the solders peak temperature is essential to minimize thermal shock. examples of the sol- dering conditions for the MLN array of suppressors are given in the tables below. once the soldering process has been completed, it is still necessary to ensure that any further thermal shocks are avoided. one possible cause of thermal shock is hot printed circuit boards being removed from the solder process and subjected to cleaning solvents at room temperature. the boards must be allowed to gradually cool to less than 50 o c before cleaning. MLN surgearray suppressor surface mount varistors multiline transient voltage surge suppressor 155 www.littelfuse.com 3 surface mount varistors
multiline transient voltage surge suppressor MLN surgearray suppressor surface mount varistors 156 www.littelfuse.com figure 12. ir reflow solder profile temperature ( o c) time (minutes) 250 200 150 100 50 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 maximum preheat dwell preheat zone temperature 222 o c ramp rate <2 o c/s 40-80 seconds above 183 o c figure 14. vapor phase solder profile temperature ( o c) time (minutes) 250 200 150 100 50 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 ramp rate preheat zone >50 o c/s maximum temperature 222 o c 40-80 seconds above 183 o c figure 13. wave solder profile temperature ( o c) time (minutes) 300 250 200 150 100 50 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 maximum wave 260 o c second preheat first preheat recommended pad outline e d a b c dimension abcde millimeters 0.89 1.65 2.54 0.46 0.79 inches 0.035 0.065 0.100 0.018 0.030 p l t s x bl bw w lwtbwbl pxs inch 0.126 0.008 0.063 0.008 0.053 max 0.016 0.004 0.007 +0.01/- 0.002 0.030 ref 0.045 0.004 0.015 0.004 millimeter 3.2 0.2 1.6 0.2 1.35 max 0.41 0.1 0.18 +0.25/-0.05 0.76 ref 1.14 0.1 0.38 0.1 mechanical dimensions table 1. pad layout dimensions
ordering information vxxMLN types v 18 1206 packing options a: 2500 piece bulk pack h: 7in (178mm) diameter reel (note) t: 13in (330mm) diameter reel (note) note: see standard shipping quantities table. device size: i.e., 120 mil x 60 mil device family tvss device maximum dc working voltage ml n series designator n: array w t end termination option w: ag/p d /p t multilayer designator 4 number of sections tape and reel specifications conforms to eia - 481, revision a can be supplied to iec publication 286 - 3 symbol description millimeters a 0 width of cavity dependent on chip size to minimize rotation. b 0 length of cavity dependent on chip size to minimize rotation. k 0 depth of cavity dependent on chip size to minimize rotation. w width of tape 8 0.2 f distance between drive hole centers and cavity centers 3.5 0.5 e distance between drive hole centers and tape edge 1.75 0.1 p 1 distance between cavity center 4 0.1 p 2 axial distance between drive hole centers and cavity centers 2 0.1 p 0 axial distance between drive hole centers 4 0.1 d 0 drive hole diameter 1.55 0.05 d 1 diameter of cavity piercing 1.05 0.05 t 1 embossed tape thickness 0.3 max t 2 top tape thickness 0.1 max note: dimensions in millimeters. standard shipping quantities k 0 t 1 t 2 d 0 p 0 d 1 p 1 a 0 p 2 b 0 f e w plastic carrier tape embossment top tape 8mm nominal product identifying label 178mm or 330mm dia. reel device size 13 inch reel ( t option) 7 inch reel ( h option) bulk pack ( a option) 1206 10,000 2,500 2,500 MLN surgearray suppressor surface mount varistors multiline transient voltage surge suppressor 157 www.littelfuse.com 3 surface mount varistors
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