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lt1618 1 sn1618 1618fas applicatio s u features descriptio u typical applicatio u the lt 1618 step-up dc/dc converter combines a tradi- tional voltage feedback loop and a unique current feedbackloop to operate as a constant-current, constant-voltage source. this fixed frequency, current mode switcher oper- ates from a wide input voltage range of 1.6v to 18v, and the high switching frequency of 1.4mhz permits the use of tiny, low profile inductors and capacitors. the current sense voltage is set at 50mv and can be adjusted using the i adj pin. available in the 10-pin (3mm 3mm) exposed pad dfn and 10-pin msop packages, the lt1618 provides a com-plete solution for constant-current applications. led backlight drivers usb powered boost/sepic converters input current limited boost/sepic converters battery chargers , ltc and lt are registered trademarks of linear technology corporation. accurate input/output current control: 5% over temperature accurate output voltage control: 1% wide v in range: 1.6v to 18v 1.4mhz switching frequency high output voltage: up to 35v low v cesat switch: 200mv at 1a available in (3mm 3mm 0.8mm) 10-pin dfn and 10-pin msop packages constant-current/ constant-voltage 1.4mhz step-up dc/dc converter efficiency curve usb to 12v boost converter (with selectable 100ma/500ma input current limit) load current (ma) efficiency (%) 1618 ta01b 9085 80 75 70 65 60 0 40 80 100 20 60 120 140 160 off on shdni adj v c v in v out 12v sw isn isp fb lt1618 r1909k r2107k v in 5v c1 4.7 f 10nf c24.7 f 1618 ta01a d1 l1 10 h 3 2 1 9 8 7 gnd 510 4 c1: taiyo yuden jmk212bj475 c2: taiyo yuden emk316bj475 d1: on semiconductor mbr0520 l1: sumida cr43-100 0.1 ? 2k 13k 20k 0v 3.3v 100ma 500ma 0v 3.3v downloaded from: http:///
lt1618 2 sn1618 1618fas v in , shdn voltage ................................................... 18v sw voltage .............................................................. 36v isp, isn voltage ...................................................... 36v i adj voltage ............................................................... 6v fb voltage .............................................................. 1.5v v c voltage .............................................................. 1.5v dd part marking t jmax = 125 c, ja = 160 c/w consult ltc marketing for parts specified with wider operating temperature ranges. lt1618edd absolute axi u rati gs w ww u package/order i for atio uu w (note 1) order part number lafq 12 3 4 5 fb isn isp i adj gnd 109 8 7 6 v c shdnv in swnc top view ms package 10-lead plastic msop junction temperature ........................................... 125 c operating temperature range (note 2) .. 40 c to 85 c storage temperature range msop ............................................... 65 c to 150 c dfn ................................................. 65 c to 125 c lead temperature (soldering, 10 sec) (msop) .... 300 c ms part marking lt1618ems order part number ltnh top view 11 dd package 10-lead (3mm 3mm) plastic dfn 10 96 7 8 45 3 2 1 v c shdnv in swsw fb isn isp i adj gnd t jmax = 125 c, ja = 43 c/w, jc = 3 c/w exposed pad (pin 11) is gnd and must be soldered to pcb electrical characteristics the denotes specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v in = 1.6v, v shdn = 1.6v, unless otherwise noted. parameter conditions min typ max units input voltage 1.6 18 v quiescent current v shdn = 1.6v, not switching 1.8 2.7 ma v shdn = 0v 0.1 1 a reference voltage measured at fb pin 1.250 1.263 1.276 v 1.243 1.263 1.283 v reference voltage line regulation 1.6v < v in < 18v 0.01 0.03 %/v fb pin bias current v fb = 1.263v, v in = 1.8v 2 12 na error amplifier voltage gain 180 v/v error amplifier transconductance ? i c = 5 a 160 mho error amplifier sink current v fb = 1.35v, v c = 1v 15 a error amplifier source current v fb = 1.10v, v c = 1v 30 a current sense voltage (isp, isn) v fb = 0v, v iadj = 0v 47.5 50 52.5 mv isp, isn pin bias currents (note 3) v isp = 1.85v, v isn = 1.80v, v iadj = 0v 50 80 a (isp, isn) common mode minimum voltage 1.8 v switching frequency v fb = 1v 1.25 1.4 1.6 mhz v fb = 0v 550 khz maximum switch duty cycle 88 92 % switch current limit (note 4) 1.5 2.1 2.8 a downloaded from: http:///
lt1618 3 sn1618 1618fas typical perfor a ce characteristics uw temperature ( c) ?0 feedback voltage (v) 125 1618 g02 0 75 1.2701.265 1.260 1.255 1.250 42 0 ? ? ?5 25 50 100 voltage current fb pin bias current (na) temperature ( c) ?0 peak current (a) 125 1618 g03 0 75 2.52.0 1.5 1.0 0.5 0 ?5 25 50 100 temperature ( c) ?0 current sense voltage (mv) 125 1618 g04 0 75 5251 50 49 48 ?5 25 50 100 i adj pin voltage (v) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 current sense voltage (mv) 1618 g05 6050 40 30 20 10 0 temperature ( c) ?0 quiescent current (ma) 125 1618 g06 0 75 2.52.0 1.5 1.0 0.5 0 ?5 25 50 100 v in = 18v v in = 1.6v fb pin voltage and bias current switch current limit current sense voltage(i adj pin = 0v) current sense voltage(v isp, isn ) quiescent current switch saturation voltage(v ce, sat ) switch current (a) 0 saturation voltage (mv) 2.0 1618 g01 0.5 1.0 1.5 500400 300 200 100 0 t j = 125 c t j = 50 c t j = 25 c note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired.note 2: the lt1618 is guaranteed to meet performance specifications from 0 c to 70 c. specifications over the 40 c to 85 c operating temperature range are assured by design, characterization, and correlationwith statistical process controls. note 3: bias currents flow into the isp and isn pins. note 4: switch current limit and switch v cesat for the dd package is guaranteed by design and/or correlation to static test. electrical characteristics the denotes specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v in = 1.6v, v shdn = 1.6v, unless otherwise noted. parameter conditions min typ max units switch v cesat i sw = 1a (note 4) 200 260 mv switch leakage current switch off, v sw = 5v 0.01 5 a shdn pin current v shdn = 1.6v 5 20 a shutdown threshold (shdn pin) 0.3 v start-up threshold (shdn pin) 1v downloaded from: http:///
lt1618 4 sn1618 1618fas pi n fu n ctio n s uuu fb (pin 1/pin 1): feedback pin. set the output voltage by selecting values for r1 and r2 (see figure 1): rr v v out 12 1 263 1 = ? ? ? ? ? ? . isn (pin 2/pin 2): current sense (? pin. the inverting input to the current sense amplifier. isp (pin 3/pin 3): current sense (+) pin. the noninverting input to the current sense amplifier.i adj (pin 4/pin 4): current sense adjust pin. a dc voltage applied to this pin will reduce the current sense voltage. ifthis adjustment is not needed, tie this pin to ground. gnd (pin 5/pin 5): ground pin. tie this pin directly to local ground plane.nc (pin 6/na): no connection for ms package. sw (na/pin 6): switch pin for dd package. connect this pin to pin 7.sw (pin 7/pin 7): switch pin. this is the collector of the internal npn power switch. minimize the metal trace areaconnected to this pin to minimize emi. v in (pin 8/pin 8): input supply pin. bypass this pin with a capacitor to ground as close to the device as possible.shdn (pin 9/pin 9): shutdown pin. tie this pin higher than 1v to turn on the lt1618; tie below 0.3v to turn it off.v c (pin 10/pin 10): compensation pin for error amplifier. connect a series rc from this pin to ground. typical valuesare 2k ? and 10nf. exposed pad (na/pin 11): the exposed pad on the dd package is gnd and must be soldered to the pcb gnd foroptimum thermal performance. typical perfor a ce characteristics uw temperature ( c) ?0 switching frequency (mhz) 125 1618 g07 0 75 1.81.7 1.6 1.5 1.4 1.3 1.2 1.1 1.0 ?5 25 50 100 v in = 18v v in = 1.6v feedback pin voltage (v) switching frequency (mhz) 1.2 1618 g08 0 0.2 0.8 1.61.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0.4 0.6 1.0 t j = 25 c shutdown pin voltage (v) 0 shdn pin current ( a) 20 1618 g09 5 10 15 5045 40 35 30 25 20 15 10 50 t j = 50 c t j = 25 c t j = 125 c switching frequency frequency foldback shdn pin current (ms/dd) downloaded from: http:///
lt1618 5 sn1618 1618fas 1.4mhz oscillator driver + + + + + 5 q q1 s r + a1 25 5 10 3 2 8 7 9 1.263v 4 1 shdn i adj gnd v c r c c c v in sw isn isp fb a2 a3 0.02 ? c1 c2 r sense v out v in r1 r2 l1 d1 figure 1. lt1618 block diagram block diagra w operatio u the lt1618 uses a constant frequency, current modecontrol scheme to provide excellent line and load regula- tion. operation can be best understood by referring to the block diagram in figure 1. at the start of each oscillator cycle, the sr latch is set, turning on power switch q1. the signal at the noninverting input of pwm comparator a3 is a scaled-down version of the switch current (summed together with a portion of the oscillator ramp). when this signal reaches the level set by the output of error amplifier a2, comparator a3 resets the latch and turns off the power switch. in this manner, a2 sets the correct peak current level to keep the output in regulation. if the error amplifier? output increases, more current is delivered to the output; if it decreases, less current is delivered. a2 has two inverting inputs, one from the voltage feedback loop, and one from the current feedback loop. whichever inverting input is higher takes precedence, forcing the converterinto either a constant-current or a constant-voltage mode. the lt1618 is designed to transition cleanly between the two modes of operation. current sense amplifier a1 senses the voltage between the isp and isn pins and provides a 25 level-shifted version to error amplifier a2. when the voltage between isp and isn reaches 50mv, the output ofa1 provides 1.263v to one of the noninverting inputs of a2 and the converter is in constant-current mode. if the current sense voltage exceeds 50mv, the output of a1 will increase causing the output of a2 to decrease, thus reducing the amount of current delivered to the output. in this manner the current sense voltage is regulated to 50mv. similarly, if the fb pin increases above 1.263v, the output of a2 will decrease to reduce the peak current level and regulate the output (constant-voltage mode). downloaded from: http:///
lt1618 6 sn1618 1618fas capacitor selectionlow esr (equivalent series resistance) capacitors should be used at the output to minimize the output ripple voltage. multilayer ceramic capacitors are an excellent choice. they have an extremely low esr and are available in very small packages. x5r and x7r dielectrics are preferred, as these materials retain their capacitance over wider voltage and temperature ranges than other dielectrics. a 4.7 f to 10 f output capacitor is sufficient for high output current designs. converters with lower output currents may needonly a 1 f or 2.2 f output capacitor. solid tantalum or oscon capacitors can be used, but they will occupy moreboard area than a ceramic and will have a higher esr for applicatio n s i n for m atio n wu u u inductor selectionseveral inductors that work well with the lt1618 are listed in table 1, although there are many other manufacturers and devices that can be used. consult each manufacturer for more detailed information and for their entire selection of related parts. many different sizes and shapes are available. ferrite core inductors should be used to obtain the best efficiency, as core losses at 1.4mhz are much lower for ferrite cores than for the cheaper powdered-iron ones. choose an inductor that can handle the necessary peak current without saturating, and ensure that the inductor has a low dcr (copper-wire resistance) to mini- mize i 2 r power losses. a 4.7 h or 10 h inductor will be a good choice for many lt1618 designs. table 1. recommended inductors l max height part ( h) (m ? ) (mm) vendor cdrh5d18-4r1 4.1 57 2.0 sumida cdrh5d18-100 10 124 2.0 (847) 956-0666 cr43-2r2 2.2 71 3.5 www.sumida.com cr43-4r7 4.7 109 3.5 cr43-100 10 182 3.5 cr54-100 10 100 4.8 lqh3c1r0m24 1.0 78 2.0 murata lqh3c2r2m24 2.2 126 2.0 (814) 237-1431 lqh3c4r7m24 4.7 260 2.0 www.murata.com the same footprint device. always use a capacitor with asufficient voltage rating. ceramic capacitors also make a good choice for the input decoupling capacitor, which should be placed as close as possible to the v in pin of the lt1618. a 1 f to 4.7 f input capacitor is sufficient for most applications. table 2 showsa list of several ceramic capacitor manufacturers. consult the manufacturers for detailed information on their entire selection of ceramic parts. table 2. recommended ceramic capacitor manufacturers vendor phone url taiyo yuden (408) 573-4150 www.t-yuden.com murata (814) 237-1431 www.murata.com kemet (408) 986-0424 www.kemet.com diode selectionschottky diodes, with their low forward voltage drop and fast switching speed, are the ideal choice for lt1618 applications. table 3 shows several schottky diodes that work well with the lt1618. many different manufacturers make equivalent parts, but make sure that the component chosen has a sufficient current rating and a voltage rating greater than the output voltage. the diode conducts cur- rent only when the power switch is turned off (typically less than half the time), so a 0.5a or 1a diode will be sufficient for most designs. the companies below also offer schottky diodes with higher voltage and current ratings. table 3. recommended schottky diodes 1a part 0.5a part vendor phone/url ups120 microsemi (510) 353-0822 ups130 www.microsemi.com ups140 mbrm120 mbr0520 on semiconductor (800) 282-9855 mbrm130 mbr0530 www.onsemi.com mbrm140 mbr0540 b120 b0520 diodes, inc (805) 446-4800 b130 b0530 www.diodes.com b140 b0540 downloaded from: http:///
lt1618 7 sn1618 1618fas applicatio n s i n for m atio n wu u u setting output voltageto set the output voltage, select the values of r1 and r2 (see figure 1) according to the following equation. rr v out 12 1 263 1 = ? ? ? ? ? ? . for current source applications, use the fb pin for over-voltage protection. pick r1 and r2 so that the output voltage will not go too high if the load is disconnected or if the load current drops below the preset value. typically choose r1 and r2 so that the overvoltage value will be about 20% to 30% higher than the normal output voltage (when in constant-current mode). this prevents the volt- age loop from interfering with the current loop in current source applications. for battery charger applications, pick the values of r1 and r2 to give the desired end of charge voltage. selecting r sense /current sense adjustment use the following formula to choose the correct currentsense resistor value (for constant current operation). r sense = 50mv/i max for designs needing an adjustable current level, the i adj pin is provided. with the i adj pin tied to ground, the nominal current sense voltage is 50mv (appearing be-tween the isp and isn pins). applying a positive dc voltage to the i adj pin will decrease the current sense voltage according to the following formula: v vv isense iadj = 1 263 0 8 25 . ( . ) for example, if 1v is applied to the i adj pin, the current sense voltage will be reduced to about 18mv. thisadjustability allows the regulated current to be reduced without changing the current sense resistor (e.g. to adjust brightness in an led driver or to reduce the charge current in a battery charger). if the i adj pin is taken above 1.6v, the output of the error amplifier (the v c pin) will be pulled down and the lt1618 will stop switching.a pulse width modulated (pwm) signal can also be used to adjust the current sense voltage; simply add an rc filterto convert the pwm signal into a dc voltage for the i adj pin. if the i adj pin is not used, it should be tied to ground. do not leave the pin floating.for applications needing only a simple one-step current sense adjustment, the circuit in figure 2 works well. if a large value resistor ( 2m ? ) is placed between the i adj pin and ground, the current sense voltage will reduce to about25mv, providing a 50% reduction in current. do not leave the i adj pin open. this method gives a well-regulated current value in both states, and is controlled by a logicsignal without the need for a variable pwm or dc control signal. when the nmos transistor is on, the current sense voltage will be 50mv, when it is off, the current sense voltage will be reduced to 25mv. figure 2 lt1618 i adj 2m full current 1618 f02 considerations when sensing input currentin addition to regulating the dc output current for current- source applications, the constant-current loop of the lt1618 can also be used to provide an accurate input current limit. boost converters cannot provide output short-circuit protection, but the surge turn-on current can be drastically reduced using the lt1618? current sense at the input. sepics, however, have an output that is dc- isolated from the input, so an input current limit not only helps soft-start the output but also provides excellent short-circuit protection. downloaded from: http:///
lt1618 8 sn1618 1618fas applicatio n s i n for m atio n wu u u figure 3 load v out l1 switch node 1618 ?f03 v in high frequency circulating path when sensing input current, the sense resistor should beplaced in front of the inductor (between the decoupling capacitor and the inductor) as shown in the circuits in the typical applications section. this will regulate the average inductor current and maintain a consistent inductor ripple current, which will, in turn, maintain a well regulated input current. do not place the sense resistor between the input source and the input decoupling capacitor, as this may allow the inductor ripple current to vary widely (even though the average input current and the average inductor current will still be regulated). since the inductor current is a triangular waveform (not a dc waveform like the output current) some tweaking of the compensation values (r c and c c on the v c pin) may be required to ensure a clean inductor ripple current while the constant-currentloop is in effect. for these applications, the constant- current loop response can usually be improved by reduc- ing the r c value, or by adding a capacitor (with a value of approximately c c /10) in parallel with the r c and c c compensation network.frequency compensation the lt1618 has an external compensation pin (v c ), which allows the loop response to be optimized for each applica-tion. an external resistor and capacitor (or sometimes just a capacitor) are placed at the v c pin to provide a pole and a zero (or just a pole) to ensure proper loop compensation.numerous other poles and zeroes are present in the closed loop transfer function of a switching regulator, so the v c pin pole and zero are positioned to provide the best loopresponse. a thorough analysis of the switching regulator control loop is not within the scope of this data sheet, and will not be presented here, but values of 2k ? and 10nf will be a good choice for many designs. for those wishing tooptimize the compensation, use the 2k ? and 10nf as a starting point. for led backlight applications where apulse-width modulation (pwm) signal is used to drive the i adj pin, the resistor is usually not included in the compensation network. this helps to provide additionalfiltering of the pwm signal at the output of the error amplifier (the v c pin). switch node considerationsto maximize efficiency, switch rise and fall times are made as short as possible. to prevent radiation and high fre- quency resonance problems, proper layout of the high frequency switching path is essential. keep the output switch (sw pin), diode and output capacitor as close together as possible. minimize the length and area of all traces connected to the switch pin, and always use a ground plane under the switching regulator to minimize interplane coupling. the high speed switching current path is shown in figure 3. the signal path including the switch, output diode and output capacitor contains nano- second rise and fall times and should be kept as short as possible. downloaded from: http:///
lt1618 9 sn1618 1618fas typical applicatio s u load current (ma) 0 efficiency (%) 8075 70 65 60 50 100 150 200 1618 ta02b 250 300 4.5w direct broadcast satellite (dbs) power supply with short-circuit protection efficiency lhcp rhcp 0v 3.3v shdni adj v c v in sw isn isp fb lt1618 r1100k r2 10k r524.9k v in 12v c1 4.7 f c c 33nf c33.3 f c43.3 f 1618 ta02a d1 l1 33 h l3 2.2 h l233 h 3 2 1 9 8 7 gnd 510 4 c1: taiyo yuden emk316bj475 (408) 573-4150 c2: taiyo yuden tmk316bj105 (408) 573-4150 c3, c4: taiyo yuden tmk325bj335 (408) 573-4150 d1: on semiconductor mbrm140 (800) 282-9855 l1, l2: sumida cr54-330 (847) 956-0666 l3: sumida cr43-2r2 (847) 956-0666 0.068 ? r c 2k c2 1 f q1 mmbt3904 q1fmmt717 zetex d2murs110 13.5v/18.5v 22khznetwork tuning r310k r41k add 5v downloaded from: http:///
lt1618 10 sn1618 1618fas 2-cell white led driver 2-cell luxeon led driver typical applicatio n s u shdni adj gnd v c v in sw isn isp fb lt1618 r12m r2 160k v in 1.6v to 3v 10khz to 50khz pwm brightness adjust c1 4.7 f c c 0.1 f c21 f 1618 ?ta03 2.49 ? d1 l1 4.7 h 20ma 32 1 9 8751 0 4 r3 5.1k c3 0.1 f c1: taiyo yuden jmk212bj475 (408) 573-4150 c2: taiyo yuden emk316bj105 (408) 573-4150 d1: on semiconductor mbr0520 (800) 282-9855 l1: sumida clq4d10-4r7 (847) 956-0666 shdni adj gnd v c v in sw isn isp fb lt1618 332k d2 124k v in 1.8v to 3v c1 1 f 100nf c21 f 1618 ?ta12 0.15 ? d1 l1 10 h 350ma 32 1 9 8751 0 4 c1, c2: taiyo yuden jmk107bj105kad1: on semiconductor mbr0520 d2: lumileds lxhl-bw02 l1: sumida cr43-100 downloaded from: http:///
lt1618 11 sn1618 1618fas typical applicatio n s u li ion white led driver shdni adj gnd v c v in sw isn isp fb lt1618 r12m r2 100k v in 2.7v to 5v 10khz to 50khz pwm brightness adjust c1 4.7 f c c 0.1 f c21 f 1618 ?ta04 2.49 ? d1 l1 10 h 20ma 32 1 9 8751 0 4 r3 5.1k c3 0.1 f c1: taiyo yuden jmk212bj475 (408) 573-4150 c2: taiyo yuden tmk316bj105 (408) 573-4150 d1: on semiconductor mbr0530 (800) 282-9855 l1: sumida clq4d10-100 (847) 956-0666 white led driver for 20 leds shdni adj gnd v c v in sw isn isp fb lt1618 r12m r2 121k v in 2.7v to 5v 10khz to 50khz pwm brightness adjust c1 4.7 f c c 0.1 f c21 f 1618 ?ta05 0.619 ? d1 l1 10 h 80ma 32 1 9 8751 0 4 r3 5.1k c3 0.1 f 51 ? 51 ? 51 ? 51 ? c1: taiyo yuden jmk212bj475 (408) 573-4150 c2: taiyo yuden tmk316bj105 (408) 573-4150 d1: on semiconductor mbr0530 (800) 282-9855 l1: sumida cr43-100 (847) 956-0666 downloaded from: http:///
lt1618 12 sn1618 1618fas typical applicatio n s u usb to 5v sepic converter efficiency usb sepic during start-up usb sepic start-up with output shorted load current (ma) 0 efficiency (%) 350 1618 f09b 100 250 8075 70 65 60 50 150 200 300 1ms/div 1618 ta10 v out 2v/div i in 50ma/div 1ms/div 1618 ta11 v out 2v/div 50ma/div shdni adj v c v in sw isn isp fb lt1618 r1316k r2 107k v in 5v c1 4.7 f 10nf c210 f 1618 ?ta09a d1 l1 10 h l210 h 3 2 1 9 8 7 gnd 510 4 0.1 ? 2k 13k 20k v out 5v c3 0.47 f i in c1: taiyo yuden jmk212bj475 (408) 573-4150 c2: taiyo yuden jmk316bj106 (408) 573-4150 c3: taiyo yuden emk212bj474 (408) 573-4150 d1: on semiconductor mbr0520 (800) 282-9855 l1: sumida cr43-100 (847) 956-0666 off on 0v 3.3v 100ma 500ma 0v 3.3v downloaded from: http:///
lt1618 13 sn1618 1618fas typical applicatio s u efficiency 12v boost converter with 500ma input current limit 12v boost converter start-up with input current limit (v in = 1.8v, i load = 40ma) 12v boost converter start-up without input current limit (v in = 1.8v, i load = 40ma) l0ad current (ma) 0 efficiency (%) 120 140 1618 ta06b 40 80 9085 80 75 70 65 60 20 60 100 160 v in = 5v v in = 3.3v shdni adj v c v in sw isn isp fb lt1618 r1909k r2 107k v in 1.8v to 5v c1 4.7 f 10nf c24.7 f 1618 ?ta06a d1 l1 10 h 3 2 1 9 8 7 gnd 510 4 0.1 ? 2k v out 12v c1: taiyo yuden jmk212bj475 (408) 573-4150 c2: taiyo yuden emk316bj475 (408) 573-4150 d1: on semiconductor mbr0520 (800) 282-9855 l1: sumida cr43-100 (847) 956-0666 i l1 50 s/div 1618 ta07 v out 5v/div i li 200ma/div 50 s/div 1618 ta08 v out 5v/div i li 200ma/div downloaded from: http:///
lt1618 14 sn1618 1618fas package descriptio u dd package 10-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1698) 3.00 0.10 (4 sides) note:1. drawing to be made a jedec package outline m0-229 variation of (weed-2). check the ltc website data sheet for current status of variation assignment 2. drawing not to scale 3. all dimensions are in millimeters 4. dimensions of exposed pad on bottom of package do not include mold flash. mold flash, if present, shall not exceed 0.15mm on any side 5. exposed pad shall be solder plated 6. shaded area is only a reference for pin 1 location on the top and bottom of package 0.38 0.10 bottom view?xposed pad 1.65 0.10 (2 sides) 0.75 0.05 r = 0.115 typ 2.38 0.10 (2 sides) 1 5 10 6 pin 1 top mark (see note 6) 0.200 ref 0.00 ?0.05 (dd10) dfn 1103 0.25 0.05 2.38 0.05 (2 sides) recommended solder pad pitch and dimensions 1.65 0.05 (2 sides) 2.15 0.05 0.50bsc 0.675 0.05 3.50 0.05 packageoutline 0.25 0.05 0.50 bsc downloaded from: http:///
lt1618 15 sn1618 1618fas package descriptio u ms package 10-lead plastic msop (reference ltc dwg # 05-08-1661) msop (ms) 0603 0.53 0.152 (.021 .006) seating plane 0.18 (.007) 1.10 (.043) max 0.17 ?0.27 (.007 ?.011) typ 0.127 0.076 (.005 .003) 0.86 (.034) ref 0.50 (.0197) bsc 12 3 45 4.90 0.152 (.193 .006) 0.497 0.076 (.0196 .003) ref 8910 7 6 3.00 0.102 (.118 .004) (note 3) 3.00 0.102 (.118 .004) (note 4) note:1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.254 (.010) 0 ?6 typ detail ? detail ? gauge plane 5.23 (.206) min 3.20 ?3.45 (.126 ?.136) 0.889 0.127 (.035 .005) recommended solder pad layout 0.305 0.038 (.0120 .0015) typ 0.50 (.0197) bsc information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. downloaded from: http:///
lt1618 16 sn1618 1618fas linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2001 lt/tp 0504 1k rev a ?printed in usa typical applicatio n s u buck mode luxeon led driver shdni adj v c v in sw isn isp fb lt1618 v in 16v c14.7 f 2.2nf 220pf 1618 ta14 d1 d2 700ma l147 h 3 2 1 9 8 7 gnd 510 4 c1: taiyo yuden tmk325bj475mn d1: philips pmeg2010 d2: lumileds ds45 l1: toko d104c 10k 0.07 ? li-ion buck-boost mode luxeon led driver shdni adj v c v in sw isp isn fb lt1618 100k10k v in 3.2v to 5v c14.7 f 10nf c24.7 f 1618 ta13 d1 d2 350ma l1 3.3 h 2 3 1 9 8 7 gnd 510 4 c1: taiyo yuden jmk212bj475kg c2: taiyo yuden emk316bj475ml d1: on semiconductor mbrm120 d2: lumileds ds25 l1: nec plc-07453r3 0.15 ? part number description comments lt1613 550ma (i sw ), 1.4mhz, high efficiency step-up dc/dc converter v in : 0.9v to 10v, v out(max) = 34v, i q = 3ma, i sd < 1 a, thinsot tm package lt1615/lt1615-1 300ma/80ma (i sw ), constant off-time, high efficiency step-up v in : 1.2v to 15v, v out(max) = 34v, i q = 20 a, i sd < 1 a, dc/dc converter thinsot package lt1930/lt1930a 1a (i sw ), 1.2mhz/2.2mhz, high efficiency step-up v in : 2.6v to 16v, v out(max) = 34v, i q = 4.2ma/5.5ma, dc/dc converter i sd < 1 a, thinsot package lt1932 constant current, 1.2mhz, high efficiency white led v in : 1v to 10v, v out(max) = 34v, i q = 1.2ma, i sd < 1 a, boost regulator thinsot package lt1944/lt1944-1 dual output 350ma/100ma (i sw ), constant off-time, v in : 1.2v to 15v, v out(max) = 34v, i q = 20 a, i sd < 1 a, (dual) high efficiency step-up dc/dc converter ms package lt1945 (dual) dual output, pos/neg, 350ma (i sw ), constant off-time, v in : 1.2v to 15v, v out(max) = 34v, i q = 20 a, i sd < 1 a, high efficiency step-up dc/dc converter ms package lt1961 1.5a (i sw ), 1.25mhz, high efficiency step-up dc/dc converter v in : 3v to 25v, v out(max) = 35v, i q = 0.9ma, i sd < 6 a, ms8e package ltc3401/ltc3402 1a/2a (i sw ), 3mhz, synchronous step-up dc/dc converter v in : 0.5v to 5v, v out(max) = 6v, i q = 38 a, i sd < 1 a, ms package lt3461/lt3461a 0.3a (i sw ), 1.3mhz/3mhz, high efficiency step-up dc/dc v in : 2.5v to 16v, v out(max) = 38v, i q = 2.8ma, i sd < 1 a, converter with integrated schottky sc70 and thinsot packages lt3463/lt3463a 250ma (i sw ), boost/inverter dual, micropower dc/dc converter v in : 2.4v to 15v, v out(max) = 40v, i q = 40 a, i sd < 1 a, with integrated schottky diodes dfn package lt3464 0.08a (i sw ), high efficiency step-up dc/dc converter with v in : 2.3v to 10v, v out(max) = 34v, i q = 25 a, i sd < 1 a, integrated schottky, output disconnect thinsot package lt3465/lt3465a constant current, 1.2mhz/2.7mhz, high efficiency white led v in : 2.7v to 16v, v out(max) = 34v, i q = 1.9ma, i sd < 1 a, boost regulator with integrated schottky diode thinsot package lt3467/lt3467a 1.1a (i sw ), 1.3mhz/2.1mhz, high efficiency step-up dc/dc v in : 2.4v to 16v, v out(max) = 40v, i q = 1.2ma, i sd < 1 a, converter with integrated soft-start thinsot package thinsot is a trademark of linear technology corporation. related parts downloaded from: http:///

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