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ltc3250-1.5/ltc3250-1.2 1 3250fa descriptio u applicatio s u features typical applicatio u n handheld computers n cellular phones n digital cameras n handheld medical instruments n low power dsp supplies n 2.7v to 5.5v input voltage range n no inductors n li-ion (3.6v) to 1.5v with 81% efficiency n low noise constant frequency operation n output voltages: 1.5v 4%, 1.2v 4% n output current: 250ma n shutdown disconnects load from v in n low operating current: i q = 35 m a n low shutdown current: i sd < 1 m a n oscillator frequency = 1.5mhz n soft-start limits inrush current at turn-on n short-circuit and overtemperature protected n low profile (1mm) sot-23 package high efficiency, low noise, inductorless step-down dc/dc converter 3250 ta1a ltc3250-1.5 v in v in 3.2v to 4.2v shdn c + c C v out gnd on off 1 f 4.7 f v out = 1.5v 4% 100ma li-ion 1 f efficiency vs input voltage (i out = 100ma) the ltc ? 3250-1.5/ltc3250-1.2 are charge pump step- down dc/dc converters that produce a 1.5v or 1.2v regulated output from a 2.7v to 5.5v input. the parts use switched capacitor fractional conversion to achieve typi- cal efficiency two times higher than that of a linear regu- lator. no inductors are required. a unique constant frequency architecture provides a low noise regulated output as well as lower input noise than conventional charge pump regulators.* high frequency operation (f osc = 1.5mhz) simplifies filtering to further reduce conducted noise. the part also uses burst mode ? operation to improve efficiency at light loads. low operating current (35 m a with no load, <1 m a in shutdown) and low external parts count (three small ceramic capacitors) make the ltc3250-1.5/ltc3250-1.2 ideally suited for space constrained battery powered appli- cations. the parts are short-circuit and overtemperature protected, and are available in a low profile (1mm) 6-pin thinsot tm package. v in (v) 3.0 3.5 4.0 4.5 5.0 5.5 efficiency (%) 3250 ta01b 100 90 80 70 60 50 40 30 20 10 0 ldo ltc3250-1.5 li-ion to 1.5v output with shutdown , ltc and lt are registered trademarks of linear technology corporation burst mode is a registered trademark of linear technology corporation thinsot is a trademark of linear technology corporation. *u.s. patent #6, 411, 531
ltc3250-1.5/ltc3250-1.2 2 3250fa symbol parameter conditions min typ max units v in ltc3250-1.5 operating voltage range l 3.1 5.5 v ltc3250-1.2 operating voltage range l 2.7 5.5 v v out ltc3250-1.5 output voltage range i out 50ma 3.1v v in 5.5v l 1.44 1.5 1.56 v i out 100ma 3.2v v in 5.5v l 1.44 1.5 1.56 v i out 250ma 3.5v v in 5v 1.44 1.5 1.56 v ltc3250-1.2 output voltage range i out 150ma 2.7v < v in < 5.5v l 1.15 1.2 1.25 v i out 250ma 2.9v v in 5v 1.15 1.2 1.25 v i in operating current i out = 0ma l 35 60 m a shutdown current shdn = 0v l 0.01 1 m a v rb burst mode operation output ripple 12 mv p-p v rc continuous mode output ripple 4 mv p-p f osc switching frequency l 1.2 1.5 1.8 mhz v ih shdn input hi voltage l 1.2 0.8 v v il shdn input low voltage l 0.8 0.4 v i ih shdn input current shdn = v in l C1 1 m a i il shdn input current shdn = 0v l C1 1 m a t on turn on time r load = 6 w 0.8 ms ltc3250-1.5 load regulation 0 i out 250ma 0.15 mv/ma ltc3250-1.2 load regulation 0 i out 250ma 0.12 mv/ma line regulation i out = 250ma 0.2 %/v r ol open-loop output impedance i out = 250ma (note 4) 1.0 w v in to gnd ................................................... C0.3v to 6v shdn to gnd ............................... C0.3v to (v in + 0.3v) i out (note 2) ....................................................... 350ma operating ambient temperature range (note 3) ........................................................... C 40 c to 85 c storage temperature range ................ C 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c order part number s6 part marking t jmax = 150 c, q ja = 230 c/w, q jc = 102 c/w ltze ltagj ltc3250es6-1.5 ltc3250es6-1.2 absolute axi u rati gs w ww u package/order i for atio uu w (note 1) electrical characteristics the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v in = 3.6v, c fly = 1 m f, c in = 1 m f, c out = 4.7 m f unless otherwise noted. consult ltc marketing for parts specified with wider operating temperature ranges. 6 c + 5 v out 4 c v in 1 top view s6 package 6-lead plastic sot-23 gnd 2 shdn 3 note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: based on long term current density limitations. note 3: the ltc3250-1.5e/ltc3250-1.2e are guaranteed to meet specified performance from 0 c to 70 c. specifications over the C40 c and 85 c operating temperature range are assured by design characterization and correlation with statistical process controls. note 4: output not in regulation; r ol = (v in /2 - v out )/i out . note 5: this ic includes overtemperature protection that is intended to protect the device during momentary overload conditions. junction temperature will exceed 125 c when overtemperature protection is active. continuous operation above the specified maximum operating junction temperature may impair device reliability.
ltc3250-1.5/ltc3250-1.2 3 3250fa no load supply current vs supply voltage output voltage vs supply voltage output voltage vs load current oscillator frequency vs supply voltage efficiency vs output current v shdn threshold voltage vs supply voltage typical perfor a ce characteristics uw v in (v) 2.7 i in ( a) 50 45 40 35 30 25 20 5.1 3250 g01 3.5 3.1 3.9 4.3 4.7 5.5 t a = C40 c t a = 25 c t a = 85 c 3.1v < v in < 5.5v (ltc3250-1.5) 2.7v < v in < 5.5v (ltc3250-1.2) v in (v) frequency (mhz) 1.8 1.7 1.6 1.5 1.4 1.3 1.2 3250 g02 t a = C40 c t a = 25 c t a = 85 c 3.1v < v in < 5.5v (ltc3250-1.5) 2.7v < v in < 5.5v (ltc3250-1.2) 2.7 4.7 3.2 3.7 4.2 5.2 v in (v) 2.7 v shdn (mv) 1200 1100 1000 900 800 700 600 500 400 4.7 3250 g03 3.2 3.7 4.2 5.2 t a = C40 c t a = 25 c t a = 85 c 3.1v < v in < 5.5v (ltc3250-1.5) 2.7v < v in < 5.5v (ltc3250-1.2) i out (ma) 0 v out (v) 50 100 150 200 3250 g04 250 1.60 1.58 1.56 1.54 1.52 1.50 1.48 1.46 1.44 1.42 1.40 300 v in = 3.6v t a = 25 c i out (ma) 1 0.1 efficiency (%) 1000 3250 g05 10 100 100 90 80 70 60 50 40 30 20 10 0 v in = 3.6v v in = 3.3v v in = 4v v in = 5v t a = 25 c v in (v) 3.0 v out (v) 1.60 1.58 1.56 1.54 1.52 1.50 1.48 1.46 1.44 1.42 1.40 5.0 3250 g06 3.5 4.0 4.5 5.5 t a = 25 c i out = 0ma i out = 250ma i out = 100ma (ltc3250-1.5) output voltage vs supply voltage output voltage vs load current efficiency vs output current (ltc3250-1.2) i out (ma) 0 v out (v) 50 100 150 200 3250 g12 250 1.30 1.28 1.26 1.24 1.22 1.20 1.18 1.16 1.14 1.12 1.10 300 v in = 3.6v t a = 25 c i out (ma) 1 0.1 efficiency (%) 1000 3250 g13 10 100 100 90 80 70 60 50 40 30 20 10 0 v in = 3v v in = 2.7v v in = 3.5v v in = 4.5v t a = 25 c v in (v) 2.7 v out (v) 1.30 1.28 1.26 1.24 1.22 1.20 1.18 1.16 1.14 1.12 1.10 4.7 3250 g14 3.2 3.7 4.2 5.2 i out = 0ma i out = 250ma i out = 100ma t a = 25 c
ltc3250-1.5/ltc3250-1.2 4 3250fa output voltage soft-start and shutdown (ltc3250-1.5) output current transient response (ltc3250-1.5) line transient response (ltc3250-1.5) typical perfor a ce characteristics uw output voltage ripple (ltc3250-1.5) input voltage ripple vs input capacitor (ltc3250-1.5) 250ma 15ma i out v out 20mv/div ac v in = 3.6v 3250 g08 3250 g09 4.5v 3.5v v in v out 20mv/div ac i out = 200ma v in 50mv/div ac v in 50mv/div ac i out = 250ma r source = 0.2 3250 g10 c i = 1 f c i = 10 f v out 20mv/div ac 3250 g11 c out = 4.7 f 1x5r16.3v i out = 250ma v in = 3.6v hi low shdn v out 500mv/div r l = 6 v in = 3.6v 3250 g07
ltc3250-1.5/ltc3250-1.2 5 3250fa v in (pin 1): input supply voltage. bypass v in with a 3 1 m f low esr ceramic capacitor. gnd (pin 2): ground. connect to a ground plane for best performance. shdn (pin 3): active low shutdown input. a low voltage on shdn disables the ltc3250-1.5/ltc3250-1.2. shdn must not be allowed to float. c C (pin 4): flying capacitor negative terminal v out (pin 5): regulated output voltage. v out is discon- nected from v in during shutdown. bypass v out with a 3 4.7 m f low esr ceramic capacitor (2.5 m f min, esr <100m w ). c + (pin 6): flying capacitor positive terminal. uu u pi fu ctio s block diagra w 3250 bd + 3 1 2 6 5 4 thermal shutdown (>160 c) switch control and soft-start 1.5mhz oscillator charge pump burst detect circuit gnd shdn v in c + c v out ltc3250-1.5 / ltc3250-1.2 v ref
ltc3250-1.5/ltc3250-1.2 6 3250fa the ltc3250-1.5/ltc3250-1.2 use a switched capacitor charge pump to step down v in to a regulated 1.5v 4% or 1.2v 4% (respectively) output voltage. regulation is achieved by sensing the output voltage through an internal resistor divider and modulating the charge pump output current based on the error signal. a 2-phase nonoverlapping clock activates the charge pump switches. on the first phase of the clock current is transferred from v in , through the flying capacitor, to v out . not only is current being delivered to v out on the first phase, but the flying capaci- tor is also being charged up. on the second phase of the clock the flying capacitor is connected from v out to ground, delivering the charge stored during the first phase of the clock to v out . using this method of switching, only half of the output current is delivered from v in , thus achieving twice the efficiency over a conventional ldo. the sequence of charging and dis-charging the flying capacitor continues at a free running frequency of 1.5mhz (typ). this constant frequency architecture provides a low noise regulated output as well as lower input noise than conventional switch-capacitor charge pump regulators. the part also has a low current burst mode operation to improve efficiency even at light loads. in shutdown mode all circuitry is turned off and the ltc3250-1.5/ltc3250-1.2 draw only leakage current from the v in supply. furthermore, v out is disconnected from v in . the shdn pin is a cmos input with a threshold voltage of approximately 0.8v. the ltc3250-1.5/ltc3250- 1.2 are in shutdown when a logic low is applied to the shdn pin. since the shdn pin is a high impedance cmos input it should never be allowed to float. to ensure that its state is defined it must always be driven with a valid logic level. short-circuit/thermal protection the ltc3250-1.5/ltc3250-1.2 have built-in short-circuit current limiting as well as overtemperature protection. during short-circuit conditions, the parts will automati- cally limit the output current to approximately 500ma. at higher temperatures, or if the input voltage is high enough to cause excessive self heating on chip, thermal shutdown circuitry will shut down the charge pump once the junction temperature exceeds approximately 160 c. it will reenable the charge pump once the junction temperature drops back to approximately 150 c. the ltc3250-1.5/ltc3250- 1.2 will cycle in and out of thermal shutdown without latch- up or damage until the short-circuit on v out is removed. long term overstress (i out > 350ma, and/or t j > 140 c) should be avoided as it can degrade the performance of the part. soft-start to prevent excessive current flow at v in during start-up, the ltc3250-1.5/ltc3250-1.2 have a built-in soft-start circuitry. soft-start is achieved by increasing the amount of current available to the output charge storage capacitor linearly over a period of approximately 500 m s. soft-start is enabled whenever the device is brought out of shutdown, and is disabled shortly after regulation is achieved. low current burst mode operation to improve efficiency at low output currents, burst mode operation was included in the design of the ltc3250-1.5/ ltc3250-1.2. an output current sense is used to detect when the required output current drops below an inter- nally set threshold (30ma typ.). when this occurs, the part shuts down the internal oscillator and goes into a low current operating state. the ltc3250-1.5/ltc3250-1.2 will remain in the low current operating state until the output has dropped enough to require another burst of current. unlike traditional charge pumps whose burst current is dependant on many factors (i.e. supply voltage, switch resistance, capacitor selection, etc.), the ltc3250- 1.5/ltc3250-1.2s burst current is set by the burst thresh- old and hysteresis. this means that the v out ripple voltage in burst mode will be fixed and is typically 12mv for a 4.7 m f output capacitor. power efficiency the power efficiency ( h ) of the ltc3250-1.5/ltc3250- 1.2 are approximately double that of a conventional linear regulator. this occurs because the input current for a 2 to 1 step-down charge pump is approximately half the output operatio u (refer to simplified block diagram)
ltc3250-1.5/ltc3250-1.2 7 3250fa current. for an ideal 2 to 1 step-down charge pump the power efficiency is given by: ho = = p p vi vi v v out in out out in out out in 1 2 2 the switching losses and quiescent current of the ltc3250-1.5/ltc3250-1.2 are designed to minimize effi- ciency loss over the entire output current range, causing only a couple % error from the theoritical efficiency. for example with v in = 3.6v, i out = 100ma and v out regulat- ing to 1.5v the measured efficiency is 80.6% which is in close agreement with the theoretical 83.3% calculation. v out capacitor selection the esr and value of capacitors used with the ltc3250- 1.5/ltc3250-1.2 determine several important parameters such as regulator control loop stability, output ripple, and charge pump strength. the value of c out directly controls the amount of output ripple for a given load current. increasing the size of c out will reduce the output ripple. to reduce output noise and ripple, it is suggested that a low esr (<0.1 w ) ceramic capacitor (4.7 m f or greater) be used for c out . tantalum and aluminum capacitors are not recommended because of their high esr. both esr and value of the c out can significantly affect the stability of the ltc3250-1.5/ltc3250-1.2. as shown in the block diagram, the ltc3250-1.5/ltc3250-1.2 use a control loop to adjust the strength of the charge pump to match the current required at the output. the error signal of this loop is stored directly on the output charge storage capacitor. thus the charge storage capacitor also serves to form the dominant pole for the control loop. to prevent ringing or instability it is important for the output capacitor to maintain at least 2.5 m f of capacitance over all condi- tions (see ceramic capacitor selection guidelines sec- tion). likewise excessive esr on the output capacitor will tend to degrade the loop stability of the ltc3250-1.5/ltc3250- 1.2. the closed-loop output resistance is designed to be 0.15 w for the ltc3250-1.5 and 0.12 w for the ltc3250-1.2. for a 250ma load current change the output voltage will change by about 37mv for the ltc3250-1.5 and by 30mv for the ltc 3250-1.2. if the esr of the output capacitor is greater than the closed-loop-output imped- ance the part will cease to roll-off in a simple one-pole fashion and poor load transient response or instability could result. ceramic capacitors typically have excep- tional esr performance and combined with a tight board layout should yield excellent stability and load transient performance. further output noise reduction can be achieved by filtering the ltc3250-1.5/ltc3250-1.2 output through a very small series inductor as shown in figure 1. a 10nh inductor will operatio u (refer to simplified block diagram) reject the fast output transients, thereby presenting a nearly constant output voltage. for economy the 10nh inductor can be fabricated on the pc board with about 1cm (0.4") of pc board trace. v in capacitor selection the constant frequency architecture used by the ltc3250-1.5/ltc3250-1.2 makes input noise filtering much less demanding than conventional charge pump regulators. on a cycle by cycle basis, the ltc3250-1.5/ ltc3250-1.2 input current will go from i out /2 to 0ma. lower esr will reduce the voltage steps caused by chang- ing input current, while the absolute capacitor value will determine the level of ripple. for optimal input noise and ripple reduction, it is recommended that a low esr 1 m f or greater ceramic capacitor be used for c in (see ceramic capacitor selection guidelines section). aluminum and tantalum capacitors are not recommended because of their high esr. figure 1. 10nh inductor used for additional output noise reduction 3250 f01 ltc3250-1.5/ ltc3250-1.2 v out gnd 4.7 f 0.22 f v out 10nh (trace inductance)
ltc3250-1.5/ltc3250-1.2 8 3250fa flying capacitor selection warning: a polarized capacitor such as tantalum or aluminum should never be used for the flying capacitor since its voltage can reverse upon start-up of the ltc3250-1.5/ltc3250-1.2. ceramic capacitors should always be used for the flying capacitor. the flying capacitor controls the strength of the charge pump. in order to achieve the rated output current it is necessary for the flying capacitor to have at least 0.4 m f of capacitance over operating temperature with a 2v bias (see ceramic capacitor selection guidelines section). if only 100ma or less of output current is required for the application the flying capacitor minimum can be reduced to 0.15 m f. ceramic capacitor selection guidelines capacitors of different materials lose their capacitance with higher temperature and voltage at different rates. for example, a ceramic capacitor made of x7r material will retain most of its capacitance from C40 c to 85 c whereas a z5u or y5v style capacitor will lose considerable capaci- tance over that range (60% to 80% loss typ.). z5u and y5v capacitors may also have a very strong voltage coefficient causing them to lose an additional 60% or more of their capacitance when the rated voltage is applied. therefore, when comparing different capacitors it is often more appropriate to compare the amount of achievable capaci- tance for a given case size rather than discussing the specified capacitance value. for example, over rated volt- age and temperature conditions, a 4.7 m f, 10v, y5v ceramic capacitor in a 0805 case may not provide any more capacitance than a 1 m f, 10v, x7r available in the same 0805 case. in fact over bias and temperature range, the 1 m f, 10v, x7r will provide more capacitance than the 4.7 m f, 10v, y5v. the capacitor manufacturers data sheet should be consulted to determine what value of capacitor is needed to ensure minimum capacitance values are met over operating temperature and bias voltage. below is a list of ceramic capacitor manufacturers and how to contact them: avx 1-(803)-448-1943 www.avxcorp.com kemet 1-(864)-963-6300 www.kemet.com murata 1-(800)-831-9172 www.murata.com taiyo yuden 1-(800)-348-2496 www.t-yuden.com vishay 1-(800)-487-9437 www.vishay.com layout considerations due to the high switching frequency and transient currents produced by the ltc3250-1.5/ltc3250-1.2 careful board layout is necessary for optimal performance. a true ground plane and short connections to all capacitors will improve performance and ensure proper regulation under all con- ditions. figure 2 shows the recommended layout configu- ration. figure 2. recommended layout the flying capacitor pins, c + and c C will have very high edge rate wave forms. the large dv/dt on these pins can couple energy capacitively to adjacent printed circuit board runs. magnetic fields can also be generated if the flying capacitors are not close to the ltc3250-1.5/ltc3250-1.2 (i.e. the loop area is large). to decouple capacitive energy transfer, a faraday shield may be used. this is a grounded pc trace between the sensitive node and the ltc3250-1.5/ ltc3250-1.2 pins. for a high quality ac ground it should be returned to a solid ground plane that extends all the way to the ltc3250-1.5/ltc3250-1.2. operatio u (refer to simplified block diagram) gnd v out v in shdn ltc3250-1.5 /ltc3250-1.2 1 f 4.7 f 1 f 3250 f02 via to ground plane
ltc3250-1.5/ltc3250-1.2 9 3250fa operatio u (refer to simplified block diagram) figure 3. maximum power dissipation vs ambient temperature thermal management for higher input voltages and maximum output current there can be substantial power dissipation in the ltc3250-1.5/ltc3250-1.2. if the junction temperature increases above approximately 160 c the thermal shut- down circuitry will automatically deactivate the output. to reduce the maximum junction temperature, a good ther- mal connection to the pc board is recommended. con- necting the gnd pin (pin 2) to a ground plane, and maintaining a solid ground plane under the device can reduce the thermal resistance of the package and pc board considerably. derating power at higher temperatures to prevent an overtemperature condition in high power applications figure 3 should be used to determine the maximum combination of ambient temperature and power dissipation. the power dissipated in the ltc3250-1.5/ ltc3250-1.2 should always fall under the line shown (i.e. within the safe region) for a given ambient temperature. the power dissipated in the ltc3250-1.5/ltc3250-1.2 is given by the expression: p v vi d in out out = ? ? ? ? 2 this derating curve assumes a maximum thermal resis- tance, q ja , of 175 c/w for the 6-pin thinsot-23. this thermal resistances can be achieved from a printed circuit board layout with a solid ground plane (2000mm 2 )on at least one layer with a good thermal connection to the ground pin of the ltc3250-1.5/ltc3250-1.2. operation outside of this curve will cause the junction temperature to exceed 140 c which may trigger the thermal shutdown circuitry and ultimately reduce the life of the device. ambient temperature ( c) ?0 power dissipation (w) ?5 02550 3250 ?f03 75 100 q ja = 175 c/w t j = 140 c 1.2 1.0 0.8 0.6 0.4 0.2 0
ltc3250-1.5/ltc3250-1.2 10 3250fa 3250 ta05a ltc3250-1.2 v in 3-cell nimh v in = 2.7v to 5v shdn c + c C v out 4 3 2 1 5 6 gnd on off 1 f 4.7 f 1 f v out = 1.2v 4% 3250 ta02a ltc3250-1.5 v in v in = 3.3v shdn c + c C v out 4 3 2 1 5 6 gnd on off 1 f 4.7 f v out = 1.5v 4% 1 f i out (ma) 1 0.1 efficiency (%) 1000 3250 ta02b 10 100 100 90 80 70 60 50 40 30 20 10 0 v in = 3.3v t a = 25 c 3250 ta03a ltc3250-1.5 v in 1-cell li-ion or 3-cell nimh shdn c + c C v out 4 3 2 1 5 6 gnd on off 1 f 1 f 4.7 f v out = 1.5v 4% i out (ma) 1 0.1 efficiency (%) 1000 3250 ta03b 10 100 100 90 80 70 60 50 40 30 20 10 0 v in = 3.6v v in = 4v v in = 5v t a = 25 c typical applicatio s u efficiency vs output current efficiency vs output current fixed 3.3v input to 1.5v output with shutdown li-ion or 3-cell nimh to 1.5v output with shutdown efficiency vs input voltage (i out = 100ma) 3-cell nimh to 1.2v output with shutdown v in (v) 3.2 2.7 efficiency (%) 5.2 4.7 3250 ta05b 3.7 4.2 100 90 80 70 60 50 40 30 20 10 0 ltc3250 ldo t a = 25 c
ltc3250-1.5/ltc3250-1.2 11 3250fa package descriptio u s6 package 6-lead plastic tsot-23 (reference ltc dwg # 05-08-1636) 1.50 ?1.75 (note 4) 2.80 bsc 0.30 ?0.45 6 plcs (note 3) datum ? 0.09 ?0.20 (note 3) s6 tsot-23 0302 2.90 bsc (note 4) 0.95 bsc 1.90 bsc 0.80 ?0.90 1.00 max 0.01 ?0.10 0.20 bsc 0.30 ?0.50 ref pin one id note: 1. dimensions are in millimeters 2. drawing not to scale 3. dimensions are inclusive of plating 4. dimensions are exclusive of mold flash and metal burr 5. mold flash shall not exceed 0.254mm 6. jedec package reference is mo-193 3.85 max 0.62 max 0.95 ref recommended solder pad layout per ipc calculator 1.4 min 2.62 ref 1.22 ref 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.
ltc3250-1.5/ltc3250-1.2 12 3250fa part number description comments ltc1514 50ma, 650khz, step up/down charge pump v in : 2.7v to 10v, v out : 3v/5v, with low battery comparator regulated output, i q : 60 m a, i sd : 10 m a, s8 package ltc1515 50ma, 650khz, step up/down charge pump v in : 2.7v to 10v, v out : 3.3v or 5v, with power on reset regulated output, i q : 60 m a, i sd : <1 m a, s8 package lt1776 500ma (i out ), 200khz, high efficiency step-down 90% efficiency, v in : 7.4v to 40v, v out(min) : 1.24v, dc/dc converter i q : 3.2ma, i sd : 30 m a, n8,s8 packages ltc1911-1.5/ltc1911-1.8 250ma,1.5mhz, high efficiency step-down 75% efficiency, v in : 2.7v to 5.5v, v out : 1.5v/1.8v, charge pump regulated output, i q : 180 m a, i sd : 10 m a, ms8 package ltc3251 500ma, spread spectrum, high efficiency up to 90% efficiency, v in : 2.7v to 5.5v, v out : 0.9v to 1.6v, step-down charge pump regulated output, i q : 9 m a, i sd : <1 m a, ms package ltc3252 dual 250ma (i out ), spread spectrum, inductorless (cs), up to 90% efficiency, v in : 2.7v to 5.5v, v out : 0.9v to 1.6v, step-down dc/dc converter i q : 60 m a, i sd : <1 m a, dfn package ltc3405/ltc3405a 300ma (i out ), 1.5mhz, synchronous step-down 95% efficiency, v in : 2.7v to 6v, v out(min) : 0.8v, dc/dc converter i q : 20 m a, i sd : <1 m a, thinsot package ltc3406/ltc3406b 600ma (i out ), 1.5mhz, synchronous step-down 95% efficiency, v in : 2.5 to 5.5v, v out(min) : 0.6v, dc/dc converter i q : 20 m a, i sd : <1 m a, thinsot package ltc3411 1.25a (i out ), 4mhz, synchronous step-down 95% efficiency, v in : 2.5v to 5.5v, v out(min) : 0.8v, dc/dc converter i q : 60 m a, i sd : <1 m a, ms package ltc3412 2.5a (i out ), 4mhz, synchronous step-down 95% efficiency, v in : 2.5v to 5.5v, v out(min) : 0.8v, dc/dc converter i q : 60 m a, i sd : <1 m a, tssop16e package ltc3440 600ma (i out ), 2mhz, synchronous buck-boost 95% efficiency, v in : 2.5v to 5.5v, v out : 2.5v to 5.5v, dc/dc converter i q : 25 m a, i sd : <1 m a, ms package ltc3441 1.2a (i out ), 1mhz, synchronous buck-boost 95% efficiency, v in : 2.4v to 5.5v, v out : 2.4v to 5.25v, dc/dc converter i q : 25 m a, i sd : <1 m a, dfn package linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 l fax: (408) 434-0507 l www.linear.com ? linear technology corporation 2001 lt/tp 1203 1k rev a ? printed in usa related parts u typical applicatio 3250-1.5 ta04 v in mode shdn rt gnd out sw1 sw2 fb v c ltc3440 7 2 8 1 5 6 3 4 9 10 10 h v in shdn gnd v out c + c C ltc3200-5 340k 200k v in shdn c2 + c2 C out c1 + c1 C gnd ltc1911-1.8 v in out c + c C shdn gnd ltc3250-1.5 10 f 1 f 1 f 1 f 1 f 1 f 22 f 10 f 4.7 f 1 f 10 f 1 f on off li-ion 5v 100ma 3.3v 500ma 1.8v 250ma 1.5v 250ma 300pf 120k 60k 5 3 2 1 6 4 1 8 2 3 6 7 5 4 5 6 4 1 3 2 multiple high efficiency outputs from single li-ion battery

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