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1 ltc3202 3202fa applicatio s u features descriptio u typical applicatio u n white led backlighting n programmable boost current source n low noise constant frequency operation n 25% less input current than doubler charge pump n high output current: up to 125ma n small application circuit n regulated output voltage or current n automatic soft-start n v in range: 2.7v to 4.5v n no inductors n 1.5mhz switching frequency n i cc < 1 m a in shutdown n available in 10-pin msop and 3mm 3mm dfn packages low noise, high efficiency charge pump for white leds the ltc ? 3202 is a low noise, constant frequency charge pump dc/dc converter that uses fractional conversion to increase efficiency in white led applications. the part can be used to produce a regulated voltage or current of up to 125ma from a 2.7v to 4.5v input. low external parts count (two flying capacitors and two small bypass capacitors at v in and v out ) make the ltc3202 ideally suited for small, battery-powered applications. an internal 2-bit dac allows led current to be adjusted for led brightness control. the ltc3202 also has thermal shutdown protection and can survive a continuous short- circuit from v out to gnd. built-in soft-start circuitry prevents excessive inrush current during start-up. high switching frequency enables the use of small external capacitors. a low current shutdown feature disconnects the load from v in and reduces quiescent current to less than1 m a. the ltc3202 is available in the 10-pin msop and 3mm 3mm dfn packages. , ltc and lt are registered trademarks of linear technology corporation. programmable white led power supply 3202 ta01 ltc3202 v out fb gnd c4 1 f c1 1 f 5, 11 3 2 c2 c2 + c1 c1 + current programming v in 3v to 4.5v 10 4 1 36 36 36 36 36 36 c3 1 f c2 1 f d0 d1 v in 8 7 96 c1, c2, c3, c4 = murata grm 39x5r105k6.3 or taiyo yuden jmk107bj105ma 0ma to 125ma total current v in (ac coupled) 20mv/div v out (ac coupled) 20mv/div 500ns/div v in = 3.6v c in = c out = 1 f i out = 60ma 3202 g09 input and output ripple
2 ltc3202 3202fa v in , v out to gnd ......................................... C0.3v to 6v d0, d1 ............................................. C0.3v to v in + 0.3v v out short-circuit duration ............................. indefinite i out (note 2) ....................................................... 150ma order part number ms part marking t jmax = 150 c, q ja = 120 c/w ltwl LTC3202EMS absolute axi u rati gs w ww u package/order i for atio uu w (note 1) consult ltc marketing for parts specified with wider operating temperature ranges. 1 2 3 4 5 d1 fb v out v in gnd 10 9 8 7 6 d0 c2 + c1 + c1 c2 top view ms package 10-lead plastic msop operating temperature range (note 3) ...C40 c to 85 c storage temperature range ..................C65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c order part number dd part marking labb ltc3202edd top view 11 dd package 10-lead (3mm 3mm) plastic dfn 10 9 6 7 8 4 5 3 2 1 d0 c2 + c1 + c1 c2 d1 fb v out v in sgnd t jmax = 150 c, q ja = 44 c/w, q jc = 3 c/w exposed pad is pgnd (pin 11) must be connected to ground plane electrical characteristics 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. the l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v in = 3.3v unless otherwise noted. note 3: the ltc3202e is guaranteed to meet performance specifications from 0 c to 70 c. specifications over the C40 c to 85 c operating temperature range are assured by design, characterization and correlation with statistical process controls. parameter conditions min typ max units input power supply v in operating voltage l 2.7 4.5 v i cc operating current i out = 0ma, v out = 3.6v, v in = d0 = d1 = 4.5v l 2.5 5 ma i shdn shutdown current v out = 0v l 1 m a feedback pin set points 0.2v setting feedback voltage d0 = 1, d1 = 0, i out = 0ma, v in = 3.6v l 188 200 212 mv 0.4v setting feedback voltage d0 = 0, d1 = 1, i out = 0ma, v in = 3.6v l 380 400 420 mv 0.6v setting feedback voltage d0 = 1, d1 = 1, i out = 0ma, v in = 3.6v l 570 600 630 mv i fb v fb = 0.8v l C50 50 na charge pump r ol open loop output impedance (1.5v in C v out )/i out v in = 3.3v, v out = 4.4v, v fb = 0 l 4.5 6 w v out load regulation ( d v out / d i out )i out = 10ma to 90ma, d v fb / d v out = 1 0.35 mv/ma clk frequency 1.5 mhz d0, d1 high level input voltage (v ih ) l 1.3 v low level input voltage (v il ) l 0.4 v input current (i ih ) do, d1 = v in l C1 1 m a input current (i il ) do, d1 = 0v l C1 1 m a
3 ltc3202 3202fa v fb set point vs input supply (200mv setting) v fb set point vs input supply (400mv setting) v fb set point vs input supply (600mv setting) v fb vs load current input current vs load current oscillator frequency vs supply voltage typical perfor a ce characteristics uw input supply (v) 2.7 set point (v) 0.21 0.20 0.19 3.0 3.3 3.6 3.9 3202 g01 4.2 4.5 i load = 20 a v d0 = v in v d1 = 0v t a = 85 c t a = 40 c t a = 25 c input supply (v) 2.7 set point (v) 0.42 0.40 0.38 3.0 3.3 3.6 3.9 3202 g02 4.2 4.5 i load = 40 a v d0 = 0v v d1 = v in t a = 85 c t a = 40 c t a = 25 c input supply (v) 2.7 set point (v) 0.63 0.60 0.57 3.0 3.3 3.6 3.9 3202 g03 4.2 4.5 i load = 60 a v d0 = v d1 = v in t a = 25 c, 85 c t a = 40 c load current (ma) 0 feedback voltage (v) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 25 50 75 100 125 150 3202 g04 v d0 = v d1 = v in c in = c out = c fly1 = c fly2 = 1 f v out ?v fb = 3.4v t a = 25 c v in = 3v v in = 3.2v load current (ma) 0 input current (ma) 60 100 3202 g05 20 40 80 160 140 120 100 80 60 40 20 0 v in = 3.6v c in = c out = c fly1 = c fly2 = 1 f t a = 25 c v out = 4.5v v out = 4v supply voltage (v) 2.7 oscillator frequency (mhz) 1.9 1.7 1.5 1.3 1.1 0.9 3.0 3.3 3.6 3.9 3202 g06 4.2 4.5 t a = 85 c t a = 40 c t a = 25 c
4 ltc3202 3202fa d1, d0 (pin 1, 10): control inputs. d0 and d1 determine the set point voltage of the fb pin (see table 1). fb (pin 2): fb is the feedback input for the regulation control loop. v out (pin 3): v out is the output of the charge pump. a low impedance 1 m f x5r or x7r ceramic capacitor is required from v out to gnd. v in (pin 4): input supply voltage. v in should be bypassed with a 1 m f to 4.7 m f low impedance ceramic capacitor. uu u pi fu ctio s gnd (pin 5): ground for the charge pump and control circuitry. this pin should be connected directly to a low impedance ground plane. c2 C , c1 C , c1 + , c2 + (pin 6, 7, 8, 9): charge pump flying capacitor pins. a 1 m f x5r or x7r ceramic capacitor should be connected from c1 + to c1 C and from c2 + to c2 C . pgnd (pin 11, exposed pad dfn only): power ground for the charge pump. this pin must be connected directly to a low impedance ground plane. short-circuit current vs supply voltage v out soft-start ramp input and output ripple input supply (v) 2.7 output current (ma) 300 280 260 240 220 200 180 3.0 3.3 3.6 3.9 4.2 4.5 3202 g07 c fly = 1 f v fb = 0v v out = 0v t a = 25 c typical perfor a ce characteristics uw v d0, d1 2v/div v out 1v/div 200 s/div v in = 3.6v c out = 1 f 3202 g08 v in (ac coupled) 20mv/div v out (ac coupled) 20mv/div 500ns/div v in = 3.6v c in = c out = 1 f i out = 60ma 3202 g09
5 ltc3202 3202fa si plified w block diagra w + 3202 bd soft-start and shutdown control 1.5mhz oscillator 2-bit dac 8 4 3 2 1 10 7 9 6 fb v in v out 5, 11 gnd c2 c2 + c1 c1 + d0 d1
6 ltc3202 3202fa figure 1. current control mode 3202 f01 ltc3202 v out fb gnd 1 f ? i led = v fb r x 5, 11 3 2 r x r x operatio u the ltc3202 uses a fractional conversion switched ca- pacitor charge pump to boost v out to as much as 1.5 times the input voltage. a two-phase nonoverlapping clock acti- vates the charge pump switches. on the first phase of the clock the flying capacitors are charged in series from v in . on the second phase of the clock they are connected in parallel and stacked on top of v in . this sequence of charging and discharging the flying capacitors continues at a free running frequency of 1.5mhz (typ). regulation is achieved by sensing the voltage at the fb pin and modulating the charge pump strength based on the error signal. the control pins, d0 and d1, program the set point of the internal digital-to-analog converter. the regu- lation loop will increase v out until fb comes to balance at the set-point voltage. table 1 shows the regulation voltage as a function of d0 and d1. table 1. feedback control voltage settings d1 d0 feedback set point voltage 0 0 shutdown 0 1 0.2v 1 0 0.4v 1 1 0.6v in shutdown mode all circuitry is turned off and the ltc3202 draws only leakage current from the v in supply. furthermore, v out is disconnected from v in . the d0 and d1 pins are cmos inputs with a threshold voltage of approximately 0.8v. the ltc3202 is in shutdown when a logic low is applied to both d0 and d1. since the d0 and d1 pins are high impedance cmos inputs they should never be allowed to float. to ensure that their states are defined they must always be driven with valid logic levels. shutdown current output voltage detection circuitry will draw a current of 5 m a when the ltc3202 is in shutdown. this current will be eliminated when the output voltage (v out ) is at 0v. to ensure that v out is at 0v in shutdown a bleed resistor can be used from v out to gnd. 10k to 100k is acceptable. short-circuit/thermal protection the ltc3202 has built-in short-circuit current limiting as well as over temperature protection. during short-circuit conditions it will automatically limit its output current to approximately 250ma. 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 when the junction tempera- ture exceeds approximately 160 c. it will reenable the charge pump once the junction temperature drops back to approximately 155 c. the ltc3202 will cycle in and out of thermal shutdown indefinitely without latchup or damage until the short-circuit on v out is removed. soft-start to prevent excessive current flow at v in during start-up, the ltc3202 has 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. the soft-start feature activates any time an input, d0 or d1, changes state. this will prevent large inrush current during initial start-up as well as when the feedback setting is changed from one value to the next. note that the set point voltage will drop to zero during the soft-start period. under heavy load conditions there may be observable droop at v out until the soft-start circuit catches up. programming the ltc3202 for voltage or current the ltc3202 can be configured to control either a voltage or a current. in white led applications the led current is programmed by the ratio of the feedback set point voltage and a sense resistor as shown in figure 1. the current of the remaining leds is controlled by virtue of their similar- ity to the reference led and the ballast voltage across the sense resistor. (refer to simplified block diagram)
7 ltc3202 3202fa in this configuration the feedback factor ( d v fb / d v out ) will be very near unity since the small signal led impedance will be considerably less than the current setting resistor r x . thus, this configuration will have the highest loop gain giving it the lowest closed-loop output resistance. like- wise it will also require the largest amount of output capacitance to preserve stability. for fixed voltage applications, the output voltage can be set by the ratio of two resistors and the feedback control voltage as shown in figure 2. the output voltage is given by the set point voltage times the gain factor 1 + r 1 /r 2 . note that the closed-loop output resistance will increase in proportion to the loop gain consumed by the resistive divider ratio. for example, if the resistor ratio is 2:1 giving a gain of 3, the closed-loop output resistance will be about 3 times higher than its nominal gain of 1 value. given that the closed-loop output resistance is about 0.35 w with a gain of 1, the closed-loop output resistance will be about 1 w when using a gain of 3. figure 2. voltage control mode charge pump strength figure 3 shows how the ltc3202 can be modeled as a thevenin equivalent circuit to determine the amount of current available from the effective input voltage, 1.5v in and the effective open-loop output resistance, r ol . figure 3. equivalent open-loop circuit figure 4. typical r ol vs temperature 3202 f02 ltc3202 v out fb gnd v out = v fb (1 + ) r1 r2 1 f r1 r2 5, 11 3 2 3202 f03 + 1.5v in r ol v out + operatio u (refer to simplified block diagram) from figure 3 the available current is given by: i vv r out in out ol = 15 . typical values of r ol as a function of temperature are shown in figure 4. when using the ltc3202 in voltage control mode, any of the three voltage settings (0.2v, 0.4v or 0.6v) can be used as the set point voltage. for optimum noise performance and lowest closed-loop output resistance the highest voltage setting will likely be the most desirable. typical values for total voltage divider resistance can range from several k w s up to 1m w . temperature ( c) ?0 output resistance ( ) 4.8 4.6 4.4 4.2 4.0 3.8 60 3202 f04 ?5 10 35 85 v fb = 0 i l = 100ma c1 = c2 = 1 f r ol = (1.5v in ?v out )/i l v in = 2.7v v in = 3.6v
8 ltc3202 3202fa r ol is dependent on a number of factors including the switching term, 1/(2f osc c fly ), internal switch resis- tances and the nonoverlap period of the switching circuit. however, for a given r ol , the amount of current available will be directly proportional to the advantage voltage 1.5v in C v out . this voltage can typically be quite small. consider the example of driving white leds from a 3.1v supply. if the led forward voltage is 3.8v and the 0.6v v fb setting is used, the advantage voltage is 3.1v ? 1.5v C 3.8v C 0.6v or only 250mv. however if the input voltage is raised to 3.2v the advantage voltage jumps to 400mva 60% improvement in available strength! note that a similar improvement in advantage voltage can be achieved by operating the ltc3202 at a lower voltage setting such as the 0.4v setting. v in , v out capacitor selection the style and value of capacitors used with the ltc3202 determine several important parameters such as regulator control loop stability, output ripple, charge pump strength and minimum start-up time. to reduce noise and ripple, it is recommended that low equivalent series resistance (esr) ceramic capacitors be used for both c in and c out . tantalum and aluminum capacitors are not recommended because of their high esr. 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 at the expense of higher minimum turn-on time and higher start-up current. the peak-to-peak output ripple is approximately given by the expression: v i fc ripplep p out osc out - @ 3 where f osc is the ltc3202s oscillator frequency (typi- cally 1.5mhz) and c out is the output charge storage capacitor. both the style and value of the output capacitor can significantly affect the stability of the ltc3202. as shown in the block diagram, the ltc3202 uses 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. 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 0.6 m f of capacitance over all conditions. likewise, excessive esr on the output capacitor will tend to degrade the loop stability of the ltc3202. the closed- loop output resistance of the ltc3202 is designed to be 0.35 w . for a 100ma load current change, the feedback voltage will change by about 35mv. if the output capacitor has 0.35 w or more of esr the closed-loop frequency response will cease to roll-off in a simple one-pole fashion and poor load transient response or instability could result. multilayer ceramic chip capacitors typically have exceptional esr performance and combined with a tight board layout should yield very good stability and load transient performance. as the value of c out controls the amount of output ripple, the value of c in controls the amount of ripple present at the input pin (v in ). the input current to the ltc3202 will be relatively constant while the charge pump is on either the input charging phase or the output charging phase but will drop to zero during the clock nonoverlap times. since the nonoverlap time is small (~25ns) these missing notches will result in only a small perturbation on the input power supply line. note that a higher esr capacitor such as tantalum will have higher input noise due to the input current change times the esr. therefore ceramic capaci- tors are again recommended for their exceptional esr performance. further input noise reduction can be achieved by powering the ltc3202 through a very small series inductor as shown in figure 5. a 10nh inductor will reject the fast current notches, thereby presenting a nearly constant current load to the input power supply. for economy the 10nh inductor can be fabricated on the pc board with about 1cm (0.4") of pc board trace. operatio u
9 ltc3202 3202fa flying capacitor selection warning: a polarized capacitor such as tantalum or alumi- num should never be used for the flying capacitors since their voltage can reverse upon start-up of the ltc3202. ceramic capacitors should always be used for the flying capacitors. the flying capacitor controls the strength of the charge pump. in order to achieve the rated output current it is necessary to have at least 0.7 m f of capacitance for each of the flying capacitors. 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. z5u and y5v capacitors may also have a very poor voltage coefficient causing them to lose 60% or more of their capacitance when the rated voltage is applied. therefore, when comparing different capaci- tors it is often more appropriate to compare the amount of achievable capacitance for a given case size rather than comparing the specified capacitance value. for example, over rated voltage and temperature conditions, a 1 m f, 10v, y5v ceramic capacitor in a 0603 case may not provide any more capacitance than a 0.22 m f, 10v, x7r available in the same 0603 case. the capacitor manufacturers data sheet should be consulted to determine what value of capacitor is needed to ensure minimum capacitances at all tempera- tures and voltages. table 2 shows a list of ceramic capacitor manufacturers and how to contact them: table 2 recommended capacitor vendors avx www.avxcorp.com kemet www.kemet.com murata www.murata.com taiyo yuden www.t-yuden.com vishay www.vishay.com for very light load applications the flying capacitor may be reduced to save space or cost. the theoretical minimum output resistance of a 2:3 fractional charge pump is given by: r vv ifc ol min in out out sc fly () . o= 15 1 2 0 where f osc is the switching frequency (1.5mhz typ) and c fly is the value of the flying capacitors. note that the charge pump will typically be weaker than the theoretical limit due to additional switch resistance, however for very light load applications the above expression can be used as a guideline in determining a starting capacitor value. power efficiency the power efficiency ( h ) of the ltc3202 is similar to that of a linear regulator with an effective input voltage of 1.5 times the actual input voltage. this occurs because the input current for a 2:3 fractional charge pump is approxi- mately 1.5 times the load current. in an ideal regulating 2:3 charge pump the power efficiency would be given by: h ideal out in out out in out out in p p vi vi v v o= = . 3 2 15 at moderate to high output power the switching losses and quiescent current of the ltc3202 are negligible and the expression above is valid. for example with v in = 3.2v, i out = 80ma and v out regulating to 4.2v the measured efficiency is 82% which is just under the theoretical 87.5% calculation. operatio u figure 5. 10nh inductor used for input noise reduction 3202 f05 ltc3202 v in v in gnd 5, 11 4 0.1 f1 f 10nh
10 ltc3202 3202fa figure 6. recommended layouts v out gnd v in layout considerations due to its high switching frequency and the transient currents produced by the ltc3202, careful board layout is necessary. a true ground plane and short connections to all capacitors will improve performance and ensure proper regulation under all conditions. figure 6 shows the recom- mended layout configurations. the flying capacitor pins c1 + , c2 + , c1 C and c2 C will have very high edge rate waveforms. 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 ltc3202 (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 ltc3202 pins. for a high quality ac ground it should be returned to a solid ground plane that extends all the way to the ltc3202. operatio u figure 7. alternative brightness control thermal management for higher input voltages and maximum output current there can be substantial power dissipation in the ltc3202. if the junction temperature increases above approxi- mately 160 c the thermal shutdown circuitry will auto- matically deactivate the output. to reduce the maximum junction temperature, a good thermal connection to the pc board is recommended. connecting the gnd pin (pin 5 and pin 11 on the dfn package) 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. brightness control using pulse width modulation an alternative approach to dimming is to use pulse width modulation rather than the internal digital to analog con- verter. by connecting both the d0 and d1 pins to a pwm signal, continuous brightness control can be achieved. frequencies from 100hz to 500hz are acceptable with a 1 m f to 4.7 m f output capacitor. v d0, d1 t 10 1 d0 d1 ltc3202 3202 f07 v out v in gnd 3202 f06 d1 d0
11 ltc3202 3202fa package descriptio u 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. ms package 10-lead plastic msop (reference ltc dwg # 05-08-1661) dd package 10-lead plastic dfn (3mm 3mm) (reference ltc dwg # 05-08-1699) 3.00 0.10 (4 sides) note: 1. drawing to be made a jedec package outline m0-229 variation of (weed-2) 2. all dimensions are in millimeters 3. 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 4. exposed pad shall be solder plated 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 0.200 ref 0.00 ?0.05 (dd10) dfn 0103 0.25 0.05 2.38 0.05 (2 sides) recommended solder pad pitch and dimensions 1.65 0.05 (2 sides) 2.25 0.05 0.50 bsc 0.55 0.05 3.35 0.05 package outline 0.25 0.05 0.50 bsc 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 8 9 10 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
12 ltc3202 3202fa 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 0803 1k ? printed in usa related parts part number description comments lt1618 constant current, constant voltage 1.4mhz, high efficiency up to 16 white leds, v in : 1.6v to 18v, v out(max) : 34v, boost regulator i q : 1.8ma, i sd : <1 m a, 10-lead ms lt1932 constant current, 1.2mhz, high efficiency white led boost up to 8 white leds, v in : 1v to 10v, v out(max) : 34v, i q : 1.2ma, regulator i sd : <1 m a, thinsot tm lt1937 constant current, 1.2mhz, high efficiency white led boost up to 4 white leds, v in : 2.5v to 10v, v out(max) : 34v, i q : 1.9ma, regulator i sd : <1 m a, thinsot, sc70 ltc3200 low noise, 2mhz, regulator charge pump white led driver up to 6 white leds, v in : 2.7v to 4.5v, i q : 8ma, i sd : <1 m a, 10-lead ms ltc3200-5 low noise, 2mhz, regulator charge pump white led driver up to 6 white leds, v in : 2.7v to 4.5v, i q : 8ma, i sd : <1 m a, thinsot ltc3201 low noise, 1.7mhz, regulator charge pump white led driver up to 6 white leds, v in : 2.7v to 4.5v, i q : 6.5ma, i sd : <1 m a, 10-lead ms ltc3250-1.5 250ma, 1.5mhz, high efficiency step-down charge pump up to 88% efficiency, v in : 3.1v to 5.5v, v out : 1.5v, i q : 35 m a, i sd : <1 m a, thinsot ltc3251/ltc3251-1.5 500ma, spread spectrum, high efficiency step-down up to 88% efficiency, v in : 2.7v to 5.5v, v out : 0.9v to 1.6v/1.5v, charge pump i q : 8 m a, i sd : <1 m a, 10-lead ms ltc3252 dual, 250ma/channel, spread spectrum, high efficiency up to 88% efficiency, v in : 2.7v to 5.5v, v out : 0.9v to 1.6v, step-down charge pump i q : 60 m a, i sd : <1 m a, dfn12 lt3465/lt3465a constant current, 1.2mhz/2.7mhz, high efficiency white up to 6 white leds, v in : 2.7v to 16v, v out(max) : 30v, i q : 2ma, led boost regulator with integrated schottky diode i sd : <1 m a, thinsot thinsot is a trademark of linear technology corporation. 3202 ta02 ltc3202 v out fb gnd c4 1 f c1 1 f 5, 11 3 2 c2 c2 + c1 c1 + v in 3v to 4.5v 10 4 1 36 36 36 36 36 36 c3 1 f c2 1 f d0 d1 v in 8 7 96 on off r2 3.9k r1 1k v c = 0v to 3v i led = ( 1 + ) 0.6v 36 r1 r2 v c 36 r1 r2 u typical applicatio led driver with linear brightness control
t h i s da t a s hee t ha s been do w n l oad f r o m : www . da t a s hee t c a t a l og . c o m d a t a s hee t s f o r e l e c t r on i cs c o m ponen t s .

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