for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. 12 34 8 7 6 5 out cxp cxnpgnd gnd in shdn aout max1595 max top view output out in input shdn gnd cxn cxp pgnd aout max1595 max1595 regulated 3.3v/5.0v step-up/step-down charge pump maxim integrated products typical operating circuit 19-2107; rev 3; 10/11 general description the max1595 charge-pump regulator generates either3.3v or 5v from a 1.8v to 5.5v input. the unique control architecture allows the regulator to step up or step down the input voltage to maintain output regulation. the 1mhz switching frequency, combined with a unique control scheme, allows the use of a ceramic capacitor as small as 1? for 125ma of output current. the com- plete regulator requires three external capacitors?o inductor is needed. the max1595 is specifically designed to serve as a high-power, high- efficiency aux- iliary supply in applications that demand a compact design. the max1595 is offered in space-saving 8-pin ?ax and high-power 12-pin tqfn packages. applications white led powerflash memory supplies battery-powered applications miniature equipment pcmcia cards 3.3v to 5v local conversion applications backup-battery boost converters 3v to 5v gsm simm cards features ? ultra-small: requires only three ceramic capacitors ? no inductors required ? up to 125ma output current ? regulated 3% output voltage ? 1mhz switching frequency ? 1.8v to 5.5v input voltage ? 220 a quiescent current ? 0.1 a shutdown current ? load disconnect in shutdown ordering information part temp range pin-package max1595eua33+ -40? to +85? 8 ?ax max1595etc33+ -40? to +85? 12 tqfn-ep* max1595eua50+ -40? to +85? 8 ?ax max1595etc50+ -40? to +85? 12 tqfn-ep* pin configurations continued at end of data sheet. selector guide part v out (v)** top m ark max1595eua33+ 3.3 max1595etc33+ 3.3 aaeh max1595eua50+ 5.0 max1595etc50+ 5.0 aaei ** contact factory for other fixed-output voltages from 2.7v to 5.0v. pin configurations + denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. ?ax is a registered trademark of maxim integrated products, inc. downloaded from: http:///
max1595 regulated 3.3v/5.0v step-up/ step-down charge pump 2 __________________________________________________ _____________________________________ absolute maximum ratings electrical characteristics (v in = 2v for max1595_ _ _33, v in = 3v for max1595_ _ _50, c in = 1?, c x = 0.22?, c out = 1?, t a = -40 to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 2) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. in, out, aout to gnd............................................-0.3v to +6v shdn to pgnd ........................................................-0.3v to +6v pgnd to gnd .......................................................-0.3v to +0.3v cxn to pgnd.....................-0.3v to (lower of in + 0.8v or 6.3v) cxp to gnd ................................-0.8v to (higher of out + 0.8v or in + 0.8v but not greater than 6v) continuous output current ...............................................150ma continuous power dissipation (t a = +70?) ?ax (derate 4.8mw/? above +70?) ..................387.8mw tqfn-ep (derate 24.4mw/? above +70?) .........1951.2mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? parameter symbol conditions min typ max units input voltage range v in 1.8 5.5 v input undervoltage lockoutthreshold 1.40 1.60 1.72 v input undervoltage lockouthysteresis 40 mv t a = 0 c to +85 c 4.85 5.05 5.15 0 < i l oa d < 125m a, v i n = + 3.0v t a = -40 c to +85 c 4.80 5.20 t a = 0 c to +85 c 3.20 3.33 3.40 0 < i load < 75ma, v in = +2.0v t a = -40 c to +85 c 3.16 3.44 t a = 0 c to +85 c 3.20 3.33 3.40 output voltage v out 0 < i load < 30ma, v in = +1.8v t a = -40 c to +85 c 3.16 3.44 v v in = +2.0v, max1595_ _ _33 220 320 no-load input current i q v in = +3.0v, max1595_ _ _50 240 350 ? switching frequency f osc i l oa d > 20m a, v ou t > v in 0.85 1.0 1.15 mhz shutdown supply current i shdn v shdn = 0v, v in = +5.5v, v out = 0v 5 ? shdn input voltage low v in l v in = 2.0v to 5.5v 0.6 v shdn input voltage high v in h v in = 2.0v to 5.5v 1.6 v shdn input leakage current 0.1 ? note 2: specifications to -40 c are guaranteed by design, not production tested. package thermal characteristics (note 1) tqfn junction-to-ambient thermal resistance ( ja )..........41?/w junction-to-case thermal resistance ( jc ).................6?/w ?ax junction-to-ambient thermal resistance ( ja ).....206.3?/w junction-to-case thermal resistance ( jc )...............42?/w note 1: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four-layer board. for detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial . downloaded from: http:///
max1595 regulated 3.3v/5.0v step-up/step-down charge pump _______________________________________________________________________________________ 3 __________________________________________typical operating characteristics (circuit of figure 4, v in = 2v for max1595_ _ _33, v in = 3v for max1595_ _ _50, t a = +25?, unless otherwise noted.) 0.1 10 1 1000 100 10000 02 13 4 5 no load supply current vs. supply voltage max1595 toc01 supply voltage (v) supply current ( a) 6 v out = 5v 200ns/div output waveform 50mv/div max1595 toc02 output waveform. ac-coupled.v in = 3.6v, i load = 100ma, c out = 1 f v out = 5v 4.90 5.00 4.984.96 4.94 4.92 5.06 11 01 0 0 1000 output voltage vs. load current max1595 toc03 load current (ma) output voltage (v) 5.045.02 v in = 3v v in = 3.6v v in = 3.3v v out = 5v 100 0 1 10 100 3v efficiency vs. load current 20 10 max1595 toc04 load current (ma) efficiency (%) 40 30 60 70 50 80 90 v in = 1.8v v in = 2.4v 2ms/div line-transient response max1595 toc07 a: input voltage: v in = 3.1v to 3.6v, 500mv/div b: output voltage: i load = 50ma, 100mv/div ab 100 0 0.1 1 10 100 1000 5v efficiency vs. load current 20 max1595 toc05 load current (ma) efficeincy (%) 40 60 8070 50 30 10 90 v in = 3.6v v in = 3.3v v in = 3v 100 s/div shutdown timing max1595 toc06 a: output voltage: r l = 100 ? , 2v/div b: shdn voltage: 2v/div a 5v b 200 s/div load-transient response max1595 toc08 a: load current: i load = 5ma to 95ma, 100ma/div b: output voltage: ac-coupled 100mv/div ab c out = 1 f 1 0 2 43 5 6 0 2 1 3 4 5 6 output voltage vs. supply voltage max1595 toc09 supply voltage (v) output voltage (v) v out = 5v, i load = 125ma v out = 3.3v, i load = 75ma downloaded from: http:///
detailed description the max1595 charge pump provides either a 3.3v or 5vregulated output. it delivers a maximum 125ma load cur- rent. in addition to boost regulating from a lower supply, it is also capable of buck regulating from supplies that exceed the regulated output by a diode drop or more. designed specifically for compact applications, a com- plete regulator circuit requires only three small external capacitors. an innovative control scheme provides con- stant frequency operation from medium to heavy loads, while smoothly transitioning to low-power mode at light loads to maintain optimum efficiency. in buck mode, switch s1 (figure 1) is switched continuously to in, while switch s2 alternates between in and out. an amount of charge proportional to the difference between the output voltage and the supply voltage is stored on c x , which gets transferred to the output when the regulation point isreached. maximum output ripple is proportional to the difference between the supply voltage and the output voltage, as well as to the ratio of the transfer capacitor (c x ) to the output capacitor (c out ). the max1595 consists of an error amplifier, a 1.23vbandgap reference, internal resistive feedback network, oscillator, high-current mosfet switches, and shutdown and control logic. figure 1 shows an idealized unregulat- ed charge-pump voltage doubler. the oscillator runs at a 50% duty cycle. during one half of the period, the trans- fer capacitor (c x) charges to the input voltage. during the other half, the doubler transfers the sum of c x and input voltage to the output filter capacitor (c out ). rather than doubling the input voltage, the max1595 provides aregulated output voltage of either 3.3v or 5.0v. shutdown driving shdn low places the device in shutdown mode. the device draws 0.1? of supply current in this mode.when driven high, the max1595 enters a soft-start mode. soft-start mode terminates when the output volt- age regulates, or after 2ms, whichever comes first. in shutdown, the output disconnects from the input. undervoltage lockout the max1595 has an undervoltage-lockout that deacti-vates the devices when the input voltage falls below 1.6v. below uvlo, hysteresis holds the device in shutdown until the input voltage rises 40mv above the lockout threshold. in s1 s2 c in c out out c x osc figure 1. unregulated voltage doubler max1595 regulated 3.3v/5.0v step-up/ step-down charge pump 4 __________________________________________________ _____________________________________ pin description pin ?ax tqfn-ep name function 11 2 a o u t analog power and sense input for error amplifier/comparator. connect to out at output filter capacitor. 21 shdn shutdown input. when shdn = low, the device turns off; when shdn = high, the device activates. in shutdown, out is disconnected from in. 3 2, 3 in input supply. can range from 1.8v to 5.5v. bypass to gnd with a 1? capacitor. 4 4 gnd ground 5 5, 6 pgnd power ground 6 7, 8 cxn negative terminal of the charge-pump transfer capacitor 7 9 cxp positive terminal of the charge-pump transfer capacitor 8 10, 11 out output. bypass to gnd with output capacitor filter. e p exposed pad. internally connected to gnd. connect to a large ground plane tomaximize thermal performance. not intended as an electrical connection point (tqfn package only). downloaded from: http:///
max1595 regulated 3.3v/5.0v step-up/step-down charge pump ___________________________________________________ ____________________________________ 5 applications information using white leds to backlight lcds is an increasinglypopular approach for portable information devices (figure 2). because the forward voltage of white leds exceeds the available battery voltage, the use of a charge pump such as the max1595 provides high effi- ciency, small size, and constant light output with chang- ing battery voltages. if the output is used only to light leds, the output capacitor can be greatly reduced. the frequency modulation of the led intensity is not dis- cernible to the human eye, and the smaller capacitor saves both size and cost. adding two schottky diodes and two capacitors imple- ments a tripler and allows the max1595_ _ _50 to regu- late a current of 75ma with a supply voltage as low as 2.3v (figure 3). capacitor selection the max1595 requires only three external capacitors(figure 4). their values are closely linked to the output current capacity, oscillator frequency, output noise con- tent, and mode of operation. generally, the transfer capacitor (c x ) will be the smallest, and the input capacitor (c in ) is twice as large as c x . higher switching frequencies allow the use of the smallerc x and c in . the output capacitor (c out ) can be any- where from 5-times to 50-times larger than c x . table 1 shows recommended capacitor values.in addition, the following equation approximates output ripple: v ripple ? i out / (2 x f osc x c out ) table 2 lists the manufacturers of recommended capaci-tors. ceramic capacitors will provide the lowest ripple due to their typically lower esr. power dissipation the power dissipated in the max1595 depends on out-put current and is accurately described by: p diss = i out (2v in - v out ) p diss must be less than that allowed by the package rating. layout considerations all capacitors should be soldered in close proximity tothe ic. connect ground and power ground through a short, low-impedance trace. the input supply trace should be as short as possible. otherwise, an additional input supply filter capacitor (tantalum or electrolytic) may be required. aout in input 2.3v 1 f shdn gnd pgnd out max1595_ _ _50 0.22 f cxp cxn 1 f output regulated 5v 75ma 1 f 0.22 f out in v in c out = 0.47 f c in = 1 f c x = 0.1 f shdn gnd cxp cxn pgnd aout max1595_ _ _50 100 ? 100 ? 100 ? figure 3. regulated voltage tripler figure 2. white led bias supply c x 0.22 f c in 1 f c out 1 f out cxn cxp shdnin out 7 4 6 3 2 8 on off gnd 5 pgnd aout 1 max1595 in figure 4. standard operating circuit downloaded from: http:///
max1595 regulated 3.3v/5.0v step-up/ step-down charge pump 6 __________________________________________________ _____________________________________ chip information process: cmos table 2. recommended capacitor manufacturers value (?) voltage (v) type size manufacturer part 11 0 x7r 0805 taiyo yuden lmk212bj105mg 0.22 10 x7r 0603 taiyo yuden lmk107bj224ma 0.47 10 x7r 0603 taiyo yuden lmk107bj474ma 0.1 10 x7r 0603 taiyo yuden lmk107bj104ma table 1. recommended capacitor values output ripple (mv) c in (?) c x (?) c out (?) 70 1 0.22 1 35 2.2 0.47 2.2 12 aout 11 out 10 out 9 cxp 8 cxn 7 cxn 4 gnd 5 pgnd 6 pgnd 1 shdn 2 in 3 in tqfn top view max1595 pin configurations (continued) package information for the latest package outline information and land patterns(footprints), go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only.package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. package type package code outline no. land pattern no. 8 ?ax u8+1 21-0036 90-0092 12 tqfn 1244+4 21-0139 90-0068 downloaded from: http:///
regulated 3.3v/5.0v step-up/down charge pump max1595 maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 7 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 2 6/09 added ep (exposed pad) and top mark information 1, 2, 4, 6 3 10/11 updated absolute maximum ratings section and added package thermal characteristics section 2 downloaded from: http:///
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