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for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maximintegrated.com. max1722/max1723/ max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 general description the max1722/max1723/max1724 compact, high-effi- ciency, step-up dc-dc converters are available in tiny, 5- pin thin sot23 packages. they feature an extremely low 1.5? quiescent supply current to ensure the highest pos- sible light-load efficiency. optimized for operation from one to two alkaline or nickel-metal-hydride (nimh) cells, or a single li+ cell, these devices are ideal for applications where extremely low quiescent current and ultra-small size are critical. built-in synchronous rectification significantly improves efficiency and reduces size and cost by eliminating the need for an external schottky diode. all three devices fea- ture a 0.5? n-channel power switch. the max1722/ max1724 also feature proprietary noise-reduction circuitry, which suppresses electromagnetic interference (emi) caused by the inductor in many step-up applications. the family offers different combinations of fixed or adjustable outputs, shutdown, and emi reduction (see selector guide ). applications features up to 90% efficiency no external diode or fets needed 1.5? quiescent supply current 0.1? logic-controlled shutdown ?% output voltage accuracy fixed output voltage (max1724) or adjustable output voltage (max1722/max1723) up to 150ma output current 0.8v to 5.5v input voltage range 0.91v guaranteed startup (max1722/max1724) internal emi suppression (max1722/max1724) thin sot23-5 package (1.1mm max height) gnd out fb 1 + 5lx batt max1722 thin sot23 top view 2 34 part temp range pin- package top mark max1722 ezk+t+ -40 c to +85 c 5 sot23 adqf max1723ezk+t -40 c to +85 c 5 sot23 adqg max1724ezk27+t -40 c to +85 c 5 sot5 adqh max1724ezk30+t -40 c to +85 c 5 sot23 adqi max1724ezk33+t -40 c to +85 c 5 sot23 adqj max1724ezk50+t -40 c to +85 c 5 sot23 adqk lx out in 0.8v to 5.5v 3.3v at up to 150ma on off batt max1724 shdn gnd 10h out typical operating circuit 19-1735; rev 1; 9/12 ordering information pagers remote controls remote wireless transmitters personal medical devices digital still cameras single-cell battery- powered devices low-power hand-held instruments mp3 players personal digital assistants (pda) pin configurations are continued at end of data sheet. pin configurations + denotes a lead(pb)-free/rohs-compliant package. t = tape and reel. selector guide appears at end of data sheet.
max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 2 maxim integrated absolute maximum ratings electrical characteristics (v batt = 1.2v, v out = 3.3v (max1722/max1723), v out = v out(nom) (max1724), shdn = out, r l = , t a = 0? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) 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. out, shdn , batt, lx to gnd ................................-0.3v to +6v fb to gnd ................................................-0.3v to (v out + 0.3v) out, lx current.......................................................................1a continuous power dissipation (t a = +70?) 5-pin thin sot23 (derate 7.1mw/? above +70?) ...571mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? soldering temperature lead(pb)-free packages..............................................+260? packages containing lead(pb)....................................+240? t a = +85? t a = +25? t a = 0? to +85? t a = +25? t a = 0? to +85? t a = +25? t a = 0? to +85? t a = +25? t a = 0? to +85? t a = +25? t a = 0? to +85? t a = +25? max1723 (note 2) max1722/max1724 shutdown current into out 0.1 ? quiescent current into out 1.5 3.6 ? quiescent current into batt 0.01 ? max1723/max1724 (notes 3, 4) (notes 3, 4) max1722/max1724 (note 4) parameter symbol min typ max units 2.633 2.767 output voltage v out 2.673 2.7 2.727 v 0.87 1.2 minimum startup input voltage 0.83 0.91 v 2.970 3.0 3.030 2.925 3.075 3.267 3.3 3.333 3.218 3.383 operating input voltage minimum input voltage 0.8 v v in 0.91 5.5 v 1.2 5.5 4.950 5.0 5.050 4.875 5.125 output voltage range v out 2 5.5 v feedback voltage v fb 1.223 1.235 1.247 v 1.210 1.260 feedback bias current i fb 1.5 20 na 2.2 n-channel on-resistance r ds(on) 0.5 1.0 ? p-channel on-resistance r ds(on) 1.0 2.0 ? n-channel switch current limit i lim 400 500 600 ma switch maximum on-time t on 3.5 5 6.5 ? synchronous rectifier zero- crossing current 52035 ma conditions max1724ezk50 max1724ezk27 t a = +25?, r l = 3k? max1724ezk30 max1722/max1723 max1722/max1723 max1724ezk33 max1722/max1723 max1722/max1724 v out forced to 3.3v t a = +25? v out forced to 3.3v v out forced to 3.3v v out forced to 3.3v max1722/max1724 max1723 (note 2) t a = +85? t a = +25? 0.01 0.5 t a = +85? t a = +25? 0.001 0.5
3 maxim integrated max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 electrical characteristics (continued) (v batt = 1.2v, v out = 3.3v (max1722/max1723), v out = v out(nom) (max1724), shdn = out, r l = , t a = 0? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) note 1: limits are 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed by design. note 2: guaranteed with the addition of a schottky mbr0520l external diode between lx and out when using the max1723 with only one cell, and assumes a 0.3v voltage drop across the schottky diode (see figure 3). note 3: supply current is measured with an ammeter between the output and out pin. this current correlates directly with actual battery supply current, but is reduced in value according to the step-up ratio and efficiency. note 4: v out forced to the following conditions to inhibit switching: v out = 1.05 v out(nom) (max1724), v out = 3.465v (max1722/max1723). v il max1723/max1724 t a = +85? t a = +25? t a = +85? t a = +25? 0.001 0.5 shdn voltage threshold v ih 500 800 mv shutdown current into batt 0.01 ? shdn input bias current 7 na max1724 (note 4) max1723/max1724, v shdn = 5.5v parameter symbol min typ max units conditions max1723/max1724 75 400 2 100 parameter symbol conditions min typ max units max1724ezk27 2.633 2.767 max1724ezk30 2.925 3.075 max1724ezk33 3.218 3.383 o utp ut v ol tag ev out max1724ezk50 4.875 5.125 v o utp ut v ol tag e rang ev out max1722/max1723 2 5.5 v feedback voltage v fb max1722/max1723 1.200 1.270 v n-channel on-resistance r ds(on) v out forced to 3.3v 1.0 ? p-channel on-resistance r ds(on) v out forced to 3.3v 2.0 ? n-channel switch current limit i lim v out forced to 3.3v 400 620 ma switch maximum on-time t on 3.5 6.5 ? synchronous rectifier zero- crossing current v out forced to 3.3v 5 35 ma quiescent current into out (notes 3,4) 3.6 ? v il max1723/max1724 75 shdn voltage threshold v ih max1723/max1724 800 mv electrical characteristics (v batt = 1.2v, v out = 3.3v (max1722/max1723), v out = v out(nom) (max1724), shdn = out, r l = , t a = -40? to +85?, unless otherwise noted.) (note 1)
max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 4 maxim integrated typical operating characteristics (figure 3 (max1723), figure 7 (max1722), figure 8 (max1724), v batt = v in = 1.5v, l = 10?, c in = 10?, c out = 10?, t a = +25?, unless otherwise noted.) 0 40 120 80 160 200 02 1345 maximum output current vs. input voltage max1722 toc04 input voltage (v) i out(max) (ma) v out = 2.5v v out = 5.0v v out = 3.3v 10 100 0.8 1.0 1.2 1.4 1.6 2.0 1.8 2.2 2.4 0.01 0.1 1 startup voltage vs. load current max1722 toc05 load current (ma) startup voltage (v) 0.6 resistive load v out = 5.0v 0 0.4 0.2 0.8 0.6 1.2 1.0 1.4 1.8 1.6 2.0 1.0 2.0 2.5 3.0 1.5 3.5 4.0 4.5 5.0 5.5 max1722 toc06 quiescent current ( a) output voltage (v) quiescent current into out vs. output voltage no load 100 0.01 0.1 1 10 100 1000 efficiency vs. load current (v out = 5.0v) max1722 toc01 load current (ma) efficiency (%) 60 80 50 70 90 v in = 2.0v v in = 3.3v v in = 4.0v v in = 1.5v v in = 1.0v l = do1606 100 0.01 0.1 1 10 100 1000 efficiency vs. load current (v out = 3.3v) max1722 toc02 load current (ma) efficiency (%) 60 80 50 70 90 v in = 2.0v v in = 2.5v v in = 1.5v v in = 1.0v l = do1606 100 0.01 0.1 1 10 100 1000 efficiency vs. load current (v out = 2.5v) max1722 toc03 load current (ma) efficiency (%) 60 80 50 70 90 v in = 1.5v v in = 2.0v v in = 1.0v l = do1606 0 0.4 0.2 0.8 0.6 1.0 1.2 -40 85 startup voltage vs. temperature max1722 toc07 temperature (c) startup voltage (v) 10-15 35 60 no load 1s/div i lx 500ma/div v out 50mv/div v lx 2v/div switching waveforms max1722 toc08 i out = 50ma, v out = 5.0v, v in = 3.3v
5 maxim integrated max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 pin description 1ms/div v shdn 1v/div 5v 0 0 2v shutdown response max1722 toc10 v in = 3.3v, v out = 5.0v, r out = 100? v out 2v/div 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 -40 -15 10 35 60 85 shutdown input threshold vs. temperature max1722 toc11 temperature ( c) shutdown threshold (mv) rising edge falling edge typical operating characteristics (continued) (figure 3 (max1723), figure 7 (max1722), figure 8 (max1724), v batt = v in = 1.5v, l = 10?, c in = 10?, c out = 10?, t a = +25?, unless otherwise noted.) max1724 max1722 max1723 out lx fb gnd shdn batt name 4 5 2 3 1 power output. out also provides bootstrap power to the ic. 4 4 internal n-channel mosfet switch drain and p-channel synchronous rectifier drain 5 5 feedback input to set output voltage. use a resistor-divider network to adjust the output voltage. see setting the output voltage section. 3 3 ground 2 2 pin shutdown input. drive high for normal operation. drive low for shutdown. 1 battery input and damping switch connection 1 function 200s/div a a: v out , 50mv/div b: i out , 20ma/div b load-transient response max1722 toc09 3.3v 50ma 0
max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 6 maxim integrated detailed description the max1722/max1723/max1724 compact, high-effi- ciency, step-up dc-dc converters are guaranteed to start up with voltages as low as 0.91v and operate with an input voltage down to 0.8v. consuming only 1.5? of quiescent current, these devices include a built-in syn- chronous rectifier that reduces cost by eliminating the need for an external diode and improves overall efficien- cy by minimizing losses in the circuit (see synchronous rectification section). the max1722/max1724 feature a clamp circuit that reduces emi due to inductor ringing. the max1723/max1724 feature an active-low shutdown that reduces quiescent supply current to 0.1?. the max1722/max1723 have an adjustable output voltage, while the max1724 is available with four fixed-output voltage options (see selector guide) . figure 1 is the max1723 simplified functional diagram and figure 2 is the max1724 simplified functional diagram. pfm control scheme a forced discontinuous, current-limited, pulse-frequency- modulation (pfm) control scheme is a key feature of the max1722/max1723/max1724. this scheme provides ultra-low quiescent current and high efficiency over a wide output current range. there is no oscillator; the inductor current is limited by the 0.5a n-channel cur- rent limit or by the 5? switch maximum on-time. following each on cycle, the inductor current must ramp to zero before another cycle may start. when the error comparator senses that the output has fallen below the regulation threshold, another cycle begins. synchronous rectification the internal synchronous rectifier eliminates the need for an external schottky diode, thus reducing cost and board space. while the inductor discharges, the p- channel mosfet turns on and shunts the mosfet body diode. as a result, the rectifier voltage drop is sig- nificantly reduced, improving efficiency without the addition of external components. low-voltage startup circuit the max1722/max1723/max1724 contain a low-volt- age startup circuit to control dc-dc operation until the output voltage exceeds 1.5v (typ). the minimum start- p n control logic startup circuitry driver gnd fb out lx current limit 1.235v reference error comparator zero- crossing detector max1723 shdn figure 1. max1723 simplified functional diagram
7 maxim integrated max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 up voltage is a function of load current (see typical operating characteristics ). this circuit is powered from the batt pin for the max1722/max1724, guaranteeing startup at input voltages as low as 0.91v. the max1723 lacks a batt pin; therefore, this circuit is powered through the out pin. adding a schottky diode in paral- lel with the p-channel synchronous rectifier allows for startup voltages as low as 1.2v for the max1723 (figure 3). the external schottky diode is not needed for input voltages greater than 1.8v. once started, the output maintains the load as the battery voltage decreases below the startup voltage. shutdown (max1723/max1724) the max1723/max1724 enter shutdown when the shdn pin is driven low. during shutdown, the body diode of the p-channel mosfet allows current to flow from the battery to the output. v out falls to approxi- mately v in - 0.6v and lx remains high impedance. shutdown can be pulled as high as 6v, regardless of the voltage at batt or out. for normal operation, con- nect shdn to the input. p n control logic startup circuitry damping switch driver gnd shdn r 1 r 2 batt lx out current limit max1724 error comparator zero- crossing detector 1.235v reference figure 2. max1724 simplified functional diagram figure 3. max1723 single-cell operation v out = 3.6v 1.2v to v out d1 10 h 10f r2 2.37m? r1 1.24m? 10f lx out shdn gnd fb max1723
max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 8 maxim integrated batt/damping switch (max1722/max1724) the max1722/max1724 include an internal damping switch (figure 4) to minimize ringing at lx and reduce emi. when the energy in the inductor is insufficient to supply current to the output, the capacitance and inductance at lx form a resonant circuit that causes ringing. the damping switch supplies a path to quickly dissipate this energy, suppressing the ringing at lx. this does not reduce the output ripple, but does reduce emi with minimal impact on efficiency. figures 5 and 6 show the lx node voltage waveform without and with the damping switch, respectively. design procedure setting the output voltage (max1722/max1723) the output voltage can be adjusted from 2v to 5.5v using external resistors r1 and r2 (figure 7). since fb leakage is 20na (max), select feedback resistor r1 in the 100k ? to 1m ? range. calculate r2 as follows: where v fb = 1.235v. rr v v out fb 21 1 =? ? ? ? ? ? ? max1722 max1724 pdrv damp ndrv timing circuit out v out v in batt lx damping switch gnd p n 1s/div 1v/div 1s/div 1v/div figure 6. lx ringing with damping switch (max1722/max1724) figure 5. lx ringing without damping switch (max1723) figure 4. simplified diagram of damping switch
9 maxim integrated max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 inductor selection the control scheme of the max1722/max1723/ max1724 permits flexibility in choosing an inductor. a 10? inductor value performs well in most applications. smaller inductance values typically offer smaller physi- cal size for a given series resistance, allowing the smallest overall circuit dimensions. circuits using larger inductance values may start up at lower battery volt- ages, provide higher efficiency, and exhibit less ripple, but they may reduce the maximum output current. this occurs when the inductance is sufficiently large to pre- vent the maximum current limit (i lim ) from being reached before the maximum on-time (t on(max) ) expires. for maximum output current, choose the inductor value so that the controller reaches the current-limit before the maximum on-time is triggered: where the maximum on-time is typically 5?, and the current limit (i lim ) is typically 500ma (see electrical characteristics table). for larger inductor values, determine the peak inductor current (i peak) by: the inductor? incremental saturation current rating should be greater than the peak switching current. however, it is generally acceptable to bias the inductor into saturation by as much as 20%, although this will slightly reduce effi- ciency. table 1 lists suggested inductors and suppliers. maximum output current the maximum output current depends on the peak induc- tor current, the input voltage, the output voltage, and the overall efficiency ( ): ii v v out max peak batt out () = ? ? ? ? ? ? 1 2 i vt l peak batt on max = () l vt i batt on max lim < () max1724 gnd batt output v out (nom) input 0.8v to v out 10 h c2 10 f shdn lx out c1 10 f off on figure 8. max1724 standard application circuit table 1. suggested inductors and suppliers max1722 gnd batt output 2v to 5.5 v input 0.8v to v out 10 h lx out fb r2 10 f r1 10 f figure 7. adjustable output circuit manufacturer inductor phone website coilcraft do1608 series do1606 series 847-639-2361 www.coilcraft.com murata lqh4c series 770-436-1300 www.murata.com sumida cdrh4d18 series cr32 series cmd4d06 series 847-545-6700 www.sumida.com sumitomo/ daidoo electronics cxld140 series +81 (06) 6355-5733 www.daidoo.co.jp toko 3df type d412f type 847-297-0070 www.toko.com
max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 10 maxim integrated for most applications, the peak inductor current equals the current limit. however, for applications using large inductor values or low input voltages, the maximum on- time limits the peak inductor current (see inductor selection section). capacitor selection choose input and output capacitors to supply the input and output peak currents with acceptable voltage rip- ple. the input filter capacitor (c in ) reduces peak cur- rents drawn from the battery and improves efficiency. low equivalent series resistance (esr) capacitors are recommended. ceramic capacitors have the lowest esr, but low esr tantalum or polymer capacitors offer a good balance between cost and performance. output voltage ripple has two components: variations in the charge stored in the output capacitor with each lx pulse, and the voltage drop across the capacitor? esr caused by the current into and out of the capaci- tor: where i peak is the peak inductor current (see inductor selection section). for ceramic capacitors, the output voltage ripple is typically dominated by v ripple(c) . for example, a 10? ceramic capacitor and a 10? induc- tor typically provide 75mv of output ripple when step- ping up from 3.3v to 5v at 50ma. low input-to-output voltage differences (i.e. two cells to 3.3v) require high- er output capacitor values. capacitance and esr variation of temperature should be considered for best performance in applications with wide operating temperature ranges. table 2 lists suggested capacitors and suppliers. pc board layout considerations careful pc board layout is important for minimizing ground bounce and noise. keep the ic? gnd pin and the ground leads of the input and output capacitors less than 0.2in (5mm) apart using a ground plane. in addition, keep all connections to fb (max1722/max1723 only) and lx as short as possible. vv v v v l vvc i ripple ripple c ripple esr ripple esr ripple c out batt out =+ () ? ? ? ? ? ? () () ( ) () ( ) () peak esr cout peak out i r - i- 2 1 2 2 table 2. suggested surface-mount capacitors and manufacturers (c1 and c2) manufacturer capacitor value description phone website 1 f to 10 f x7r ceramic avx 10 f to 330 f taj tantalum series tps tantalum series 843-448-9411 www.avxcorp.com 1 f to 22 f x5r/x7r ceramic 10 f to 330 f t494 tantalum series kemet 68 f to 330 f t520 tantalum series 864-963-6300 www.kemet.com sanyo 33 f to 330 f tpc polymer series 408-749-9714 www.secc.co.jp taiyo yuden 33f to 330 f x5r/x7r ceramic 800-368-2496 www.t-yuden.org tdk 1f to 10 f x7r ceramic 847-803-6100 www.tdk.com vishay sprague 10 f to 330 f 594d tantalum series 595d tantalum series 203-452-5664 www.vishay.com
11 maxim integrated max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 gnd out fb 15 l x shdn thin sot23 top view 2 34 gnd out 15 l x batt max1724 thin sot23 2 34 shdn max1723 pin configurations (continued) package information for the latest package outline information and land patterns (foot- prints), go to www.maximintegrated.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. sot23 z5+1 21-0013 90-0241 selector guide part output (v) shdn lx damping max1722ezk adjustable no yes max1723ezk adjustable yes no max1724ezk27 fixed 2.7 yes yes max1724ezk30 fixed 3.0 yes yes max1724ezk33 fixed 3.3 yes yes max1724ezk50 fixed 5.0 yes yes
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. 12 ________________________________maxim integrated 160 rio robles, san jose, ca 95134 usa 1-408-601-1000 2012 maxim integrated products, inc. the maxim logo and maxim integrated are trademarks of maxim integrated products, inc. max1722/max1723/max1724 1.5a i q , step-up dc-dc converters in thin sot23-5 revision history revision number revision date description pages changed 0 7/01 initial release 1 9/12 added lead-free and tape-and-reel designations and added soldering temperatures 1, 2

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