RT9266B features z z z z z 1.0v low start-up input voltage at 1ma load z z z z z 25 a quiescent (switch-off) supply current z z z z z zero shutdown mode supply current z z z z z 90% efficiency z z z z z 550khz switching frequency at 3.3v v dd z z z z z providing flexibility for using internal and external power switches z z z z z small sot-23-6 package z z z z z rohs compliant and 100% lead (pb)-free pin configurations applications z pda z dsc z lcd panel z rf-tags z mp3 z portable instrument z wireless equipment ordering information general description the RT9266B is a compact, high efficiency, and low voltage step-up dc/dc converter with an adaptive current mode pwm control loop, includes an error amplifier, ramp generator, comparator, switch pass element and driver in which providing a stable and high efficient operation over a wide range of load currents. it operates in stable waveforms without external compensation. the low start-up input voltage below 1v makes RT9266B suitable for 1 to 4 battery cells applications with a 500ma internal switch. the 550khz high switching rate minimized the size of external components. besides, the 25 a low quiescent current together with high efficiency maintains long battery lifetime. (top view) sot-23-6 marking information for marking information, contact our sales representative directly or through a richtek distributor located in your area, otherwise visit our website for detail. note : there is no pin1 indicator on top mark for sot-23-6 type, and pin 1 will be lower left pin when reading top mark from left to right. en ext gnd lx vdd fb 4 23 5 6 1 RT9266B package type e : sot-23-6 operating temperature range p : pb free with commercial standard g : green (halogen free with commer- cial standard) 1 of 4 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
typical application circuit figure 1. RT9266B typical application for portable instruments figure 2. RT9266B for higher current applications test circuit vdd en ext gnd lx fb RT9266B c2 1uf r1 1.6m/3m r2 980k/1m l1 3.3 to 10 uh v in d1 ss0520 v out 3.3v/5v c3 10uf c1 10uf vdd en ext gnd lx fb RT9266B c2 1uf r1 1.6m/3m r2 980k/1m l1 3.3 to 10 uh v in d1 ss0520 v out 3.3v/5v c3 10uf c1 10uf q1 n mos vdd en ext gnd lx fb RT9266B c2 1uf r1 1.6m/3m r2 980k/1m l1 10uh v in d1 ss0520 v out 3.3v/5v c3 10uf c4 100p a i (v dd ) a + i (v in ) c5 10uf 2 of 4 4008-318-123 sales@twtysemi.com http://www.twtysemi.com RT9266B product specification
function block diagram functional pin description pin name pin function en chip enable (active high) ext output pin for driving external nmos gnd ground lx pin for switching vdd input positive power pin of RT9266B fb feedback input pin internal reference voltage for the error amplifier is 1.25v. + - loop control circuit 1.25v vdd r2 q3 n mos en fb q1 n mos r1 lx1 shut down over temp. detector vdd RT9266B ext gnd 3 of 4 4008-318-123 sales@twtysemi.com http://www.twtysemi.com RT9266B product specification
absolute maximum ratings z supply v oltage ----------------------------------------------------------------------------------------------------- ? 0.3v to 7v z lx pin switch voltage -------------------------------------------------------------------------------------------- ? 0.3v to 6.5v z other i/o pin v oltages ------------------------------------------------------------------------------------------- ? 0.3v to (v dd + 0.3v) z lx pin switch current -------------------------------------------------------------------------------------------- 2.5a z ext pin driver current -------------------------------------------------------------------------------------------- 200ma z package thermal resistance sot-23-6 , jc ------------------------------------------------------------------------------------------------------ 145 c/w z operating junction temperature ------------------------------------------------------------------------------- 125 c z storage temperature range ------------------------------------------------------------------------------------ ? 65 c to +150 c electrical characteristics (v in = 1.5v, v dd set to 3.3v, load current = 0, t a = 25c, unless otherwise specified) parameter symbol test conditions min typ max units start-up voltage v st i l = 1ma -- 0.98 1.05 v operating vdd range v dd vdd pin voltage 2 -- 6.5 v no load current i (v in ) i no load v in = 1.5v, v out = 3.3v -- 150 -- a switch-off current i (v dd ) i switch off v in = 6v -- 25 -- a shutdown current i (v in ) i off en pin = 0v, v in = 4.5v -- 0.01 1 a feedback reference voltage v ref close loop, v dd = 3.3v 1.225 1.25 1.275 v switching frequency f s v dd = 3.3v -- 550 -- khz maximum duty d max v dd = 3.3v -- 95 -- % lx on resistance v dd = 3.3v -- 0.35 -- current limit setting i limit v dd = 3.3v -- 0.5 -- a current limit delay time v dd = 3.3v -- 300 -- ns ext on resistance to v dd v dd = 3.3v -- 5 -- ext on resistance to gnd v dd = 3.3v -- 5 -- line regulation (refer to v fb ) v line v in = 1.5 ~ 2.5v, i l = 50ma -- 12 -- mv/v load regulation (refer to v fb ) v load v in = 2.5v, i l = 1 ~ 100ma -- 0.25 -- mv/ma en pin trip level v dd = 3.3v 0.4 0.8 1.2 v temperature stability for vout t s -- 50 -- ppm/ c thermal shutdown t sd -- 165 -- c thermal shutdown hysterises t sd -- 10 -- c 4 of 4 4008-318-123 sales@twtysemi.com http://www.twtysemi.com RT9266B product specification
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