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high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 1 o f 15 3g24n - rev.p001 general description t he ec92 11 is a fix e d s w itch i ng freq u en c y ( 1 .5mhz t y pic al ), current - m o de, step - up r e g u la t o r w i t h an i n te g rated n - c h an n el mosfe t . t he devi c e al l o w s the us a ge of s mall i n ductors and output c a pacit o rs for portable devi c es. t he current - m o de c o ntrol scheme p r ovi d es fast transie n t response a n d good o u tput v o lta g e accura c y . t he ec92 11 i n clu d es u n der - v olta g e loc k out, current li m it, a n d over - tem p e rat u re shutd o w n p r event i ng d a m a ge in the event of an output o v erl oa d . featur e s wide 2.7v to 6v input voltage range buil t \ in 0.2 n \ channel mosfet buil t \ in soft \ start high eff i c ien c y up to 90% < 1 m a quiescent current d u ring shutdown current \ mode operation stable with ceramic outp u t capacitors fast transient response current \ limit protection over \ temperature protection with hysteresis available in a so t 23 \ 6 package lead free and green devices available (rohs compl i ant) applications cell phone and smart phone pda, pmp, mp3 digital camera boost regulators pin configurations figu r e 1 pin c o nfigu r ation o f ec9 211 ( t o p v i e w )
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 2 o f 15 3g24n - rev.p001 pin description pin number pin name description 1 lx switch pin. connect this pin to inductor/d i ode here. 2 gdn gnd 3 fb feedback input. the devi c e senses fee d back voltage via fb and r e gulate the vo l tage at 1.23v. connecting fb with a resistor \ divider from the output that sets the output voltage. 4 en enable control input. forcing this pin above 1.0v enables the de v i ce. forcing t h i s pin below 0.4v to shut it down. in shutdown, all functions ar e disabled to decrease the supply current below 1 a . do not l e f t this pin floating. 5 in main supply pin. must be closely decoupled to gnd with a 2. 2 f or greater ceramic capacitor. 6 nc orderi n g information part number package marking marking information ec 9211nnb3r sot23 - 6 9 2 11f 1. starting with underlined 2, a bar is for production year 2012. the next bar is mark on top of first 1 is for year 2013. the next bar is mark on bottom of first 1 is for year 2014.the next bar is mark on top of second 1 is year for 2015. the naming pattern continues with consecutive characters for later years. 2. f is the week of production. the big char acter of a~z is for the week of 1~26, and small a~z is for the week of 27~52.
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 3 o f 15 3g24n - rev.p001 package types s o t23 - 6 figu r e 2 . p ac k age t yp e s of ec921 1 function block figu r e 3 f u n c t i o n block diag r am of ec92 1 1
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 4 o f 15 3g24n - rev.p001 absol u te maximum rati n gs note1: stresses b e y ond those listed under "absol u te maximum r ating s " m a y cause p ermanent d ama g e to the device. t hese are stress r atings only and functional operation of the device at the s e or a n y o ther conditions b e y ond t hose i ndicated under "re c ommended o p e r ating condit i ons" is not implied. exposure to ab s olute maximum r at i ng conditions for ex t ended p er i ods m a y affect d evice reliability re co m m e nd e d o p e ra t i n g c o n d i t i o n s thermal characteristics s y mbol parameter t y pical va l ue unit ja junction - t o - amb i ent resistance in f r e e a i r sot23 - 6 2 2 0 /w jc junction - t o - case resistance sot23 - 6 1 2 0 /w
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 5 o f 15 3g24n - rev.p001 electrical characteristics ( t a = 25c , unless otherwise specified ) s y mbol parameter tes t condit i ons ec92 1 1 unit mi n. t y p . max. v in i np u t v o lta g e ta= \ 40 ~ 85 t j = - 40~12 0 2.7 --- 6 v idd1 input dc bias current vfb = 1. 3 v, n o s witching --- 3 00 \ --- ua idd2 vfb = 1. 1 v, switching --- 2 5 ma isd en=g n d --- \ --- 1 a uvlo t hresho l d volt a g e vin rising 2.0 2.2 2.4 v uvlo hystere s is voltage vin falling 50 1 0 0 1 5 0 mv v r ef regulated f e ed b ack voltage v i n =2.7v~6v, ta = 25 1. 2 12 1. 2 3 1. 2 48 v v i n =2.7v~6v, ta = - 40 ~ 85 1. 2 05 --- 1. 2 55 ifb fb input c u rr e nt - 50 --- 50 na f s w s w itching f r eq u en c y 1 .2 5 1.5 1. 7 5 mhz r o n power s w itch on resistance --- 0.2 --- ilim power s w itch c u rrent limit 2.2 --- --- a lx leakage c u r r ent ven = 0v, vlx = 0 v or 6v, v i n = 6v - 1 --- 1 ua d m ax lx ma x i mum du t y c y cle 92 95 98 % tss soft \ s t art du ration --- 2 3 ms vten en voltage th re shold ven rising 0.4 0.7 1 v en voltage h y s t eresis --- 0.1 --- v ilen en leakage c ur rent ven=5v, vin = 5v - 1 --- 1 ua totp over \ temperature protection t j ris i ng --- 150 --- over \ temperature protection t j fall i ng --- 40 ---
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 6 o f 15 3g24n - rev.p001 typical perf or man ce characteristics
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 7 o f 15 3g24n - rev.p001 typical perf or man ce characteristics(cont.)
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 8 o f 15 3g24n - rev.p001 operati n g waveforms
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 9 o f 15 3g24n - rev.p001 operati n g waveforms(cont.)
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 10 o f 15 3g24n - rev.p001 typical application circuit figure 4 . t ypi ca l 5v to 12v supply figure 5 . st a n dard 3.3v to 5 v supply
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 11 o f 15 3g24n - rev.p001 typical application circuit(cont.) figure 6 . multiple output for tft - l c d power supply
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 12 o f 15 3g24n - rev.p001 function description m a in control lo o p t he EC9211 is a constant frequ e n c y a n d c u rrent - mo d e s w i tching reg u lator. in n o rmal o p erati o n, the intern a l n c ha n nel p o w e r mosfet is turned o n ea c h c y cle w h en the o scillator s e ts an inter n al rs lat c h, and th e n turned off w h en a n inter n al co m parator (icmp) resets the latch. t he peak i n ductor c u rrent at w h ich i cmp resets the rs l a tch is contro l l ed b y the vol t a ge on the co m p node w h ich is t h e o u tput of the err o r amplifier (e a mp). an exter n al resistive d ivi de r connect e d b e t w e en v out and grou n d al l o w s the eamp to rece i ve an ou t put feed b ack volt a g e v fb at fb pin. w hen the lo a d curr en t increases, it causes a s l i g htly to dec r ease i n v fb assoc i ated w i t h the 1.23v re f e ren c e , w h i c h i n turn, it caus e s the comp voltage to increa s e unt i l the aver a ge i nductor cur r ent matches the n e w l o ad curr en t. vin und e r - vo l t a ge lo ck out (uvlo) t he under - vol t age l o ck o ut (uvlo) circuit c o mpares the i n p u t volta g e at vin w i t h the u v lo thr e sh o ld to en sure the i nput v o lta g e is hi g h e n ou g h for reli a ble o p e ration. t he 10 0 mv (typ) h y ste r esis prev e n ts sup pl y trans i ents fr o m causi n g a r e start. once the input volta g e e x c e e d s the uvlo ris i ng thres h o l d, startup be g ins. w hen the in p u t volta g e falls b e l o w t h e uvlo fall i ng thresh o ld, the contro l ler turns off the converter. soft - start t he ec92 11 h a s a bu i lt - in so f t - start to control the out p u t voltage rise dur i ng sta r t - up. duri n g s o ft - start, an inte r nal ra m p volt a ge, con n ected to the o n e of the p o sitive i nputs o f the error amp l ifier, raises u p to repla c e the refe r ence v o lta g e (1.23v t y pic a l) until the ramp volt a ge r eac h es the re f eren c e volt a g e . current - limit protection t he ec92 11 monitors the i n d u ctor current, fl o w s thro u gh t h e n - ch a nn e l mosfe t , and lim i ts the current peak at current - l imit level to p r ev e n t loads a nd the ec92 11 from dama g ing d u r in g over l oad or s h ort - circuit co n d i tions. o v er - t e mperature prot ec tion (otp) t he over - temperature cir c uit l i mits the juncti o n temperatu r e of the ec92 11 . w hen the juncti o n temperatu r e e x c eeds 1 5 0 , a thermal sensor turns o f f the p o w e r m osfet all o w in g the devi c es to cool. t he thermal sensor a l l o w s the converters to start a soft - start process a nd r e gu l ates the ou t put volta g e a g ain after the ju nction temperatu r e c o ols b y 4 0 . t h e o t p is desi g ned w i t h a 40 h y s t eresis to l o w e r the ave r a g e juncti o n t e mperatu r e ( t j ) dur i ng conti n u o us th e rmal over l o a d con d i t ions i n c r eas i ng the l ifet i me of the devi c e. enable/shu td o w n drivi n g en to the gr o u n d pla c es the ec92 1 1 in shutd o w n m ode. when in s h ut d o w n , the in t e r n al p o w e r mosfet turns off, all inter n al circ u itry s h uts d o w n , and the qu i es c ent sup pl y c u r r ent redu c es to 1 a ma x i m u m.
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 13 o f 15 3g24n - rev.p001 application information inp u t c a p ac itor s e l ec tion t he input cap a citor ( c in ) red u ces the rip p le o f the input cur r ent dr a w n from the input su p p l y a nd re d u ces n o i se in j e ction i n to the ic. t he reflected ri p p le v o lta g e w i ll b e sma l l e r w h en a n i n p u t capa c itor w ith l a rger c a pacit a n ce is us e d . f o r relia b le o pe ra tion, it is recomm e n d ed to select the capacitor w i t h maximum vol t a ge rating at l e ast 1.2 times of the maximum i n p u t voltage. t he capa c itors sh o u ld b e p l aced c l ose to the vin and the gnd. indu c tor s e l e c tion select i ng a n i n ductor w ith l o w dc resistance r edu c es co n du c tion losses a nd a ch ieves h igh efficien c y. t he efficien c y is m o de r ated w h ilst us i ng s m all ch i p i n duct o r w h ich o pera t es w i t h h i g h er in d u ctor core l o sses. t herefore, it is neces s a r y to take fur t her cons i derat i on w h i l e ch o o si n g an ad e q u ate i nductor. ma i n l y, the in d u ctor val u e determ i nes the inductor r i pp l e current: larger in d u ctor val u e results in sm a l l e r in d u ctor rip p le curr e nt and l o w e r con d ucti o n lo s ses of the con v erter. h o w e v e r , larger i n duct o r value ge n erates s l o w er lo a d transi e nt respon s e. a reas o na b le de sign rule is to set t he rip p le curr e nt, i l , to be 30% to 50% of the maximum a v erage i n d u ctor current,i l(av g ) . t h e in d u ctor va lu e can be obt a i n ed as bel o w , w h e r e v in = input vol t a g e v out = output volta g e f s w = s w itch i n g frequen c y i n mhz i out = maximum output curr e nt in amp. = efficien c y i l /i l(av g ) = ind u ctor ripp l e cur r ent/aver a ge c u rrent (0.3 to 0.5 t y pical) t o avoid the saturati o n of the inductor, the i nductor s h o u ld be rated at least for the m a xim u m input curr e nt of the converter plus the in d u ctor ri p p le cur r ent. t h e maximum input current is calcu l ated as b e l o w : t he peak in du ctor current is cal c u l ated as the fol l o w i ng eq uati o n: output capacitor selection t he current - mode contr o l sc h eme of the ec92 1 1 all o w s t h e usage of ti n y ce r a mic capa c itors. t h e hi g her c a pac i tor value p r ov i des go o d l o ad tra n sients res p on s e. ceramic c ap a citors w ith l o w esr val u es ha v e the l o w e st output voltage r i pp l e and a r e recomm e nd e d. if required, tan t alum c a pacito r s m a y b e used as w e ll. t he outp u t ripple is the s u m of the volt a ges across the esr and the i d e a l o u tput ca p a cito r .
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 14 o f 15 3g24n - rev.p001 application information(cont.) i ou t put c a p ac itor s e l ec tion (con t .) w h e r e i p e ak is the peak i n d u ct o r current. f o r ceramic c a pacitor a pp l ica t ion, the o u tput volta g e rip p le i s dom i nated b y t he v cou t . w hen ch o o s i ng t h e in p u t and o u tput ceramic c a pac i tors, the x5r o r x7r w i t h the i r good tem p er a ture and voltage characteristics are recomm en ded. out p ut v o lta g e setting t he output voltage is set b y a resistive d ivi de r. t he exter n al resistive d ivi de r is connect e d to the out p u t w h ich a ll o w s re mote volta g e sen s i n g as sh o w n in t y p i c al a p pli ca tion cir c u its. a sug g esti o n of the m a xi m u m val u e of r1 is 2 m and r2 is 200 k for k e e p ing the m i nim u m current that prov i des e n o u gh noi s e reject i on abi l i t y th r ou g h the resistor d iv i der. t he output volta g e can b e calcu l ated as b e l o w : diode selection t o achieve the high effic i en c y, a schott k y d i ode must be u sed. t he current rating of the d i ode m u st meet the peak curr e nt rating of the convert e r. l a y out con s id e r a tion for all s w itch in g p o w e r su p p l i es, the l a y o ut is an import a nt step in the des i gn e sp e cia ll y at hi g h peak cur r ents and s w it c h i n g frequ e ncies. if the l a y o ut is n o t c a reful l y d o n e , the regula t or might sh o w n o ise pr o b lems a nd d u t y c y cle j itter. 1. t he input c a pacitor s h ou l d be p l ac e d clo s e to the vin a n d the gnd w i t h o u t a n y v i a h o les for good i n p u t voltage filte r ing. 2. t o minimize cop p er trace con n e c ti o n s that can in j e ct noi s e into the s y stem, the inductor s h o ul d be p l ac e d as close as p o ss i ble to the l x pin to m inimi z e the n oi se cou p li n g in t o other circ u its. 3. since the f e ed b ack p i n and ne t w o rk is a h i gh im p ed a nce circuit the fee d back n e t w o rk sh o u ld be rout e d a w a y from the i n d u ctor. t he feedback pin a nd fe e d ba ck ne t w o rk sh o u ld b e sh i e l d ed w ith a gro u nd p l a n e o r trace to min i mize n o ise co u p li n g into t h is circuit. 4. a star grou n d con n ecti o n o r grou n d p l ane minimi z e s gr ou nd shifts and n o i s e is recomm en ded.
high efficiency 1.5mhz, step up regulator EC9211 e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 15 o f 15 3g24n - rev.p001 package information s o t23 - 6 p ack a ge out l ine dimensions

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