www .belling.com.cn v1.1 1 BL9309 5 .5 v 2 . 0 a 1 .3 m h z synch r o n o u s bu c k con v e r ter ge n er a ti o n de s cr i pti o n t he BL9309 is a hig h - e f fici en c y , d c - t o - d c ste p - d o w n s w it c h i n g re g u l at o rs, ca p a b le o f d elivering up to 2 a o f o u t p ut cur r e n t . t he d e v i ce op e r ates fr o m a n i n p ut volt a ge r a n g e o f 2 .5 v to 5 . 5 v and p ro v id e s an o u t p ut voltage f r o m 0 .6 v to vi n , m a king t he BL9309 id e al for l o w voltage p o w er c o n v e r s ions. r unni n g at a f i xed fre q u e n c y o f 1 .3 mhz all o w s t he use o f s m all e x t e r nal c o m p o ne n t s, s u c h as ce r a m ic in p ut and o ut p ut c ap s, as w ell as s m all i n d uctors, w h ile s t ill p r o v i d ing l o w o u t p ut r ip p les. t h i s l o w noise o u t pu t al o n g w i t h i t s excell e nt e f f ici e n c y achie v ed b y t he i n t e r nal s y n c h r o nous r e ctifie r , m ak in g BL9309 an ide a l green r ep lac e m e n t for la r ge p o w er c o n s u m i n g l i near r eg u l a to r s. inter nal sof t - s tart c o n t r o l cir c u i t r y r e d uc e s i n r ush curre n t. sho r t - cir c u i t a nd t h e r m a l - o verlo a d p r o tecti o n i m p r o v e s d es i gn r elia b il it y . t he BL9309 is available in a so t 23 - 6 and sot23 - 5 p acka g e. fe a tures ? hi g h e f fici e n c y : up to 9 7 % ? capa b le o f deliver i n g 2 a ? 1.3 mhz s w it c h i ng fr e q ue n c y ? no e x t e r nal s c hottky di od e n e e d ed ? l i ght - lo a d m o d e ? internal c o m p e n sation a nd s o f t - start ? c u r r e n t m o d e co n t r o l ? 0 . 6 v re f e r ence f o r l o w o u t p ut volt a ges ? l o g i c control s hutd o w n (i q < 1 u a ) ? t her m al shutd o w n a nd u v l o ? a vailable in so t 23 - 6 and sot23 - 5 applic a tio n s ? dig i tal c a m e r as ? m p 3 and mp4 p la y e r s ? set t o p b o xes ? w irel e ss and d s l m o d e m s ? usb s u pp lied devic e s in n o t e boo ks ? p o rta b le d e v i ces typical applic a tion ci r cuit pin assi g n m e n t order infor m a t ion part no package temperature tape & reel BL9309 sot23 - 6 - 40 ~ +85 3000/reel BL9309 sot23 - 5 - 40 ~ +85 3000/reel
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 2 pin descripti o n pin no symbol descripttion sot23 - 6 sot23 - 5 1 1 en enable pin 2 2 gnd ground 3 3 sw power switch output 4 4 in power supply input 5 nc not connected 6 5 fb feedback input pin abso l ute maxi m um r a ti n gs (note 1) p a r a m e t er v a lue max inp u t v o lt a ge 6 . 5 v max o p e r ati n g ju n c tion t e m p e r ature( tj ) 125 ? c ambie n t t e m p e r ature( t a) - 40 ? c C 85 ? c max i m u m p o w er d i s s ip a ti o n so t 23 - 5 400 m w sto r age t e m p e r ature( t s) - 40 ? c - 150 ? c l ead t e m p e r ature & t i m e 260 ? c, 1 0 s n o te 1 : a b solute m a ximum ra t ings i ndicate l i m i t s b e yond w h i ch d a m age to t he d e v ice m a y o c c u r . rec o mm e nd e d o p e r ating r a n ge i ndicat e s c o nditio n s f o r w h i c h t he d evice is fu n c t ional, b ut d o not gu a r antee spe c i f ic p e r f o r m ance l i m i t s. ele c tric a l c h a r acte ri s t ics state dc a nd ac elect ri cal spe c i f ic a tions u nder p a r ticu l ar te s t c o nditio n s w h i c h g u a r a n t ee spe c i f ic p e r f o r m a n c e l i m i t s. t h i s a s sum e s t h a t the d evice is w i t h i n t he o p e r at i ng r a n g e. sp e c i f icati o ns a r e not g uaranteed f o r p a r a m ete r s w here no l i m i t is g i v e n, h o w e ve r , t h e t y p ical va l ue is a go o d i n d icati o n o f d e v ice p e r f o r m a nce. recom m anded o per a ting ran g e sy m b ol ite m s v al u e unit v i n vin s u pp l y v o lt a ge 2 .5 to 5 .5 v t opt o p e r ating t e m p e r a t ure - 4 0 to + 8 5 electric a l ch a r a cteristics (no t e 2 , 3 ) ( v dd = 5 v , t a =2 5 ? c)
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 3 sim p li f ied b l ock di a gram op e r a tion des c ription the BL9309 hi g h - efficien c y s witching reg u la t o r is a s mall, simp l e, d c - t o - dc ste p - do wn c o n v e r t er capa b le of delivering up t o 2 a o f o u t p u t curre n t. the d e vice o p erates in p u l s e - width m o d u l ati o n ( pwm) at 1 . 3 mhz from a 2 .5 v to 5 . 5v in p ut v o l tage and p r o vi d es an o u tput v o ltage fr o m 0. 6 v o n , ma k ing the BL9309 id e al for o n - board pos t - r egu l a t ion ap p licat i o ns. an i n te r nal synch r o nous re c tifier imp r o v es efficien c y and eli m ina t es the t y pi c al sc h o t t ky fr e e - wh e eling dio d e . using t h e o n resi s tance o f t h e in t ernal hi g h - side mosfet to sen s e sw i tchi n g curre n ts eli m ina t es cur r ent - sense resi s t o r s , furt h e r imp r o ving eff i cien c y and c o st. l o op oper a t i on BL9309 uses a pwm cur r e n t - m o de c o n t r o l s ch e m e . an o pe n - l oo p c ompa r a t or c ompa r es the i n t eg r a te d v o l t a g e - f e edback sig n al a g ain s t the s u m o f the a mplified cur r e n t - sen s e sig n al a nd the slope c ompens a t i on r amp. a t each risi n g ed g e o f t h e i n t ernal clock, the i n t ernal hi g h - side mosf e t tur n s o n u n til the pwm c o mpa r a t o r t er m in a t es the o n c y c l e. during this o n - t i m e , cur r e n t r a m ps up th r o u gh the in d uc t o r , s o u r cing cur r e n t t o the o utp u t and st o ring ene r g y in th e in d u c t o r . the cur r e n t m o de f e edback s y s te m r egu l a te s the peak in d uc t o r cur r e n t as a fu n ct i o n o f the o utp u t v o l t a g e e r r o r sig n al. during the o f f c y c l e, the i n t ernal hi g h - side p - cha n nel mos f et tur n s o f f , and the i n t er n al lo w - si d e n - cha n nel mo s fet tur n s o n. the in d uc t o r r elea s es t h e s t o r ed ene r g y a s its cu rr e n t r a mps d o wn while s till p r ovid i ng cur r e n t t o the o utp u t. curre n t s e nse an i n t ernal cur r e n t - sen s e amplifier sens e s t h e cur r e n t th r o u g h the hi g h - side mosfet d u ring o n t i me a nd p r o d u ces a p r o p o rti o nal c u r r e n t sig n al, which i s u s ed t o sum with the s l o pe c ompens a t i o n sig n al. the su m m e d sig n al t h en is c o m pa r ed with the er r o r a mpl i fier o utp u t by the p wm c ompa r a t o r t o te rmin a t e the o n cy cle. curre n t l i mit the r e is a cy cl e - by - cy c l e cur r e n t li m it o n the hi gh - si de mosfet o f 2 . 5 a . when the cur r e n t flowing o ut o f s w e x c eeds this l i mi t , the hi g h - side m osfet tur n s o f f a n d the s ynch r o nous r e ctifier tur n s o n. BL9309 utili z es a f r eque n cy f o l d - back m o de t o p r e v e n t o v erhe a ting d u r ing shor t - ci r cu i t o utp u t c o n ditions. the d e v i ce e n t e r s f r e q u ency f o l d - back m o de when the fb v o l t a g e d r o p s bel o w 2 00 m v , limiting the cur r e n t t o 2 . 5 a and r educi n g p ow er dissip a t i o n . nor m al o p e r a ti o n r es u mes u p o n r e m o v al o f the s h o r t - ci r cuit c o n d it i o n.
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 4 sof t - s t art BL9309 has a i n t ernal s o f t - st art ci r cuit r y t o r educe s u p ply inr u sh cur r e n t d u ri n g st artup c o n d it i o ns. wh e n the d e v i ce e xits u n der - v o l t a g e l o c k o ut (uv l o), sh u t d o wn m o d e, o r r est ar t s f o l l o wing a the r ma l - o v erlo a d e v e n t, t h e l s o ft - s t art ci r cu i try s l o w l y r a mps up cur r e n t a v aila b le a t s w . uv l o a n d the r mal sh u t d o w n if in d r o ps b e l o w 2 . 5 v , the uv l o c i r cuit in h ibits sw itc hi n g. once in rises a b o v e 2. 5 v , the u v l o clea r s, and the s o ft - s t art seq u ence ac t i v a t es. the r ma l - o v er l o ad pr o t ect i o n l i mits t o t al p o w e r dissi p a ti o n in the d e vic e . when the ju n ct i o n te mp e r a tu r e ex c e e ds t j= + 1 5 0 c , a ther m al sen s o r f o r ces the d e vice i n t o sh u t d o w n , allo w ing the die t o c ool. t h e the r mal s ensor tur n s t h e d e vice o n a g ain a f t er the j u n cti o n t e m p e r a tu r e c ools by 1 5 c, r esu l ting in a p u l s ed o u tput d u ring c o n tinu o us o v erl o ad c o n d it i o ns. f o l lo w ing a the r ma l - sh u t d o w n c o n d iti o n, the s o ft - s t art s e q u ence begins.
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 5 typical o per a ting char a cteri s tics tes t ed u n der t a = 2 5 ? c , u nle s s ot h er w i se spec i fi e d
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 6
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 7 applic a tion in f orm a tion s e t t i ng outp u t v o l t a g es outp u t v o l t a g es a r e s et b y e x te r nal r es ist o r s. the fb_ th r eshold i s 0 . 6 v . r t op = r b o t [( v out / 0 . 6) - 1] i n p u t ca p a c it o r sele c t i on the in p ut c apaci t o r in a d c - t o - d c c o n v e rt er r educes cur r e n t pea k s d r a wn f r om the b a tt ery o r o ther in p ut po w er s o u r c e and r edu c es s wi t chi n g n o ise in the c o n t r o ll e r . t h e i mpedan c e o f the in p ut c apaci t o r a t the swi t chi n g f r eque n cy s h o u l d be less than th a t o f t h e in p ut s o u r ce s o hi g h - f r eq u ency s wi t chi n g cur r e n ts do not pass th r o u g h the in p ut s o u r c e. the o utp u t c apac i t o r k e eps o u tput rip p le s m a ll and ensu r es c o n t r o l - l o o p st abi l it y . the o utp u t c apac i t o r mu s t al s o h a v e l o w i m p edance a t the s wi t chi n g f r e q u enc y . ce r a mi c , p o l y m e r , and t a n t alum c apaci t o r s a r e sui t abl e , w i th c e r amic e x hi b iting the l o wes t e s r and hi g h - f r eque n cy i mpedan c e . outp u t ripple w i th a c e r a m ic o utp u t c a p aci t o r is ap pr o xi m a t ely a s f o l l o w s: v r ipple = i l(p e ak ) [1 / ( 2 x f osc x c o u t )] if the c apaci t o r has sign i fi c a n t e sr, the o u tput ri p ple c o m p o ne n t due t o c apaci t o r e sr is as f o l l o w s: v r ipple( e s r ) = i l(p e ak) x e sr outp u t cap a c i t or a nd i n d u c t or s e lec t ion f o l l o w the be l ow t able f o r i n d uc t o r and output c ap se l ect i o n: v out 1.2v 1.5v 1.8v 2.5v 3.3v c out 33 ? f 33 ? f 22 ? f 22 ? f 10 ? f l 1.5 ? h 1.5 ? h 2.2 ? h 3.3 ? h 4.7 ? h if much s maller v alu e s a r e used, in d uc t o r cur r e n t ris e s, and a la rg er o u tput c ap a ci t ance m a y b e r equi r ed t o su p p r ess o utp u t rip p le. la r g er v al u es than l i de a l c an be used t o o b t ain hi g her o u tput cur r e n t, b u t t ypi c al l y with la r g er ind u c t o r si z e. l a y o u t guideline l a y o u t is criti c al t o achi e v e clean and s t able o pe r a ti o n. t h e sw it chi n g p o w er s t a g e r equi r es partic u l ar a tt e n t i o n. f o ll o w these gui d elines f o r g oo d p c bo a r d l a y o u t : 1) place d e c o u p ling c apaci t o r s as c l o se t o the i c as p o ss i b l e 2) connect in p ut and o ut p ut c apaci t o r s t o the s a me p o w er g r o u n d node with a s t ar g r o u n d c o n fig u r a tion then t o ic g r o u n d. 3) k eep the hi g h - cur r e n t p a t hs as short and wide as possib le. k e ep the p a th o f s wi t chi n g cur r e n t ( c1 t o i n and c1 t o g n d) s h o rt. a v o i d vias in the swi t chi n g p a ths. 4) if possible, c o n n e ct i n , s w , and gnd sepa r a t e l y t o a la rg e c o p p er a r e a t o h elp c oo l the ic t o furt h e r imp r o v e e f f i cien c y and l o n g - t erm r eliabil i t y . 5) ensu r e all f eedba c k c o n n e cti o ns a r e s h o rt and di r ec t . pl a ce the f eedback r esi s t o r s as c l o se t o the ic a s possible. 6) r o u t e hig h - speed s wi t chi n g nodes aw a y fr om s ensiti v e analog a r ea.
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 8 l p a ck a ge out l ine s y m b ol s o t2 3 - 6 m i l l i m e t e r s i nc h e s m in m ax m in m ax a 1 . 0 5 0 1 . 2 5 0 0 . 0 4 1 0 . 0 4 9 a 1 0 . 0 0 0 0 . 1 0 0 0 . 0 0 0 0 . 0 0 4 a 2 1 . 0 5 0 1 . 1 5 0 0 . 0 4 1 0 . 0 4 5 b 0 . 3 0 0 0 . 4 0 0 0 . 0 1 2 0 . 0 1 6 c 0 . 1 0 0 0 . 2 0 0 0 . 0 0 4 0 . 0 0 8 d 2 . 8 2 0 3 . 0 2 0 0 . 1 1 1 0 . 1 19 e 1 . 5 0 0 1 . 7 0 0 0 . 0 5 9 0 . 0 6 7 e1 2 . 6 5 0 2 . 9 5 0 0 . 1 0 4 0 . 1 16 e 0 . 9 5 0 t y p 0 . 0 3 7 t y p e1 1 . 8 0 0 2 . 0 0 0 0 . 0 7 1 0 . 0 7 9 l 0 . 7 00 ref 0 . 0 28 ref l 1 0 . 3 0 0 0 . 6 0 0 0 . 0 1 2 0 . 0 2 4 0 8 0 8
BL9309 5 .5 v 2 . 0 a 1 . 3 mhz s y nch r o n o us buck co n v erter www .belling.com.cn v1.1 9 package sot23 - 5 devices per reel 3000 unit mm package specification
|
