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december 2010 doc id 13496 rev 2 1/25 1 L9777 lo w po w e r v o ltage regulator features op er at ing dc sup p ly vo lta g e r ang e 5. 6 v to 31 v lo w cu rren t con s um pti o n (110 a typ @ i ou t = 0) hig h pr e cisio n ou tp ut vo lta g e ( 2 %) lo w dr op ou t volt age vdd t r a c king r e g u la to r swit chab le on /o ff by vdd _ en pin re se t c i rc uit se ns ing th e o u t p u t v o lt ag e do wn to 1 v. do u b le r e se t fu nc tion ad jus t a b le r e s e t th re sh old exte rn al ca pacit or t o set nm i/ re se t po wer u p de lay a n d wat chd og f r e que ncy o v e r t e m p er at ur e pr ot ec tio n wid e t e m p er at ur e r a n g e (t j = - 40 c t o 1 50 c) sh or t circ uit pr oo f suit ab le fo r us e in a u t o mo tiv e e l ec tr on ics description th e l9 777 is a mo nolit hi c int e g r at ed lo w d r o p r e g u lat o r wh ich ca n su pp ly up t o 2 00 ma, a v a ilab l e in t h e p o wer sso -1 2 pa c ka g e . i t is desig ned t o sup p ly m i cr op ro ce sso r syst ems u nde r se v e r e cond iti ons of a u t o mo t i v e ap p licat ion s an d th er ef or e eq u i pp ed w i th a ddit i on al pr ot ect i on f u n c t i on s a gain s t o v er lo ad, sh or t cir cu i t a n d o v er te m p e r at ur e . o f cour se th e l9 777 ca n also be u s e d in ot he r ap p licat ion s wh er e a regulated v o ltage is re qu ir ed . powersso-12 (exp os ed di e pa d) t ab l e 1. de vi ce s u mmary or der code p a c k a g e p ac k i ng l 9777 a p o w ersso-12 t ra y l 9777 b p o w ersso-12 t ra y l9 777 b1 3tr p o w ersso-12 t ap e and ree l l9 777 c p o w ersso-12 t ra y www.st.com http://
contents L9777 2/25 doc id 13496 rev 2 contents 1 b loc k diagrams and pins configur ation . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 1 b loc k diag r a m (opt ion a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 2 o ption b f eatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1. 3 o ption c f eatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 a bsolute maxim u m ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3 functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3. 1 v oltage re gula tor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3. 2 r eset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3. 3 n mi and reset dr iv er dela y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.4 r eset adjustab le threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3. 5 w atchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4 vdd regulated v o lta g e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5 vdd_lo w (option c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 6 d e v ice options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6. 1 o ption a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6. 2 o ption b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 6. 3 o ption c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7 e lectrical and thermal c haracteristics . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8 p ac ka g e inf o rm ation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 9 r e v ision histor y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
L9777 list of tables doc id 13496 rev 2 3/25 list of tab l es tab l e 1. de vice su m m a r y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 tab l e 2. pin de sc rip t io n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 tab l e 3. abs o lu te m a xim u m r a t i ng s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 tab l e 4. elec tr ical an d th er m a l ch ar ac ter i stic s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 tab l e 5. re visio n his t o r y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4
list of figures L9777 4/25 doc id 13496 rev 2 list of figures figu re 1 . bloc k d i a g r a m ( o p t io n a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 figu re 2 . pac k a g e p i n co nf igu r a t io n (o pt ion s a a n d b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 figu re 3 . bloc k d i a g r a m ( o p t io n b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 figu re 4 . bloc k d i a g r a m ( o p t io n c) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 figu re 5 . pac k a g e p i n co nf igu r a tio n (o pt ion c ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 figu re 6 . vcc ve rsu s ou tp ut cu rr e n t ivcc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 figu re 7 . filter t i me b e t w e e n vc c a n d n m i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 figu re 8 . re se t tim e d i ag ra m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 figu re 9 . filter t i me b e t w e e n nm i an d res e t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 figure 10. r eset and nmi drivers fall time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 figu re 1 1 . r e sist o r d i vide r to a d ju st th e un d e r vo lta g e t h r e s h o l d . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 4 figu re 1 2 . w a t ch do g tim i n g wav e f o r m s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5 figu re 1 3 . v dd_ l o w filte r tim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 7 figu re 1 4 . p ow er sso -1 2 me ch a n ic al d a t a a n d p a c kag e d i me n sio ns . . . . . . . . . . . . . . . . . . . . . . . . . 2 3
L9777 block diagrams and pins configuration doc id 13496 rev 2 5/25 1 bloc k dia g rams and pins configuration 1. 1 bloc k dia g ram (option a) figu re 1. bloc k dia g ram ( opt ion a) 1. 2 option b f e atures vdd can sust ain sho r t to 40 v reg a r d le ss of vi bat t e r y v o lt ag e current capability of vdd scaled do wn to 50 ma wi th dropout of 1.5 v (max .) i n def au lt con d it ion , vdd an d wd f unct i on s ar e disa b l e d using 2 p u ll do wn curr en t o n vdd_ en an d wd_ e n pin sta n d b y cu rr en t consu m pt ion r e d u ced t o 10 0 a (t yp . ) figu re 2. p a c k a g e p i n c onf igu r at io n (op t ions a and b) wa tc h d o g vi vbatt wd d c d ti m i ng nmi wd_ en gnd vc c c vcc ivc c = 200ma vol tag e re f e r e n c e low vo l t ag e re set st a r t u p 3r r vo f f + _ 1. 2 6 v reset iwd _en radj delay vd d_e n vd d rnmi r r ese t rw d v d c timing ivd d =10 0 ma c vdd vm u x th 10 ivd d_en vc c reset nmi d vdd_en wd wd_en vi timing vcc vdd gnd radj 1 3 2 4 5 6 10 9 8 7 11 12 pinconfa_b
block diagrams and pins configuration L9777 6/25 doc id 13496 rev 2 figu re 3. bloc k dia g ram ( opt ion b) figu re 4. bloc k dia g ram ( opt ion c) 1. 3 option c f e atures vdd can sust ain sho r t to 40 v reg a r d le ss of vi bat t e r y v o lt ag e current capability of vdd scaled do wn to 50 ma w i th dro pout of 1.5v (max.) i n def au lt con d it ion , vdd an d wd f unct i on s ar e disa b l e d using 2 p u ll do wn curr en t o n vdd_ en an d wd_ e n pin doub le reset function remo v e d and pin reset used to detect un der v oltage condition on vdd regulated v o ltage (vdd _lo w pin) watchdog vi vba t t wd d c d ti m i n g nmi wd _ e n gnd vcc c vcc i v cc =200 ma vol t ag e r e fe renc e low voltage reset start up 3r r voff + _ 1. 26 v reset iwd_en radj delay vdd_en vd d rnmi rreset rwd v d c timing ivdd= 50 ma c vdd vmuxth 10 ivdd_en watchdog vi vba tt wd d c d nmi wd _e n gn d vcc c vcc i v cc= 200m a vo ltage r e fe renc e low voltage reset start up 3r r voff + _ 1.26v vdd_low iwd_en radj vdd_en vdd rnmi rvdd_low rwd v d ivdd = 50ma c vdd vmuxth 10 ivdd_en low voltage reset 300mv
L9777 block diagrams and pins configuration doc id 13496 rev 2 7/25 figu re 5. p a c k a g e p i n c onf igu r at io n (op t ion c) t a b l e 2. pin des c ript io n pin# i/o n ame f unction 1 o reset/vdd_lo w option a & b : reset output. this pin i s set lo w if n m i outpu t goe s l o w f o r adju stab l e filter ti me opt i o n c: vdd_l o w outpu t this pin i s set lo w when u nder v o ltag e on vdd is detected 2o n m i no n ma ska b le i n t e rr up t ou tp ut this pin is set lo w when lo w v o ltage on vcc is de te cted o r frequ ency of w d si gnal is too lo w . 3i d n m i/ re set po w e r up de l a y . exter nal cap on this pi n se ts the ti me re sp onse of th e vc c l o w v o ltage de te ctor and the time re spon se of the w a tchdo g mo nitor . 4 i vdd_en vdd con t rol . opt i o n a: if th is p i n is lo w vdd output v o ltag e is n o t a v ail a b l e (con nect this pi n to vcc or left floa ti ng to s witch on vdd outpu t v o ltage) option b & c: if this pi n is l o w o r le ft fl oating vdd ou tp ut v o ltage is n o t a v ail a b le (co nnect this pin to vcc to s witch on vdd regulator) 5i w d w a tch dog in put. if the fre que ncy a t this inpu t pi n is too lo w , the nmi ou tp ut is activ a te d lo w 6i w d _ e n w a tch dog functio n e nab le/disa b le opt i o n a: if th is p in is lo w th e w a tchdog functio n i s d isab l ed, i f connected to vc c o r le ft fl oating the w a tchdo g fu ncti on is en ab l ed. option b & c: if thi s pi n is l o w o r floa ti ng, the w a tchd og function i s d i sab l ed, if con nect ed to vcc th e w a tchdog function i s en ab l ed. 7i v i inpu t v ol t a ge blo c k to gnd wi th a cap a citor o f v a l ue at l east 1 00 nf vdd_low nmi d vdd_en wd wd_en vi n.c. vcc vdd gnd radj 1 3 2 4 5 6 10 9 8 7 11 12 pinconfc
block diagrams and pins configuration L9777 8/25 doc id 13496 rev 2 8i t i m i n g option a & b: re set filt er time exter nal cap on thi s pi n se ts the del a y time betw e en nmi an d reset output opt i o n c: not used an d sh oul d be left floa ti ng or shor ted to g r oun d. 9o v c c v o l t a ge regu lator output exter nal cap cvcc 220 n f is need ed to stab iliz e the regu lator 10 o v d d vdd output re gul ate d v o ltag e s witched o n /off b y vdd_en pin . exter nal cap cvdd =10 0 n f is nee ded to sta b ili z e the regu lator 1 1 gnd g round 12 i r ad j vcc un der v o ltag e thre sh old adj u stme nt by conne ctin g th is p i n to a n e xter n a l re si sto r di vider vs . vcc , is po ssib l e to set the vcc un der v o ltag e thre shold . if this pi n is conne cte d to gnd the un der v o l t ag e th reshol d is set b y int e r n al c i rcuit. t a b l e 2. pin des c ript io n ( c on tin u ed ) pin# i/o n ame f unction
L9777 absolute maximum ratings doc id 13496 rev 2 9/25 2 absolute maxim u m ratings t a b l e 3. abs o l u te ma xi m u m rat i ngs sym b ol p a rame ter m in. m ax. u n it in pu t v o ltag e vi v vi v o ltage -0.3 40 v i vi current inter n al li mi te d vcc v vcc v o ltage -0.3 5 . 5 v i vc c current inter n al li mi te d nmi v nm i v o ltage -0.3 vc c+0.3 v i nmi current inter n al li mi te d d v d v o ltage -0.3 vc c+0.3 v current inter n al li mi te d radj v radj v o ltage -0.3 vc c+0.3 v i radj current inter n al li mi te d wd v wd v o ltage -0.3 vc c+0.3 v i wd current inter n al li mi te d wd_ e n v wd _ e n v o ltage -0.3 vc c+0.3 v i wd _ e n current inter n al li mi te d vdd_en v vdd_en v o ltage -0.3 vc c+0.3 v i vdd_en current inter n al li mi te d reset v reset v o ltage -0.3 vc c+0.3 v i reset current inter n al li mi te d
absolute maximum ratings L9777 10/25 doc id 13496 rev 2 ti mi ng vi + 0.3 (op t. a) 40v (op t . b) not connecte d (opt. c) v tim i ng v o ltage -0.3 - v i ti mi ng current inter n al li mi te d vdd v vdd v o ltage -0.3 v i + 0.3 ( o pt. a) 40v (opt. b) 40v (opt. c) v i vd d current inter n al li mi te d te m p e r a t u r e t j j unction tempe r ature - 4 0 150 c esd v o lta g e le vel v es d hbm-mil std 88 3c -1.5 1 . 5 k v t a b l e 3. abs o lute ma xim u m rat i ngs (c ont in ue d) sym b ol p a rame ter m in. m ax. u n it
L9777 functional description doc id 13496 rev 2 11/25 3 functional description 3. 1 v o lta g e regulator th is d e vice su pply an a l w a ys a c t i v e 5 v re gula t ed v o lt ag e on p i n v cc w i th a cu rr en t cap abil i ty up t o 20 0 ma. v cc v o lt a ge ha s a n accu r a cy o f 2 % o v er a wid e supp ly v o lt ag e (v i = 5. 6 v t o 3 1 v) and te mpe r at ur e r a n g e ( t j = -4 0 c to 1 5 0 c ) . a sh o r t c i rc uit pr ot ec tio n t o gn d is pr o vid ed ( se e fi gur e 6 ). by m ean s of t r a c kin g re gula t o r , it is a v aila b l e a secon d o u t p u t re gul at ed v o lt ag e o n pin vdd with a current capability up to 50m a. this regulated output is s witchab le on/off b y e xter n al pin vd d_en. figu re 6. vcc v e r s us o u tput cu rren t ivcc 3. 2 reset th e re set cir c u i t mo nit o r s t he o u t put v o lt ag e vcc . i n case of int e r nal r e set t h r e sho l d, if t he o u t put v o lt ag e st a ys low e r t h a n vccun f o r a filt e r tim e trr, t hen nmi goe s lo w . th is f ilt er t i me d epe nd s on t h e dista n ce be tw ee n th e vcc ou tp ut a nd t h e u nde r v o lt ag e reset threshold (vccu n): this so lu tio n incre a ses t h e n o ise imm uni ty o f t he v o lt ag e reg u la to r b e - c a u se th e f ilte r t i me be tw ee n th e re se t e v e n t and t h e f a lling of nmi o u t put ch an ges a c cor d in g to th e dep t h of spik e on ou tp ut v o lt age ( see f o llo wing p i ct ur e) . a minim u m filt er tim e of 1 s ( t rr1) is gua r a n t e ed if vcc goe s d o wn t o 2. 5 v and v s > 5. 6 v . figu re 7. f i lte r time be twe e n vcc a nd nm i o t h e r w ise , in ca se o f e xt e r nal r e set t h r e sho l d f i x e d b y me ans of e xte r n a l r e sist or di vid e r o n p i n radj , t h e r e is only a const ant f ilte r t i me (t rradj) of 1 s mi n v a lue . vcc vccref ivcc ishort ilim vcc nmi tr r1 vcc nmi v1 tr r2 v ccu n 2.5v
functional description L9777 12/25 doc id 13496 rev 2 i n bo th ca se s , if th e ou tp ut v o lta ge vcc b ecome s lo w e r t han 2. 0v (t yp ) t ha n nm i ma y go imm edi at ely lo w wit h out an y d e la y . th e nmi lo w sig nal is gua r a n t e ed f o r a n ou tp ut v o lta g e vcc g r ea te r t han 1 v . when vcc returns o v er vccu n thres h old nmi goes high with a filter time trd . this time is obtained b y 127 per i od of an oscillator with an additional initia l time . the os cillator per i od is g i v en b y : wh er e: i c r = 2 0 a (t yp ) is a cu rr ent int e r nally ge ner at ed, i d r = 2 0 a (t yp ) is a cu rr ent int e r nally ge ner at ed, vdu = 1. 24 v an d vdrl = 0 . 62 v ar e two typ i ca l in te r n al th re sh old s , cd is t h e e x te r n a l ca pacit an ce o n pin d . trd is giv e n b y: trd ( s ) = t0 + 127 x t o sc = 0. 62 *10 - 3 + 7. 87 4* 1 06 * cd ( t yp ) where t0 is the initial r a mp betw een 0 v and vdu as in f i gur e 8 . figu re 8. res e t t i me dia g ram i f nmi out pu t g oes to 0 v f o r f ilt er time tresdf (wh i ch is fix e d b y e xte r n al ca p on t i mi ng pin) also the r eset signal goes to 0 v . re s e t lo w signal is guar a nteed f o r vcc > 1 v . figu re 9. f i lte r time be twe e n nmi a nd reset to sc vdu v drl ? cd ? >@ irc --------------- ----------------- ----------------- --------- - vdu v drl ? cd ? >@ ird --------- ----------------- ----------------- --------------- - + = trr < t r r t rd = t 0 + 127 tos c tosc trd = t0 + 127 tosc tosc vdu vdrl nmi vd vcc r run vcc u n res e t tr esd f tresdr trr < tresdf < tr esd f tr esd f vtimin g vb gap trd = t0 + 127 to s c nmi reset < t re s df tresdf nmi reset < tresdf tresdf
L9777 functional description doc id 13496 rev 2 13/25 3.3 nmi and reset driver dela y nmi and reset pins are dr iv en b y bipolar tr ansistor with a maxi m u m current capability inter n ally limited of v a lue r e spe c t i v e ly inmi l an d i r esl. f o r this reason, when the dr iv ers are activ a te d, the capacitor s present on pin nmi or r eset a r e d i scha rg ed wit h co nst ant cu rr en t. the w a v e f o r m on o u t p u t pin is a v o lt ag e r a mp wit h a slop e line a r l y d e p end ent on e x t e r n a l cap a cit ance . th e f a ll tim e nee de d b y dr iv er s t o d i scha rg e e xt e r n al ca pa cit o r ca n be calcula t e d in f i rst a ppr o xima t io n using t h is e xpr ession. wh er e v is t h e v o lt a ge dif f er ence b e t w ee n 90 % a nd 10 % o f t o t a l v o lt ag e s w in g of th e tr an sit i on , ce x t is th e to ta l p i n c a p a cita n c e a nd ilim is the current lim it at ion o f t he dr iv e r ( i resl an d i n m i l ) . figure 10. r eset and nmi driver s fall time t fa ll v c ex t ? () i lim - ---- ---- ---- --- ---- ---- ---- - = r e set ( v ) ti me (s) 5 90% vsw 10% vs w vsw tfall vresl
functional description L9777 14/25 doc id 13496 rev 2 3. 4 reset adjustab le threshold th e un der v o lt age t h resh old v a lu e (vccun) can b e set b e t w e en 0. 7vcc ( t yp .) and 0. 96 vcc (t yp ) b y c o n n e c t i ng e x te r n a l re sist or d i vider to radj pin (see fig u r e 11 ). this f e a t u r e can be used wit h micr opr ocessor s t hat gu ar a n t ee a saf e op er a t io n with sup p ly v o l t a ge lo w e r t han in t e r n al re se t t h r e sho l d. t he calcula t io n of th is t h r e shol d is giv e n b y : vcc un_e x t = vrad jth (1+ r 1/r2) (neglec t ing radj input c u rrent) whe r e : vradjth=1. 2v (t yp) a nd vccun_e x t is t h e r e set th re sh old. i f t h is f e at ur es is no t n eed ed, radj pin ha s t o be co nne ct ed to g n d , in t h is ca se th e in te r n a l und er v o lta ge t h r e sho l d v a lue is 0. 94 *vcc (t yp . ) . fi gu re 11 . r es is to r div i d e r t o a d j u st the u nder v o l t a g e thr esh ol d 3. 5 w a tc hdog th e w a tchd og in put wd mon i t o rs a conn ect ed micro cont r o ller . if pulse s ar e missing, th e o u t put nmi is se t t o lo w . the m i nim u m wd fr eq uen cy to a v oi d rese t e v e n t can be set wit h th e e x ter n al ca pa cito r cd . t h e w a tc hd og c i rcu i t ch ar ge s a n d dis cha r g e s t h e c a p a c i to r c d with the constant currents iw c and iwd , c o un ting the n u mber of os cillations as f o r tr d dela y ti me . if no r i s i ng edge is sensed on pi n wd betw een 48 os cillation per iods (tw o p - tw o l , t i me a to b in figu re 1 2 ), a w a t ch d o g re se t is g e n e r a te d. t o pr e v en t t h is re se t the micr ocon tr olle r m u st g ene r a t e a po sitiv e e dge d u r i n g th is t i me wind o w in o r de r t o re se t t h e counter . min i m u m f r e que ncy o f micr opr ocessor in pu t signa l ca n be calcula t e d using f o llo win g e qua tio n : tw o p - tw ol = 4 8 * t o sc = 2. 97 6*1 0 6 *c d s ev er y wd p o sit i v e edg e re se t s t he cou n t e r a nd ma k e s a synchr on iza t ion be tw ee n int e r n al os cillator and e xter n al w d input signal. synchr on iza t io n is r e a liz ed cha ngi ng t he cur r e n t f r om char gin g to disch a r g ing i f r i sing ed ge is detected dur i ng r i s i ng r a mp on cd (time d in f i gur e 12 ). ot her wise if r i sing e dge is detected dur i ng f a lling r a mp on cd , no curren t in v e rsion is perf or med (time e). this oper ation leads to a maxim u m error of half oscillation pe r i od on tw op - tw ol time windo w . w h en nmi goes lo w f o r w a tchdog reset, the counter will go on f o r other 16 c o unts , retur n ing to initial st at e ( t im e b t o c in fig u r e 12 ). du r i ng th is t i me (t w o l) t he nmi r e ma ins lo w and wd edg es a r e m a sk ed , so th e tw o l re se t t i me is f u lly gu ar a n t e e d . th e w a tchd og o per at ion is not act i v e only if wd_en input pin is s e t lo w . radj vcc L9777 r1 r2
L9777 functional description doc id 13496 rev 2 15/25 i n t h is case t he capa cito r cd , whe n not used f o r vcc un de r v olt a g e co nd itio n, is pulle d do wn to 0 v b y a n a c t i v e s wit ch . at t i me f w e can se e t h at du r i ng tw ol re set t i me , wd_en p i n is n o t sensed , so t h e w a t ch- d og f u n c t i on can be disab l e d only when t w ol is fin i sh ed . i n th is w a y a f u ll r e set t i me is g uar ant ee d e v en in th is con d it ion. figu re 12 . w at c hdog t i ming wa v e f o r m s 0 1 2 3 47 63 0 1 2 3 0 1 5 0 1 2 3 47 48 63 0 wd_en nmi cd 0 1 2 3 47 63 0 1 2 3 0 1 5 0 1 2 3 4 7 4 8 6 3 0 wd _en nm i cd twol twop wd counter twol twop wd coun ter c o u n t e r st a t e i s i n c r em en t e d w h en t hig h th r e sh old is re ac h e d he twol 48 osc twol 48 osc th e watc hd og d i sab le i s se nse d on ly w hen t w ol i s f i n i sc hed a b c d e f vdth h vdthl 48 osc 16 os c cu rren t in ve r s io n on cap cd no current inversion reset vdth h vdthl 48 o s c 16 os c current inversion on ca p cd no cu rr e n t in ve rs io n reset tr esdf filter time
vdd regulated voltage L9777 16/25 doc id 13496 rev 2 4 vdd regulated v o lta g e l 977 7 pr o v id es a se co nd r egu lat e d v o lta g e in t r a c kin g with vcc m a in r egu lat o r cap a b l e t o source load wit h up to 100 ma output current capability . vdd t r a c kin g re gula t or f u n c t i on is cont r o lled b y vdd_en inpu t pin . i f p i n is set high vdd v o l t a ge be comes a v a ilab l e . i f p i n is set lo w or lef t f l oa tin g re gula t o r is d i sab l ed. note that vdd regulator will be disab l e also in c a s e of under v oltage conditi on on vc c main regulator , s o at po w e r up regulator will s t ar t up only when vcc r i ses o v er under v o ltage t h r e sho l d with out trd po w e r u p de la y t i me , e v en if vdd_en pin is se t hig h .
L9777 vdd_low (option c) doc id 13496 rev 2 17/25 5 vdd_lo w (option c) vdd_lo w circu i t mo nit o r s vdd r egu lat ed v o ltage . when vd d f a lls belo w vddu n f o r a filter time tfvd d vd d_lo w out p u t v o lta ge is se t lo w . vddun is a r e f e r ence v o lta ge 30 0 mv (t yp) lo w e r than vcc regulated v o ltage . filt e r t i me tf vdd is sp ik e de pen de nt as trr1 f o r vcc r e g u lat o r so t he sam e co nside r at ion applies als o in this case . figu re 13 . v dd_lo w f i lt er t i m vdd vdd_low tfvdd11 vcc vdd_low vddun - 100mv tfv dd2 vddun 2.5 v
device options L9777 18/25 doc id 13496 rev 2 6 de vice options 6. 1 option a th is is th e sta nda rd con f i gur a t ion with vdd out pu t cap a b l e to so ur ce u p to 100 m a t o an e x t e r n a l lo ad wit h lo w dr op out (4 00 mv ma x. ) a nd do ub le re set f u n c t i o n pr o v ide d (nmi an d reset output). not e t h a t as w e can see in absolu t e se ct ion vdd and t i m i ng pin are ca pab le t o susta i n on ly sho r t to vi pin . wit h th is o p t i on in put digi ta l p i ns vdd_en and wd_en are b o t h pu lled u p b y 5 a typ cur r e n t so ur ce ( m inim u m quie s ce nt cu rr ent is 1 1 0 a typ . ). 6. 2 option b wit h th is o p t i on vdd a nd ti mi ng pins ar e bo th cap a b l e t o su sta i n sh or t t o 4 0 v reg a r d le ss o f vi bat t e r y v o lt ag e . t o pr o v id e t h is f e at ur e a ser i e s dio de is int r odu ce d bet w e en vi pin a nd vdd po w e r p m os s o urc e . in this configur atio n c u rrent capability on vd d output is s c al ed d o wn t o 50 ma while dro p o u t v o lta ge in cr ea se s t o 1. 5v (m ax). all o t h e r f e a t u r e s ar e un - changed and doub le res e t capability is mai n tained. i n op tio n b vdd_en and wd_en are bot h pu lled d o wn wit h 10 a t y p in te r n al cu rr en t sou r ce so minim u m quie s ce nt cur r ent is r edu ce d t o 100 a typ . 6. 3 option c using opt io n c vdd is ca pa b l e t o sust ain sh or t t o 4 0 v as in o p t i on b . vdd out p u t curr en t is scaled do wn to 5 0 ma and d r o pou t in cr ea se u p t o 1. 5 v ( m ax) . doub le reset f eature is remo v e d and r eset pi n is used to monitor vdd output v o ltage ( v dd_l o w p i n) . a sp ik e d epe nd ent f ilt er t i me simila r to vcc m a in re gula t o r i s p r o v ide d a nd same lo w v o ltage res e t spec ifications applie s to b i p o la r ou tp ut d r iv er (v dd_ lo w dr iv e r ) . f o r t h is rea s on ti mi ng pin is no mo re u s e d an d ca n be le ft flo a t i ng o r shor t e d t o g r oun d. no te th at nm i ou tp u t p i n be h a v e s n o r m ally a s in o p t i on a an d be co m e s th e m a in r e se t sign al f o r vcc a nd w a tchd og mo nit o r . as in opt ion b vdd_ en a nd wd_ e n a r e b o t h pulle d do wn with 1 0 a t yp in te r n al cu rr en t sou r ce so minim u m quie sce nt cur r ent is r edu ce d t o 100 a typ .
L9777 electrical and thermal characteristics doc id 13496 rev 2 19/25 7 electrical and thermal c h aracteristics v i = 5 . 6v to 3 1 v , t j = -4 0 c t o +1 50 c u n less ot her wise sp ecifie d. t a b l e 4. el ec tri c a l a nd the rmal c hara c t e ri st i c s pin s ymbol p ara m eter t e st c o ndition m in. t y p . m ax. unit gener a l vcc v c cref ou tp ut v o lt age v i = 5.6 to 31 v i vc c = 0 to 200 ma 4. 9 5 .0 0 5 . 1 v vcc i short shor t circ uit current v cc = 0 v 1 50 2 5 0 5 00 ma vcc i li m1 o u t p u t cu rre nt l i m i t a ti on 21 0 3 0 0 60 0 m a vi, vcc i qs0 c u rre nt co n sum pt ion with w a tchdog n o t a c tiv e i qs0 = i vi -i vcc op ti on a v i =1 3.5 v , i vc c = 0 ma, wd_ e n = 0 v vdd_en = 0 v (vdd disab l ed ) -1 1 0 2 2 0 a op ti on b v i = 13.5 v , i vcc = 0 ma, wd_ e n flo a ting or lo w , vdd_en floa ti ng or lo w (vdd disab l ed ) -1 0 0 2 0 0 a op ti on c v i = 13.5 v , i vcc = 0 ma, wd_ e n flo a ting or lo w , vdd_en floa ti ng or lo w (vdd reset ac tiv e ) -4 0 0 7 0 0 a i qs 20 0 c u rre nt co n sum pt ion iq s20 0 = i vi -i vcc v i = 13.5 v , i vc c = 200 m a -2 3 m a vi, vcc v dp1 dropo ut v o ltage i vc c = 2 00 ma - 2 00 4 0 0 m v vcc v li ne1 lin e re gulation v o l t a g e v i = 5.6 to 3 1 v i vc c = 0 to 200 ma -- 25 mv vcc v lo a d 1 loa d regul ation v o l t a g e i vc c = 0 to 200 ma - - 25 mv vcc svr rip ple reje cti on f r = 10 0 hz 55 - - db -t w th er ma l protecti on te mperatu r e - 1 50 - 1 90 c -t wh th er ma l protecti on te mperatu r e h ysteresis -- 1 0 - c nmi nmi v nm il nmi ou tp ut lo w v o ltage r ext = 5 k to v cc , v cc > 1 v - - 0 .4 v nmi i nmilk nmi ou tp ut le akage current v nmi = 5 v - - 1 a nmi r nmi pull up in ter nal resistance - 1 22 55 0 k
el ect ri ca l an d the rmal cha r ac ter i s t i c s L9777 20/25 doc id 13496 rev 2 nmi v ccun vcc und er v o ltage th reshol d radj = 0 v 4. 5v 0 . 9 4 vcc 0.96 vcc - radj v radjth th reshol d f o r vcc unde r v o l t ag e detection - 1 .15 1 .20 1 .25 v radj v rjm u xt h th reshol d f o r r a dj m u lt ipl e x e r co mpar a t o r - 0 .52 0 .62 0 .72 v dv d u nmi timing h i gh th reshol d - 1 .14 1 .24 1 .34 v d v d r l n mi timing lo w thresh old - 0.52 0.62 0.72 v di rc c h ar ge cu rre n t v i = 13 .5 v v d = 0.1 v 10 20 40 a di rd discha r ge current v i = 13 .5 v v d = 2.5 v 10 20 40 a nmi t rr 1 nmi spi k e d epen den t fi lt er t i me in case o f inter n al res e t threshold v cc > 2 v radj = 0v 1- - s nmi t r r adj nmi f i x e d fil t e r t i me in case of e xter nal reset th reshol d exter n al resistor divi der on radj (see fi gure 11 ). v cc > 2 v 12 . 5 5 s nmi t rd nmi po w e r up de la y v i = 13.5 v , cd= 10 nf 45 80 1 1 5 m s nmi i nmil nmi li mi ta tio n current - 5 - 25 m a reset (option a & b) rese t v res l reset outpu t lo w v o l t a g e r ext = 5 k to v cc , v cc > 1 v - - 0 .4 v rese t i reset lk reset output leakage current -- - 1 a rese t i res l reset limitation c u rr ent - 5 2 5 m a rese t t resdf reset dela y from nmi f a l ling e dge c ti mi ng = 2.2 nf 3 5 0 5 50 7 5 0 s rese t t resdr reset dela y from nmi r i sin g edge -- - 1 s rese t r rese t pull up in ter nal resistance - 1 22 55 0 k vdd_lo w (option c) vdd_ lo w v v d d _low l reset outpu t lo w v o l t a g e r ex t = 5 k to v cc , v cc > 1 v - - 0 .4 v vdd_ lo w i vdd _low lk reset output leakage current -- - 1 a vdd_ lo w i vdd_ low l reset limitation c u rr ent - 5 - 25 ma vdd_ lo w r vdd_l o w pull up in ter nal resistance - 1 22 55 0 k t a b l e 4. el ec tri c a l a nd the rmal c h ara c t e ri st i cs ( c ont i n ued) pin s ymbol p ara m eter t e st c o ndition m in. t y p . m ax. unit
L9777 electrical and thermal characteristics doc id 13496 rev 2 21/25 vdd_en vdd_en v vddthl vdd_en in put l o w th reshol d -- - 0.30 v cc v vdd_en v vddt hh vdd_en in put h i gh th reshol d - 0.70 v cc -- v vdd_en v vddhy vd d _ en h yst er esi s - 2 0 0 50 0 8 0 0 mv vdd_en i vd d _ e n pull up cur r ent option a - 2. 5 5 1 0 a vdd_en i vd d _ e n pull do wn current op ti on b a nd c - 5 10 20 a vdd (option a) vdd , vcc d iffvr ou tp ut v o l t ag e d iff erence betw een vdd an d vcc i vd d =1 to 100 ma -25 - 25 mv vdd i li m2 vdd outpu t limitation current - 1 10 2 0 0 4 00 ma v i,vdd v dp2 dropo ut v o ltage i vd d = 1 00 m a - 2 0 0 40 0 m v vdd v li ne2 vdd lin e re gula t i on vo l t a g e v i = 5.6 to 31 v i vd d = 1 to 100 ma -- 2 5 m v vdd v lo a d 2 vdd loa d re gul ati on vo l t a g e i vd d = 1 to 100 ma - - 25 mv vdd (option b) vdd , vcc d iffvr ou tp ut v o l t ag e d iff erence betw een vdd an d vcc i vd d = 1 to 50ma v i = 6 . 6 to 31v -25 - 25 mv vdd i li m2 vdd outpu t limitation current v i = 6.6 to 3 1v 55 1 00 2 40 m a v i,vdd v dp2 dropo ut v o ltage i vd d = 5 0ma; v i = 6. 6 to 3 1 v - - 1 .5 v vdd v li ne2 vdd lin e re gula t i on vo l t a g e i vd d = 1 to 50ma v i = 6 . 6 to 31v - - 25 mv vdd v lo a d 2 vdd loa d re gul ati on vo l t a g e i vd d = 1 to 50ma v i = 6 . 6 to 31v - - 25 mv t a b l e 4. el ec tri c a l a nd the rmal c h ara c t e ri st i cs ( c ont i n ued) pin s ymbol p ara m eter t e st c o ndition m in. t y p . m ax. unit
el ect ri ca l an d the rmal cha r ac ter i s t i c s L9777 22/25 doc id 13496 rev 2 vdd (option c) vdd , vcc d iffvr ou tp ut v o l t ag e d iff erence betw een vdd an d vcc i vd d = 1 to 50 ma v i = 6.6 to 3 1 v -25 - 25 mv vdd i li m2 vdd outpu t limitation current v i = 6.6 to 3 1 v 5 5 1 00 2 4 0 m a v i,vdd v dp2 dropo ut v o ltage i vd d = 5 0 ma; vi = 6. 6 to 3 1 v - - 1 .5 v vdd v li ne2 vdd lin e re gula t i on vo l t a g e v i = 6.6 to 3 1 v i vd d = 1 to 50 ma -- 2 5 m v vdd v lo a d 2 vdd loa d re gul ati on vo l t a g e i vd d = 1 to 50 ma v i = 6.6 to 3 1 v -- 2 5 m v vdd v ddun vdd und er v o ltage th reshol d v i = 6.6 to 3 1 v v cc - 4 00 v cc - 30 0 v cc - 20 0 mv vdd t fvd d vdd spik e de pend ent und er v o ltage filter ti me vdd transi t io n from 5 v to 4 v 1 - - s wd wd v wdt h h in put high v o ltage - - - 0. 3 v cc v wd v wd thl in put lo w v o ltag e - 0. 7 v cc -- v wd v wdhy wd in put h ysteresis - 2 50 5 0 0 8 00 mv wd r wd pull do wn re sisto r - 1 5 3 5 8 0 k di wd c c h ar ge cu rre n t v d = 0.1 v ; v i = 1 3 . 5 v 1 02 04 0 a di wd d discha r ge current v d = 2.5 v ; v i = 1 3 . 5 v 1 02 04 0 a dv dthl lo w thresho l d - 0.52 0.62 0.72 v dv dt hh hig h thre sh old - 1.14 1.24 1.34 v dt wo p w a tchd og per iod cd =1 0 nf 20 40 80 ms dt wol w a tchd og outpu t lo w ti me cd =1 0 nf 5 10 20 m s wd_ e n wd_ e n v we nt l wd_ e n i npu t lo w vo l t a g e -- - 0.30 v cc - wd_ e n v went h wd_ e n i npu t hig h vo l t a g e - 0.70 v cc --- wd_ e n v wenhy wd_ e n i npu t h ysteresi s - 2 00 5 0 0 8 00 mv wd_ e n i wd_en pull up cur r ent option a - 2. 5 5 1 0 a wd_ e n i wd_en pull do wn current op ti on b a nd c - 5 10 20 a t a b l e 4. el ec tri c a l a nd the rmal c h ara c t e ri st i cs ( c ont i n ued) pin s ymbol p ara m eter t e st c o ndition m in. t y p . m ax. unit
L9777 package information doc id 13496 rev 2 23/25 8 p a c k a g e inf o rmation i n or de r t o mee t en viro nme n t a l re qu ire m en ts , st of f e rs th ese de vices in dif f er ent g r ad es of ecop a c k ? pa c k age s , d epe nd ing on th eir le v e l of e n vir onm ent a l com p lian c e . eco p a c k ? spe c if icat ion s , g r ade d e f i nit i on s an d pr od uct sta t us a r e a v aila b l e a t : ww w . st .co m . ecop a c k ? is an st tr ade mar k . figure 14. powersso-12 mechanical data and package dimensions outline and mechanical data 7392413 a 16 12 7 gauge plane 0.25 mm sea ting plane bottom view h x 45? d c l e e h y x b a a2 c a1 k c ddd di m. mm inch mi n . t y p . ma x. m i n. ty p . m ax . a 1 .2 50 1. 620 0 . 0 4 9 0 .0 02 a1 0.0 00 0. 100 0 .0 0 0 0 .0 04 a2 1.1 00 1. 650 0 .0 4 3 0 .0 65 b 0 .2 30 0. 410 0 . 0 0 9 0 .0 16 c 0 .1 90 0. 250 0 . 0 0 7 0 .0 10 d (1 ) 4 .8 00 5. 000 0 . 1 8 9 0 .1 97 e 3 .8 00 4. 000 0 . 1 5 0 0 .1 57 e 0 .80 0 0. 03 1 h 5 .8 00 6. 200 0 . 2 2 8 0 .2 44 h 0 .2 50 0. 500 0 . 0 1 0 0 .0 20 l 0 .4 00 1. 270 0 . 0 1 6 0 .0 50 k 0 ?8 ? 0 ?8 ? x 1 .9 00 2. 500 0 . 0 7 5 0 .0 98 y 3 .6 00 4. 200 0 . 1 4 2 0 .1 65 dd d 0 .1 0 0 0. 00 4 not e: 1. d doe s no t inc lud e m o ld fla s h o r p r ot rus ion s or ga te bu r r s . m o l d fl a s h p o t r us io n s or ga te bu r r s s h a l l n o t ex - c e ed 0. 15mm (.0 06in c h ) in tot al . po w er s s o -1 2 ( e x p os ed p a d)
revision history L9777 24/25 doc id 13496 rev 2 9 re vision histor y t a b l e 5. re vi si on hi st ory date re vision desc ription of c h ang e s 10-ma y-200 7 1 in iti a l rele ase . 14 -d ec-2010 2 chan ged esd parameter v a lu es i n ta b l e 3 . mo dified se ctio n 1 .3: option c f e a t ure s on p age 6 . mo dified se ctio n 6 .3: option c on pa ge 18 . upda te d t a b l e 4 : el ectr ical and the r mal cha r acter i stics on page 1 9 . d o cu me nt st at us p r om ot ed f r o m p r e l i m i n a r y da ta to datashe et.
L9777 d o c id 134 96 re v 2 25/25 pl ea se r e ad c a re fu lly : inf or m at i on i n t hi s d ocumen t i s p r o vi ded so l el y i n co nnecti on wi th st pr oducts. s t mi cr oelect roni cs nv an d i t s su bsi d i a r i e s (? st ? ) re ser ve th e ri ght t o ma ke ch anges , co rr ec ti o ns, mo di f i c at i on s o r i m p r o vem ent s , t o t hi s d ocume nt , and t he pr oducts a nd ser vi c es de scr i bed h e r ei n at any t i me, with ou t no tic e. al l st pr odu ct s a r e s o l d pu rs ua nt to s t ? s t e r m s an d co nd it i o n s of sal e . pur c h a s e r s a r e so le l y r e s pon si bl e fo r t h e c hoi c e , se le ct i o n an d us e o f th e s t pr od uc ts an d s e r v i c e s d e s c r i b e d he re in , and st as s u m es no li a b i l i t y wh at so ev er r e l a t i n g t o t h e cho i ce, se le ct i o n o r u se o f t h e s t pr odu ct s a nd s e r v i c e s de sc ri be d he re in . no l i c e nse , e x p r e s s o r i m pl i e d , b y e s t o p pel or ot he rw is e, t o an y i n t e l l e c t u a l pr op er ty ri gh t s i s gr an te d u nde r t h i s doc ume n t . i f an y pa rt of t h i s do cume n t re f e r s t o an y t h i r d pa rt y p r o duc t s or se rv ic es i t sh al l n o t be d e e m ed a li ce ns e gr an t b y st fo r t h e use of su ch t h i r d par ty pr od uc ts or ser vi c es, or an y in t el l e ct ual p r o per t y c ont a i n ed t her e i n or con si dered as a war r ant y c over i n g t he u se i n a ny manner w hat s oev er o f su ch th i r d p a r t y pr od uct s o r se rv i ces or a n y i n t e ll e c t u a l pr op er t y co nt ai ne d t her ei n . unle ss o t her w ise se t for t h in s t ?s t e rms and co nditions o f sa le s t disc laims an y ex pres s or imp l ied warrant y wit h r espe ct to th e use and/or sa le of st p roduct s in cluding withou t limit ation imp l ied warrant ie s of merch antab il it y, fitne ss f or a parti cul ar p urpos e (and t heir e quivale nts under the laws of any j urisdiction), o r inf rin gement o f any pat e nt, copy right or oth e r in tel lect ual pro pert y rig ht. unle ss e xpre ssly appr oved in writing b y an aut horized st re pres enta tive, st p roduct s are not reco mmended , author iz ed or warrant ed f or us e in milita ry, air cra ft, sp ace, l i f e sa ving, or l i f e su staining appl ications, nor in p roduct s or sy ste ms where failure or malf unction may resu lt in per sonal inj ury , deat h, or s eve re prop erty o r environme ntal d amage. st p roduct s whic h are not s pecified as "automo t ive grade " may only b e used in autom otive app l ications a t user?s own risk. res al e of st pr oduct s wi t h pr ovisions d i f f er ent f r o m t he s t at eme nt s and/ or t echni c al feat ur es s et f o rt h i n this d ocume nt s hal l i mme di at el y v o i d an y wa rr an t y g r a n t e d by st fo r th e s t p r o duc t or se rv i c e de scr i b e d h e r e i n a n d sh al l no t cr ea te or e x t e n d i n any man n e r wha t s o e v er, a n y l i ab il ity of st. st a nd t h e s t lo go a r e tr ad ema r k s or re gi st er ed t r ad emar ks of s t i n va ri ou s co un tr i es. in f o r m at i on i n t h i s do cu men t su pe rs ed es a nd r e p l a c e s al l i n fo rma t i o n pr ev io us ly s u p p l i e d . th e st l o g o is a re gi ste r e d tr ad ema r k o f s t m icr o e l e c t r o n i c s . a ll ot he r n a m es a r e th e pr op er ty of th ei r r e s p e c tiv e ow n e r s . ? 2 0 1 0 s t mic r o e l ec tr on ic s - a l l ri gh ts re se rv ed s t mi cr oe le ctr o n i c s gr ou p of co mp an ie s aus t r al i a - b el gi um - b r a zi l - can ada - ch ina - cz ech rep ubl i c - f i nl and - fr ance - ger m any - ho ng k ong - i ndi a - is rael - i t a l y - ja pa n - m a l a y s i a - ma lt a - mo ro cc o - p h i l i p pi ne s - si ng ap or e - sp ai n - s w ed en - swi t zer l a n d - un it ed ki ngd om - u n i t e d st at e s of amer i c a www .s t.co m

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