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AIC1642 3-pin one-cell step-up dc/dc converter features description a guaranteed start-up from less than 0.9 v. high efficiency. low quiescent current. less number of external components needed. low ripple and low noise. fixed output voltage: 2.7v, 3.0v, 3.3v, 3.7v, 4.5v and 5v. space saving packages: sot-23, sot-89 and to-92. applications pagers. cameras. wireless microphones. pocket organizers. battery backup suppliers. portable instruments. the AIC1642 is a high efficiency step-up dc/dc converter for applications using 1 to 4 nimh bat- tery cells. only three external components are re- quired to deliver a fixed output voltage of 2.7v, 3.0v, 3.3v, 3.7v, 4.5v or 5v. the AIC1642 starts up from less than 0.9v input with 1ma load. pulse frequency modulation scheme brings optimized performance for applications with light output loading and low input voltages. the output ripple and noise are lower compared with the circuits operating in psm mode. the pfm control circuit operating in 100khz (max . ) swit ching rat e result s in smaller passiv e components. the space saving sot-23, sot- 89 and to-92 packages make the AIC1642 an ideal choice of dc/dc converter for space con- scious applications, like pagers, electronic cameras, and wireless microphones. typical application circuit d1 gs s s 1 2 vout sw gnd a i c 1642-27 a i c 1642-30 a i c 1642-33 a i c 1642-37 a i c 1642-45 a i c 1642-50 c2 47 f + v ou t l1 10 0 h v in + c1 22 f one cell step-up dc/dc conv erter a n alog integrations corporation si-soft research center ds-1642p-05 010405 3a1, no.1, li-hsin rd. i , science park , hsinchu 300, taiw an , r.o.c. te l: 886-3-5772500 fa x : 886-3-5772510 www. anal og.c o m .tw 1
! ! AIC1642 ! ! ! ?! ordering information t o - 92 t o p vi ew 1 : g nd 2: v o u t 3: s w 1 2 3 1 2 3 so t - 8 9 t o p vi ew 1 : g nd 2: v o u t 3: s w pac ki n g t y pe tr : ta p e & re e l tb : t u b e bg : ba g pac kag e t y pe u: s o t- 2 3 x: s o t- 8 9 z : t o - 92 c: co m m e rci a l p: l ead fr e e c o m m er c i al o u t p u t vo l t ag e 2 7 : 2. 7v 3 0 : 3. 0v 3 3 : 3. 3v 37 : 3. 7 v 4 5 : 4. 5v 5 0 : 5. 0v a i c 1642 - x x xxxx e x am pl e: a i c 164 2- 27c x t r 2. 7v v e r s i o n, i n s o t - 89 p a c k ag e & t a pe & r e e l pa c k i ng t y pe a i c 164 2- 27p x t r 2. 7v v e r s i o n, i n le ad f r ee s o t - 89 p a c k age & t ape & r eel p a c k i ng t y pe pi n c o nf i g u r a t i o n s o t - 23 t o p vi ew 1 : g nd 2: s w 3: v o u t 1 3 2 ! part no. cx px a i c 1 6 4 2 - 2 7 a m 2 7 a m 2 7 p a i c 1 6 4 2 - 3 0 a m 3 0 a m 3 0 p a i c 1 6 4 2 - 3 3 a m 3 3 a m 3 3 p a i c 1 6 4 2 - 3 7 a m 3 7 a m 3 7 p a i c 1 6 4 2 - 4 5 a m 4 5 a m 4 5 p a i c 1 6 4 2 - 5 0 a m 5 0 a m 5 0 p sot-23 marking part no. cu pu a i c 1 6 4 2 - 2 7 g m 2 7 g m 2 7 p a i c 1 6 4 2 - 3 0 g m 3 0 g m 3 0 p a i c 1 6 4 2 - 3 3 g m 3 3 g m 3 3 p a i c 1 6 4 2 - 3 7 g m 3 7 g m 3 7 p a i c 1 6 4 2 - 4 5 g m 4 5 g m 4 5 p a i c 1 6 4 2 - 5 0 g m 5 0 g m 5 0 p sot-89 marking ! 2 !
! ! AIC1642 ! ! ! ?! absoluate maximum ratings supply voltage (vout pin) .6v sw pin voltage 6v sw pin switch current 0.6a operating temperature range -40 c to 85 c maximum junction temperature 125 c storage temperature range -65 c to 150 c lead temperature (soldering 10 sec.) 260 c ! absolute m aximum ratings are those values beyond which the life of a device may be impaired. ! ?! test circuit ! d1 gs s s 12 vo ut sw gnd a i c 1642-27 a i c 1642-30 a i c 1642-33 a i c 1642-37 a i c 1642-45 a i c 1642-50 c2 22 f + v ou t l1 100 h v in + c1 47 f i in ! v s v sw a i c1642 vo u t sw gn d i s ! fig. 1 test circuit 1 fig. 2 test circuit 2 f os c a i c1 642 v s vo u t sw gn d 10 0 ! fig. 3 test circuit 3 3 !
AIC1642 electrical characteristics (t a =25 c, i out =10ma, unless otherw i se specified) (note1) p a r a m e t e r t e s t c o n d i t i o n s test ckt symbo l m i n . t y p . max. unit output voltage AIC1642-27 v in =1. 8 v AIC1642-30 v in =1. 8 v AIC1642-33 v in =2. 0 v AIC1642-37 v in =2. 0 v AIC1642-45 v in =3. 0 v AIC1642-50 v in =3. 0 v 1 v out 2.633 2.925 3.218 3.607 4.387 4.875 2.700 3.000 3.300 3.700 4.500 5.000 2.767 3.075 3.382 3.792 4.613 5.125 v start-up voltage i out =1ma , v in :0 2 v 1 v start 0 . 8 0 . 9 v min. hold-on voltage i out =1ma , v in :2 0 v 1 v hold 0 . 7 v no-load input current i out =0ma 1 i in 1 5 a supply current AIC1642-27 AIC1642-30 AIC1642-33 AIC1642-37 AIC1642-45 AIC1642-50 v s =v out x 0.95 measurement of the ic in- put current (vout pin) 2 i s1 42 50 60 65 70 90 a supply current AIC1642-27 AIC1642-30 AIC1642-33 AIC1642-37 AIC1642-45 AIC1642-50 v s =v out + 0.5v measurement of the ic in- put current (vout pin) 2 i s2 7 7 7 7 7 7 a sw leakage current v sw =6v , v s =v out + 0.5v 2 0 . 5 a 4
AIC1642 electrical characteristics (continued) p a r a m e t e r t e s t c o n d i t i o n s test ckt symbo l m i n . t y p . max. unit s w s w it ch-on resis- tance AIC1642-27 AIC1642-30 AIC1642-33 AIC1642-37 AIC1642-45 AIC1642-50 v s =v out x 0.95, v sw =0. 4 v 2 r on 2.2 2.1 2.0 2.0 1.9 1.9 ? oscillator duty cycle v s =v out x 0.95 measurement of the sw pin waveform 3 d u t y 6 5 7 5 8 5 % max. oscillator freq. v s =v out x 0.95 measurement of the sw pin waveform 3 f os c 8 0 1 0 5 1 3 0 khz e f f i c i e n c y 1 8 5 % note 1: specifications are production tested at t a =25 c. specifications over the -40 c to 85 c operating tem- perature range are assured by design, characterizati on and correlation with statistical quality controls (sqc). 5
AIC1642 typical performance characteristics test circuit refer to typical application circuit capacitor (c2) : 47 f (tantalum type) diode (d1) : 1n5819 schottky type fig . 4 ai c 164 2-27 l oad r e g u lat i on ( l = 1 0 0 h cd 5 4 ) 0 20 40 60 80 10 0 12 0 14 0 16 0 18 0 2. 2 2. 3 2. 4 2. 5 2. 6 2. 7 2. 8 v in =2. 0v v in =1. 8 v v in =1. 5 v v in =1. 2 v v in =0. 9 v outp ut v o l t ag e (v) output c u rrent (ma) fig. 5 a i c 164 2-27 ef fici e n cy (l =100 h cd5 4 ) 0 20 40 60 80 10 0 12 0 14 0 16 0 18 0 55 60 65 70 75 80 85 v in =2. 0 v v in =1. 8 v v in =1. 5 v v in =1.2v v in =0.9v e f f i ci e n cy ( % ) ou tpu t current ( m a ) fi g. 6 ai c 1 64 2- 27 lo ad r e g u l a t i o n ( l= 47 h cd5 4) 0 20 40 60 80 100 120 140 160 180 200 220 240 2. 3 2. 4 2. 5 2. 6 2. 7 2. 8 v in =2 . 0 v v in =1 . 8 v v in =1. 5 v v in =1 . 2 v v in =0 . 9 v ou tp ut v o lt age (v) ou t p u t cur r ent (m a) 240 85 fig . 7 ai c 1 6 42- 27 ef f i cie n cy (l =47 h cd5 4) ef ficiency (%) ou tp ut c u rre nt ( m a ) 0 20 40 60 80 100 120 140 16 0 18 0 200 220 50 55 60 65 70 75 80 v in =2 . 0 v v in =1. 8 v v in =1. 5 v v in =1 . 2 v v in =0 . 9 v fig. 8 ai c16 42-2 7 s t a r t-u p & h o ld-o n v o lt age (l =47 h cd5 4 ) 0 2 4 6 8 10 12 14 16 18 0. 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 1. 0 st a r t u p hold on i nput v o lt age (v) out p ut cu rrent ( ma ) fig. 9 aic 164 2 -27 s t art- up & hold - o n v o lt age (l=100 h cd54) 0 2 4 6 8 10 12 14 16 18 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 s t art up ho l d o n i nput v o lt age ( v ) out p ut curr e n t ( ma ) 6
AIC1642 typical performance characteristics (continued) fig. 10 ai c1642-27 o u t put v o lt age vs. t e m peratur e ou tput v o lt a ge ( v ) t e mper ature ( c) -40 -20 0 20 40 60 80 10 0 2.60 2.62 2.64 2.66 2.68 2.70 2.72 2.74 2.76 2.78 2.80 fig. 1 1 aic1 642- 27 switching frequency v s . t e mperat ure swit ching fr equen cy ( k hz) t e mper ature ( c) -40 - 20 0 20 40 60 80 10 0 40 60 80 10 0 12 0 14 0 16 0 fig. 12 ai c1642-27 m a x i mum duty cyc l e vs. t e mperatur e m a ximum duty c ycle (%) t e mper ature ( c) -4 0 -20 0 20 40 60 80 10 0 70 72 74 76 78 80 fig . 13 AIC1642- 2 7 sw t u r n on resist an ce vs. t e mperat u r e sw t u r n o n resist ance ( ? ) t e mper ature ( c) -4 0 -2 0 0 20 40 60 80 100 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 fig. 14 AIC1642-27 supply cur r ent v s . t e mper a t ure supply cur r ent ( a) t e mper ature ( c) -40 -2 0 0 20 40 60 80 100 5 10 15 20 25 30 35 40 45 0 10 20 30 40 50 60 70 80 90 100 11 0 12 0 13 0 14 0 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 v in =2.0 v v in =1.8 v v in =1.5 v v in =1 .2 v v in =0 . 9 v f i g. 1 5 ai c16 42- 30 l oad re gul at io n ( l =10 0 h, cd54) outpu t v o lt age v ou t (v) ou tpu t cu rre nt (ma) 7
AIC1642 typical performance characteristics (continued) 0 20 40 60 80 100 12 0 14 0 160 18 0 50 55 60 65 70 75 80 85 v in = 2.0 v in = 1. 8 v v in = 1.5v v in = 1.2v v in = 0. 9v fig. 16 aic16 42-30 e f fic i e n cy ( l =10 0 h, cd54) e f fi cie n cy (%) outp ut cu rrent (ma ) fig. 17 ai c1642- 30 load regul ati on (l=47 h cd54) 0 20 40 60 80 100 12 0 140 16 0 180 200 220 2. 2 2. 3 2. 4 2. 5 2. 6 2. 7 2. 8 2. 9 3. 0 3. 1 v in =2 .0 v v in =1 .8 v v in =1 . 5 v v in =1 .2 v v in =0 .9 v output v o lt age (v) o u tput current (m a) 22 5 fi g . 18 aic 1 6 4 2 - 3 0 ef fi ci en cy (l =47 h c d 54) 0 25 50 75 100 12 5 150 175 20 0 50 55 60 65 70 75 80 85 v in =2 .0 v v in =1. 8 v v in =1 . 5 v v in =1 .2 v v in =0 .9 v ef ficiency (%) o u tput curr e n t (ma) 0 2 4 6 8 10 12 14 16 18 20 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 fig. 19 aic164 2- 30 s t art - up & hold - on v o lt age (l=100 h cd54) st a r t u p hol d o n input v o lt age (v) o u t put cur r ent (ma) 0 2 4 6 8 10 12 14 16 18 20 0. 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 1. 0 fi g. 20 ai c1642-30 s t ar t- u p & hold-on v o lt age ( l =47 h cd54) s t art up ho l d o n inpu t v o lt age (v) output curr ent ( m a) fi g. 21 ai c1642-30 o u t put v o lt age vs. t e m peratur e ou tput v o lt a ge ( v ) t e mper ature ( c) -40 -2 0 0 20 40 60 80 100 2. 90 2. 92 2. 94 2. 96 2. 98 3. 00 3. 02 3. 04 3. 06 3. 08 3. 10 no load 8
AIC1642 typical performance characteristics (continued) fi g. 22 ai c1642-30 swi t ch ing fr eq uency vs. t e m peratur e swit ching fr equen cy ( k hz) t e mper ature ( c) -40 - 20 0 20 40 60 80 10 0 40 60 80 10 0 12 0 14 0 16 0 fi g. 23 ai c1642-30 m a x i mum duty cyc l e vs. t e mperatur e m a ximum duty c ycle (%) t e mper ature ( c) -4 0 -20 0 20 40 60 80 10 0 70 72 74 76 78 80 fig . 24 AIC1642- 3 0 sw t u r n on resi st an ce vs. t e mperat u r e sw t u r n o n resist ance ( ? ) t e mper ature ( c) -4 0 -2 0 0 20 40 60 80 100 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 fi g. 25 AIC1642-30 suppl y cur r ent v s . t e mper a t ure supply cur r ent ( a) t e mper ature ( c) -40 -2 0 0 20 40 60 80 100 5 10 15 20 25 30 35 40 45 0 25 50 75 10 0 125 15 0 17 5 200 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 v in = 2.0v v in = 1.8v v in = 1.5v v in = 1. 2 v v in = 0.9v fig. 26 ai c1642-33 load regulatio n (l=100 h, cd54) o u tp ut v o lt age (v) output cur r ent ( m a) 0 25 50 75 10 0 12 5 15 0 175 20 0 50 55 60 65 70 75 80 85 90 v in =2 . 0 v v in = 1. 8 v v in = 1.5 v v in = 1. 2v v in = 0.9v fig. 27 AIC1642-33 ef fici ency (l=100 h, cd 54) ef f i ciency (%) o u t put cu r r ent (ma) 9
AIC1642 typical performance characteristics (continued) 0 25 50 75 100 12 5 15 0 17 5 200 225 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 fi g. 28 AIC1642-33 l oad regul ation ( l =47 h, cd54) v in = 2. 0v v in = 1.8v v in = 1.5v v in = 1.2v v in = 0.9v out put v o lt age ( v ) output cur r ent ( m a) 0 25 50 75 100 12 5 150 17 5 200 225 250 40 45 50 55 60 65 70 75 80 85 90 v in = 2. 0 v v in = 1.8v v in = 1.5v v in = 1. 2v v in = 0.9v fig. 29 AIC1642-33 ef fi cienc y ( l =47 h, cd54) e f fici e n cy ( % ) o u t put cur r ent (ma) 0 2 4 6 8 10 12 14 16 18 20 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 fi g. 30 ai c1642-33 s t ar t- u p & hold-on v o lt age ( l =10 0 h cd54) s t art up h o ld on in put v o lt age ( v ) out p u t cur r ent (ma) fig. 31 AIC1642-33 output v o l t age vs . t e mper ature out put v o lt a ge v out (v) t e mperatur e ( c) -40 -20 0 20 40 60 80 100 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 no l oad fi g. 32 ai c1642-33 swi t ch ing fr eq uency vs. t e m peratur e swit ching fr equen cy ( k hz) t e mper ature ( c) -40 - 20 0 20 40 60 80 10 0 40 60 80 10 0 12 0 14 0 16 0 f i g . 33 ai c1 64 2- 3 3 m a x i mum d u t y c y c l e v s . t e mpe r at ur e ma ximum du ty cycle (% ) t e mp er at ur e ( c) -4 0 -2 0 0 20 40 60 80 10 0 70 72 74 76 78 80 10
AIC1642 typical performance characteristics (continued) fig . 34 AIC1642- 3 3 sw t u r n on resi st an ce vs. t e mperat u r e sw t u r n o n resist ance ( ? ) t e mper ature ( c) -4 0 -2 0 0 20 40 60 80 100 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 fi g. 35 AIC1642-33 sup p ly cur r ent v s . t e mperat ure supply cur r ent i dd1 ( a) te m p erat u r e ( c ) -40 -20 0 20 40 60 80 10 0 10 15 20 25 30 35 40 45 fig . 36 ai c16 42- 37 lo ad reg u lat i on ( l =10 0 h) o u t p u t v o lt ag e (v ) out p ut cur r ent ( m a) 0 25 50 75 100 12 5 150 17 5 20 0 225 250 275 2. 4 2. 5 2. 6 2. 7 2. 8 2. 9 3. 0 3. 1 3. 2 3. 3 3. 4 3. 5 3. 6 3. 7 3. 8 v in =2 . 5 v v in =2.0v v in =1.8v v in =1.2v v in =0.9v fig. 37 ai c1 642 -3 7 ef f i cien cy ( 100 h) e f f i ci en cy (%) out p ut cur r ent ( m a) 0 25 50 75 100 12 5 150 17 5 200 225 250 40 45 50 55 60 65 70 75 80 85 90 v in =2.5v v in =2.0v v in =1 . 8 v v in =1.2v v in =0.9v fig. 3 8 aic164 2- 37 loa d re gulatio n (l =47 h) o u t p u t v o lt ag e (v ) out p ut cur r ent ( m a) 0 25 50 75 100 125 150 175 20 0 22 5 250 275 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 v in =2.5v v in =2.0v v in =1.8v v in =1.2v v in =0.9v fig . 39 ai c16 42- 37 ef f i cienc y (4 7 h) e f f i ci en cy (%) out p ut cur r ent ( m a) 0 25 50 75 10 0 125 150 17 5 200 22 5 25 0 27 5 40 45 50 55 60 65 70 75 80 85 90 v in =2.5v v in =2.0v v in =1.8v v in =1.2v v in =0.9v 11
AIC1642 typical performance characteristics (continued) f i g. 4 0 aic164 2- 37 s t ar t-up & hold- on v o lt ag e ( l =1 00 h) i n pu t v o lt ag e (v ) out p ut cur r ent ( m a) 0 5 10 15 20 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 hol d on s t ar t up fig . 41 aic16 42- 37 output v o lt age v s . t e m p er at u r e o u t p u t v o lt ag e (v ) t e mper atur e ( c) -4 0 -2 0 0 20 40 60 80 100 3. 40 3. 45 3. 50 3. 55 3. 60 3. 65 3. 70 3. 75 3. 80 3. 85 3. 90 3. 95 4. 00 no load fig . 42 ai c16 42- 37 sw itching fr eq uenc y v s . t e mp era t u re s w it c h in g fr eq ue ncy (k hz) t e mper atur e ( c) -4 0 -2 0 0 20 40 60 80 10 0 40 60 80 100 120 140 160 fig. 43 ai c1 642 -3 7 maximum dut y cy cle v s t e mper atur e max i mum du t y cy cle ( % ) t e mper atur e ( c) -4 0 -2 0 0 20 40 60 80 10 0 70 72 74 76 78 80 fig. 44 ai c1 642 -45 l oad reg u lat i on ( l =10 0 h) ou t p ut v o lt a g e ( v ) out p ut cur r ent ( m a) 0 50 100 15 0 20 0 25 0 300 350 40 0 2. 2 2. 4 2. 6 2. 8 3. 0 3. 2 3. 4 3. 6 3. 8 4. 0 4. 2 4. 4 4. 6 v in =3. 0 v v in =1.5v v in =2 .0 v v in =1 .2 v v in =0.9v fig. 45 ai c1 642 -45 ef f i cien cy ( l =10 0 h) e f f i ci en cy (%) out p ut cur r ent ( m a) 0 50 10 0 150 20 0 250 300 350 400 50 55 60 65 70 75 80 85 90 v in =3 . 0 v v in =1 . 5 v v in =2.0v v in =1 . 2 v v in =0. 9 v 12
AIC1642 typical performance characteristics (continued) fig. 4 6 aic164 2- 45 loa d r egulation (l =100 h) ou t p ut v o lt a g e ( v ) out p ut cur r ent ( m a) 0 50 100 15 0 20 0 25 0 300 350 40 0 2. 2 2. 4 2. 6 2. 8 3. 0 3. 2 3. 4 3. 6 3. 8 4. 0 4. 2 4. 4 4. 6 v in =3. 0 v v in =1.5v v in =2 .0 v v in =1 .2 v v in =0.9v fig . 47 a i c16 42- 45 s t a r t-u p & hold- o n v o lt ag e ( l =1 00 h) i n put v o l t ag e ( v ) out p ut cur r ent ( m a) 0 5 10 15 20 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 hold on s t ar t up fig . 48 ai c16 42- 45 output v o lt age v s . t e m p er at u r e ou t p ut v o lt a g e ( v ) t e m p er ature ( c) -4 0 -2 0 0 20 40 60 80 10 0 4. 0 4. 1 4. 2 4. 3 4. 4 4. 5 4. 6 4. 7 4. 8 4. 9 5. 0 no load f i g. 4 9 a i c1 64 2 - 4 5 s u pp ly cu rr en t v s . t e m p e r a t ur e su pp ly cu rr e n t ( a) te m p er ature ( c ) -40 -2 0 0 20 40 60 80 10 0 10 20 30 40 50 60 70 80 90 fig . 50 a i c16 42- 45 sw itching fr equ enc y v s . t e mpe r a t u r e s w it c h in g fr eq ue ncy (k hz ) t e mper atur e ( c) -4 0 - 20 0 20 40 60 80 100 40 60 80 100 120 140 160 fig. 51 ai c 1642 -4 5 m a x i mum duty cy c l e v s . t e m p er at u r e max i mum du t y cy cle ( % ) t e mper atur e ( c) -40 -2 0 0 20 40 60 80 100 70 72 74 76 78 80 13
AIC1642 typical performance characteristics (continued) fig. 52 aic164 2- 45 sw t u r n on re sist a n c e v s . t e mper atur e s w t u r n on r e s i st an ce ( ? ) t e mper atur e ( c) -4 0 -20 0 20 40 60 80 10 0 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 1. 8 0 50 10 0 150 20 0 25 0 30 0 35 0 400 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0 4. 5 5. 0 5. 5 v in =1 . 2 v v in =3 .0 v v in =2 . 0 v v in =1 . 5 v v in =0.9 v f i g . 53 ai c 164 2- 5 0 lo ad r e g u l a t i on ( l= 1 0 0 h cd5 4 ) o u t p ut v o lt a g e (v) ou tp ut cu rren t (m a) 0 50 10 0 15 0 20 0 25 0 30 0 35 0 40 0 20 30 40 50 60 70 80 90 10 0 v in =1 . 2 v fig . 54 ai c1 64 2-5 0 ef f i c i e n cy (l=1 0 0 h c d 5 4 ) v in =3 . 0 v v in =2 .0v v in =1.5 v v in =0.9 v ef fici e n cy (%) ou tp ut cu r r e n t (m a) 0 50 100 15 0 20 0 25 0 30 0 35 0 40 0 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0 4. 5 5. 0 5. 5 fig . 55 aic16 4 2-5 0 l o a d re g u la tion (l =4 7 h c d 5 4 ) v in =1 . 2 v v in =3.0 v v in =2 . 0 v v in =1 . 5 v v in =0 . 9 v o u tp ut v o lt ag e ( v ) out p u t curre nt ( m a) 0 50 100 15 0 20 0 250 30 0 35 0 400 4 5 50 55 60 65 70 75 80 85 90 fig . 5 6 aic16 4 2-5 0 ef f i cien cy ( l =4 7 h c d 5 4 ) e f f i cie n cy (%) ou tp ut cu rr e n t (m a) v in =1 . 2 v v in =3.0 v v in =2 . 0 v v in =1.5 v v in =0.9 v 0 2 4 6 8 10 12 14 16 18 20 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 1. 8 fi g. 57 a i c 1 64 2- 50 s t a r t - up & h o l d - o n v o l t age (l = 1 00 h cd50 ) i n pu t v o lt ag e (v ) output cu rr ent ( m a) s t ar t up ho l d o n 14
AIC1642 typical performance characteristics (continued) f i g. 5 8 aic164 2- 50 output v o lt a ge v s . t empe ra t u r e ou t p ut v o l t a g e v out (v ) t e m p er at u r e ( c) -4 0 -2 0 0 20 40 60 80 100 4. 4 4. 5 4. 6 4. 7 4. 8 4. 9 5. 0 5. 1 5. 2 5. 3 no load fig. 59 aic164 2- 50 sw it c h ing fre que ncy v s . t e mper atur e s w it c h in g fr eq ue ncy (k hz ) t e mper atur e ( c) -4 0 -20 0 20 40 60 80 100 40 60 80 100 120 140 160 fig. 60 ai c 1642 -5 0 m a x i mum duty cy c l e v s . t e m p er at u r e max i mum du t y cy cle ( % ) t e mper atur e ( c) -40 -2 0 0 20 40 60 80 100 70 72 74 76 78 80 f i g. 6 1 aic164 2- 50 sw t u r n on r e sis t anc e v s . t e mpe r a t ur e s w t u r n on r e s i st an ce ( ? ) t e mper atur e ( c) -4 0 -20 0 20 40 60 80 10 0 0. 0 0. 2 0. 4 0. 6 0. 8 1. 0 1. 2 1. 4 1. 6 1. 8 -40 -20 0 20 40 60 80 10 0 10 20 30 40 50 60 70 80 90 100 fig . 62 ai c16 42- 50 sup p ly cur r e n t v s . t e mp era t u re s u pp ly cu rre nt i dd1 ( a) t e mper atur e ( c) v ou t 50m v/di v load s t ep 50m a / div fig. 6 3 l oad t r an sient re sp ons e (l1 =100 h, c 2 = 4 7 f, v in =2v) 10m a 15
AIC1642 typical performance characteristics (continued) v ou t 20m v / di v v in 0.5v/di v fig. 64 l i n e t r a n sien t res pons e (l 1 =1 00 h, c 2 =47 f) block diagram + gn d vo ut sw 1. 25 v re f . 1m en a b l e - o s c, 10 0k hz pin descriptions pin 1 : gnd - ground. must be low imped- ance; sorer directly to ground plane. pin 2 : vout - ic supply pin. connect vout to the regulator output. pin 3 : sw ? internal drain of n-mosfet swit ch. 16
! ! AIC1642 ! ! ! ?! application information ! ! general description ! AIC1642 pfm (pulse frequency modulation) controller ics combine a switch mode regulator, n- channel power mosfet, precision voltage refer- ence, and voltage detector in a single monolithic device. they offer extreme low quiescient current, high efficiency, and very low gate threshold voltage to ensure start-up with low battery voltage (0.8v typ.). designed to maximize battery life in portable products, and minimize switching losses by only switching as needed service the load. 17 pfm controllers transfer a discrete amount of en- ergy per cycle and regulat e the output voltage by modulating switching frequency with the constant turn-on time. switching frequency depends on load, input voltage, and inductor value, and it can range up to 100khz. the sw on-resistance is typically 1.9 to 2.2 ? t o minimize swit ch losses. when the output voltage drops, the error compara- tor enables 100khz oscillator that turns on the mosfet around 7.5us and 2.5us off time. turning on the mosfet allows inductor current to ramp up, storing energy in a magnetic field. when mosfet turns off that force inductor current through diode to the output capacitor and l oad. as the stored energy is depleted, the current ramp down until the diode turns off. at this point, inductor may ring due to re- sidual energy and stray capacitance. the output capacitor stores charge when current flowing through the diode is high, and release it when cur- rent is low, thereby maintaining a steady voltage across the load. as the load increases, the output capacitor dis- charges faster and the error comparator initiates cycles sooner, increasing the switching frequency. the maximum duty cycle ensure adequate time for energy transfer to output during the second half each cycle. depending on circuit, pfm controller can operate in either discontinuous mode or con- tinuous conduction mode. continuous conduction mode means that the inductor current does not ramp to zero during each cycle. + vi n sw v ou t ex t i d i ou t is w ic o i in i pk i in v ex t i sw i out t di s char ge co. v sw dis c har ge c o . i d t discontinuous conduction mode !
! ! AIC1642 ! ! ! 18 i pk i in v ext i sw i out v sw i d t continuous conduction mode in the continuous mode, the switching fre- quency is ( ) ? ? ? ? ? ? ? + ? + ? ? + ? + ? + ? + = sw d out in d out on sw d out sw in sw d out in d out on sw v v v v v v t 1 )] v v v v v ( 2 x [1 * ) v v (v v v v t 1 f where vsw = switch drop and proportion to out- put current. ! inductor selection ! to operate as an efficient energy transfer ele- ment, the inductor must fulfill three require- ments. first, the inductance must be low enough for the inductor to store adequate en- ergy under the worst case condition of mini- mum input voltage and switch on time. second, the inductance must also be high enough so maximum current rating of AIC1642 and induc- tor are not exceed at the other worst case con- dition of maximum input voltage and on time. lastly, the inductor must have sufficiently low dc resistance so excessive power is not lost as heat in the windings. but unfortunately this is inversely related to physical size. continuous conduction mode at the boundary between continuous and dis- continuous mode, output current (i ob ) is deter- mined by minimum and maximum input voltage, output voltage and output current must be established in advance and then inductor can be selected. ) x 1 ( * t * l v * 2 1 * v v i on in out in ob ? ? ? ? ? ? ? = in discontinuous mode operation, at the end of the switch on time, peak current and energy in the inductor build according to where vd is the diode drop, l t * ) r r ( x on s on + = ? ? ? ? ? ? + ? ? ? ? ? ? ? ? + = ) t * l rs ron exp( 1 * rs r v i on on in pk r on = switch turn on resistance, r s = inductor dc resistance () ? ? ? ? ? ? ? ? ? ? ? ? ? ? 2 x 1 * t * l v on in t on = switc h on time in the discontinuous mode, the switching fre- quency (fsw) is on in t l v ? (simple loss equation), fsw = ) x (1 t v ) (i * ) v v (v * (l) * 2 2 on 2 in out in d out + ? + where l t * ) r r ( x on s on + = !
! ! AIC1642 ! ! ! e l = 2 ipk l 2 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? + ? ? ? ? ? ? ? ? ? + = 2 x 1 * t * 2l v v i * 2 x v v v v v i on sw in out sw in sw d out pk power required from the inductor per cycle must be equal or greater than valley current (iv) is ) fsw 1 ( * ) (i * ) v v (v /f p out in d out sw l ? + = ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + = 2 x 1 * t * 2l vsw v i * 2 x vsw v v v v i on in out in sw d out v in order for the converter to regulate the output. when loading is over iob, pfm controller oper- ates in continuous mode. inductor peak current can be derived from table 1 indicates resistance and height for each coil. pow e r inductor ty pe inductance ( ? 2 2 0 . 1 0 0 . 7 4 7 0 . 1 8 0 . 5 ds1608 1 0 0 0 . 3 8 0 . 3 2.9 2 2 0 . 0 8 2 . 7 coilcraft smt type (www.coilcraft.com ) do3316 4 7 0 . 1 4 1 . 8 5.2 47 0.25 0.7 sumida smt type cd54 100 0.50 0.5 4.5 47 0.25 0.7 hold smt type pm54 1 0 0 0 . 5 0 0 . 5 4.5 hold smt type pm75 33 0.11 1.2 5.0 capacitor selection most of the input supply is supplied by the input bypass capacitor, the capacitor voltage rating should be at least 1.25 times greater than a maximum input voltage. a poor choice for an output capacitor can result in poor efficiency and high output ripple. ordinary aluminum electrolytic, while inexpensive may have unacceptably poor esr and esl. there are low esr aluminum capacitors for switch mode dc-dc converters which work much well than general unit. tantalum capacitors provide still better performance at more expensive. os- con capacitors have extremely low esr in a small size. if capacitance is reduced, output rip- ple will increase. diode selection speed, forward drop, and leakage current are the three main considerations in selecting a rectifier diode. best performance is obtained with schot- tky rectifier diode such 1n5819. motorola makes mbr0530 in surface mount. for lower output power a 1n4148 can be used although efficiency and start-up voltage will suffer substantially. 19 !
AIC1642 20 component pow e r dissipation operating in discontinuous mode, power loss in the winding resistance of inductor can be ap- proximate equal to () () out out f out d on l p * v v v * r * l t 3 2 pd ? ? ? ? ? ? + ? ? ? ? ? ? = where p out =v out * i out ; r s =inductor dc r; v d = diode drop. the power dissipated in a switch loss is () () out out in d out on on sw p * v v v v * r * l t 3 2 pd ? ? ? ? ? ? ? + ? ? ? ? ? ? = the power dissipated in rectifier diode is () out out d p * v v pdd ? ? ? ? ? ? = physical dimensions (unit: mm) sot-23 0 0. 9 0 0. 3 0 1.50 2.6 0 2.8 0 0. 0 8 0. 3 0 0. 0 5 e l1 l e1 c e e1 d b a2 a1 0 . 95 bsc 8 0.6 0 1.90 bsc 0. 60 ref 1. 3 0 1. 7 0 3. 00 3. 00 0.2 2 0.5 0 0.1 5 c a a2 b wi t h p l a t i n g view b l1 l seat i ng pla n e gauge p l a n e 0.2 5 a1 s e ct i o n a- a bas e meta l e1 e aa see view b d 0. 9 5 mi n. s y m b o l a 1 .45 max. so t- 2 3 m i ll i m et er s e e1
! ! AIC1642 ! ! ! a c e1 e sot-89 21 to-92 b 0.89 l mi ll i m et e r s to -92 max. 5.33 a s y m b o l mi n . 4.32 0.47 4. 1 9 2. 6 6 1. 3 9 5.20 2. 6 6 b d e e1 l j e s 0. 3 6 3. 1 8 2.42 1. 1 5 3. 4 3 12 . 7 0 4.45 2.03 b1 d d1 h e l 0.36 3.94 2.29 1.50 4.40 0.35 0.44 e1 h d e e d1 c b1 b 3.00 b s c 1.20 4.25 0.48 2. 6 0 1.83 4.60 0.44 0.56 1.50 bs c 1.40 min . s y m b o l a 1.60 ma x. sot- 89 mi llim e ters !
! ! AIC1642 ! ! ! note: information provided by aic is believed to be accurate and reli able. how e ver, w e cannot assume responsibility for use of any circuitry other than circuitry entirely em bodied in an aic product; nor for any infringement of patents or other rights of thir d par- ties that may result from its use. we reserve the right to change the circuitry and spec ifications w i thout notice. life support policy : aic does not authorize any aic product for us e in life support devices and/or sy stems. life support device s or sy stems are devices or sy stems w h ich, (i) are intended for surg ical implant into the body or (ii) support or sustain life, a nd w hose failure to perform, w hen properly used in accordance w i th instructions for use provided in the labeling, can be reasonabl y expected to result in a significant injury to the user. 22 !

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