e l ek tr on isch e b a u e lemen te 01 -jun-2002 rev. a page 1 of 6 http://www.secosgmbh.com/ any changing of specification will not be informed individual d e s c r i p t i o n t h e s 5 j2596m series of regulators are monolithic integrated circuit t h a t p r o v i d e s a l l a c t i v e f u n c t i o n s f o r a s t e p - d o w n ( b u c k ) s w i t c h i n g r e g u l a t o r , c a p a b l e o f d r i v i n g 3 a l o a d w i t h e x c e l l e n t l i n e a n d l o a d r e g u l a t i o n . t h e s e d e v i c e s a r e a v a i l a b l e i n f i x e d o u t p u t v o l t a g e s o f 3 . 3 v , 5 v , 1 2 v a n d a n a d j u s t a b l e o u t p u t v e r s i o n . t h e s 5 j2596m s e r i e s i o e r a t e a t a s w i t c h i n g f r e q u e n c y o f 1 5 0 k h z ; t h u s a l l o w i n g s m a l l e r s i z e d f i l t e r c o m p o n e n t s t h a n w h a t w o u l d b e n e e d e d w i t h l o w e r f r e q u e n c y s w i t c h i n g r e g u l a t o r s . a v a i l a b l e i n s t a n d a r d 5 - l e a d t o - 252 package. other feature include a guaranteed 4% to tolerance on output voltage under specified input voltages and output load conditions. the 150khz 15% is on the oscillator frequency. external shutdown is included, featuring 80ua(typ.) standby current. the output switch includes cycle-by cycle current limiting, as well as thermal shutdown for full protection under fault conditions. * o p e r a t i n g v o l t a g e c a n b e u p t o 2 2 v * u s e s r e a d i l y a v a i l a b l e s t a n d a r d i n d u c t o r s * t h e r m a l s h u t d o w n a n d c u r r e n t l i m i t p r o t e c t i o n * 3 . 3 v , 5 v , 1 2 v a n d a d j u s t a b l e o u t p u t v e r s i o n s * t t l s h u t d o w n c a p a b i l i t y * b u i l t - i n t t l o n / o f f c o n t r o l * g u a r a n t e e d 3 a o u t p u t c u r r e n t * 1 5 0 k h z f i x e d f r e q u e n c y i n t e r n a l o s c i l l a t o r f e a t u r e s block diagram * high-effciency step-down regulator * positive to negative converter * one-ch switching regulators simple applications s5 j2596m 150 khz, 3a pwm step-down dc/dc converter r e f . m i n . m a x . r e f . m i n . m a x . a 6 . 3 5 6 . 7 3 g 0 . 4 5 0 . 6 0 b 5 . 2 1 5 . 4 6 h 2 . 2 0 2 . 4 0 c 9 . 4 0 1 0 . 2 0 j 0 . 4 6 0 . 5 8 d 2 . 4 0 3 . 0 0 k 0 0 . 1 5 p 1 . 2 7 r e f . l 0 . 9 0 1 . 5 0 s 0 . 5 0 0 . 8 0 m 5 . 4 0 5 . 5 9 m i l l i m e t e r m i l l i m e t e r
e l e k t r o n i s c h e b a u e l e m e n t e h t t p : / / w w w . s e c o s g m b h . c o m / a n y c h a n g i n g o f s p e c i f i c a t i o n w i l l n o t b e i n f o r m e d i n d i v i d u a l 01-jun-2002 rev. a page 2 of 6 t a g e d o e s n o t s a g b e l o w t h e m i n i m u m d r o p o u t v o l t a g e d u ri n g t h e l o a d v h i g h e r t h a n v o u t i n o r d e r f o r t h e d e v i c e t o d e s c r i p ti o n g n d t y p i c a l l y a l a rg e s t o r a g e c a p a c i t o r i s c o n n e c t e d f r o m t h i s p i n t o g r o u n d t o i n s u r e t h a t t h e i n p u t 1 . 3 v o r o p e n = o u t p u t e n a b l e . n c pin function pin name pin# function v in 1 this is the positi ve input supply for the ic switching regulator. a suitable input bypass capacitor m u s t b e p r e s e n t a t t h i s p i n t o m i n i m i z e v o l t a g e t r a n s i e n t s a n d t o s u p p l y t h e s w i t c h i n g c u rr e n t needed by regulator. output 2 internal switch. the voltage at this pin switches between (+v in - v sat ) and approximately - 0 . 5 v , with a duty cycle of approximately v out /v in . t o m i n i m i z e c o u p l i n g t o s e n s i t i v e c i rc u i t r y , t h e pc board copper area connected to this pin should be keep to a minimum. ground 3 circuit ground feedback(fb) 4 senses the regulated output voltage to complete the feedback loop . on/off(sd) 5 al l o w s t h e s w i t c h i n g r e g u l a t o r c i rc u i t t o b e s h u t d o w n u s i n g l o g i c l e v e l s i g n a l s . t h u s d r o p t h e t o t a l input supply current to approximately 150 a. pulling this pin below a t h r e s h o l d v o l t a g e o f approximately 1.3v turns the regulator on, and pulling this pin above 1.3v (up to a maximum o f 1 8 v) s h u t s t h e r e g u l a t o r d o w n . i f t h i s s h u t d o w n f e a t u r e i s n o t n e e d e d , o n / o f f p i n c a n b e w i r e d t o the ground pin. absolute maximum ratings parameter symbol ratings unit supply voltage v cc 24 v on/off pin input voltage vsd -0.3 ~ +18 v feedback pin voltage v fb -0.3 ~ +18 v output voltage to ground v out -1 v power dissipation p d internally limited w storage temperature t st -65 ~ +150 : operating temperature t op -40 ~ +125 : operating voltage v op +4.5 ~ +22 v s 5 j 2596m electrical characteristics s p e c i f i c a t i o n s i n b o l d fa c e ty p e a r e f o r f u l l o p e r a ti n g te m p e r a t u r e r a n g e . t h e o t h e r t y p e a r e f o r t j = 2 5 : . pa r a m e te r sy m b o l c o n d i t i o n s m i n t y p m a x u n i t o u t p u t f e e d b a ck v f b 5 v i n 2 2 v , 0 . 2 a i l o ad 3 a v o u t = 3 v 1 . 1 9 3 / 1 . 1 8 0 1 . 2 3 0 1 . 2 6 7 / 1 . 2 8 0 v ef f i ci e n cy v i n = 1 2 v , i l o ad = 3 a , v o u t = 3 v 7 4 % s 5 j 2596m-33 electrical characteristics s p e c i f i c a t i o n s i n b o l d fa c e ty p e a r e f o r f u l l o p e r a ti n g te m p e r a t u r e r a n g e . t h e o t h e r t y p e a r e f o r t j = 2 5 : . pa r a m e te r sy m b o l c o n d i t i o n s m i n t y p m a x u n i t o u t p u t f e e d b a ck v f b 5 . 5 v v i n 2 2 v 0 . 2 a i l o ad 3 a 3 . 1 6 8 / 3 . 1 3 5 3 . 3 3 . 4 3 2 / 3 . 4 6 5 v ef f i ci e n cy v i n = 1 2 v , i l o ad = 3 a 7 5 % s 5 j 2596m-50 electrical characteristics s p e c i f i c a t i o n s i n b o l d fa c e ty p e a r e f o r f u l l o p e r a ti n g te m p e r a t u r e r a n g e . t h e o t h e r t y p e a r e f o r t j = 2 5 : . pa r a m e te r sy m b o l c o n d i t i o n s m i n t y p m a x u n i t o u t p u t f e e d b a ck v f b 8 v v i n 2 2 v 0 . 2 a i l o ad 3 a 4 . 8 0 / 4 . 7 5 5 . 0 5 . 2 0 / 5 . 2 5 v ef f i ci e n cy v i n = 1 2 v , i l o ad = 3 a 8 0 % s 5 j 2596m-12 electrical characteristics s p e c i f i c a t i o n s i n b o l d fa c e ty p e a r e f o r f u l l o p e r a ti n g te m p e r a t u r e r a n g e . t h e o t h e r t y p e a r e f o r t j = 2 5 : . pa r a m e te r sy m b o l c o n d i t i o n s m i n t y p m a x u n i t o u t p u t f e e d b a ck v f b 1 5 v v i n 2 2 v 0 . 2 a i l o ad 3 a 1 1 . 5 2 / 1 1 . 4 0 1 2 1 2 . 4 8 / 1 2 . 6 0 v ef f i ci e n cy v i n = 1 6 v , i l o ad = 3 a 8 9 % s 5 j 2 5 9 6 m 1 5 0 k h z , 3 a p w m s t e p - d o w n d c / d c c o n v e r t e r m u s t b e p r e s e n t a t t h i s p i n t o m i n i m i z e v o l t a g e t r a n s i e n t s a n d t o s u p p l y t h e s w i t c h i n g c u r r e n t . t o m i n i m i z e c o u p l i n g t o s e n s i t i v e c i r c u i t r y , t h e p c 0 . 5 v , a l l o w s t h e s w i t c h i n g r e g u l a t o r c i r c u i t t o b e s h u t d o w n u s i n g l o g i c l e v e l s i g n a l s . t h u s d r o p t h e t o t a l t h r e s h o l d v o l t a g e o f 1 8 v ) s h u t s t h e r e g u l a t o r d o w n . i f t h i s s h u t d o w n f e a t u r e i s n o t n e e d e d , o n / o f f p i n c a n b e w i r e d t o o f 1 8 v ) s h u t s t h e r e g u l a t o r d o w n . i f t h i s s h u t d o w n f e a t u r e i s n o t n e e d e d , o n / o f f p i n c a n b e w i r e d t o
01-jun-2002 rev. a page 3 of 6 h t p : / / w w w . s e c o s g m b h . c o m / a n y c h a n g i n g o f s p e c i f i c a t i o n w i l l n o t b e i n f o r m e d i n d i v i d u a l e l e k t r o n i s c h e b a u e l e m e n t e s5 j2596m 150 khz, 3a pwm step-down dc/dc converter a l l o u t p u t v o l t a g e v e r s i o n e l e c t r i c a l c h a r a c t e r i s t i c s s p e c i f i c a t i o n s i n b o l d fa c e ty p e a r e f o r f u l l o p e r a ti n g te m p e r a t u r e r a n g e . t h e o t h e r t y p e a r e f o r t j = 2 5 : . pa r a m e te r sy m b o l c o n d i t i o n s m i n t y p m a x u n i t f e e d b a ck b i a s cu rre n t i f b v f b = 1 . 3 v (a d j u s t a b l e v e rs i o n o n l y ) - -1 0 -5 0 / -1 0 0 n a o s ci l l a t o r f re q u e n cy f o sc 1 2 7 / 1 1 0 1 5 0 1 7 3 / 1 7 3 kh z o s ci l l a t o r f re q u e n cy o f s h o rt ci rcu i t p ro t e ct f sc p w h e n cu rre n t l i m i t o ccu rre d a n d v f b < 0 . 5 v , t a = 2 5 : . 5 1 5 2 5 kh z sa t u ra t i o n v o l t a g e v sa t i l o ad = 3 a n o o u t s i d e c i rcu i t v f b = 0 v f o rce d ri v e o n - 1 . 4 1 . 6 / 1 . 7 v m a x. d u t y cyc l e ( o n ) v f b = 0 v f o rce d ri v e o n - 1 0 0 - m a x. d u t y cyc l e ( o f f ) d c v f b = 1 2 v f o rce d r i v e o f f - 0 - % c u rre n t l i m i t i c l pe a k cu rre n t n o o u t s i d e c i rcu i t v f b = 0 v f o rce d ri v e o n 3 . 6 4 . 5 5 . 5 / 6 . 5 a o u t p u t = 0 v , n o o u t s i d e ci rcu i t v f b = 1 2 v f o rce d r i v e o f f - - -2 0 0 u a o u t p u t l e a ka g e cu rre n t i l o u t p u t = -1 v , v i n = 2 2 v - -5 - m a q u i e s ce n t cu rre n t i q v f b = 1 2 v f o rce d r i v e o f f - 5 1 0 m a v i l l o w (r e g u l a t o r o n ) - - - 0 . 6 o n / o f f p i n l o g i c i n p u t t h re s h o l d v o l t a g e v i h h i g h (r e g u l a t o r o f f ) 2 . 0 - - v o n / o f f p i n l o g i c i n p u t cu rre n t i h v l o g i c = 2 . 5 v ( r e g u l a t o r o f f ) - - -0 . 0 1 o n / o f f p i n i n p u t cu rre n t i l v l o g i c = 0 . 5 v ( r e g u l a t o r o n ) - -0 . 1 -1 u a s t a n d b y q u i e s ce n t cu rre n t i st by o n / o f f p i n = 5 v , v i n = 1 2 v - 1 5 0 2 0 0 u a j c ju n ct i o n t o c a s e - 1 0 - t h e r m a l r e s i s t a n ce j a ju n ct i o n t o a m b i e n t w i t h co p p e r a re a o f a p p ro xi m a t e l y 2 c m 2 - 5 0 - : / w u n l e s s o t h e r w i s e s p e c i f i e d , v i n = 1 2 v f o r 3 . 3 v , 5 v , a d j u s t a b l e v e rs i o n a n d v i n = 1 8 v f o r t h e 1 2 v v e rs i o n . i l o a d = 0 . 5 a f u n c t i o n d e s c r i p t i o n t h e t o - 2 5 2 - 5 l s u rf a c e m o u n t p a c k a g e t a b i s d e s i g n e d t o b e s o l d e ri n g t o t h e c o p p e r o n a p ri n t e d c i rc u i t b o a r d . t h e c o p p e r a n d t h e b o a r d a r e t h e h e a t s i n k f o r t h i s p a c k a g e a n d t h e o t h e r h e a t p r o d u c i n g c o m p o n e n t s , s u c h a s t h e c a t c h d i o d e a n d i n d u c t o r . t h e pc b o a r d c o p p e r a r e a t h a t t h e p a c k a g e i s s o l d e r e d t o s h o u l d b e a t l e a s t 0 . 8 i n 2 a n d i d e a l l y s h o u l d h a v e 2 o r m o r e s q u a r e i n c h e s o f 2 o z . ad d i t i o n a l c o p p e r a r e a i m p r o v e t h e t h e r m a l c h a r a c t e r i s t i c s , b u t w i t h c o p p e r a r e a s g r e a t e r t h a n a p p r o x i m a t e l y 6 i n 2 , o n l y s m a l l i m p r o v e m e n t s i n h e a t d i s s i p a t i o n a r e r e a l i z e d . i f f u rt h e r t h e r m a l i m p r o v e m e n t s a r e n e e d e d , d o u b l e s i d e d , m u l t i - l a y e r pc b o a rd w i t h l a r g e c o p p e r a r e a s a n d / o r a i rf l o w w i l l b e r e c o m m e n d e d . t h e s 5 j 2 5 9 6 m j u n c t i o n t e m p e r a t u r e r i s e s a b o v e a m b i e n t t e m p e r a t u r e w i t h a 3 a l o a d a n d d i f f e r e n t i n p u t a n d o u t p u t v o l t a g e s . t h e d a t a w a s t a k e n w i t h t h e c i rc u i t o p e r a t i n g a s a b u c k -s w i t c h i n g r e g u l a t o r w i t h a l l c o m p o n e n t s m o u n t e d o n a pc b o a rd t o s i m u l a t e t h e j u n c t i o n t e m p e r a t u r e u n d e r a c t u a l o p e r a t i n g c o n d i t i o n s . t h i s c u r v e c a n b e u s e d f o r a q u i c k c h e c k f o r t h e a p p r o x i m a t e j u n c t i o n t e m p e r a t u r e f o r v a r i o u s c o n d i t i o n s , b u t b e a w a r e t h a t t h e r e a r e m a n y f a c t o rs t h a t c a n a f f e c t t h e j u n c t i o n t e m p e r a t u r e . w h e n l o a d c u rr e n t h i g h e r t h a n 3 a a r e u s e d , d o u b l e s i d e d o r m u l t i - l a y e r pc b o a r d s w i t h l a r g e c o p p e r a r e a s a n d / o r a i rf l o w m i g h t b e n e e d e d , e s p e c i a l l y f o r h i g h a m b i e n t t e m p e r a t u r e s a n d h i g h o u t p u t v o l t a g e s . f o r t h e b e s t t h e r m a l p e rf o r m a n c e , w i d e c o p p e r t r a c e s a n d g e n e r o u s a m o u n t s o f p ri n t e d c i rc u i t b o a r d c o p p e r s h o u l d b e u s e d i n t h e b o a r d l a y o u t . (o n e e x c e p t i o n t o t h i s i s t h e o u t p u t (s w i t c h ) p i n , w h i c h s h o u l d n o t h a v e l a r g e a r e a s o f c o p p e r . ) l a rg e a r e a s o f c o p p e r p r o v i d e t h e b e s t t r a n s f e r o f h e a t (l o w e r t h e r m a l r e s i s t a n c e ) t o t h e s u rr o u n d i n g a i r , a n d m o v i n g a i r l o w e rs t h e t h e rm a l r e s i s t a n c e e v e n f u rt h e r . p a c k a g e t h e r m a l r e s i s t a n c e a n d j u n c t i o n t e m p e r a t u r e ri s e n u m b e r s a r e a l l a p p r o x i m a t e , a n d t h e r e a r e m a n y f a c t o rs w i l l a f f e c t t h e s e n u m b e rs . s o m e o f t h e s e f a c t o rs i n c l u d e b o a r d s i z e , s h a p e , t h i c k n e s s , p o s i t i o n , l o c a t i o n a n d e v e n b o a rd t e m p e r a t u r e . o t h e r f a c t o rs a r e , t r a c e w i d t h , t o t a l p ri n t e d c i rc u i t c o p p e r a r e a , c o p p e r t h i c k n e s s , s i n g l e o r d o u b l e -s i d e d , m u l t i -l a y e r b o a r d a n d t h e a m o u n t o f s o l d e r o n t h e b o a rd . t h e e f f e c t i v e n e s s o f t h e pc b o a r d t o d i s s i p a t e h e a t a l s o d e p e n d s o n t h e s i z e , q u a n t i t y a n d s p a c i n g o f o t h e r c o m p o n e n t s o n t h e b o a rd , a s w e l l a s t h e s u rr o u n d i n g a i r i s s t i l l o r m o v i n g . f u rt h e rm o r e , s o m e o f t h e s e c o m p o n e n t s s u c h a s t h e c a t c h d i o d e w i l l a d d h e a t t o t h e p c b o a r d a n d t h e h e a t c a n v a r y a s t h e i n p u t v o l t a g e c h a n g e s . f o r t h e i n d u c t o r , d e p e n d i n g o n t h e p h y s i c a l s i z e , t y p e o f c o r e m a t e r i a l a n d t h e d c r e s i s t a n c e , i t c o u l d e i t h e r a c t a s a h e a t s i n k t a k i n g h e a t a w a y f r o m t h e b o a rd , o r i t c o u l d a d d h e a t t o t h e b o a rd .
e l ek tr on isch e b a u e lemen te 01 -jun-2002 rev. a page 4 of 6 http://www.secosgmbh.com/ any changing of specification will not be informed individual t y p i c a l a p p l i c a t i o n c i r c u i t ( 1 ) f i x e d t y p e c i r c u i t (2 )ad j u s t a b l e t yp e c i rcu i t (3 )d e l a y s t a r t c i rcu i t s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 s 5 e 2 5 9 6 m - 3 3 b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e b m k f e s 5 j 2 5 9 6 m s 5 j 2 5 9 6 m s 5 j 2 5 9 6 m - 3 3 3 5 s 5 j 2 5 9 6 m 1 5 0 k h z , 3 a p w m s t e p - d o w n d c / d c c o n v e r t e r
e l ek tr on isch e b a u e lemen te 01 -jun-2002 rev. a page 5 of 6 http://www.secosgmbh.com/ any changing of specification will not be informed individual t y p i c a l p e r f o r m a n c e c h a r a c t e r i s t i c s s 5j2596m 150 khz, 3a pwm step-down dc/dc converter
e l e k t r o n i s c h e b a u e l e m e n t e h t t p : / / w w w . s e c o s g m b h . c o m / a n y c h a n g i n g o f s p e c i f i c a t i o n w i l l n o t b e i n f o r m e d i n d i v i d u a l 01-jun-2002 rev. a page 6 of 6 t a g e d o e s n o t s a g b e l o w t h e m i n i m u m d r o p o u t v o l t a g e d u ri n g t h e l o a d v h i g h e r t h a n v o u t i n o r d e r f o r t h e d e v i c e t o d e s c r i p ti o n g n d t y p i c a l l y a l a rg e s t o r a g e c a p a c i t o r i s c o n n e c t e d f r o m t h i s p i n t o g r o u n d t o i n s u r e t h a t t h e i n p u t 1 . 3 v o r o p e n = o u t p u t e n a b l e . n c s5 j2596m 150 khz, 3a pwm step-down dc/dc converter
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