e l ek tr on isch e b a u e lemen te s 5 u21 78 cmos low dropout voltage regulator * highly accurate 1.5% f e a t u r e s * low temperature coefficient * over-temperature shutdown * very low dropout voltage * noise reduction bypass capacitor * short circuit current fold-back * guaranteed 1. 5 a output * current limiting * portable electronics applications * pc peripherals * wireless devices * battery powered widgets * instrumentation typical application circuit functional block diagram * power-saving shutdown mode the s 5 u 2178 is stable with an output capacitance 4.7 m f or greater. bypass and ground. of the s 5 u 21 7 8 series positive,linear regulators feature low quiescent current ( 45 m a typ.) with low dropout voltage, making them ideal f or battery applications. output voltage are set at the factory and trimmed to 1.5% accuracy.these rugged devices have both thermal shutdown and current fold-back to prevent device failure under the "worst" of operating conditions. in applications requiring a low noise, regulated supply, place a 1000pf capacitor between description 01 -jun-2002 rev. a page 1 of 6 http://www.secosgmbh.com/ any changing of specification will not be informed individual r o h s c o m p l i a n t p r o d u c t m i l l i m e t e r r ef . m i n . m a x . r ef . m i n . m a x . a 4 . 4 0 4 . 8 0 c 2 1 . 2 5 1 . 4 5 b 0 . 6 6 0 . 9 1 l 2 1 . 2 7 r e f . l 4 0 . 0 0 0 . 3 0 b d 8 . 6 9 . 0 c 0 . 3 6 0 . 5 e 1 . 7 0 r e f . l 1 2 . 2 9 2 . 7 9 l 1 4 . 6 1 5 . 8 e 9 . 8 0 1 0 . 4 0 ? 8 ? m i l l i m e t e r S5U2178
h t t p : / / w w w . s e c o s g m b h . c o m / e l e k t r o n i s c h e b a u e l e m e n t e 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 ) + 1 t o ( t ) + 1 t o a b s o l u t e m a x i m u m r a t i n g s pa r a m e te r sy m b o l r a ti n g s u n i t i n p u t m a x v o l t a g e v i n 8 v o u t p u t c u r r e n t i o u t p d / ( v i n - v o ) a o u t p u t v o l t a g e v o u t 1 . 5 ~ 5 . 0 v o p e r a t i n g a m b i e n t t e m p e r a t u r e t o p r - 4 0 ~ + 8 5 : ju n ct i o n t e m p e r a t u r e t j - 4 0 ~ + 1 2 5 m a x i m u m j u n c t i o n t e m p e r a t u r e t j m a x 1 5 0 t h e r m a l r e si st a n ce j c 5 : / w i n t e r n a l p o w e r d i ss i p a t i o n ( ? t = 1 0 0 : ) p d 3 0 0 0 m w e d s c l a ssi f i ca t i o n b 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 v i n = v o u t ( t ) + 2 v , v en = v i n , t a = 2 5 : u n l e s s o t h e rw i s e pa r a m e te r sy m b o l c o n d i t i o n m i n t yp m a x u n i t o u t p u t v o l t a g e v o u t (e) (n o t e 1 ) v e n = v e h m i n , i o = 1 m a - 1 . 5 % v o u t ( t ) (n o t e 2 ) 1 . 5 % v o u t p u t c u rre n t i o v o u t > 1 . 2 v 1 . 5 - - a c u rre n t l i m i t i l i m v o u t > 1 . 2 v 1 . 5 2 . 0 - a l o a d r e g u l a t i o n r eg l o a d i o = 1 m a t o 1 . 5 a - 1 0 . 2 1 % 1 . 5 v < v o u t ( t ) 2 . 0 v - - 1 3 0 0 2 . 0 v < v o u t ( t ) 2 . 8 v - - 8 0 0 d ro p o u t v o l t a g e v d r o p o u t i o = 1 . 5 a v o = v o u t ( e ) - 2 % 2 . 8 v < v o u t ( t ) - - 6 0 0 m v q u i e s ce n t c u rre n t i q i o = 0 m a - 4 5 7 0 a g ro u n d pi n c u rre n t i g n d i o = 1 m a ~ 1 . 5 a - 4 5 - a v o u t ( t ) < 2 . 0 v - 0 . 1 5 - 0 . 1 5 2 . 0 v v o u t ( t ) < 4 . 0 v - 0 . 1 0 . 0 2 0 . 1 l i n e r e g u l a t i o n r eg l i n e i o = 1 m a v i n = v o u t ( t ) + 1 t o v o u t ( t ) + 2 4 . 0 v v o u t ( t ) - 0 . 4 - 0 . 4 % i n p u t v o l t a g e v i n n o t e 3 - 7 v o ve r t e m p e r a t u r e s h u t d o w n o t s - 1 5 0 - : o ve r t e m p e r a t u r e h y st e r i si s o t h - 3 0 - : o u t p u t v o l t a g e t e m p e ra t u re c o e f f i ci e n t t c - 3 0 - p p m / : sh o rt c i rcu i t c u rre n t i s c v o u t < 0 . 4 v - 7 5 0 - m a f = 1 kh z - 5 0 - po w e r su p p l y r e j e ct i o n psr r i o = 1 0 0 m a c o = 4 . 7 f c e r a m i c f = 1 0 kh z - 2 0 - d b f = 1 kh z - 7 5 - po w e r su p p l y r e j e ct i o n psr r i o = 1 0 0 m a c o = 4 . 7 f c e r a m i c c b y p = 0 . 0 1 f f = 1 0 kh z - 5 5 - d b o u t p u t v o l t a g e n o i s e e n f = 1 0 h z ~ 1 0 0 kh z i o = 1 0 m a , c b y p = 0 f c o = 4 . 7 f - 3 0 - v r m s o u t p u t v o l t a g e n o i s e e n f = 1 0 h z ~ 1 0 0 kh z i o = 1 0 m a , c b y p = 0 . 0 1 f c o = 4 . 7 f - 3 0 - v r m s v e h 2 . 0 - v i n v en i n p u t t h re s h o l d v e l 0 - 0 . 4 v i e h v i n = 7 v - - 0 . 1 a en i n p u t b i a s c u rre n t i e l v e n = 0 v , v i n = 7 v - - 0 . 5 a sh u t d o w n su p p l y c u rre n t i s d v i n = 5 v , v o u t = 0 v , v e n = 0 v - 0 . 5 2 a s 5 u 21 78 cmos low dropout voltage regulator
01-jun-2002 rev. a page 3 of 6 h t t p : / / w w w .s e c o sg m b h .c o m/ a n y c ha n g i n g o f s pe c if i c a t i o n w ill no t b e i n f o r m ed i nd i v i dual e l e k t r o n i s c h e b a u e l e m e n t e s 5 u 2 1 7 8 - 1 5 p a r t n u m b e r m a r k i n g o u t p u t v o l t a g e p a r t n u m b e r m a r k i n g o u t p u t v o l t a g e 8 g 1 5 2 1 . 5 v x x x x o r d e r i n g i n f o r m a t i o n ( c o n t d . ) s 5 u 2 1 7 8 - 2 5 8 g 2 5 2 2 . 5 v x x x x s 5 u 2 1 7 8 - 1 8 8 g 1 8 2 1 . 8 v x x x x s 5 u 2 1 7 8 - 3 3 8 g 3 3 2 3 . 3 v x x x x s 5 u 2 1 7 8 - 4 7 8 g 4 7 2 4 . 7 v x x x x s 5 u 2 1 7 8 - 5 0 8 g 5 0 2 5 . 0 v x x x x d e t a i l e d d e s c r i p t i o n t h e s 5u 2 1 78 o f c o m s r e g u l a t o r s c o n t a i n a p m o s p a s s t r a n s i s t o r , v o l t a g e r e f e r e n c e , e r r o r a m p l i f i e r , o v e r - c u r r e n t p r o t e c t i o n a n d t h e r m a l s h u t d o w n . t h e p - c h a n n e l p a s s t r a n s i s t o r r e c e i v e s d a t a f r o m t h e e r r o r a m p l i f i e r , o v e r - c u r r e n t s h u t d o w n , a n d t h e r m a l p r o t e c t i o n c i r c u i t s . d u r i n g n o r m a l o p e r a t i o n , t h e e r r o r a m p l i f i e r c o m p a r e s t h e o u t p u t v o l t a g e t o a p r e c i s i o n r e f e r e n c e . o v e r - c u r r e n t a n d t h e r m a l s h u t d o w n c i r c u i t s b e c o m e a c t i v e w h e n t h e j u n c t i o n t e m p e r a t u r e e x c e e d s 1 4 0 c , o r t h e c u r r e n t e x c e e d s 2 . 2 a . d u r i n g t h e r m a l s h u t d o w n , t h e o u t p u t v o l t a g e r e m a i n s l o w . n o r m a l o p e r a t i o n i s r e s t o r e d w h e n t h e j u n c t i o n t e m p e r a t u r e d r o p s b e l o w 1 2 0 c . t h e s 5u 2 1 78 b e h a v e s l i k e a c u r r e n t s o u r c e w h e n t h e l o a d r e a c h e s 2 . 2 a . h o w e v e r , i f t h e l o a d i m p e d a n c e d r o p s b e l o w 0 . 3 , t h e c u r r e n t d r o p s b a c k t o 6 0 0 m a t o p r e v e n t e x c e s s i v e p o w e r d i s s i p a t i o n . n o r m a l o p e r a t i o n i s r e s t o r e d w h e n t h e l o a d r e s i s t a n c e e x c e e d s o f 0 . 7 5 . o o t h e s 5 u 2 1 7 8 i s s t a b l e w i t h a n o u t p u t c a p a c i t a n c e t o g r o u n d o f 4 . 7 u f o r g r e a t e r . c e r a m i c c a p a c i t o r s h a v e t h e l o w e s t e s r , a n d w i l l o f f e r t h e b e s t a c p e r f o r m a n c e . c o n v e r s e l y , a l u m i n u m e l e c t r o l y t i c c a p a c i t o r s e x h i b i t t h e h i g h e s t e s r , r e s u l t i n g i n t h e p o o r e s t a c r e s p o n s e . u n f o r t u n a t e l y , l a r g e v a l u e c e r a m i c c a p a c i t o r s a r e c o m p a r a t i v e l y e x p e n s i v e . o n e o p t i o n i s t o p a r a l l e l a 0 . 1 u f c e r a m i c c a p a c i t o r w i t h a 1 0 u f a l u m i n u m e l e c t r o l y t i c . t h e b e n e f i t i s l o w e s r , h i g h c a p a c i t a n c e , a n d l o w o v e r a l l c o s t . a s e c o n d c a p a c i t o r i s r e c o m m e n d e d b e t w e e n t h e i n p u t a n d g r o u n d t o s t a b i l i z e v i n . t h e i n p u t c a p a c i t o r s h o u l d b e a t l e a s t 0 . 1 u f t o h a v e a b e n e f i c i a l e f f e c t . a third capacitor can be connected between the by-pass pin and gnd. this capacitor can be a low cost polyester a l l c a p a c i t o r s s h o u l d b e p l a c e d i n c l o s e d p r o x i m i t y t o t h e p i n s . a " q u i e t " g r o u n d t e r m i n a t i o n i s d e s i r a b l e . t h i s c a n b e a c h i e v e d w i t h a " s t a r " c o n n e c t i o n . e n a b l e w h e n e n p i n i s p u l l e d l o w , t h e p m o s p a s s t r a n s i s t o r s h u t s o f f , a n d a l l i n t e r n a l c i r c u i t s a r e p o w e r e d d o w n . i n t h i s s t a t e , t h e q u i e s c e n t c u r r e n t i s l e s s t h a n 1 u a . t h i s p i n b e h a v e s m u c h l i k e a n e l e c t r o n i c s w i t c h . 1 0 0 k r e s i s t o r i s n e c e s s a r y b e t w e e n v e n so u r ce a n d e n p i n w h e n v e n i s h i g h t h a n v i n . ( n o t e : t h e r e i s n o i n t e r n a l p u l l - u p f o r e n p i n . i t c a n n o t b e f l o a t i n g . ) [ film variety between the value of 0.001~0.01uf. a large capacitor improves the ac ripple rejection, but also makes the output come up slowly. this "soft" turn-on is desirable in some applications to limit turn-on surges. e x t e r n a l c a p a c i t o r s [ [ n o t e 1 : v o u t ( e) = ef f e c t i v e o u t p u t v o l t a g e ( i . e . t h e o u t p u t v o l t a g e w h e n v o u t (t ) + 2 . 0 v i s p r o v i d e d a t t h e vi n p i n w h i l e m a i n t a i n i n g a c e rt a i n i o u t v a l u e ). 2 : v o u t (t ) = s p e c i f i e d o u t p u t v o l t a g e 3 : v i n ( m i n ) = v o u t + v d r o p o u t s 5u 21 78 cmos low dropout voltage regulator
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 c h a r a c t e r i s t i c s c u r v e s 5u 21 78 cmos low dropout voltage regulator
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 5 of 6 S5U2178 cmos low dropout voltage regulator
0 1 - j u n - 2 0 0 2 r e v . a p a g e 6 o f 6 h t t p : / / w w w .s e c o sg m b h .c o m/ a n y c ha n g i n g o f s pe c if i c a t i o n w ill no t b e i n f o r m ed i nd i v i dual e l e k t r o n i s c h e b a u e l e m e n t e s 5u 21 78 cmos low dropout voltage regulator
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