e l ek tr on isch e b a u e lemen te se108 5 3a low dropout positive adjustable or fixed-mode regulator d e s c r i p t i o n the SE1085 is a low dropout at positive adjustable or fixed-mode regulator with min. of 3 a output current capability. the product is specifically designed to provide well-regulated supply for low voltage ic applications such as high-speed bus termination and low current 3.3v logic supply. SE1085 is also well suited for other applications such as vga cards. SE1085 is guaranteed to have lower than 1.4 v dropout at full load current making it ideal to provide well regulated outputs of 1.25 to 5v with 4.7 to 12v input supply. * 3-terminal adjustable or f ixed 1.5v,1.8v,2.5v,3.3v,5.0v f e a t u r e s * 1.4 v max. dropout full load current * output current limiting * fast transient response * built-in thermal shutdown 01 -jun-2002 rev. a page 1 of 4 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 typical circuit ref. min. max. ref. min. max. a 4.40 4.80 c1 1.25 1.45 b 0.76 1.00 b1 1.17 1.47 c 0.36 0.50 l 13.25 14.25 d 8.60 9.00 e 2.54 ref. e 9.80 10.4 l1 2.60 2.89 l4 14.7 15.3 ? 3.71 3.96 l5 6.20 6.60 a1 2.60 2.80 millimeter millimeter block diagram 3.3v/3a 2.5v/3a
dc supply voltage power dissipation storage temperature range operating juction temperature range parameter symbo l ratings unit v v in -0.3 to 12 0~+150 -65~+150 a b s o l u t e m a x i m u m r a t i n g s p d t st t op c o c o internally limited pin descriptions 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 4 name i/o pin# function adj (gnd) 1 adjustable (ground only for fixed mode) vout o 2 the output of the regulator. a minimum of 10uf capacitor must be connected from this pin to ground to insure stability. vin i 3 the input pin of regulator .typically a large storage capacitor is connected from this pin to ground to insure that the input vol tage does not sag below the min. dropout voltage during the load 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 transient response .this pin must always be 1.5 v higher than vout in order for the device to 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 regulate properly. 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 pa r a m e te r c o n d i ti o n s m i n t y p m a x u n i t r e f e r e n c e v o l t a g e s e1 0 8 5 - ad j i o = 1 0 m a , t j = 2 5 , (vi n -v o u t )= 1 . 5 v 1 . 2 2 5 1 . 2 5 0 1 . 2 7 5 v s e1 0 8 5 - 1 . 5 i o = 1 0 m a , t j = 2 5 , 3 v vi n 1 2 v 1 . 4 7 0 1 . 5 0 0 1 . 5 3 0 v s e1 0 8 5 - 1 . 8 i o = 1 0 m a , t j = 2 5 , 3 . 3 v vi n 1 2 v 1 . 7 6 4 1 . 8 0 0 1 . 8 3 6 v s e1 0 8 5 - 2 . 5 i o = 1 0 m a , t j = 2 5 , 4 v vi n 1 2 v 2 . 4 5 0 2 . 5 0 0 2 . 5 5 0 v s e1 0 8 5 - 3 . 3 i o = 1 0 m a , t j = 2 5 , 4 . 8 v vi n 1 2 v 3 . 2 3 5 3 . 3 0 0 3 . 3 6 5 v o u t p u t v o l t a g e s e1 0 8 5 - 5 . 0 i o = 1 0 m a , t j = 2 5 , 6 . 5 v vi n 1 2 v 4 . 9 0 0 5 . 0 0 0 5 . 1 0 0 v l i n e r e g u l a t o r s e1 0 8 5 - xxx i o = 1 0 m a , v o u t + 1 . 5 < vi n < 1 2 - - 0 . 2 % s e1 0 8 5 ad j v i n = 3 . 3 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 ) - - 1 % s e1 0 8 5 - 1 . 5 v i n = 3 . 0 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 - 1 2 1 5 m v s e1 0 8 5 - 1 . 8 v i n = 3 . 3 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 ) - 1 5 1 8 m v s e1 0 8 5 - 2 . 5 v i n = 4 . 0 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 ) - 2 0 2 5 m v s e1 0 8 5 - 3 . 3 v i n = 5 . 0 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 ) - 2 6 3 3 m v l o a d r e g u l a t i o n s e1 0 8 5 - 5 . 0 v i n = 8 . 0 v , 0 m a< i o < 3 a, t j = 2 5 ( n o t e 1 , 2 ) - 4 0 5 0 m v d r o p o u t v o l t a g e (v i n -v o u t ) s e1 0 8 5 - xxx i o = 3 a( v o u t = 1 % v o u t ) - 1 . 3 1 . 4 v c u rr e n t l i m i t s e1 0 8 5 - xxx v i n -v o u t = 5 v 3 . 1 - - a m i n i m u m l o a d c u r r e n t s e1 0 8 5 - xxx 0 t j 1 2 5 - 5 1 0 m a t h e rm a l r e g u l a t i o n t a = 2 5 , 3 0 m s p u l s e - 0 . 0 0 8 0 . 0 4 % / w f = 1 2 0 h z , c o u t = 2 5 u f , t a n t a l u m , i o = 3 a r i p p l e r e j e c t i o n s e1 0 8 5 - xxx v i n = v o u t + 3 v - 6 0 7 0 d b t e m p e r a t u r e s t a b i l i t y i o = 1 0 m a - 0 . 5 - % t h e rm a l r e s i s t a n c e j u n c t i o n ? t o -a m b i e n t ( n o h e a t s i n k ; n o a i r f l o w ) - 8 3 - / w t h e rm a l r e s i s t a n c e j u n c t i o n -t o -c a s e c o n t r o l c i rc u i t r y / p o w e r t r a n s i s t o r - 0 . 6 5 / 2 . 7 - / w n o t e 1 : s e e t h e r m a l r e g u l a t i o n s p e c i f i c a t i o n s f o r c h a n g e s i n o u t p u t v o l t a g e d u e t o h e a t i n g e f f e c t s . l i n e a n d l o a d r e g u l a t i o n a r e m e a s u r e d a t a c o n s t a n t j u n c t i o n t e m p e r a t u r e b y l o w d u t y c y c l e p u l s e t e s t i n g . l o a d r e g u l a t i o n i s m e a s u r e d a t t h e o u t p u t l e a d = 1 / 1 8 ? f ro m t h e p a c k a g e . n o t e 2 : l i n e a n d l o a d r e g u l a t i o n a r e g u a r a n t e e d u p t o t h e m a x i m u m p o w e r d i s s i p a t i o n o f 1 5 w . po w e r d i s s i p a t i o n i s d e t e r m i n e d b y t h e d i f f e r e n c e i n i n p u t a n d o u t p u t a n d t h e o u t p u t c u r r e n t . g u a r a n t e e d m a x i m u m p o w e r d i s s i p a t i o n w i l l n o t b e a v a i l a b l e o v e r t h e f u l l i n p u t / o u t p u t r a n g e . n o t e 3 : q u i e s c e n t c u rr e n t i s d e f i n e d a s t h e m i n i m u m o u t p u t c u rr e n t r e q u i r e d i n m a i n t a i n i n g r e g u l a t i o n . a t 1 2 v i n p u t / o u t p u t d i f f e r e n t i a l t h e d e v i c e i s g u a r a n t e e d t o r e g u l a t e i f t h e o u t p u t c u rr e n t i s g r e a t e r t h a n 1 0 m a. s e108 5 3 a low dropout positive adjustable or f i xed-mode regulator
01-jun-2002 rev. a page 3 of 4 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 f u n c t i o n a l d e s c r i p t i o n i n t r o d u c t i o n t h e s e 1 0 8 5 a d j u st a b l e o r f i x e d - m o d e l o w d r o p o u t ( l d o ) r e g u l a t o r i s a 3 t e r m i n a l d e vi ce w h i ch ca n e a s i l y b e p r o g r a m m e d b y i n t e r n a l m a s k ch a n g e t o a n y vo l t a g e w i t h i n t h e r a n g e o f 1 . 2 5 t o v i n - 1 . 4 v . t h e s e 1 0 8 5 o n l y n e e d s 1 . 4 v d i f f e r e n t i a l b e t w e e n v i n a n d v o u t t o m a i n t a i n o u t p u t r e g u l a t i o n , i n a d d i t i o n , t h e o u t p u t vo l t a g e t o l e r a n ce s a r e a l so e x t r e m e l y t i g h t a n d t h e y i n c l u d e t h e t r a n s i e n t r e sp o n se a s p o r t o f t h e sp e ci f i ca t i o n . f o r e x a m p l e , i n t e l v r e sp e ci f i ca t i o n ca l l s f o r a t o t a l o f + / - 1 0 0 m v i n c l u d i n g i n i t i a l t o l e r a n ce , l o a d r e g u l a t i o n a n d 0 t o 3 a l o a d st e p . t h e s e 1 0 8 5 i s sp e ci f i c a l l y d e si g n e d t o m e e t t h e f a st cu r r e n t t r a n s i e n t n e e d s a s w e l l a s p r o vi d i n g a n a ccu r a t e i n i t i a l vo l t a g e , r e d u ci n g t h e o ve r a l l sys t e m co s t w i t h t h e n e e d f o r f e w e r o u t p u t ca p a c i t o r s . l o a d r e g u l a t i o n s i n ce t h e s e 1 0 8 5 i s o n l y a 3 t e r m i n a l d e vi ce , i t i s n o t p o s si b l e t o p r o vi d e t r u e r e m o t e se n si n g o f t h e o u t p u t vo l t a g e a t t h e l o a d . b u t i t ca n su p p l y g o o d l o a d r e g u l a t i o n b y i n t e r n a l f e e d b a ck b yp a ss t h e e x t e r n a l l o s s s u ch a s a d j u st a b l e m o d e . s t a b i l i t y t h e s e 1 0 8 5 r e q u i r e s t h e u se o f a n o u t p u t ca p a c i t o r a s p a r t o f t h e f r e q u e n cy co m p e n sa t i o n i n o r d e r t o m a ke t h e r e g u l a t o r st a b l e . f o r m o st a p p l i c a t i o n s a m i n i m u m o f 1 0 u f a l u m i n u m e l e ct r o l y t i c ca p a c i t o r i n su r e s b o t h st a b i l i t y a n d g o o d t r a n s i e n t r e sp o n se . t h e r m a l d e s i g n t h e s e 1 0 8 5 i n co r p o r a t e s a n i n t e r n a l sh u t d o w n t h a t p r o t e ct s t h e d e vi ce 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 ce e d s t h e m a x i m u m a l l o w a b l e j u n c t i o n t e m p e r a t u r e s. a l t h o u g h t h i s d e vi ce ca n o p e r a t e w i t h j u n c t i o n t e m p e r a t u r e s i n t h e r a n g e o f 1 5 0 : , i t i s r e co m m e n d e d t h a t t h e se l e ct e d h e a t si n k b e ch o se n su ch t h a t d u r i n g m a x i m u m co n t i n u o u s l o a d o p e r a t i o n t h e j u n c t i o n t e m p e r a t u r e i s ke p t b e l o w t h e t e m p e r a t u r e . l a y o u t c o n s i d e r a t i o n t h e o u t p u t ca p a c i t o r s m u s t b e l o c a t e d a s c l o se t o t h e v o u t t e r m i n a l o f t h e d e vi ce a s p o ss i b l e . i t i s r e co m m e n d e d t o u se a se ct i o n o f a l a ye r o f t h e p c b o a r d a s a p l a n e t o co n n e ct t h e v o u t p i n t o t h e o u t p u t ca p a c i t o r s t o p r e ve n t a n y h i g h f r e q u e n cy o sci l l a t i o n t h a t m a y r e su l t d u e t o e x ce ssi ve t r a ce i n d u ct a n ce . s e108 5 3 a low dropout positive adjustable or f i xed-mode regulator
01-jun-2002 rev. a page 4 of 4 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 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 3 a s e108 5 3 a low dropout positive adjustable or f i xed-mode regulator
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