e l ek tr on isch e b a u e lemen te d e s c r i p t i o n 01 -jun-2002 rev. a page 1 of 5 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 functional block diagram s e 2 1 3 8 1 . 5 a c m o s l o w d r o p o u t v o l t a g e r e g u l a t o r t h e s e 21 38 is stable w i t h a n o u t p u t c a p a c i t a n c e o f 4 . 7 m f o r g r e a t e r . t h e s e 21 38 positive,linear regulators feature low quiescent c u r r e n t ( 4 5 m a t y p . ) w i t h l o w d r o p o u t v o l t a g e , m a k i n g t h e m i d e a l f o r b a t t e r y a p p l i c a t i o n s . these rugged devices have both 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 f o l d - b a c k t o p r e v e n t d e v i c e f a i l u r e u n d e r t h e " w o r s t " o f o p e r a t i n g c o n d i t i o n s . f e a t u r e s * low temperature coefficient * over-temperature shutdown * very low dropout voltage * high accurate 1.5% * short circuit current fold-back * guaranteed 1.5 a output * current limiting * portable electronics applications * pc peripherals * wireless devices * battery powered widgets * instrumentation SE2138 SE2138-15 part number marking output voltage part number marking output voltage 8t152 1.5v xxxx ordering information(contd.) SE2138-19 8t192 1.9v xxxx SE2138-18 8t182 1.8v xxxx SE2138-25 8t252 2.5v xxxx SE2138-33 8t332 3.3v xxxx SE2138-50 8t502 5.0v xxxx SE2138-47 8t472 4.7v xxxx
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 5 absolute maximum ratings parameter symbol ratings unit input max voltage v in 8 v output current i out p d /( v in- v o) a output voltage v out 1.5~5.0 v operating ambient temperature topr -40 ~ +85 : junction temperature tj -40 ~ +125 : maximum junction temperature tj max 150 : jc (non-conductive epoxy) * 24 /w : thermal resistance ja 80 /w : internal power dissipation pd 1.6 w eds classification b *measure jc on backside center of tab. electrical characteristics vin =v out (t)+2v, ta=25 : unless otherwise noted parameter symbol condition min typ max unit output voltage v out (e) (note1) i o =1ma -1.5% v out (t) (note2) 1.5% v output current i o v o >1.2v 1.5 - - a current limit i l i m v o >1.2v 1.5 2.0 - a load regulation reg load v i n =v out (t)+2v, i o =1ma to 1.5a -1 0.2 1 % 1.4vSE2138 1.5a cmos low dropout voltage regulator
01-jun-2002 rev. a page 3 of 5 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 ( t ) + 1 t o detailed description the SE2138 of coms regulators contain a pmos pass transistor,voltage reference, error amplifier,over-current protection and thermal shutdown.the p-channel pass transistor receives data from the error amplifier, over-current shutdown, and thermal protection circuits. during normal operation, the error amplifier compares the output voltage to a precision reference. over-current and thermal shutdown circuits become active when the junction temperature exceeds15 0 c, or the current exceeds 2.2a. during thermal shutdown, the output voltage remains low. normal operation is restored when the junction temperature drops below 120 c.the s e2138 behaves like a current source when the load reaches 2.2a. however, if the load impedance drops below 0.3 , the current drops back to 600ma to prevent excessive power dissipation. normal operation is restored when the load resistance exceeds of 0.75 . o o external capacitors the SE2138 is stable with an output capacitance to ground of 4.7uf or greater. ceramic capacitors have the lowest esr, and will offer the best ac performance. conversely, aluminum electrolytic capacitors exhibit the highest esr, resulting in the poorest ac response. unfortunately, large value ceramic capacitors are comparatively expensive. one option is to parallel a 0.1uf ceramic capacitor with a 10uf aluminum electrolytic. the benefit is low esr, high capacitance, and low overall cost. a second capacitor is recommended between the input and ground to stabilize v in. the input capacitor should be at least 0.1uf to have a beneficial effect. all capacitors should be placed in closed proximity to the pins. a "quiet" ground termination is desirable. this can be achieved with a "star" connection. [ [ characteristics curve SE2138 1.5a cmos low dropout voltage regulator
e l ek tr on isch e b a u e lemen te 01 -jun-2002 rev. a page 5 of 5 http://www.secosgmbh.com/ any changing of specification will not be informed individual SE2138 1.5a 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 5 s e2138 1.5a cmos low dropout voltage regulator
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