1 www.semtech.com SC4625 1.7mhz high efficiency monolithic 0.5a synchronous buck converter power management SC4625 is a bicmos integrated fet, synchronous, 0.5a step-down regulator. it operates at the typical switching frequency of 1.7mhz and enables the user to choose a very small and inexpensive external output inductor and capacitor. fully internally compensated current-mode control loop provides a fast transient response and ensures excellent line and load regulation. the SC4625 operates from 2.5v to 5.5v, features internal p-mos and n-mos power switches and is implemented as a current-mode pulse-width- modulated (pwm) control scheme. multiple modes of operation are available to achieve high performance and efficiency and makes the SC4625 ideally suited for electronic devices where size is at premium. these modes are: pwm fixed frequency, synchronous and asynchronous load dependent, pulse-skipping at very light load, and low-dropout 100% duty cycle mode, by continuously turning on the upper p-mosfet. description features applications ? fully integrated mosfet switches and compensation ? 1.7mhz fixed frequency operation ? input voltage range: 2.5v to 5.5v ? adjustable output voltage from 0.5v to v in ? pulse-skipping mode operation at light load ? 100% duty cycle in low-dropout mode ? over-temperature shutdown ? mlp-10 lead free package. this product is fully weee and rohs compliant ? -40c to +125c junction temperature range ? wlan and bluetooth ? applications ? distributed power systems ? micro dc-dc converters ? usb-based dsl modems ? point-of-load regulation ? fpga core and i/o supplies ? set-top boxes ? battery-powered devices (1 li -ion or 3 nimh/nicd) revision: november 30, 2005 typical application circuit l1 c3 + _ vin vout c1 ph 1 vin 2 nc 3 reg 7 nc 8 gnd 9 gnd 10 en 5 fb 6 nc 4 u1 SC4625 r2 r1 c2
2 ? 2005 semtech corp. www.semtech.com SC4625 power management absolute maximum ratings r e t e m a r a p l o b m y sm u m i x a ms t i n u e g a t l o v y l p p u sv n i 6 o t 3 . 0 -v e g a t l o v h c t i w s t u p t u ov h p 6 o t 3 . 0 -v b f d n a n e t a e g a t l o v v o t 3 . 0 - n i 3 . 0 +v t n e r r u c t u p t u o s u o u n i t n o c 1a n o i t a p i s s i d r e w o pd pd e t i m i l y l l a n r e t n ia t n e i b m a o t n o i t c n u j e c n a t s i s e r l a m r e h t a j 0 6w / c e g n a r e r u t a r e p m e t n o i t c n u j g n i t a r e p ot j 5 2 1 + o t 0 4 -c e g n a r e r u t a r e p m e t e g a r o t st g t s 0 5 1 + o t 5 6 -c ) s 0 4 - 0 1 ( e r u t a r e p m e t w o l f e r r i g k p t0 6 2 +c ) l e d o m y d o b n a m u h ( g n i t a r d s e 2v k exceeding the specifications below may result in permanent damage to the device, or device malfunction. operation outside of th e parameters specified in the electrical characteristics section is not implied. electrical characteristics unless otherwise specified: v in = 3.3v, v o = 1.25v, i o = 300ma; -40c t j = t a +125c. r e t e m a r a ps n o i t i d n o c t s e tn i mp y tx a ms t i n u e g n a r e g a t l o v y l p p u s 5 . 25 . 5v t n e r r u c t n e c s e i u qv = n e n i v , b f ) g n i h c t i w s t o n ( v 6 . 0 =0 5 4a v 0 = n e1 . 0a e g a t l o v k c a b d e e f d e t a l u g e r 7 8 40 0 53 1 5v m n o i t a l u g e r e n i l e g a t l o v t u p t u ov n i i , v 6 . 3 o t v 0 . 3 = d a o l , a m 0 0 3 = t j t = a c 5 2 = 2 . 05 . 0% n o i t a l u g e r d a o l e g a t l o v t u p t u oi < a m 0 1 d a o l t , a m 0 0 5 < j t = a c 5 2 =6 . 0% e l c y c y t u d m u m i x a mv b f v 4 . 0 =0 0 1% t i m i l t n e r r u cv b f v 4 . 0 =6 . 08 . 00 . 1a e c n a t s i s e r - n o h c t i w si h p v , a m 0 0 3 = b f v 4 . 0 =6 . 0 ? i h p v , a m 0 0 3 - = b f v 6 . 0 =6 . 0 ? y c n e u q e r f r o t a l l i c s ot j t = a c 5 2 =5 5 . 17 . 15 8 . 1z h m
3 ? 2005 semtech corp. www.semtech.com SC4625 power management electrical characteristics unless otherwise specified: r e t e m a r a ps n o i t i d n o c t s e tn i mp y tx a ms t i n u t n e r r u c t u p n i e l b a n e 1 . 0a h g i h , d l o h s e r h t e l b a n e 6 . 1v w o l , d l o h s e r h t e l b a n e 4 . 0v n w o d t u h s e r u t a r e p m e t - r e v o 0 6 1c n w o d t u h s e r u t a r e p m e t - r e v o s i s e r e t s y h 5 1c v in = 3.3v, v o = 1.25v, i o = 300ma; -40c t j = t a +125c.
4 ? 2005 semtech corp. www.semtech.com SC4625 power management r e b m u n t r a pe g a k c a p ) 1 ( t ( e g n a r . p m e t j ) t r t l m 5 2 6 4 c s ) 2 ( 0 1 - p l mc 5 2 1 + o t c 0 4 - pin configuration ordering information notes: (1) only available in tape and reel packaging. a reel contains 2500 devices. (2) lead free product. this product is fully weee and rohs compliant. pin descriptions # n i pe m a n n i pn o i t c n u f n i p 1h p. t u p t u o s t e f s o m r e w o p l a n r e t n i . e d o n e s a h p 2n i v. d n g o t r o t i c a p a c s s a p y b s e r i u q e r . e g a t l o v y l p p u s 8 , 4 , 3c n. d e t c e n n o c t o n 5n e. e c i v e d e h t n w o d r e w o p l l i w n e l e v e l w o l a 6b f k r o w t e n r e d i v i d r o t s i s e r l a n r e t x e e h t o t t c e n n o c , r e i f i l p m a r o r r e e h t o t t u p n i . e g a t l o v t u p t u o e h t t e s o t 7g e r . r o t i c a p a c f 1 0 . 0 a h t i w d n g o t d e s s a p y b e b t s u m . r o t a l u g e r l a n r e t n i 0 1 , 9d n g. r e h t e g o t d e i t e b o t s n i p h t o b . d n u o r g d a p l a m r e h td n g . s a i v e l p i t l u m g n i s u e n a l p d n u o r g o t t c e n n o c . s e s o p r u p g n i k n i s t a e h r o f d a p top view (mlp-10) marking information top view yyww = datecode (example: 0015) xxxx = semtech lot no. (example: 00101) 4625 yyww xxxx
5 ? 2005 semtech corp. www.semtech.com SC4625 power management block diagram driver current limit switching logic gate oscillator slope comp pwm ea ref zero detect fb en ph vin gnd 0.5v regulator reg
6 ? 2005 semtech corp. www.semtech.com SC4625 power management application schematic + _ v in=3.3v vout = 1.25v ph 1 vin 2 nc 3 reg 7 nc 8 gnd 9 gnd 10 en 5 fb 6 nc 4 u1 SC4625 r1 10k r2 6.65k c1 1uf c3 2.2uf l1 2.2uh c2 0.01
7 ? 2005 semtech corp. www.semtech.com SC4625 power management outline drawing - mlp-10 min aaa bbb b e l n d c e a1 a2 a dim millimeters nom dimensions max nom inches min max .114 .118 .122 2.90 3.00 3.10 - - - - l aser mark) indicator pin 1 1 n 2 notes: controlling dimensions are in millimeters (angles in degrees). coplanarity applies to the exposed pad as well as terminals. 2. 1. .003 .007 .042 10 .009 .048 - .000 .031 (.008) 0.08 0.23 10 .011 .052 0.18 1.06 .039 - .002 - 0.00 0.80 1.31 0.30 1.21 - 0.05 1.00 (0.20) .004 0.10 0.50 bsc .020 bsc 0.30 .012 .020 .016 0.40 0.50 a aaa c a2 seating plane a1 a bxn bbb c a b b e c c d lxn e e .074 .079 .083 1.87 2.02 2.12
8 ? 2005 semtech corp. www.semtech.com SC4625 power management land pattern - mlp-10 .087 .055 2.20 1.40 .150 .020 .012 .037 3.80 0.30 0.95 0.50 (.112) .075 1.90 (2.85) k h x this land pattern is for reference purposes only. consult your manufacturing group to ensure your company's manufacturing guidelines are met. notes: 1. inches dimensions g k h x y p z c dim millimeters y z g (c) p semtech corporation power management products division 200 flynn road, camarillo, ca 93012 phone: (805)498-2111 fax (805)498-3804 contact information
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