power management 1 www.semtech.com sc431 adjustable shunt regulator revision: april 23, 2008 the sc431 is a three terminal adjustable shunt regulator with thermal stability guaranteed over temperature. the output voltage can be adjusted to any value from 2.5v (v ref ) to 30v with two external resistors. the sc431 has a typical dynamic output impedance of 0.25 ? . active output circuitry provides a very sharp turn on characteristic, making the sc431 an excellent replacement for zener diodes. the sc431 shunt regulator is available with four voltage tolerances (0.5%, 1.0% and 2.0% over t a = -40 c to +85 c and 0.5% over t a = -40 c to +125 c) and two package options (sot-23-3 and so-8). this allows the designer the opportunity to select the optimum combination of cost and performance for their application. ? linear regulators ? adjustable supplies ? switching power supplies ? battery operated computers ? instrumentation ? computer disk drives ? wide operating current range 130a to 150ma ? low dynamic output impedance 0.25 ? typ. ? trimmed bandgap design + 0.5% ? alternate for tl1431, tl431, lm431 & as431 ? industrial temperature range ? available in sot-23-3 and so-8 packages. also available in lead-free, fully weee and rohs compliant. notes: 1) set v out according to the following equation: 1 r i 2 r 1 r 1 v v ref ref out + ? ? ? ? ? ? + = 2) choose the value for r as follows: ? the maximum limit for r should be such that the cathode current, i z , is greater than the minimum operating current (130a) at v in(min) . ? the minimum limit for r should be such that i z does not exceed 150ma under all load conditions, and the instantaneous turn-on value for i z does not exceed 200ma. both of the following conditions must be met: ma 200 v r (max) in min (to limit instantaneous turn-on i z ) ma 150 i v v r (min) out out (max) in min + ? (to limit i z under normal operating conditions) applications typical application circuit (1)(2) features description
2 ? 2008 semtech corp. www.semtech.com power management sc431 absolute maximum ratings electrical characteristics 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 e d o h t a c v z 1 3v t n e r r u c e d o h t a c s u o n i t n o c i z 0 5 1a m t n e r r u c t u p n i e c n e r e f e r i f e r 0 1a m t t a n o i t a p i s s i d r e w o p a c 5 2 = 3 - 3 2 - t o s 8 - o s p d 7 3 . 0 8 7 . 0 w e c n a t s i s e r l a m r e h t 3 - 3 2 - t o s 8 - o s a j 6 3 3 3 6 1 w / c e g n a r e r u t a r e p m e t t n e i b m a g n i t a r e p o 2 - x c 1 3 4 c s , 1 - x c 1 3 4 c s , 5 . - x c 1 3 4 c s q x c 1 3 4 c s t a 5 8 + o t 0 4 - 5 2 1 + o t 0 4 - 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 o t j 0 5 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 s t g t s 0 5 1 + o t 5 6 -c s d n o c e s 0 1 ) g n i r e d l o s ( e r u t a r e p m e t d a e l t d a e l 0 0 3c ) l e d o m y d o b n a m u h ( g n i t a r d s e v d s e 2v k , 5 . - x c 1 3 4 c s q x c 1 3 4 c s 1 - x c 1 3 4 c s r e t e m a r a pl o b m y sn o i t i d n o cn i mp y tx a mn i mp y tx a ms t i n u e g a t l o v e c n e r e f e rv f e r v z v = f e r i , z a m 0 1 = ) 1 ( 2 8 4 . 25 9 4 . 27 0 5 . 20 7 4 . 25 9 4 . 20 2 5 . 2v v f e r n o i t a i v e d p m e tv v e d v z v = f e r ,i z a m 0 1 = ) 1 ( 87 185 2 v m n i e g n a h c f o o i t a ri z , a m 0 1 = ? v z v o t v 0 1 = f e r 5 . 0 -7 . 2 -5 . 0 -7 . 2 -v / v m v f e r v n i e g n a h c o t z i z , a m 0 1 = ? v z v 0 1 o t v 0 3 =0 . 1 -0 . 2 -0 . 1 -0 . 2 - t u p n i e c n e r e f e r t n e r r u c i f e r k 0 1 = 1 r ? = 2 r , , i z a m 0 1 = ) 2 ( 5 . 04 5 . 04a i f e r e r u t a r e p m e t n o i t a i v e d i ) v e d ( f e r k 0 1 = 1 r ? = 2 r , , i z a m 0 1 = ) 2 ( 4 . 02 . 14 . 02 . 1 a e d o h t a c e t a t s - f f o t n e r r u c i ) f f o ( z v f e r v , v 0 = z v 0 3 = ) 3 ( 4 0 . 00 5 . 04 0 . 00 5 . 0a t u p t u o c i m a n y d e c n a d e p m i r z v , z h k 1 < f z v = f e r i z a m 0 0 1 o t a 0 3 1 = ) 1 ( 5 2 . 00 5 . 05 2 . 00 5 . 0 ? g n i t a r e p o m u m i n i m t n e r r u c i ) n i m ( z v z v = f e r ) 1 ( 0 3 10 3 1a z ref v v ? ? 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. unless specified:t a = 25c. values in bold apply over full operating ambient temperature range.
3 ? 2008 semtech corp. www.semtech.com power management sc431 test circuit 3 off-state test circuit 2 v z > v ref test circuit 1 v z = v ref electrical characteristics (cont.) 2 - x c 1 3 4 c s r e t e m a r a pl o b m y sn o i t i d n o cn i mp y tx a ms t i n u e g a t l o v e c n e r e f e rv f e r v z v = f e r i , z a m 0 1 = ) 1 ( 5 4 4 . 25 9 4 . 25 4 5 . 2v v f e r n o i t a i v e d p m e tv v e d v z v = f e r ,i z a m 0 1 = ) 1 ( 5 10 3 v m v n i e g n a h c f o o i t a r f e r o ti z , a m 0 1 = ? v z v o t v 0 1 = f e r 5 . 0 -7 . 2 -v / v m v n i e g n a h c z i z , a m 0 1 = ? v z v 0 1 o t v 0 3 =0 . 1 -0 . 2 - t n e r r u c t u p n i e c n e r e f e ri f e r k 0 1 = 1 r ? = 2 r , i , z a m 0 1 = ) 2 ( 5 . 04a i f e r n o i t a i v e d e r u t a r e p m e ti ) v e d ( f e r k 0 1 = 1 r ? = 2 r , ,i z a m 0 1 = ) 2 ( 4 . 02 . 1 a t n e r r u c e d o h t a c e t a t s - f f oi ) f f o ( z v f e r v , v 0 = z v 0 3 = ) 3 ( 4 0 . 00 5 . 0a e c n a d e p m i t u p t u o c i m a n y dr z v , z h k 1 < f z v = f e r i , z a m 0 0 1 o t a 0 3 1 = ) 1 ( 5 2 . 00 5 . 0 ? t n e r r u c g n i t a r e p o m u m i n i mi ) n i m ( z v z v = f e r ) 1 ( 0 3 1a z ref v v ? ? unless specified:t a = 25c. values in bold apply over full operating ambient temperature range. notes: (1) see test circuit 1 below. (2) see test circuit 2 below. (3) see test circuit 3 below. n i mx a ml o b m y s v , e g a t l o v e d o h t a c z v f e r 0 3v i , t n e r r u c e d o h t a c z 0 3 1 . 00 5 1a m test circuits recommended operating conditions
4 ? 2008 semtech corp. www.semtech.com power management sc431 e c n a r e l o t% 5 . 0% 5 . 0% 0 . 1% 0 . 2 e g n a r e r u t a r e p m e t t n e i b m ac 5 8 + o t c 0 4 -c 5 2 1 + o t c 0 4 -c 5 8 + o t c 0 4 -c 5 8 + o t c 0 4 - 3 - 3 2 - t o s ) 1 ( r t 5 . - k s c 1 3 4 c sr t q k s c 1 3 4 c sr t . 1 - k s c 1 3 4 c sr t . 2 - k s c 1 3 4 c s 3 - 3 2 - t o s ) 3 ( , ) 1 ( t r t 5 . - k s c 1 3 4 c st r t q k s c 1 3 4 c st r t 1 - k s c 1 3 4 c st r t 2 - k s c 1 3 4 c s 8 - o s ) 2 ( r t 5 . - s c 1 3 4 c sr t q s c 1 3 4 c sr t . 1 - s c 1 3 4 c sr t . 2 - s c 1 3 4 c s 8 - o s ) 3 ( ) 2 ( t r t 5 . - s c 1 3 4 c st r t q s c 1 3 4 c st r t . 1 - s c 1 3 4 c st r t . 2 - s c 1 3 4 c s so-8 (top view) sot-23-3 (top view) notes: (1) only available in tape and reel packaging. a reel contains 3000 devices. (2) only available in tape and reel packaging. a reel contains 2500 devices. (3) ?t? at end of part number indicates ?lead free?. this product is fully weee and rohs compliant. pin configurations block diagram ordering information symbol
5 ? 2008 semtech corp. www.semtech.com power management sc431 marking information sot-23-3 (top view) 4 3 1 4 3 1 yyww = datecode (example: 0008) xxxxx = semtech lot # (example: 00101) so-8 (top view) so-8 (bottom view) xxxxx sc 431cs yyww
6 ? 2008 semtech corp. www.semtech.com power management sc431 -300 -200 -100 0 100 200 300 -2-10123 v z (v) i z ( a) v z = v ref t a = 25 o c -150 -100 -50 0 50 100 150 -2-10123 v z (v) i z (ma) v z = v ref t a = 25 o c 0 0.1 0.2 0.3 0.4 0.5 -50 -25 0 25 50 75 100 125 150 t j (c) v ref / v z (-mv/v) i z = 10ma ? v z = 3v to 30v 2.485 2.490 2.495 2.500 2.505 2.510 2.515 -50 -25 0 25 50 75 100 125 150 t j (c) v ref (v) v z = v ref i z = 10ma 0 20 40 60 80 100 -50 -25 0 25 50 75 100 125 150 t j (c) i ref (na) i z = 10ma r1 = 10k ? r2 = 0.001 0.01 0.1 1 10 100 -50 -25 0 25 50 75 100 125 150 t j (c) i z(off) v z = 30v v ref = 0v cathode current vs. cathode voltage cathode current vs. cathode voltage reference voltage vs. junction temperature reference input current vs. junction temperature ratio of delta reference voltage to delta cathode voltage vs. junction temperature off-state cathode current vs. junction temperature typical characteristics
7 ? 2008 semtech corp. www.semtech.com power management sc431 0.01 0.1 1 10 100 1.0e+03 1.0e+04 1.0e+05 1.0e+06 1.0e+07 f (hz) r z ( ) i z = 10ma t a = 25c -20 -10 0 10 20 30 40 50 60 70 80 1.0e+02 1.0e+03 1.0e+04 1.0e+05 1.0e+06 f (hz) a v (db) -630 -585 -540 -495 -450 -405 -360 -315 -270 -225 -180 phase shift (deg) i z = 10ma t a = 25c small-signal gain and phase shift vs. frequency reference impedance vs. frequency test circuit - stability stability boundary condition for shunt regulation vs. cathode current and load capacitance typical characteristics (cont.) test circuit - small-signal gain and phase
8 ? 2008 semtech corp. www.semtech.com power management sc431 reference ipc-sm-782a. 2. e .037 0.95 y y g z c e x e1 e1 .075 1.90 notes: 1. this land pattern is for reference purposes only consult your manufacturing group to ensure your company's manufacturing guidelines are met. dim y z g x c millimeters inches (2.20) .055 .141 .039 .031 (.087) 1.40 3.60 1.00 0.80 dimensions e e1 d e1 e bxn 12 3 a1 a2 a 3x a bbb c a b b h 0.25 c seating plane gauge see detail a plane 0 c l l1 detail a 1.40 1.20 n 33 0 - 8 0 8 0 - .055 .047 datums and to be determined at datum plane -a- -b- 2. -h- c seating plane aaa c bbb .008 0.20 aaa .004 0.10 inches .114 l1 e d b e c .012 .003 .082 a1 dim a min .000 .035 0.51 0.18 2.64 0.30 0.08 2.10 .022 - .075 - .093 .020 .007 .104 (0.55) 1.90 bsc - - 2.37 2.90 millimeters max 0.10 1.12 min dimensions 0.01 max nom - - .004 .044 nom 0.89 - - controlling dimensions are in millimeters (angles in degrees). notes: or gate burrs. dimensions "e1" and "d" do not include mold flash, protrusions 3. 1. 3.04 2.80 .110 .120 e1 .037 0.95 bsc l .015 .020 0.50 0.40 .024 0.60 a2 .035 .037 0.95 0.88 .040 1.02 e1 .051 1.30 side view land pattern - sot-23-3 outline drawing - sot-23-3
9 ? 2008 semtech corp. www.semtech.com power management sc431 see detail detail a a .050 bsc .236 bsc 8 .010 .150 .189 .154 .193 .012 - 8 0.25 1.27 bsc 6.00 bsc 3.90 4.90 - .157 .197 3.80 4.80 .020 0.31 4.00 5.00 0.51 bxn 2x n/2 tips seating aaa c e/2 2x 12 n a d a1 e1 bbb c a-b d ccc c e/2 a2 (.041) .004 .008 - .028 - - - - 0 .016 .007 .049 .004 .053 8 0 0.20 0.10 - 8 0.40 0.17 1.25 0.10 .041 .010 .069 .065 .010 1.35 (1.04) 0.72 - 1.04 0.25 - - - 1.75 1.65 0.25 0.25 - .010 .020 0.50 - c l (l1) 01 0.25 gage plane h h 3. dimensions "e1" and "d" do not include mold flash, protrusions or gate burrs. -b- controlling dimensions are in millimeters (angles in degrees). datums and to be determined at datum plane notes: 1. 2. -a- -h- side view a b c d e h plane reference jedec std ms-012, variation aa. 4. l1 n 01 bbb aaa ccc a b a2 a1 d e e1 l h e c dim min millimeters nom dimensions inches min max max nom e (.205) (5.20) z g y p (c) 3.00 .118 1.27 .050 0.60 .024 2.20 .087 7.40 .291 x inches dimensions z p y x dim c g millimeters this land pattern is for reference purposes only. consult your manufacturing group to ensure your company's manufacturing guidelines are met. notes: 1. reference ipc-sm-782a, rlp no. 300a. 2. outline drawing - so-8 land pattern - so-8 h c n a r b n a w i a t 0 8 3 3 - 8 4 7 2 - 2 - 6 8 8 : l e t fx a0 9 3 3 - 8 4 7 2 - 2 - 6 8 8 : h b m g d n a l r e z t i w s h c e t m e s h c n a r b n a p a j 0 5 9 0 - 8 0 4 6 - 3 - 1 8 : l e t 1 5 9 0 - 8 0 4 6 - 3 - 1 8 : x a f h c n a r b a e r o k tl e7 7 3 4 - 7 2 5 - 2 - 2 8 : f6 7 3 4 - 7 2 5 - 2 - 2 8 : x a ) . k . u ( d e t i m i l h c e t m e s 0 0 6 - 7 2 5 - 4 9 7 1 - 4 4 : l e t 1 0 6 - 7 2 5 - 4 9 7 1 - 4 4 : x a f e c i f f o i a h g n a h s t0 3 8 0 - 1 9 3 6 - 1 2 - 6 8 : l e 1 3 8 0 - 1 9 3 6 - 1 2 - 6 8 : x a f l r a s e c n a r f h c e t m e s 0 0 - 2 2 - 8 2 - 9 6 1 ) 0 ( - 3 3 : l e t 8 9 - 2 1 - 8 2 - 9 6 1 ) 0 ( - 3 3 : x a f f o y r a i d i s b u s d e n w o - y l l o h w a s i g a l a n o i t a n r e t n i h c e t m e s . a . s . u e h t n i s r e t r a u q d a e h s t i s a h h c i h w , n o i t a r o p r o c h c e t m e s h b m g y n a m r e g h c e t m e s 3 2 1 - 0 4 1 - 1 6 1 8 ) 0 ( - 9 4 : l e t 4 2 1 - 0 4 1 - 1 6 1 8 ) 0 ( - 9 4 : x a f contact information for semtech international ag
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