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1 www.semtech.com SC2738 ultra low output voltage dual linear fet controller power management revision: november 16, 2004 description features the SC2738 is an ultra low output voltage dual power supply controller designed to simplify power management for desktop pcs and graphics cards. it is part of semtech?s smart ldo tm family of products. the SC2738 has two user adjustable outputs that can be set anywhere be- tween 0.5v and 3.3v (v in = 12v, anywhere between 0.5v and 1.8v for v in = 5v) using two external resistors per output. SC2738 features for each output include tight output voltage regulation (3.5% over -40c to +85c), enable controls, open drain power good signals, under-voltage protection and soft start. the enable pins allow the part to enter a very low power standby mode. pulling them high enables the outputs. the power good pins are open drain and assert low when the voltage at their respective adjust pins is below 88% (typ.) of nominal. if the voltage at the adjust pin is below 50% (typ.) of nominal, the under-voltage protection circuitry will shut down that output. the SC2738 is available in an msop-10 surface mount package. ? 3.5% reference voltage ? two independant and fully adjustable outputs ? wide supply voltage range permits operation from 5v or 12v rails ? very low quiescent current (500a typical with both outputs enabled and 5v input) ? indivdual enable control for each output ? individual power good monitoring and signalling for each output ? gate drives from input supply enable use of n-channel mosfets ? user selectable dropout voltage ? individual under-voltage protection for each output ? msop-10 surface mount package ? desktop pcs ? graphics cards ? simple dual power supplies typical application circuit applications out1 enable r3 20.0k out1 power good u1 SC2738 1 2 3 4 5 6 7 8 9 10 drv1 adj1 en1 pgd1 gnd pgd2 en2 adj2 drv2 in c1 0.1uf (1) vin2 r4 10.0k r6 2k (2) c5 10nf (2) out2 enable vout1 vin1 notes: (1) additional capacitance may be required if far from supply (2) optional soft-start components c6 0.1uf q1 4 1 2 3 5 6 7 8 vout2 out2 power good c7 10nf (2) c3 100uf, 25mohm poscap c4 100uf, 25mohm poscap r1 11.0k 5v or 12v in r5 2k (2) c2 0.1uf (1) r2 10.0k ? ? ? ? ? ? + ? = 2 r 1 r 1 5 . 0 v 1 out ? ? ? ? ? ? + ? = 4 r 3 r 1 5 . 0 v 2 out
2 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management absolute maximum ratings r e t e m a r a pl 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 s t u p n iv n i 2 . 3 1 + o t 3 . 0 -v s n i p e v i r dv v r d 0 . 8 + o t 3 . 0 -v s n i p d o o g r e w o p d n a t s u j d av j d a v , d g p 5 . 5 + o t 3 . 0 - ) 1 ( v s n i p e l b a n ev n e v o t 3 . 0 - n i v t n e i b m a o t n o i t c n u j e c n a d e p m i l a m r e h t a j 3 1 1w / c e s a c o t n o i t c n u j e c n a d e p m i l a m r e h t c j 2 4w / 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 ot a 5 8 + 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 ot 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 st g t s 0 5 1 + o t 5 6 -c . 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 lt 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 ed s e2 v k r e t e m a r a pl o b m y ss n o i t i d n o c t s e tn i mp y tx a ms t i n u n i e g a t l o v y l p p u sv n i 5 . 42 . 3 1 v t n e r r u c t n e c s e i u qi q v n i v 5 =0 0 5 0 0 7 a v n i v 2 1 =0 0 6 0 0 9 a t n e r r u c y b d n a t si ) f f o ( q w o l n e h t o b1 . 0 0 . 1 a v , w o l n e h t o b n i v 2 1 = 0 . 5 1 t u o k c o l e g a t l o v r e d n u d l o h s e r h t t r a t sv o l v u v n i g n i s i r5 7 . 3v s i s e r e t s y hv t s y h v n i g n i l l a f0 5 . 0v electrical characteristics unless specified: t a = 25c, v in = v en = 5v 5%, v pwr (1) = 1.5v 5%, 0a i out 3a. values in bold apply over full operating ambient temperature range. note: (1) or v in , if v in 5v. 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. exposure to absolute maximum rated conditions for extended periods of time may affect device reliability.
3 ? 2004 semtech corp. www.semtech.com SC2738 power management notes: (1) if v th(uv) is exceeded for longer than 50 s (nom.) the protection circuitry will shut down that output. (2) during startup only, v th(pgd) is -6% (typ.), then switches to -12% (typ.). r e t e m a r a pl o b m y ss n o i t i d n o c t s e tn i mp y tx a ms t i n u n e d l o h s e r h t t u p n i e l b a n ev h i n o t u p t u o 3 . 1 v v l i f f o t u p t u o 7 . 0 t n e r r u c s a i b t u p n i e l b a n ei n e v n e v 0 =0a v n i v = n e v 2 1 r o v 5 = 1 -1 + j d a t n e r r u c s a i b t u p n i t s u j d ai j d a v j d a v 5 . 0 = 0 0 1 - 0 0 0 1 + a n e g a t l o v e c n e r e f e rv j d a % 5 . 3 - 0 0 5 . 0 % 5 . 3 + v v r d t n e r r u c t u p t u oi v r d p u t r a t s , g n i c r u o s v l i t n u ( ) d g p ( h t ) d e h c a e r s i 0 1a p u t r a t s r e t f a , g n i c r u o s 7 . 0 0 . 2a m g n i k n i s 0 5 3 0 0 7a e g a t l o v t u p t u ov v r d i , n o l l u f v r d v , a m 0 = n i v 2 1 = 6 . 6 9 . 6v i , n o l l u f v r d v , a m 0 = n i v 5 = 0 7 . 4 5 8 . 4 n o i t c e t o r p e g a t l o v r e d n u d l o h s e r h t p i r t ) 1 ( v ) v u ( h t n i p j d a t a d e r u s a e m 0 4 0 5 0 6 v % j d a d g p d l o h s e r h t d o o g r e w o p ) 2 ( v ) d g p ( h t n i p j d a t a d e r u s a e m 5 1 - 2 1 - 9 - v % j d a e g a t l o v w o l c i g o l t u p t u ov d g p v j d a i , v 4 . 0 = d g p a m 1 - = 4 . 0 v e g a k a e l d o o g r e w o p t n e r r u c i d g p v j d a v 0 , v 5 . 0 = v d g p v n i 1 - 0 1 + a t r a t s t f o s e m i t e s i r t u p t u o v % 0 1 t u o v % 0 9 o t t u o v t u o v 5 0 . 1 = t r c d n g - v r d d e c a l p t o n =0 5 1s c d n g - v r d f n 0 1 =0 5 8 r e i f i l p m a r o r r e n i a g p o o l n e p oa l o v 2 5b d h t d i w d n a b n i a gw b g1z h m electrical characteristics (cont.) unless specified: t a = 25c, v in = v en = 5v 5%, v pwr (1) = 1.5v 5%, 0a i out 3a. values in bold apply over full operating ambient temperature range.
4 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management pin descriptions top view (msop-10) r e b m u n t r a p ) 1 ( e g a t l o v t u p t u oe g a k c a p t r t s m i 8 3 7 2 c s ) 2 ( m o r f . j d a h t o b v 3 . 3 o t v 5 . 0 0 1 - p o s m 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 configuration ordering information n i pe m a n n i pn o i t c n u f n i p 11 v r dk 1 ~ e c n a d e p m i t u p t u o , 1 # r o t a l u g e r f o t u p t u o ? n i a t n i a m o t t e f s o m l e n n a h c - n n a f o e t a g e h t s e v i r d . v 1 t u o . 2 r d n a 1 r y b t e s 21 j d a d n a , e g a t l o v - r e d n u d n a d o o g r e w o p r o f e g a t l o v t u p t u o e h t g n i s n e s r o f d e s u . t u p n i e s n e s 1 # r o t a l u g e r : ) 1 e g a p n o t i u c r i c n o i t a c i l p p a o t r e f e r ( s w o l l o f s a e g a t l o v t u p t u o e h t t e s o t v ) x a m ( t u o v r o f v 3 . 3 = n i v r o f v 8 . 1 , v 2 1 = n i . v 5 = 31 n e . t a o l f o t w o l l a t o n o d . d e s u g n i e b t o n f i n i o t t c e n n o c . l o r t n o c e l b a n e h g i h e v i t c a 41 d g pv r o f t u p t u o l a n g i s d o o g r e w o p 1 t u o v n e h w w o l s l l u p t u p t u o n i a r d n e p o . 1 t u o v ( w o l e b s i ) m o n ( 1 t u o . ) % 2 1 - 5d n g. d n u o r g 62 d g pv r o f t u p t u o l a n g i s d o o g r e w o p 2 t u o v n e h w w o l s l l u p t u p t u o n i a r d n e p o . 2 t u o v ( w o l e b s i ) m o n ( 2 t u o . ) % 2 1 - 72 n e . t a o l f o t w o l l a t o n o d . d e s u g n i e b t o n f i n i o t t c e n n o c . l o r t n o c e l b a n e h g i h e v i t c a 82 j d a d n a , e g a t l o v - r e d n u d n a d o o g r e w o p r o f e g a t l o v t u p t u o e h t g n i s n e s r o f d e s u . t u p n i e s n e s 2 # r o t a l u g e r : ) 1 e g a p n o t i u c r i c n o i t a c i l p p a o t r e f e r ( s w o l l o f s a e g a t l o v t u p t u o e h t t e s o t v ) x a m ( t u o v r o f v 3 . 3 = n i v r o f v 8 . 1 , v 2 1 = n i . v 5 = 92 v r dk 1 ~ e c n a d e p m i t u p t u o , 2 # r o t a l u g e r f o t u p t u o ? n i a t n i a m o t t e f s o m l e n n a h c - n n a f o e t a g e h t s e v i r d . v 2 t u o . 4 r d n a 3 r y b t e s 0 1n i. y l p p u s v 2 1 + r o v 5 + ? ? ? ? ? ? + ? = 2 r 1 r 1 5 . 0 v 1 out ? ? ? ? ? ? + ? = 4 r 3 r 1 5 . 0 v 2 out
5 ? 2004 semtech corp. www.semtech.com SC2738 power management block diagram (0.94 vbg at start-up) (0.94 vbg at start-up)
6 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management applications infomation theory of operation the SC2738 dual linear fet controller provides a simple way to drive two n-channel mosfets to produce tightly regulated output voltages from one or two available, higher, supply voltages. it takes its power from either a 5v or 12v supply, drawing typically 500a while operating. it contains an internal bandgap reference which is compared to the output voltages via resistor dividers. these resistor dividers are external and user selectable . depending upon the input voltage used for the device, the drive pin (drv1, drv2) can pull up to a guaranteed minimum of 6.6v (from 12v supply) or 4.7v (from 5v supply). thus the device can be used to regulate a large range of output voltages by careful selection of the external mosfets (see component selection, below). the SC2738 includes an active high enable control (en1, en2) for each output. if this pin is pulled low, the related drive pin is pulled low, turning off the n-channel mosfet. if the pin is pulled up to 1.8v v en v in , the drive pin will be enabled. this pin should not be allowed to float. each output has a power good output (pgd1, pgd2) which are open drain outputs that pull low if the related output is below the power good threshold (-12% of the programmed output voltage typical, -6% typical at start- up). the power good circuitry is active if the device is enabled, regardless of the state of the over current latch. the power good circuitry is not active if that particular output is disabled. also included for each output is an overcurrent protection circuit that monitors the output voltage. if the output voltage drops below 50% (typ.) of nominal, as would occur during an overcurrent or short condition, the device will pull the drive pin low and latch off. the device will need to have the power supply or enable pin toggled to reset the latch condition. each output latches independently (i.e. if one output latches off, the other output will function normally). drive outputs and soft start the drive outputs for each output are source and sink capable. the sink current is typically 0.8ma at 5v in (1ma at 12v in). the source current is typically 2ma at 5v in and 3.75ma at 12v in during normal operation. the high side drive voltage is generated from v in by a 7v (nominal) low dropout regulator, thus at 12v in, 6.9v is available and at 5v in, 4.85v is available (since the ldo will be in dropout). at start-up, the source current available from the drive pins is limited to 10a (typical) until the power good threshold is reached, at approximately 6% below nominal output voltage. at this point the full drive capability is enabled. with this constant current source at start-up, it is a simple matter to use a small capacitor on the drive pin to slow this rate of rise. the rate of rise of the drive pin voltage will be: s / v c i dt dv ss drv drv = a 10nf soft start capacitor will give a 1ms output rise time for v in = 12v and v out = 1.05v, for example. the output rise time will of course depend upon the gate threshold of the mosfet being used. please refer to the output rise time chart on page 12 showing typical output rise times. for very low esr output capacitors (<5m ? ) and very high soft start capacitance (>100nf), it may be necessary to add a resistor in series with the soft start capacitor to ensure stability. generally, however, this resistor is not required, as this is a very unlikely situation. the soft start capacitance does not adversely affect transient response since the drive current capability is 200 times higher once the device has started. ocp and power supply sequencing the SC2738 has output under-voltage protection that looks at a particular output to see if it is a) less than 50% (typical) of it?s nominal value and b) v drv for that output is within 350mv (typical) of maximum. if both of these criteria are met, there is a 50s (typical) delay and then the output is shut down. this provides inherent immunity to uv shutdown at start-up (which may occur while the output capacitors are being charged) since v drv has a very slow rate of rise with i drv limited to 10a. at start-up, it is necessary to ensure that the power supplies and enables are sequenced correctly to avoid erroneous latch-off. for uv latch-off not to occur at start- up due to sequencing issues, the key is that the voltage
7 ? 2004 semtech corp. www.semtech.com SC2738 power management applications infomation (cont.) supplied to the mosfet drain should be greater than the output under-voltage threshold when that output is enabled. this assumes that the drop through the pass mosfet is negligible. if not, then this drop needs to be taken into account also since: v out = v drain - (i out x r ds(on) ). if the supply to the SC2738 in pin comes up before the supply to the mosfet drain, then that output should be enabled as the supply to the mosfet drain is applied - the power good signal for this rail would be ideal. if the power supply to the mosfet drain comes up before the power supply to the SC2738 in pin, then the output can either be enabled with the supply to the in pin or after- wards. please see the example below. example: SC2738 powered from 5v, output 1 powered from 1.8v set for 1.5v out, output 2 not shown for simplicity. worst case under-voltage threshold is 60% (over temperature) of 1.5v, or 0.9v. the typical enable threshold is ~1v. see figure 1 below. component selection output capacitors: low esr capacitors such as sanyo poscaps or panasonic sp-caps are recommended for bulk capacitance, with ceramic bypass capacitors for decoupling high frequency transients. input capacitors: placement of low esr capacitors such as sanyo poscaps or panasonic sp-caps at the input to the mosfet (v drain ) will help to hold up the power supply during fast load changes, thus improving overall transient response. if v drain is located at the bulk capacitors for the upstream voltage regulator, additional capacitance may not be required. in this case a 0.1f ceramic capacitor will suffice. the input supply to the SC2738 should be bypassed with a 0.1f ceramic capacitor. SC2738 supply comes up before mosfet drain supply mosfet drain supply comes up before SC2738 supply figure 1: power supply sequencing
8 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management mosfets: very low or low threshold n-channel mosfets are required. selecting fets rated for v gs of 2.7v or 4.5v will depend upon the available drive voltage (6.9v from 12v in or 4.85v from 5v in), the output voltage and output current. for the device to work under all operating conditions, a maximum r ds(on) must be met to ensure that the output will never go into dropout: ? ? = ) max ( out ) max ( out ) min ( in ) max )( on ( ds i v v r note that r ds(on) must be met at all temperatures and at the minimum v gs condition. setting the output voltage: the adjust pins connect directly to the inverting input of the error amplifiers, and the output voltage is set using external resistors (please refer to the typical application circuit on page 1). using output 1 as an example, the output voltage can be calculated as follows: ? ? ? ? ? ? + ? = 2 r 1 r 1 5 . 0 v out the input bias current for the adjust pin is so low that it can be safely ignored. to avoid picking up noise, it is recommended that the total resistance of the feedback chain be less than 100k ? . please see table 1 on this page for recommended resistor values for some standard output voltages. all resistors are 1%, 1/10w. the maximum output voltage that can be obtained from each output is determined by the input supply voltage and the r ds(on) and gate threshold voltage of the external mosfet. assuming that the mosfet gate threshold voltage is sufficiently low for the output voltage chosen and the worst-case drive voltage, v out(max) is given by: ) max )( on ( ds ) max ( out ) min ( drain ) max ( out r i v v ? ? = ) v ( t u o vk ( 3 r r o 1 r ? ? ? ? ? )k ( 4 r r o 2 r ? ? ? ? ? ) 5 0 . 10 . 1 10 . 0 1 2 . 10 . 4 10 . 0 1 5 . 10 . 0 20 . 0 1 5 . 23 . 5 43 . 1 1 3 . 34 . 3 63 . 1 1 table 1: recommended resistor values for SC2738 design example goal: 1.5v5% static and 7% transient @ up to 4a from 2.5v5% and 5v5% total window for dc error and ripple is 75mv. total window for transient is 105mv. since this device is linear, and assuming that it has been designed to not ever enter dropout, we do not have ripple on the output. the dc error for this output is the sum of: v ref accuracy = 3.5% = 52.5mv feedback chain tolerance = 1% = 15mv load regulation = 0.25% = 3.8mv set resistors per table 1 should be 20.0k ? (top) and 10.0k ? (bottom). total dc error = 4.75% = 71.3mv this leaves 2.25% = 33.7mv for the load transient esr spike, therefore: ? = = m 4 . 8 a 4 mv 7 . 33 r ) max ( esr bulk capacitance required is given by: f dv t di c ) min ( bulk ? = where di is the maximum load current step, t is the maximum regulator response time and dv is the allowable voltage droop. therefore with di = 4a, t = 1s, and dv = 33.7mv: applications infomation (cont.)
9 ? 2004 semtech corp. www.semtech.com SC2738 power management f 119 10 7 . 33 10 1 4 c 3 6 ) min ( bulk = ? ? ? = ? ? so if we use 1% v out set resistors we would select 2 x >100f, 18m ? poscaps for output capacitance (which assumes that local ceramic bypass capacitors will absorb the balance of the (9 - 8.4)m ? esr requirement - otherwise 15m ? capacitors should be used). if we use 0.1% set resistors, then the total dc error becomes 3.85% = 57.8mv, leaving 3.15% = 47.2mv for the esr spike. in this case: ? = = m 8 . 11 a 4 mv 2 . 47 r ) max ( esr and f 85 10 2 . 47 10 1 4 c 3 6 ) min ( bulk = ? ? ? = ? ? so for 0.1% resistors we could use 1 x 100f, 12m ? poscaps for output capacitance. the input capacitance needs to be large enough to stop the input supply from collapsing below -5% (i.e. the design minimum) during output load steps. if the input to the pass mosfet is not local to the supply bulk capacitance then additional bulk capacitance may be required. mosfet selection: since the input voltage to the SC2738 is 5v5%, the minimum available gate drive is: v 825 . 2 ) 575 . 1 4 . 4 ( v gs = ? = so a mosfet rated for v gs = 2.7v will be required, with an r ds(on)(max) (over temp.) given by: ? = ? = ? = m 22 4 ) 5 . 1 375 . 2 ( i ) v v ( r ) max ( out out ) min ( in ) max ) on ( ds obviously, if a 12v rail is available to power the SC2738, the number of fet options increases dramatically. layout guidelines the advantages of using the SC2738 to drive external mosfets are a) that the bandgap reference and control circuitry are in a die that does not contain high power dissipating devices and b) that the device itself does not need to be located right next to the power devices. thus very accurate output voltages can be obtained since changes due to heating effects will be minimal. the 0.1f bypass capacitor should be located close to the supply (in) and gnd pins, and connected directly to the ground plane. the feedback resistors should be located at the device, with the sense line from the output routed from the load (or top end of the droop resistor if passive droop is being used) directly to the feedback chain. if passive droop is being used, the droop resistor should be located right at the load to avoid adding additional unplanned droop. sense and drive lines should be routed away from noisy traces or components. for very low input to output voltage differentials, the input to output / load path should be as wide and short as possible. where greater headroom is available, wide traces may suffice. power dissipation within the device is practically negligible, thus requiring no special consideration during layout. the mosfet pass devices should be laid out according to the manufacturer?s guidelines for the power being dissipated within them. applications infomation (cont.)
10 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management quiescent current vs. junction temperature vs. input voltage standby current vs. junction temperature vs. input voltage start threshold vs. junction temperature enable input threshold voltage vs. junction temperature reference voltage vs. junction temperature drive pin output current (sourcing) at startup vs. junction temperature vs. input voltage typical characteristics 0 100 200 300 400 500 600 700 800 900 -50 -25 0 25 50 75 100 125 t j (c) i q (a) both v en = 5v both v adj < v bg v in = 5v v in = 12v 0.01 0.1 1 10 100 -50 -25 0 25 50 75 100 125 t j (c) i q(off) (a) v in = 12v v in = 5v both v en = 0v 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -50 -25 0 25 50 75 100 125 t j (c) v uvlo (v) v in rising v in falling 0.490 0.492 0.494 0.496 0.498 0.500 0.502 0.504 0.506 0.508 0.510 -50 -25 0 25 50 75 100 125 t j (c) v adj (mv) v in = v en = 5v 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 -50 -25 0 25 50 75 100 125 t j (c) v ih/l (v) v in = 5v v ih v il 0 2 4 6 8 10 12 14 16 18 20 -50 -25 0 25 50 75 100 125 t j (c) i drv (a) v in = 12v v en = 5v v adj < v th(pgd) v in = 5v
11 ? 2004 semtech corp. www.semtech.com SC2738 power management drive pin output current (sourcing) vs. junction temperature vs. input voltage drive pin output current (sinking) vs. junction temperature vs. input voltage typical characteristics (cont.) drive pin output voltage (full on) vs. junction temperature vs. input voltage under voltage trip threshold vs. junction temperature power good threshold vs. junction temperature power good logic low output voltage vs. junction temperature 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -50 -25 0 25 50 75 100 125 t j (c) i drv (ma) v en = 5v v adj < v bg v in = 12v v in = 5v 0 200 400 600 800 1000 1200 -50 -25 0 25 50 75 100 125 t j (c) i drv (a) v en = 5v v adj > v bg v in = 5v v in = 12v 0 1 2 3 4 5 6 7 8 -50 -25 0 25 50 75 100 125 t j (c) v drv (v) v en = 5v i drv = 0ma v adj < v bg v in = 12v v in = 5v -60 -58 -56 -54 -52 -50 -48 -46 -44 -42 -40 -50 -25 0 25 50 75 100 125 t j (c) v th(uv) (%v adj ) v in = v en = 5v -15.0 -12.5 -10.0 -7.5 -5.0 -2.5 0.0 -50 -25 0 25 50 75 100 125 t j (c) v th(pgd) (%v adj ) v in = v en = 5v startup only normal operation 0 25 50 75 100 125 150 175 200 -50 -25 0 25 50 75 100 125 t j (c) v pgd (mv) v in = v en = 5v v adj = 0.4v i pgd = -1ma
12 ? 2004 semtech corp. www.semtech.com SC2738 preliminary power management output rise time at startup vs. soft start capacitance vs. input voltage typical characteristics (cont.) 0.1 1 10 100 0.1 1 10 100 c drv (nf) t r(out) (ms) v en = 5v t j = 25c v out = 1.05v c out = 100f, 25m ? i out = 0a mosfet = irf7311 v in = 5v v in = 12v v in = 5v, 1.2v in to 1.05v out i out = 0.01a to 2.51a to 0.01a c out = 2 x 100f, 25m ? trace 1: v out , 20mv/div., offset 1v trace 2: v drv , 2v/div. trace 3: 1.2v in, 50mv/div., offset 1v trace 4: load fet drain timebase: 20s/div. load rise/fall times 35a /s load transient response, no passive droop v in = 5v, 1.2v in to 1.05v out i out = 0.01a to 2.51a to 0.01a c out = 1 x 100f, 25m ? r droop = 20m ? trace 1: v out , 20mv/div., offset 1v trace 2: not connected trace 3: 1.2v in, 50mv/div., offset 1v trace 4: load fet drain timebase: 20s/div. load rise/fall times 35a /s load transient response, with passive droop
13 ? 2004 semtech corp. www.semtech.com SC2738 power management outline drawing - msop-10 semtech corporation power management products division 200 flynn road, camarillo, ca 93012 phone: (805)498-2111 fax (805)498-3804 contact information land pattern - msop-10 bbb c a-b d dimensions "e1" and "d" do not include mold flash, protrusions 3. or gate burrs. datums and to be determined at datum plane controlling dimensions are in millimeters (angles in degrees). -b- notes: 1. 2. -a- -h- side view a b c d h plane 0 .010 .004 - .016 .003 .024 (.037) - .000 .030 - - - - 0.25 0.10 8 0 - 8 0.60 (.95) .032 .009 0.40 0.08 .043 .006 .037 0.75 0.00 - 0.80 0.23 - 0.95 1.10 0.15 - - - e .193 bsc .020 bsc detail aaa c seating indicator ccc c 2x n/2 tips pin 1 2x e/2 10 see detail a1 a a2 bxn d 0.25 a plane gage .003 e1 12 n .114 .114 .118 .118 .007 - 10 01 c (l1) l a 0.08 3.00 3.00 4.90 bsc 0.50 bsc .122 .122 2.90 2.90 .011 0.17 3.10 3.10 0.27 - reference jedec std mo-187 , variation ba. 4. dim ccc a1 e bbb aaa 01 l1 n l d e1 e a2 b c a millimeters nom inches dimensions min nom max min max e this land pattern is for reference purposes only. consult your manufacturing group to ensure your company's manufacturing guidelines are met. notes: 1. p (c) x z g y .063 .224 .011 .020 .098 (.161) 5.70 1.60 0.30 0.50 2.50 (4.10) millimeters dimensions dim inches y z g p x c

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