mic38300 3a superlnr? low noise high effic i ency regulator adv ance d information superlnr is a trademark of micrel, inc. mlf and mi c r o l eadfram e are re gistered tradema r k of amkor tech nologies micrel inc. ? 2180 fortu ne drive ? san jose, ca 95131 ? usa ? tel +1 ( 40 8 ) 944 -08 00 ? fax + 1 (408) 474-1000 ? htt p :/ /www.micrel.com july 200 7 m999 9-07 060 7 (408) 9 44-0 8 0 0 ge neral d e s c ription the mic383 00 is a 3a pea k, 2.2a continu o u s output curre n t step down conve r t e r and the first device in a new gene ration of superl n r? providing th e benefits of ldo s in re spe c t to ease of use, fa st tran sient perfo rman ce, high psrr an d low noi se wh ile offering t he efficien cy of a swit ching regulator. as output v o ltage s mov e lower, the output noi se and transi ent respon se of a swit chin g re g u lator b e com e an increa sing challen ge for design e rs. by combining a swit che r wh o s e outp u t is slav ed to the input of a high perfo rman ce ldo, hi gh eff i cien cy is a c h i eved with a clea n low noi se ou tput. the mi c38 300 is d e sig ned to p r ovide less than 5m v of pea k to pea k noi se and ove r 7 0 d b of psrr at 1 k hz. f u rth e rmore, th e a r chite c tu re o f the mic383 00 i s optimize d for fast load tra n sie n ts allo wi ng to maintain le ss than 30 mv of output voltage d e viation even durin g ultra fast loa d ste p s , ma king th e mic383 00 a n ideal choi ce for lo w voltage asics and oth e r di gital ics. the mic383 00 features a fu lly integrated swit ching regul ator an d ldo combo , operate s wi th input voltages from 3.0v to 5.5v inpu t and offers adju s table output voltages d o wn to 1.0v. the mic383 00 is offere d in the small 28-pi n 4 6 0.9mm mlf ? packag e and can op erate fro m ?4 0 c to +125 c. data sheet s and suppo rt doc umentatio n can be fou nd o n micrel?s web site at www. micrel.com fe ature s ? 3a pea k outp u t current ? 2.2a contin uo us op erating cu rre nt ? input voltage ran ge: 3.0v to 5.5v ? adjusta b le ou tput voltage down to 1.0v ? output noi se less than 5m v ? ultra fa st tran sient pe rform ance ? uniq ue switcher pl us l d o architectu re ? fully integrat ed mosfet swit che s ? micro-po wer shutd o wn ? easy upg rad e from ldo a s po we r dissi pation become s an i s sue ? thermal shut down and cu rrent limit prot ection ? 4mm 6mm 0.9mm ml f ? packa ge applicati o ns ? point-of-l oad appli c ation s ? networkin g , server, ind u st ri al power ? w i reles s base-s tations ? sensitive rf appli c ation s _ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ ___ _ __ ___ _ __ ___ ___ ___ ___ _ ty pical a pplic ation 0 10 20 30 40 50 60 70 80 90 10 100 1k 10k 100k frequency (hz) mic 38300 p s r r
mic r el, inc . mic38 300 july 200 7 2 m999 9-07 060 7 (408) 9 44-0 8 0 0 block di agram pvin sw switch control v oltag e reference vref ven mic38300 swo lpf ldoin ldoout fb en agnd a vin pgnd ordering inform ation part nu mb er output cu rren t voltage (1 ) j unc tion t e mp eratu re ran g e pack ag e mic383 00hy h l 3.0a adj ?40c to + 1 2 5 c pb-f r ee 28-pi n 4x6 mlf ? note : for additional voltage opt ions, contact micrel.
mic r el, inc . mic38 300 july 200 7 3 m999 9-07 060 7 (408) 9 44-0 8 0 0 pin c onfi gur ation sw 5 1 sw sw sw sw 2 3 4 10 6 7 8 9 24 28 27 26 25 23 11 19 22 21 20 18 16 13 14 15 17 12 sw swo swo swo swo swo sw fb ep a d av i n lpf a gnd pgnd ep a d pgnd pgnd en pvin l d oou t l d oou t ldo i n ldo i n pvin 28-pin 4mm x 6mm ml f ? (m l) (top vie w ) pin d e s c r i ption pin number mic383 00hy h l pin name pin name 1, 2, 3, 4, 5 sw o s w itc h (o utput ): t h is is the output of the pf m s w itch er. 6, 23, 24, 25, 26, 27, 28 sw s w itc h no de: f l oatin g for t y p i cal ap plic at ions. attach ex ternal resist or from lpf to increas e h y st eretic fre que nc y . 7, 22 epad exp o se d he at-sink pa d. recommend to co nnect to pg nd . 8 a v i n anal og sup p l y voltag e: suppl y for the an alo g control circ uit r y . req u ires b y pass ca pacit or to groun d. 9 l p f lo w pass f ilte r : f l oating for typ i cal a p p licati ons. attach external resist or from sw to increase h y ster eti c frequenc y. 1 0 a g n d anal o g g r oun d . 1 1 f b f eedb ack: input to the error amplifi e r. con nect to the e x ternal res i stor divid e r net w o rk to set the output voltage. 12, 13 ldo o u t ldo o u tput (o utput): o u tput of voltage re gu lator. place ca pacitor to gro u nd to b y pass the o u tput voltag e. nomin a l b y p a s s capacitor is 1 0 f . 14, 15 ldo i n ldo input: connect to sw outpu t. requir e s a b y pass cap a citor to grou n d . 16, 17 pvin input sup p l y v o ltag e (input): requ ires b y p a ss capacitor to g nd. 1 8 e n enab le (input): logic lo w w i ll shut do w n th e device, re duci n g the qui esce nt current to less than 50 a. t h i s pin can a l so be use d as an und er-volta ge lockout functi o n b y c onn ectin g a resistor div i der from en/uvlo pin to vin and g nd. 19, 20, 21 pg nd po w e r g r ou nd. note : p r efix h indicates v out >1v, prefix l indicates v out is betw e e n 0.7v to 1v.
micrel, inc. mic38300 july 2007 4 m9999-070607 (408) 944-0800 absolute maximum ratings (1) supply voltage (v in ) .........................................................6v output switch voltage (v sw ) ...........................................6v output switch current (i sw ) .............................................8a ldo output voltage (v out ) .............................................6v logic input voltage (v en , v lq )..........................vin to ?0.3v power dissipation .................................. in ternally limited (3) storage temperature (t s )...................?65c t j +150c esd rating (4) ................................................................. 2kv operating ratings (2) supply voltage (v in ) ...................................... 3.0v to 5.5v junction temperature range ........ ?40c t j +125c enable input voltage (v en ) ................................. 0v to v in package thermal resistance 4mm 6mm mlf-28 ( t ja ) .............................40c/w electrical characteristics (5) t a = 25c with v in = v en = 5v; v en = v in ; i out = 10ma, v out = 1.8v. bol d values indicate ?40c t j +125c, unless noted. parameter conditions min typ max units supply voltage range 3.0 5.5 v under-voltage lockout threshold turn-on 2.75 v uvlo hysteresis 100 mv ldo quiescent current i out = 0a, 1 ma turn-on time v out to 5% of regulation, i i load = 3a 200 350 s shutdown current v en = 0v 35 50 a feedback voltage 1% 2.5% 0.99 0.975 1 1 1.01 1.025 v v feedback current 1 a v in ? v o ; dropout voltage i load = 3.0a 1.2 v current limit v fb = 0.9v nom 4.5 6 a output voltage load regulation v out = 1.8v, 10ma to 3a 0.3 1 % output voltage line regulation v out = 1.8v, v in from 3.0v to 5.5v 0.35 0.5 %/v output ripple i load = 2a, c outldo = 20f, c outsw = 20f lpf=25k ? 5 mv over-temperature shutdown 150 c over-temperature shutdown hysteresis 20 c enable input enable input threshold regulator enable 0.90 1 1.1 v enable hysteresis 20 120 200 mv enable input current 0.01 a notes: 1. exceeding the absolute maximum rating may damage the device. 2. the device is not guaranteed to function outside its operating rating. 3. the maximum allowable power dissipation of any t a (ambient temperature) is p d(max) = (t j(max) ? t a ) / ja . exceeding the maximum allowable power dissipation will result in excessive die temperatur e, and the regulator will go into thermal shutdown. 4. devices are esd sensitive. handl ing precautions recommended. human body model, 1.5k in series with 100pf. 5. specification for packaged product only.
mic r el, inc . mic38 300 july 200 7 5 m999 9-07 060 7 (408) 9 44-0 8 0 0 ty pical characteri stics 0 10 20 30 40 50 60 70 80 90 10 100 1k 10k 100k frequency (hz) mic 3 8 300 ps r r 1.780 1.785 1.790 1.795 1.800 1.805 1.810 1.815 1.820 0 0.5 1.0 1.5 2.0 2.5 3.0 load current (a) load regulation v in = 3.3v v out = 1.8v c out = 10f 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 01 23 4 5 input voltage (v) out p ut vo lt ag e vs. i n put v o ltage v out = 1.8v c out = 10f 10ma 2a 1.72 1.74 1.76 1.78 1.80 1.82 1.84 1.86 1.88 output v o ltage vs. tempera t ure 20 40 60 80 temperature (c) v in = 3.3v c out = 10f i out = 10ma 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 -40 10 60 110 160 210 temperature (c) th er mal shutdo wn v in = 3.3v v out = 1.8v c out = 10f 0 10 20 30 40 50 60 70 80 90 0 0.5 1.0 1.5 2.0 2.5 3.0 load current (a) mic 38300 effici ency v in = 5v v out = 3.3v c out = 10f 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) e n ab le t h re s hol d v out = 1.8v c out = 10f 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 3.0 3.5 4.0 4.5 5.0 5.5 input voltage (v) cur r e n t li mi t vs. i n put v o ltage v out = 1.8v c out = 10f
mic r el, inc . mic38 300 july 200 7 6 m999 9-07 060 7 (408) 9 44-0 8 0 0 functi onal characteristics v in = 3.3v, v out = 1.8v, c out = 10f, inductor = 47 0nh
mic r el, inc . mic38 300 july 200 7 7 m999 9-07 060 7 (408) 9 44-0 8 0 0 applicati on inf o rm ation enable input the mic38 300 featu r e s a tt l/cmos com p atible positive l ogi c enabl e inp u t f o r o n /off cont rol of the device. high e nabl e s the regul ator while l o w di sabl es the regul ator. in shutd o wn the reg u lato r co nsum es very little curre n t (o nly a fe w mi croam peres o f leakage ). for simple appli c ations the en able (e n) ca n be conn ect ed to v in (in ) . input ca paci tor vin provide s power to t he mosfet s for the switch mode re gulat or se ction, al ong with the cu rrent limiti ng sen s in g. du e to the high swit chin g spe e d s , a 10f cap a cito r is recom m en ded clo s e to vin and the p o w er grou nd (pg n d) pin fo r byp a ssing. analog v in (avin) p r ovid es po wer to t he a nalo g su pply circuitry. avin an d vin must be tie d together. careful layout sho u ld be co nsi dered to en su re high fre que ncy swit chin g no ise cau s e d by vin is redu ce d b e fore rea c hin g avin. a 1f capacito r as cl ose to avin as possibl e is re comm end ed. outpu t c a pa citor the mic38 3 00 req u ire s an output ca pacito r for st able operation. as a cap l d o, the mic3 8300 can o p e rate with ceramic output cap a citors of 1 0 f o r g r ea ter. values of g r e a ter tha n 10 f improve tra n sie n t re sp on se and n o ise redu ction at high f r equ ency. x7 r/x5r diele c tric-typ e cera mic capa citors a r e re co mmen ded becau se of their sup e rio r temp eratu r e pe rform a n c e. x7r-type ca pacito r s cha nge c apa cita nce by 15% over their ope rati ng tempe r at ure rang e a nd are the most stable type of cerami c c apa citors. large r o u tput cap a cita nces ca n be a c hi ev ed by pl acing tantalu m or aluminu m el ectrolytics in parall e l wit h the cera mic cap a cito r. fo r example, a 100f elect r olytic in parallel with a 10f cerami c can provide the transi ent an d hig h freque ncy no ise pe rform a nce of a 100 f ceramic at a signifi cantly lowe r cost. specifi c und ersho o t/oversh oot performance will depend on both the values and esr/esl of the ca pa citors. for le ss than 5mv noise perfo rman ce at higher current load s, 20f capa citors are recomme nd ed at ldoi n and ldo o ut. lo w p ass fil t er pin the mic3 83 00 features a low pa ss fi lter (lpf ) pin for adju s ting th e switch er frequ en cy. by tuning the freque ncy, th e user can f u rthe r impro v e output rip p le without lo sing efficiency. a d justable regulator d esign *c ff 0.1f r1 r2 out adj 1.0v *required only for large values of r1 and r2 a d ju stab le re g u l ato r w i th r esisto rs the a d ju sta b le mic383 00 outp u t voltage can be prog ram m ed from 1v to 5.0v using a resi stor di vide r from output to the sns pin. resi stors can be quite la rge, up to 100 k ? becau se of the very high input imped a n ce and l o w bia s cu rrent of t he sen s e a m plifier. fo r large v a lue re sist o r s ( > 5 0 k ? ) r1 should b e bypassed by a small ca pa cit o r (c ff = 0.1 f bypa ss capa citor) to a v oid instability due to phase la g at the adj/sns input. the output re sisto r divide r values a r e ca lculate d by: ? 1 ? 1 2 1 1 r r v v out efficiency considera t ion s efficiency is defined a s the amou nt of useful o u tput power, divide d by the amount of powe r sup p lied. 100 % _ u ? ? 1 ? u u in in out out i v i v efficiency maintainin g high efficie n c y se rves t w o pu rp ose s . it redu ce s po wer di ssipatio n in the po we r su pply, re du cing the need for heat sinks and t herm a l de si gn con s id eratio n s and it red u ces con s umpti on of cur r ent for battery p o we red ap plicati ons. re du ce d cur r ent dr aw from a batter y increa se s the devices o peratin g time and is critical in h and hel d devi c e s . ther e a r e two types of lo sses i n swit ching conve r t e rs; dc lo sse s a nd switchi ng losse s . dc l o sse s are si mply the po we r di ssi pation of i 2 r. powe r i s dissipate d in the high si de swit ch du ring the on cycle. po wer lo ss is e qual to the high si de mosfet r dson multiplied by the swi t ch cur r e n t 2 . dur i ng the off cycle, the low side n- ch an nel mosfet co ndu cts, al so dissipatin g power. de vice oper ating cur r ent al so r e d u ce s effici en cy. the prod u c t of the quie s cent (ope rating ) curr ent and th e sup p ly voltage is anoth e r dc loss. over 10 0ma, efficien cy lo ss i s d o mina ted by mos f et r dson and inducto r losse s . higher in put supply volta ges will increase t he gate to s our ce threshold on the internal mosfets, r edu cing the i n ternal rd dson . this impr oves efficiency by reducing dc losses in the device. all but the indu ctor l o sse s ar e in here n t to the device. in which
mic r el, inc . mic38 300 july 200 7 8 m999 9-07 060 7 (408) 9 44-0 8 0 0 ca se, indu ct o r sele ct ion b e com e s in cr e a sin g ly crit ic a l in efficien cy cal c ulatio ns. as the inducto r s ar e red u ce d in size, the dc r e si stan ce (dcr) can become q u ite signifi cant. t he dcr lo sse s ca n be calculated as follows : 100 _ 1 _ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? + ? = d out out out out p l i v i v loss efficiency efficiency loss due to dcr is minimal at light loads and gain s sig n ificance as the l oad is in cr ea sed. indu ctor sele ction b e comes a tr ade -off betwee n efficien cy and s i ze in this cas e . l_p d = i out 2 d cr from that, the lo ss in efficien cy due to ind u c tor resi stan ce ca n be cal c ul ated as follo ws;
mic r el, inc . mic38 300 july 200 7 9 m999 9-07 060 7 (408) 9 44-0 8 0 0 package inform ation 28-pin 4mm x 6mm ml f (ml)
mic r el, inc . mic38 300 july 200 7 10 m999 9-07 060 7 (408) 9 44-0 8 0 0 re comm ende d la ndi ng pat tern lp # hmlf46t-28ld-lp-1 all units are in mm tolerance 0.05 if not noted maximum thermal performance. red circle indicates thermal via. size should be .300-.350 mm in diameter and it should be connected to gnd plane for micrel, inc. 2180 fortune drive san jose, ca 9513 1 usa t e l + 1 (408) 9 44-0 800 f a x + 1 (408) 47 4-1 000 w eb http:/ w w w . m i crel.co m the information f u rnished b y micrel in this data sh eet is belie ved to be accurate and reliable. ho w e ver, no responsibility is a ssumed by micr el for its use. micrel reserves the right to change circuitry a nd specifications at an y time w i tho u t notification to the customer. micrel products are not designed or autho ri zed for use as components in life support app liances, devices or sy stems where malfu nction of a product r e a s o n a b l y b e expected to res u lt in personal injury . life suppo rt devices or sy ste m s are devices or s y stems that (a ) are in tende d f o r s u r g i c a l i m p l a into the bod y or (b) support o r sustain life, and w h o s e failure to perf o rm can be re asonabl y e x pected to result in a significan t injury to th e user. a purchaser?s use or sale of micrel produc ts for use in life support app liances, devices or s y stems is a purchaser?s ow n risk and purchaser agre e s to full y indemnif y micrel for an y damages resulting from such use or sale. c a n n t ? 2007 micrel, in corporated.
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