lr2596 150khz, 3a pwm buck dc/dc converter description the lr2596 is monolithic ic that design for a step-down dc/dc converter, and own the ability of driving a 3a load without a dditional transistor component. the output version included 3.3v, 5v, 12v and an adjustable type. it operates at a switching frequency of 150khz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. other features include a guaranteed 4% tolerance on output voltage under specified input voltage and output load conditions, and 15% on the oscillator frequency. regarding protected function, thermal shutdown is to prevent over temperature operating from damage, and current limit is against over current operating of the output switch. features ? 3.3v, 5v, 12v and adjustable ? adjustable version output voltage range: 1.4-37v ? 4% max over line and load conditions ? 150khz 15% fixed switching frequency ? ttl shutdown capability ? operating voltage can be up to 40v ? output load current: 3a ? to220-5l and to263-5l packages ? low power standby mode ? thermal-shuntdown and current-limit protection ? high efficiency ? built-in switching a transistor on chip, requires only 4 external components applications ? simple high-efficiency step-down regulator ? positive to negative converter ? on-card switching regulators connection diagrams lr2596 series to220-5l package to263-5l package 1 2 4 5 3 side view top view metal tab gnd to220-5l pins 1,3,5 pins 2,4 5 - on/off 4 - feed back 3 - ground 2 - output 1 - vin side view top view metal tab gnd to263-5l 5 - on/off 4 - feed back 3 - ground 2 - output 1 - vin leshan radio company, ltd. 1/7
pin connections absolute maxium rating (note1) parameter symbol value unit supply voltage v cc 40 v on/off pin input voltage v sd -0.3~+25 v feedback pin voltage v fb -0.3~+25 v output voltage to ground v out -1 v power dissipation p d internally limited w operating temperature t opr -40~+125 o c storage temperature t stg -65~+150 o c operating voltage v op +4.5~+40 v electrical characteristics (continued) specifications with boldface type apply over for full operating temperature range, the other type are for t j =25 o c (note 2) part no. parameter symb ol conditions min. typ. (note3) max. (note4) unit output voltage v out 4.75v v in 40v, 0.2a i load 3a 3.168 3.135 3.3 3.342 3.465 v lr2596-3.3 efficiency v in =12v, i load =3a - 73 - % output voltage v out 7v v in 40v, 0.2a i load 3a 4.800 4.750 5.0 5.200 5.250 v lr2596-5.0 efficiency v in =12v, i load =3a - 80 - % output voltage v out 15v v in 40v, 0.2a i load 3a 11.52 11.40 12.0 12.48 12.60 v lr2596-12 efficiency v in =25v, i load =3a - 90 - % output voltage v out 4.5v v in 40v, 0.2a i load 3a v out programmed for 3v 1.261 1.248 1.300 1.339 1.352 v lr2596-adj efficiency v in =12v, v out =3v, i load =3a - 73 - % current source bias 1.235v reference 2.5v regulator start up comp + - comp + - 200mv 220mv driver thermal limit 150khz osc. comp + - amp + - output gnd vin sd fb r1=2.5k r2 comp + - current limit ++ r 3a switch leshan radio company, ltd. lr2596 2/7
all output voltage versions electrical characteristics specifications with boldface type apply over for full operating temperature range, the other type are for t j =25 o c (unless otherwise specified, v in =12v for the 3.3v, 5v, and adjustable version and v in =24v for the 12v version, i load =500ma) parameter symbol test condition min. typ. max. unit device parameters feedback bias current i b adjustable version only, v fb =1.3v - 10 50 100 na oscillator frequency f o (note 5) 127 110 150 173 173 khz saturation voltage v sat i out =3a (note 6,7) - 1.3 1.4 1.5 v max. duty cycle (on) min. duty cycle (off) dc (note 7) (note 8) - 100 0 - % current limit i cl peak current (note 6,7) 3.6 4.5 5.5 6.5 a output leakage current i l output=0v (note 6,8) - - 50 ua quiescent current i q (note 8) - 5 10 ma standby quiescent current i stby on/off pin=5v (note 9) - 150 250 300 ua to220-5l - 2.5 - jc to263-5l junction to case - 3.5 - o c/w to220-5l - 28 - thermal resistance ja (note 10) to263-5l junction to ambient - 23 - o c/w on/off control v ih low (regulator on) - 0.6 on/off pin logic input threshold voltage v il high (regulator off) 2.0 1.3 - v i ih v logic =2.5v (regulator off) - 5 15 on/off pin input current i il v logic =0.5v (regulator on) - 0.02 5 ua note 1: absolute maximum ratings indicate limits beyond which damage to the device may occur. o perating ratings indicate condit ions for which the device is intended to be functional, but do not guarantee specific performance limit s. for guaranteed specifications and te st conditions, see the electrical characteristics. note 2: external components such as the catch diode, inductor, input and output capacitors, and voltage programming resistors c an affect switching regulator system performance. note 3: typical numbers are at 25 o c and represent the most likely norm. note 4: all limits guaranteed at room temperature (standard type fa ce) and at temperature extremes (bold type face). all room t emperature limits are 100% production tested. all limits at temperature extremes are guaranteed via correlation using standard statistical qualit y control (sqc) methods. all limits are used to calc ulate average outgoing quality level (aoql). note 5: the switching frequency is reduced when the second stage current limit is activated. note 6: no diode, inductor or ca pacitor connected to output pin. note 7: feedback pin removed from output and connected to 0v to force the output transistor switch on. note 8: feedback pin removed from output and connected to 12v for th e 3.3v, 5v, adj. version, and 15v for the 12v version, to force the output transistor switch off. note 9: v in =40v. note 10: junction to ambient thermal resist ance. (with copper area of approximately 3in 2 ) leshan radio company, ltd. lr2596 3/7
characteristics curve normalized output voltage -1.5 -1 -0.5 0 0.5 1 1.5 0 25 50 75 100 125 150 175 junction temperature ( o c) output voltage change (%) .. v in =12v i load =200ma shutdown quiescent current 0 20 40 60 80 100 120 140 160 0 10203040 supply voltage (v) current (ua) v on /v off =5v t j =25 o c switch current limit 5.20 5.30 5.40 5.50 5.60 5.70 5.80 5.90 6.00 0 25 50 75 100 125 150 junction temperature ( o c) switch current limit (a ) v in =12v v out =5v switch saturation voltage 0.80 0.90 1.00 1.10 1.20 1.30 01234 switch current (a) saturation voltage (v) v in =12v t j =25 o c on/off pin current (sinking) 0 2 4 6 8 10 12 0 5 10 15 20 25 30 on/off pin voltage (v) current (ua) v in =40v t j =25 o c leshan radio company, ltd. lr2596 4/7
typical application circuit fig.1 fixed type circuit fig.2 adjustable output voltage versions d2596 a d j ustable out p ut d1 1n5825 l1 47uh c2 220uf 2 out p ut 5 3 1 in p ut + unre g ulated dc in p ut 4 c1 680uf r1 r2 1k l o a d d2596 fix output d1 1n5825 l1 33uh l o a d c2 220uf 2 output 5 on/off 3 gnd 1 input + unregulated dc input 4 feedback c1 680uf lr2596 lr2596 leshan radio company, ltd. lr2596 5/7
to-263-5l dimension to-220-5l dimension b a i g h d e f c o q k a1 a1 a1 j r1 r2 l m n p r r3 r3 r3 s a1 a c d e f h j g k 123 b 45 i l dim min. max. a 9.9 10.30 b - #7.10 c 15.20 15.60 d - *1.70 e 4.50 4.70 f - *1.27 g 8.20 8.60 h 0.05 0.25 i 5.10 5.50 j 2.44 2.64 k - #7.00 l - #4.48 a1 0 o 7 o #: ref, *: typical, unit: mm marking: d 2 5 9 6 pb free mar k pb-free: " . " normal: none control code u date code product series adj,3.3,5.0, - note: green label is used for pb-free packing pin style: 1.vin 2.output 3.ground 4.feed back 5.on/off material: ? lead solder plating: sn60/pb40 (normal), sn/3.0ag/0.5cu or pure-tin (pb-free) ? mold compound: epoxy resin family, flammabilit y solid burnin g class: ul94v-0 5-lead to-263 plastic package dbmi package code: u dim min. max. a 10.10 10.50 b 2.55 2.95 c 3.20 3.60 d 7.90 8.30 e 12.50 12.90 f 22.30 22.70 g 3.20 3.60 h 0.70 0.90 i 6.60 7.00 j 4.40 4.80 k 1.17 1.37 l 17.00 18.00 m 16.00 16.40 n 17.00 19.00 o 2.30 2.70 p 3.30 4.10 q 0.28 0.48 r 7.62 8.02 s 22.90 23.30 r1 1.85 1.95 r2 1.20 1.30 r3 2.80 3.20 a1 4.5 o 5.5 o *: typical, unit: mm marking: d 2 5 pb free mark pb-free: " . " normal: 9 6 e control code date code - product series adj,3.3,5.0,12 note: green label is used for pb-free packing pin style: 1.vin 2.output 3.ground 4.feed back 5.on/off material: ? lead solder plating: sn60/pb40 (normal), sn/3.0ag/0.5cu or pure-tin (pb-free) ? mold compound: epoxy resin family, flammability solid bu rning class: ul94v-0 5-lead to-220 plastic package dbmi package code: e leshan radio company, ltd. lr2596 6/7
soldering methods for dbmi?s products 1. storage environment: temperature=10 o c~35 o c humidity=65%15% 2. reflow soldering of surface-mount devices profile feature sn-pb eutectic assembly pb-free assembly average ramp-up rate (t l to t p ) <3 o c/sec <3 o c/sec preheat - temperature min (ts min ) - temperature max (ts max ) - time (min to max) (ts) 100 o c 150 o c 60~120 sec 150 o c 200 o c 60~180 sec ts m a x t o t l - ramp-up rate <3 o c/sec <3 o c/sec time maintained above: - temperature (t l ) - time (t l ) 183 o c 60~150 sec 217 o c 60~150 sec peak temperature (t p ) 240 o c +0/-5 o c 260 o c +0/-5 o c time within 5 o c of actual peak temperature (t p ) 10~30 sec 20~40 sec ramp-down rate <6 o c/sec <6 o c/sec time 25 o c to peak temperature <6 minutes <8 minutes 3. flow (wave) soldering (solder dipping) products peak temperature dipping time pb devices. 245 o c 5 o c 5sec 1sec pb-free devices. 260 o c +0/-5 o c 5sec 1sec figure 1: temperature profile t p t l ramp-down ramp-up ts max ts min critical zone t l to t p t s preheat t l t p 25 t 25 o c to peak time temperature leshan radio company, ltd. lr2596 7/7
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