ap1503 300khz, 2.5a pwm buck dc/dc converter this datasheet contains new product information. anachip corp. reserves the rights to modify the product specification without notice. no liability is assumed as a result of the use of this product. no rights under any patent accompany the sale of the product. rev. a3 mar. 11, 2004 1/5 features - output voltage: 3.3v - 300khz + 15% fixed switching frequency - voltage mode non-synchronous pwm control - thermal-shutdown and current-limit protection - on/off shutdown control input - operating voltage can be up to 22v - output load current: 2.5a - sop-7l packages - low power standby mode - built-in switching transistor on chip applications - simple high-efficiency step-down regulator - on-card switchin g regulators - positive to negative converter - dsl modems - portable computers - regulated wall adapters - distributed power general description the ap1503 series are monolithic ics designed for step-down dc/dc converte rs, and own the ability of driving a 2.5a load without additional transistor components. due to reducing the number of external component, the board space can be saved easily. the external shutdown function can be controlled by logic level and then come into standby mode. the external compensation makes feedback control have good line and load regulation. 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. the ap1503 series operates at a switching frequency of 300khz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. other features include a guaranteed + 2% tolerance on output voltage under specified input voltage and output load conditions, and + 15% on the oscillator frequency. the output version included fixed 3.3v, 5v. the packages are available in a standard sop-7 lead package. pin assignment sop7 with heat sink vb vin comp sd fb gnd vo 7 6 5 2 3 4 1 pin descriptions name description v in operating voltage input vb boost pin sd on/off shutdown fb output voltage feedback control comp compensation pin gnd ground vo switching output
ap1503 300khz, 2.5a pwm buck dc/dc converter anachip corp. www.anachip.com.tw rev.a3 ma r. 11 2004 2/5 ordering information output version package packing s : sop-7l ap1503 xx x -33 : 3.3v blank : tube a : taping x x lead free blank : normal l : lead free package block diagram current source bias 1.235v reference 2.5v regulator 300khz osc. start up + + _ + _ thermal limit pre-driver comp comp gnd vo vin sd fb 220mv 200mv 3a switch + _ _ amp comp frequecy compen- sation comp vb
ap1503 300khz, 2.5a pwm buck dc/dc converter anachip corp. www.anachip.com.tw rev.a3 mar. 11, 2004 3/5 absolute maximum ratings symbol parameter rating unit v cc supply voltage +26 v v sd on/off pin input voltage -0.3 to +25 v v fb feedback pin voltage -0.3 to +25 v v out output voltage to ground -1 v p d power dissipation internally limited w t st storage temperature -65 to +150 o c t op operating temperature -40 to +125 o c v op operating voltage +7 to +40 v electrical characteristics (a ll output voltage versions) unless otherwise specified, v in =12v for 3.3v, 5v, i load = 0.5a symbol parameter conditions min. typ. max. unit 255 300 345 f osc oscillator frequency 230 360 khz 0.5 v sat saturation voltage i sw =2a v b =v in +2.5v. 0.4 0.6 v max. duty cycle (on) v fb =0v force driver on 90 dc min. duty cycle (off) v fb =6v force driver off 0 % 3.5 i cl current limit peak current no outside circuit v fb =0 force driver on 3 3.25 4 a output = 0 no outside circuit v fb =6v force driver off -1 ua i l output = -1 output leakage current v in =24v -1 ma comp min sw threshold duty cycle=0%,f b =3.5v 0.04 v c 2a i sw threshold 0.8 v v b min v b above switch i sw =2a 2.6 3 v i sw =1a 120 i b boost current i sw =2a 130 140 ma i q quiescent current v fb =6 force driver off 5 10 ma 150 i stby standby quiescent current on/off pin=5v v in =24v 80 200 ua v il low (regulator on) - 0.6 v ih on/off pin logic input threshold voltage high (regulator off) 2.0 1.3 - v i h on/off pin logic input current v logic =2.5v (off) -0.1 i l on/off pin input current v logic =0.5v (on) -1 ua jc thermal resistance sop-7l junction to case 20 o c/w ja thermal resistance with copper area of approximately 0.5 in 2 sop-7l junction to ambient 50 o c/w
ap1503 300khz, 2.5a pwm buck dc/dc converter anachip corp. www.anachip.com.tw rev.a3 mar. 11, 2004 4/5 electrical characteristics (continued) symbol parameter conditions typ. limit unit out v output voltage 7v < v in < 24v 0.2a < i load < 2.5a 3.3 3.23/ 3.2 3.37/ 3.4 v v min v max ap1503-3.3v efficiency v in = 12v, i load =2a 79 % specifications with boldface type are for full operating temperature range, the other type are for t j =25oc. typical application circuit 17 6 3 4 7v dc input c in capacitor fb sd d1 schottky diode vin gnd vo ap1503 -33 co capacitor inductor l1 3.3v/2.5a output load 2 vb d2 schottky diode comp 5 cc cb
ap1503 300khz, 2.5a pwm buck dc/dc converter anachip corp. www.anachip.com.tw rev.a3 mar. 11, 2004 5/5 marking information ( top view ) logo output type 33 : 3.3v id code: internal year: "01" = 2001 "02" = 2002 xth week: 01~52 ~ 1 4 ac ap1503 xx yy ww x x 5 7 blank: normal l: lead free package package information package type: sop-7l a c c2 b1 d e e b2 f c3 c1 dimensions in millimeters dimensions in inches symbol min. nom. max. min. nom. max. a 5.79 5.99 6.19 0.228 0.236 0.244 b1 3.83 3.91 3.99 0.151 0.154 0.157 b2 3.78 3.86 3.94 0.149 0.152 0.155 c 4.80 4.87 4.94 0.189 0.192 0.194 c1 1.57 1.67 1.77 0.062 0.066 0.070 c2 0.32 0.4 0.48 0.013 0.016 0.019 c3 1.17 1.27 1.37 0.046 0.050 0.054 d 0.19 0.22 0.25 0.007 0.009 0.010 e 1.04ref 0.041ref e 0.48 0.68 0.88 0.019 0.027 0.035 f 1.35 1.45 1.55 0.053 0.057 0.061 7 o 7 o
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