1/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a pwm control 2a step-down converter ? general description AX3113A consists of step-down switching r egulator with pwm control. these devise include a reference voltage source, oscillation circuit, error amplifier, internal pmos and etc. AX3113A provides low-ripple power, hi gh efficiency, and excellent transient characteristics. the pwm control circuit is abl e to the duty ratio linearly form 0 up to 100%. an enable function, an over cu rrent protect function and short circuit protect function are built inside, and when ocp or scp happens, t he operation frequency will be reduced. also, an internal compensation block is built in to minimum external component count. with the addition of an internal p-channel po wer mos, a coil, capacitors, and a diode connected externally, these ics can function as step-down switching regulators. they serve as ideal power supply units for portable dev ices when coupled with the sop-8l package, providing such outstanding features as low current consum ption. since this converter can accommodate an input voltage up to 23v, it is also suitable for the operation via an ac adapter. ? features - input voltage 4.5v to 23v - output voltage 0.8v to v cc - duty ratio 0% to 100% pwm control - oscillation frequency 330khz typ. - current limit (cl), enable function. - thermal shutdown function. - short circuit protect (scp). - built-in internal sw p-channel mos. - sop-8l pb-free package.
2/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? block diagram vcc oscillation circuit reference voltage + - vss ven en fb sw thermal shutdown - pwm switched control circuit current limit nc ? pin assignment the package of AX3113A is sop-8l; the pin assignment is given by: ( top view ) 1 2 3 4 8 7 6 5 fb sop-8l vcc en vss vss sw sw nc name description fb feedback pin en power-off pin h normal operation(step-down) l step-down operation stopped (all circuits deactivated) nc no connect pin vcc ic power supply pin sw switch pin. connect external inductor and diode here. v ss gnd pin ? order/marking information order information top marking package type s: sop-8l AX3113A x x packing blank : tube a : taping logo y ax 3 part number id code:internal ww: 01~52 year: 10=2010 11=2011 1 13 ywwx AX3113A a
3/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? absolute maximum ratings (at t a = 25c) characteristics symbol rating unit vcc pin voltage v cc v ss - 0.3 to v ss + 25 v feedback pin voltage v fb v ss - 0.3 to v cc v on/off pin voltage v en v ss - 0.3 to v cc + 0.3 v switch pin voltage v sw v ss - 0.3 to v cc + 0.3 v power dissipation pd internally limited mw storage temperature range t st -40 to +150 c operating junction temperature range t j -20 to +125 c operating supply voltage v op 4.5 to 23 v output current i out 0 to 2 a thermal resistance from junction to case jc 25 c/w thermal resistance from junction to ambient ja 70 c/w note : ja is measured with the pcb copper area(need connect to sw pins) of approximately 1 in 2 (multi-layer). ? eselectrical characteristics (v in = 12v, v out =3.3v, t a =25c, unless otherwise specified) characteristics symbol conditions min typ max units feedback voltage v fb i out =0.1a 0.784 0.800 0.816 v quiescent current i ccq v fb =1.2v force driver of f - 3 5 m a feedback bias current i fb i out =0.1a - 0.1 0.5 ua shutdown supply current i sd v en =0v - 2 10 ua current limit i cl 2.5 - - a line regulation v out /v out v cc = 8v~23v, i out =0.2a - 1 2 % load regulation v out /v out i out = 0.1 to 2a - 0.2 0.5 % oscillation frequency f osc sw pin 260 330 400 khz switching rising time tr i out =2a - 15 - ns switching falling time tf i out =2a - 15 - ns en pin logic input threshold voltage v enh hi g h ( re g ulator on ) 2.0 - - v v enl low ( re g ulator off ) - - 0.8 en pin input current i enh v en =2.5v (on) - 20 - ua i enl v en =0.3v (off) - -10 - ua internal mosfet r dson r dson v cc =12v, v fb =0v - 100 130 m ? efficiency effi v cc = 12v, v out = 5v i out = 1a - 92 - % i out = 2a 91
4/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? application circuit c2 470uf c4 470uf 1 2 l1 33uh r1 6.8k r2 1.3k vin+12v on/off vout = 5v/2a r4 100k d1 b340 c8 0.1uf fb en nc vcc sw sw vss vss AX3113A c3 0.1uf c6 0.1uf r1 r2 vfb = 0.8v ; r2 suggest 0.8k ~ 6k vout = vfb x (1 + ) ? function descriptions pwm control the AX3113A consists of dc/dc converters that employ a pulse-width modulation (pwm) system. in converters of the AX3113A, t he pulse width varies in a range from 0 to 100%, according to the load current. the ri pple voltage produced by the switching can easily be removed through a filter becaus e the switching frequency remains constant. therefore, these converters provide a low-ri pple power over broad r anges of input voltage and load current. setting the output voltage application circuit item shows the basic application circuit with adjustable output version. the external resistor sets the out put voltage according to the following equation: ? ? ? ? ? ? ? ? ? 2 1 1 8 . 0 r r v v out table 1 resistor select for output voltage setting v out r2 r1 5v 1.3k 6.8k 3.3v 1.5k 4.7k 2.5v 2.2k 4.7k 1.8v 2k 2.5k 1.5v 2.2k 2.0k 1.2v 3k 1.5k 1.0v 3k 0.75k
5/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? typical characteristics v in vs. i cc and i ccq 3 3.2 3.4 3.6 3.8 4 4.2 4.4 4.6 4.8 5 5 7 10 12 15 18 20 23 v in (v) i cc and i ccq (ma) i cc i ccq v in vs. i sd 0 2 4 6 8 10 12 14 16 18 20 5 7 10 12 15 18 20 23 v in (v) i sd (ua) v en =0v v in vs. current limit 1 1.5 2 2.5 3 3.5 4 4.5 5 5 7 10 12 15 18 20 23 v in (v) current lim it (a ) v in vs. v fb 0.75 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83 0.84 0.85 5 7 10 12 15 18 20 23 v in (v) v fb (v) i out =0.1a v in vs. frequency 260 280 300 320 340 360 380 400 5 7 10 12 15 18 20 23 v in (v) frequency (khz) v in vs. en 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 5 7 10 12 15 18 20 23 v in (v) en (v) v enl v enh
6/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? typical characteristics (continues) v in vs. r ds (on) 0 50 100 150 200 250 5 7 10 12 15 18 20 23 v in (v) r ds(m ) i out vs. v fb 0.76 0.78 0.8 0.82 0.84 0 10 100 300 500 800 1000 1500 2000 i out (ma) v fb (v) v in =12v i out vs. frequrncy 260 280 300 320 340 360 380 400 100 300 500 800 1000 1500 2000 i out (ma) frequency (khz) v in =12v v fb vs. temperature 0.76 0.77 0.78 0.79 0.8 0.81 0.82 0.83 0.84 -40c -20c 0c 25c 50c 85c 105c 125c temperature v fb (v) v in =12v temperature vs. frequency 260 280 300 320 340 360 380 400 -40c -20c 0c 25c 50c 85c 105c 125c temperature frequency (khz) temperature vs. r ds(on) 50 70 90 110 130 150 -40c -20c 0c 25c 50c 85c 105c 125c temprtature r ds(on) v in =12v, i out =1a
7/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? typical characteristics (continues) i out vs. efficiency 0 10 20 30 40 50 60 70 80 90 100 0 10 100 300 500 1000 1500 2000 i out (ma) efficiency (%) v out =3.3v v out =5v v in =12v i out vs. efficiency 0 10 20 30 40 50 60 70 80 90 100 0 10 100 300 500 1000 1500 2000 i out (ma) efficiency (%) v out =3.3v v out =2.5v v in =5v v out =1.8v
8/8 axelite confidential materials, do not copy or distribute without written consent . rev.1.3 aug.16, 2010 a x3113a ? package outlines detail a l h e a a2 a1 e d 7 (4x) b y c detail a symbol dimensions in millimeters dimensions in inches min. nom. max. min. nom. max. a - - 1.75 - - 0.069 a 1 0.1 - 0.25 0.04 - 0.1 a 2 1.25 - - 0.049 - - c 0.1 0.2 0.25 0.0075 0.008 0.01 d 4.7 4.9 5.1 0.185 0.193 0.2 e 3.7 3.9 4.1 0.146 0.154 0.161 h 5.8 6 6.2 0.228 0.236 0.244 l 0.4 - 1.27 0.015 - 0.05 b 0.31 0.41 0.51 0.012 0.016 0.02 e 1.27 bsc 0.050 bsc y - - 0.1 - - 0.004 0 o - 8 o 0 o - 8 o mold flash shall not exceed 0.25mm per side jedec outline: ms-012 aa
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