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1/1 1 ax elite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 pwm s tep-down controller ? general description the AX2201 integrates pulse- width-modulation (pwm) control circuit into a single chip. these d evise include a reference voltage source, oscillation circuit, error amplifier and etc. AX2201 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 external p-channel power mos, a coil, capacitors, and a diode connected externally, these components can function as step-down switching regulators. they serve as ideal power supply units for portable devices when coupled with the sop-8l and msop-8l mini -package, providing such outstanding features as low current consumption. since this converter can accommodate an input voltage up to 24v, it is also suitable for the operation via an ac adapter. ? fea tures - input voltage 3.6v to 23v - output voltage 0.25v to v cc - led backlight and high power led application - duty ratio 0% to 100% pwm control - oscillation frequency 330khz. - current limit (cl), enable function. - thermal shutdown function. - short circuit protect (scp). - external sw p-channel mos. - low esr output capacitor (multi-layer chip capacitor (mlcc)) application. - msop-8l and sop-8l pb-free packages. v?mw`r?y?b? www.gofotech.com
2/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? block diagram gate vcc reference voltage + - vss v en en fb lx - pwm switched control circuit thermal shutdown oscillation circuit comp ? pin assignmet these packages of AX2201 are msop-8l and so p-8l; the pin assignment is given by: ( top view ) 1 2 3 4 8 7 6 5 AX2201 lx en fb vss vcc gate comp nc msop - 8l and sop - 8l name description fb feedback pin en shutdown control input. h normal operation(step-down) l shutdown mode comp compensation pin nc no connectin g pin v cc ic power suppl y pin gate gate drive for external p-channel mosfet. lx lx is the current sense input. v ss gnd pin ? order/marking information order information top marking xx x package type s: sop-8l u8:msop-8l AX2201 packing blank : tube a : taping logo y ax 2 part number id code:internal ww:01~52 year: 10=2010 11=2011 2 01 ywwx v?mw`r?y?b? www.gofotech.com
3/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? absolute maximum ratings (at t a = 25 c) characteristics symbol rating unit v cc 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 temperature range t op -20 to +125 c operating supply voltage v op +3.6 to +23 v thermal resistance from junction to case sop-8l jc 35 c/w msop-8l 45 thermal resistance from junction to ambient sop-8l ja 120 c/w msop-8l 200 note : e ja is measured with the pcb copper area of approximately 1 in 2 (multi-layer). ? electrical characteristics (v cc = 12v, t a = 25c, unless otherwise specified) characteristics symbol conditions min typ max units feedback voltage v fb i out =0.1a 0.24 0.25 0.26 v quiescent current i ccq v fb =1.2v force driver off 3 5 ma 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 line regulation v out /v out v cc = 5v~23v, i out =0.2a - 1 2 % load regulation v out /v out i out = 0.1 to 3a - 0.2 0.5 % oscillation frequency f osc1 sw pin 260 330 400 khz en pin logic input threshold voltage v sh high (regulator on) 2.0 - - v v sl low (regulator off) - - 0.8 en pin input current i sh v en =2.5v (on) - 20 - ua i sl v en =0.3v (off) - -10 - ua lx rise time t lxr c lx =1000pf - 80 - ns lx fall time t lxf c lx =1000pf - 80 - efficiency (pmos=ap9435m) effi v out = 5v i out = 2a - 92 - % i out = 3a - 91 - thermal shutdown temp t sd - 140 - c v?mw`r?y?b? www.gofotech.com
4/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? application circuit a. 1w/3w led*1 for dc input recommend operating conditions led i led r2 vcc range inductor (l1) input capacitor (c3) 1w led*1 350m 0.715 ? /0.125w 5~23v 22uh 10uf(mlcc) 100uf(el) 3w led*1 750m 0.333 ? /0.25w 5~23v 22uh 22uf(mlcc) 100uf(el) 900m 0.278 ? /0.5w 5~23v 22uh 22uf(mlcc) 100uf(el) 1w+1w led 350m 0.715 ? /0.125w 10~23v 15uh 10uf(mlcc) 100uf(el) 3w+3w led 750m 0.333 ? /0.25w 10~23v 15uh 22uf(mlcc) 100uf(el) 900m 0.278 ? /0.5w 10~23v 15uh 22uf(mlcc) 100uf(el) 1w+1w+1w led 350m 0.715 ? /0.125w 14~23v 10uh 10uf(mlcc) 100uf(el) 3w+3w+3w led 750m 0.333 ? /0.25w 14~23v 10uh 22uf(mlcc) 100uf(el) 900m 0.278 ? /0.5w 14~23v 10uh 22uf(mlcc) 100uf(el) v?mw`r?y?b? www.gofotech.com
5/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 b. 1w/3w led*1 for ac input c8 4.7uf m1 pmos l1 1 2 r2 r4 100k u1 8 1 3 4 5 6 7 2 fb en nc vcc gate lx gnd comp d1 b340 ap9435 led ac 12v in ac d4 ac d3 ac d2 ac d1 c2 c9 1uf r5 100k r3 4.7k d2 1n4148 option recommend operating conditions led i led r2 inductor (l1) input capacitor (c2) 1w led*1 350m 0.715 ? /0.125w 22uh 220uf(el) 3w led*1 750m 0.333 ? /0.25w 22uh 330uf(el) 900m 0.278 ? /0.5w 22uh 470uf(el) 1w+1w led 350m 0.715 ? /0.125w 15uh 330uf(el) 3w+3w led 750m 0.333 ? /0.25w 15uh 820uf(el) 900m 0.278 ? /0.5w 15uh 1000uf(el) v?mw`r?y?b? www.gofotech.com
6/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? function descriptions pwm control the AX2201 integrates pulse- width-modulation (pwm) control circuit into a single chip. the pulse width varies in a range from 0 to 100%, according to the load current. the ripple voltage produced by the switching can easily be removed through a filter because the switching frequency remains constant. theref ore, these controllers provide a low-ripple power over broad ranges of input voltage and load current. compensation the comp pin connects r5 and c9 to g nd, the c9 use 1uf and r5 use 100k for all condition. the option circuit for co mpensation is connecting r4 and a 4148 diode to v out . in order to protect sh ort circuit and thermal shutdown release for led. setting the i led current application circuit item shows the basic application circuit with AX2201 adjustable output version. the external resistor sets the led output current acco rding to the following equation: ? ? ? ? ? ? ? 2 25.0 r v i led table 1 resistor select fo r led output current setting i led r2 20ma 12.5 ? 5mw 350ma 0.715? 87.5mw 750ma 0.333? 189mw 1.5a 0.167? 375mw v?mw`r?y?b? www.gofotech.com
7/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 inductor selection for most designs, low inductance values ar e physically smaller but require faster switching, which results in some efficiency loss. the inductor value can be derived from the following equation: ? ? f i v vvv l lx l in out in out ?? ?? ? ? where is inductor ripple cu rrent. large value inductors lower ripple current and small value inductors result in high ripple currents. choose inductor ripple current approximately 15% (setting 10% to 30%) of t he maximum input current 3a, i l =0.45a. the dc current rating of the inductor shoul d be at least equal to the maximum load current plus half the ripple current to prevent core saturation (3a+0.3a). input capacitor selection the input capacitor reduces the surge cu rrent drawn from the input and switching noise from the device. the input capacitor impedance at the switch ing frequency shall be less than input source impedance to prevent high frequency switching current passing to the input. a low esr input capacitor size d for maximum rms current must be used. the capacitor voltage rating should be at least 1.5 times great er than the input voltage, and often much higher voltage ratings are needed to satisfy. output capacitor selection the output capacitor is required to keep t he output voltage ripple small and to ensure regulation loop stability. the output capacitor must have low impedance at the switching frequency. a low esr capacitor sized for maximum rms current must be used. the low esr requirements needed for lo w output ripple voltage. the capacitor voltage rating should be at least 1.5 times great er than the input voltage, and often much higher voltage ratings are needed to satisfy. v?mw`r?y?b? www.gofotech.com
8/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 layout guidance when laying out the pc board, the following suggestions should be taken to ensure proper operation of the AX2201. these items are also illustrated graphically in below. 1. the power traces, including the pmos dr ain and source trace, t he schottky and the c2 trace should be kept short, direct and wide to allow large current flow. 2. connect the c3 to the v cc pins and gnd of the AX2201 as closely as possible to get good power filter effect. 3. keep the switching node, away from the sensitive fb node. 4. do not trace signal line under inductor. v?mw`r?y?b? www.gofotech.com
9/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? typical characteristics temperature vs. iccq (vcc=12v) 2 2.4 2.8 3.2 3.6 4 -40 -25 0 25 50 85 105 125 temperature ( ) iccq (ma) temperature vs. shutdown current (vcc=12v) 0 2 4 6 8 10 -40-250 255085105125 temperature ( ) shutdown current (ua) temperature vs. vfb (vcc=12v iout300ma rcomp=100k) 0.24 0.244 0.248 0.252 0.256 0.26 -40 -25 0 25 50 85 105 125 temperature ( ) vfb (v) temperature vs. frequency (vcc=12v vout=3.3v) 0 80 160 240 320 400 480 -40 -25 0 25 50 85 105 125 temperature ( ) frequency (khz) line regulation (vout=3.3v) 0.245 0.247 0.249 0.251 0.253 0.255 0.257 3.6v 4v 5v 12v 15v 20v 22v 23v vcc vfb (v) iout vs. effi (vcc=12v) 70 75 80 85 90 95 100 0.5 1 1.5 2 iout (a) effi (% ) vout=3.3v vout=5v iout vs. effi (vcc=12v, pmos=ap9435) v?mw`r?y?b? www.gofotech.com
10/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 ? package outlines (1) sop-8l detail a l e d 7 (4x) b y 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 v?mw`r?y?b? www.gofotech.com
11/11 axelite confidential materials, do not copy or distribute without written consent . rev.1.0 jul.07, 2010 AX2201 (2) msop-8l e1 e 0.25 a2 a1 a c symbol dimensions in millimeters dimensions in inches min. nom. max. min. nom. max. a - - 1.1 - - 0.043 a 1 0 0.08 0.15 0 0.003 0.006 a 2 0.75 0.85 0.95 0.03 0.033 0.037 b 0.22 0.3 0.38 0.009 0.012 0.015 c 0.08 0.15 0.23 0.003 0.006 0.009 d 2.9 3 3.1 0.114 0.118 0.122 e 4.8 4.9 5 0.189 0.193 0.197 e1 2.9 3 3.1 0.114 0.118 0.122 e 0.65 bsc 0.026 bsc l 0.4 0.6 0.8 0.016 0.024 0.031 y - - 0.1 - - 0.004 0o 4o 8o 0o 4o 8o jedec outline: mo-187 aa v?mw`r?y?b? www.gofotech.com

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