ap1510 pwm control 3a step-down converter this datasheet contains new product information. anachip corp. re serves 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. 1.4 nov 17, 2005 1/7 ? features - input voltage: 3.6v to 23v. - output voltage: 0.8v to v cc . - duty ratio: 0% to 100% pwm control - oscillation frequency: 300khz typ. - soft-start, current limit, enable function - thermal shutdown function - built-in internal sw p-channel mos - sop-8l pb-free package. ? applications - pc motherboard - lcd monitor - graphic card - dvd-video player - telecom equipment - adsl modem - printer and other peripheral equipment - microprocessor core supply - networking power supply ? general description ap1510 consists of step-down switching regulator with pwm control. these devices include a reference voltage source, oscillation circuit, error amplifier, internal pmos and etc. ap1510 provides low-ripple power, high efficiency, and excellent transient characteristics. the pwm control circuit is able to vary the duty ratio linearly from 0 up to 100%. this converter also contains an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. an enable function, an over current protect function and a short circuit protect function are built inside, and when ocp or scp happens, the operation frequency will be reduced from 300khz to 30khz. also, an internal compensation block is built in to minimum external component count. with the addition of an internal p-channel power 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 devices when coupled with the sop?8l mini-package, providing such outstanding features as low current consumption. since this converter can accommodate an input voltage up to 23v, it is also suitable for the operation via an ac adapter. ? pin assignments 1 2 3 4 8 7 6 5 fb output ocset ap1510 output en vss vss v cc ? pin descriptions name pin description fb 1 feedback pin. en 2 power-off pin h: normal operation (step-down operation) l: step-down operation stopped (all circuits deactivated) ocset 3 add an external resistor to set max output current. v cc 4 ic power supply pin output 5 6 switch pin. connect external inductor/diode here. minimize trace area at this pin to reduce emi. v ss 7 8 gnd pin
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 2/7 ? ordering information ap 1510 x x package packing s: sop-8l blank : tube a : taping ? block diagram oscillation circuit reference voltage source with soft start pwm-switched control circuit + - vss v en en 100ua ocset fb vcc thermal shutdown output ? absolute maxi mum ratings symbol parameter rating unit v cc v cc pin voltage v ss - 0.3 to v ss + 25 v v fb feedback pin voltage v ss - 0.3 to v cc v v en en pin voltage v ss - 0.3 to v in + 0.3 v v output switch pin voltage v ss - 0.3 to v in + 0.3 v p d power dissipation internally limited mw t opr operating temperature range -20 to +125 o c t stg storage temperature range -40 to +150 o c caution: the absolute maximum ratings are rated values exceeding which the product could suffer physical damage. these values m ust therefore not be exceeded under any conditions.
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 3/7 ? electrical characteristics (v in = 12v, t a =25 c , unless otherwise specified) symbol parameter conditions min. typ. max. unit v in input voltage -- 3.6 - 23 v v fb feedback voltage i out =0.1a 0.784 0.8 0.816 v i fb feedback bias current i out =0.1a - 0.1 0.5 a i sw switch current -- 3.5 - - a i sss current consumption during power off v en =0v - 10 - a ? v out /v out line regulation v in = 5v~23v, i out =0.2a - 1 2 % ? v out /v out load regulation i out = 0.1 to 3a - 0.2 0.5 % f osc oscillation frequency measure waveform at sw pin 240 300 360 khz f osc1 frequency of current limit or short circuit protect measure waveform at sw pin 10 - - khz v sh evaluate oscillation at sw pin 2.0 - - v sl en pin input voltage evaluate oscillation stop at sw pin - - 0.8 v i sh -- - 20 - a i sl en pin input leakage current -- - -10 - a i ocset ocset pin bias current -- 75 90 105 a t ss soft-start time -- 0.3 2 5 ms v in =5v, v fb =0v - 110 150 r dson internal mosfet rdson v in =12v, v fb =0v - 70 100 m ? effi efficiency v in = 12v, v out = 5v i out = 3a - 91 - % ja thermal resistance junction-to-ambient - 65 - o c/w ? typical application circuit ap1510 + - v ss en c c r a r b d1 fb vcc output cvcc v out =5v/3a v in r ocset ocset c out c in optional c ocset c en r en option 100k note: v out = v fb x (1+r a /r b ) r b =0.7k~5k ohm l1 22uh 6.8k 1.3k 3.9k 0.1uf + - c 0.1uf 470uf 470uf 0.1uf v in =12v, i max =3a v out 2.5v 3.3v 5v l1 value 15uh 18uh 22uh
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 4/7 ? typical performance characteristics ap1510 vin v.s. frequency (vout=3.3v; iout=0.2a) 300 305 310 315 320 325 330 335 340 345 350 0 5 10 15 20 25 vin (v) fosc (khz) ap1510 vin v.s. fb (vout=3.3v; iout=0.2a) 0.74 0.75 0.76 0.77 0.78 0.79 0.80 0.81 0.82 0.83 0.84 0 5 10 15 20 25 vin (v) fb (v) ap1510 line regulation (vout=3.3v; iout=0.2a) 3.10 3.15 3.20 3.25 3.30 3.35 3.40 0 5 10 15 20 25 vin(v) vout(v) 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 0.0 1.0 2.0 3.0 4.0 iout (a) vout (a) ap1510 load regulation (vin=12v) ap1510 efficiency 0 10 20 30 40 50 60 70 80 90 100 0.0 1.0 2.0 3.0 iout (a) efficiency (%) vout:5.0v vout:3.3v
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 5/7 ? typical performance char acteristics (continued) ap1510 vout ripple (vin=12v; vout=3.3v; iout=0.1a) ap1510 vout ripple (vin=12v; vout=3.3v; iout=3a) ? test circuit a fb vcc vss en open open fb vcc vss en + - oscillation output output a fb vcc vss en + - + - v output ocset ocset ocset
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 6/7 ? function description pwm control the ap1510 consists of dc/dc converters that employ a pulse-width modulation (pwm) system. in converters of the ap1510, 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. therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current. under voltage lockout the under voltage lockout circuit of the ap1510 assures that the high-side mosfet driver outputs remain in the off state whenever the supply voltage drops below 3.3v. normal operation resumes once v cc rises above 3.5v. r ds(on) current limiting the current limit threshold is setting by the external resistor connecting from v cc supply to ocset. the internal 100ua sink current crossing the resistor sets the voltage at pin of ocset. when the pwm voltage is less than the voltage at ocset, an over-current condition is triggered. r i r i ocset ocset ds(on) load = see above formula for setting the current limit value. ? marking information 8 5 ( top view ) logo part no. id code: internal year: "01" =2001 "02" =2002 xth week: 01~52 ~ 14 ap1510 yy ww x
ap1510 pwm control 3a step-down converter anachip corp. www.anachip.com.tw rev. 1.4 no v 17, 2005 7/7 ? package information package type: sop-8l view "a" l c view "a" h e a a2 a1 b e d 7 (4x) 0.015x45 7 (4x) y dimensions in millimeters dimensions in inches symbol min. nom. max. min. nom. max. a 1.40 1.60 1.75 0.055 0.063 0.069 a1 0.10 - 0.25 0.040 - 0.100 a2 1.30 1.45 1. 50 0.051 0.057 0.059 b 0.33 0.41 0.51 0.013 0.016 0.020 c 0.19 0.20 0.25 0.0075 0.008 0.010 d 4.80 5.05 5.30 0.189 0.199 0.209 e 3.70 3.90 4.10 0.146 0.154 0.161 e - 1.27 - - 0.050 - h 5.79 5.99 6.20 0.228 0.236 0.244 l 0.38 0.71 1.27 0.015 0.028 0.050 y - - 0.10 - - 0.004 0 o - 8 o 0 o - 8 o
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