ap2008 pwm buck controller ap2008 rev. 1 1 of 8 december 2006 www.diodes.com ? diodes incorporated ? pwm buck control circuitry ? operating voltage can be up to 20v ? under voltage lockout (uvlo) protection ? short circuit pr otection (scp) ? soft-start circuit ? variable oscillator frequency -- 300khz max ? 0.77v voltage reference output ? 8-pin sop package ? sop-8l: available in ?green? molding compound (no br, sb) the ap2008 integrates pulse-wi dth-modulation (pwm) control circuit into a single chip, mainly designs for power-supply regulator. all the functions included an on-chip 0.77v reference output, an error amplifier, an adjusted oscillator, a soft-start, uvlo, scp circuitry, and a push-pull output circuit. switching frequency can be adjustable by trimming ct. during low v cc situation, the uvlo makes sure that the outputs are off until the internal circuit is operational normally. ? backlight inverter ? lcd monitor ? xdrom, xdsl product ? dc/dc converters in computers, etc. ap2008 x x x package packing s: sop-8l -u : tube -13 : taping lead free g : green note: 1. pad layout as shown on diodes inc. suggested pad layout document ap 02001, which can be found on our website at http://www.diodes.com/d atasheets/ap02001.pdf . features general description applications ordering information tube or bulk 13? tape and reel device (note 1) package code packaging quantity part number suffix quantity part number suffix ap2008s s sop-8l 100 - u 2500/tape & reel -13
ap2008 pwm buck controller ap2008 rev. 1 2 of 8 december 2006 www.diodes.com ? diodes incorporated 1 2 3 8 7 6 5 4 out gnd scp ss fb vcc ct comp ( top view ) sop-8l name description ct timing capacitor fb voltage feedback ss soft-start. comp feedback loop compensation out pwm output gnd ground vcc supply voltage scp short circuit protection block diagram bandgap reference out pwm amplifier fb v cc scp ct error amplifier comp uvlo gnd 0.7v 1.5v + - 2.5v internal use 0.77v iss + - vcc oscillator 10k-300khz / ct value ss + + - pin assignments pin descriptions
ap2008 pwm buck controller ap2008 rev. 1 3 of 8 december 2006 www.diodes.com ? diodes incorporated absolute maximum ratings symbol parameter rating unit v cc supply voltage 22 v v i amplifier input voltage 20 v v o collector output voltage v cc -1.0v v i source source current 200 ma i sink sink current 200 ma t op operating temperature range -20 to +85 o c t st storage temperature range -65 to +150 o c recommended operating conditions symbol parameter min. max. unit v cc supply voltage 3.6 20 v v i amplifier input voltage 1.05 1.45 v v o collector output voltage vcc-1.5 v i fb current into feedback terminal 45 a r f feedback resistor 100 k ? c t timing capacitor 100 6800 pf f osc oscillator frequency 10 300 khz t op operating free-air temperature -20 85 oc
ap2008 pwm buck controller ap2008 rev. 1 4 of 8 december 2006 www.diodes.com ? diodes incorporated electrical characteristics (t a =25oc, v cc =6v, f=200 khz) reference (ref) symbol parameter conditions min. typ. max. unit comp connect to fb 0.755 0.770 0.785 v t a = -20oc ~ 25oc -0.1 1 % v ref output voltage change with temperature t a = 25oc ~ 85oc -0.2 1 % under voltage lockout (uvlo) symbol parameter conditions min. typ. max. unit v ut upper threshold voltage (v cc ) 2.9 v v lwt lower threshold voltage (v cc ) 2.4 v v ht hysteresis (v cc ) i o(ref) = 0.1ma t a = 25oc 500 mv short-circuit protection (scp) control symbol parameter conditions min. typ. max. unit v it input threshold voltage t a = 25oc 0.60 0.67 0.75 v v stb standby voltage no pull up 100 130 160 mv v lt latched input voltage no pull up 50 100 mv i scp input (source) current v i = 0.7v, t a = 25oc -10 -15 -20 a v ct comparator threshold voltage (comp) 1.5 v oscillator (osc) symbol parameter conditions min. typ. max. unit f osc frequency c t =270 pf 200 khz standard deviation of frequency c t =270 pf 10 ? f osc frequency change with voltage v cc =3.6v ~ 20v 1 % error-amplifier symbol parameter conditions min. typ. max. unit v io input offset voltage v o (fb)=0.77v 6 mv i io input offset current v o (fb)=0.77v 100 na i ib input bias current v o (fb)=0.77v 160 500 na v cm common-mode input voltage range v cc =3.6v ~ 20v 1.05 1.45 v av open-loop voltage amplification r f =200 k ? 70 80 db gbw unity-gain bandwidth 1.5 mhz cmrr common-mode rejection ratio 60 80 db v oh max. output voltage v ref -0.1 v v ol min. output voltage 1 v i oi output (sink) current (comp) v id = -0.1v, v o = 0.77v 0.5 1.6 ma i oo output (source) current (comp) v id = 0.1v, v o = 0.77v -45 -70 a
ap2008 pwm buck controller ap2008 rev. 1 5 of 8 december 2006 www.diodes.com ? diodes incorporated electrical characteristics (continued) (t a =25oc, v cc =6v, f=200 khz) output section symbol parameter conditions min. typ. max. unit i leak leakage current v o = 20v 10 a sink current v in = 12v 200 ma i drv source current v in = 12v 200 ma v sat output saturation voltage i o = 10 ma 1.0 1.5 v i sc short-circuit output current v o = 6v 120 ma pwm comparator symbol parameter conditions min. typ. max. unit v t0 ct=6800pf 0.6 0.7 v v t100 input threshold voltage at f = 10 khz (comp) maximum duty cycle 1.2 1.3 v total device symbol parameter conditions min. typ. max. unit i cca average supply current c t = 270pf 6 10 ma soft start symbol parameter conditions min. typ. max. unit v ss soft-start voltage 2.3 v i ss constant charge current 20 a typical application circuit l1 10uh r1 r2 c3 470uf output step-down dc/dc converter c2 10nf (optional) vcc = 12v p mos q1 1 2 3 8 7 6 5 4 out fb vcc comp gnd scp ss ct c6 220nf c5 50nf c4 270pf 1k 4k c1 470uf 5a r3 30k c4 50nf (optional) 1v/5a
ap2008 pwm buck controller ap2008 rev. 1 6 of 8 december 2006 www.diodes.com ? diodes incorporated typical characteristics reference output voltage vs. power-supply voltage 0.755 0.76 0.765 0.77 0.775 0.78 0.785 4 6 8 101214161820 vcc-power supply voltage (v) vref- reference output voltage (v) a verage supply current vs. power-supply voltage 0 1 2 3 4 5 048121620 vcc - power-supply voltgae (v) icc-average supply current (ma) average supply current vs. ambient temperatrue 2 3 4 5 6 7 -50 -25 0 25 50 75 100 t a - ambient temperatrure( ) i cc - average supply current (ma) v ct vs. frequency 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 100 200 300 frequency (khz) v ct (v) vct(min) vct(max) oscillator frequency vs. timing capacitance 0 50 100 150 200 250 300 350 100 600 1100 1600 2100 2600 3100 3600 4100 4600 5100 5600 6100 6600 ct-timing capacitor (pf) fosc - frequency (khz) scp time-out period vs. scp capacitance 0 5 10 15 20 25 30 35 45 90 135 180 225 270 315 360 405 450 495 cscp - scp capacitance (nf) tscp-scp time-out period (ms)
ap2008 pwm buck controller ap2008 rev. 1 7 of 8 december 2006 www.diodes.com ? diodes incorporated typical characteristics (continued) soft-start time (ts) vs. soft-start capacitor (css) 0 5 10 15 20 25 30 25 50 75 100 125 150 175 200 css (nf) ts (ms) (1) sop-8l year: "01" =2001 "02" =2002 xth week: 01~52 ~ ap2008 (top view) yy ww part number logo x g : green 5 8 4 1 internal code x marking information
ap2008 pwm buck controller ap2008 rev. 1 8 of 8 december 2006 www.diodes.com ? diodes incorporated package information ( unit: mm ) (1) sop-8l 1.27typ 0.3/0.5 7 ~9 4.80/5.30 3.70/4.10 5.79/6.20 0.20typ 7 ~9 3.70/4.10 0.38/1.27 0.08/0.25 gauge plane 0.254 seating plane 0.35max. 45 detail "a" detail "a" 1.30/1.50 1.75max. important notice life support diodes incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or ot her changes without further notice to any product herein. diodes incorporated does not assume any liability arising out of the application or use of any pr oduct described herein; neither does it convey any license under its patent rights, nor the rights of others. the user of products in such applications shall a ssume all risks of such use and will agree to hold diodes incorporated and all the companies whose products are represented on our website, harmless against all dam ages. diodes incorporated products are not authorized for use as critical components in life support devices or systems without the e xpressed written approval of the president of diodes incorporated.
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