IZ1583 ver.00/10.11.2008 1 general description the IZ1583 is a step-down regulator with a built in internal power mosfet. the ic provide 3a continuous output current over a wide supply voltage range. the ic can be used as distributed power source, battery charger, pre-regulator for linear regulators. features ? w i de supply voltage range 4,75 ? 23 v. ? w i de operating tem p erature range -40 ? +85 o c. ? active m ode consum ption current (m ax.) 1,2 m a . ? chip dim e nsions 1,91 1,42 m m . ? ics are available for shipm e nt in chip form on unsawn wafers ? functionality ic perf orm s driving of power built in mosfet switch, quantity of energy transf erred to load is regulated by m eans of mosfet on-tim e (pulse-width m odulation). so ouput voltage practically do not depends from load. table 1 ? contact pad description pad number symbol description 01 bs n-channel power output mosfet switch drive input 02 v cc ic supply pin. connected to 6,5v ? 32 v power source. bypass vcc to gnd with a suitably large capacitor to eliminate noise on the input to the ic. 03 sw power switch output. sw has to be connected by output lc filter to the output load and by mentioned capacitor to bs. 04 gnd common pin (ground) 05 fb feedback input, has to be connected by a resistive voltage divider to output voltage 06 comp frequency compensation node has to be connected by series rc net- work to gnd 07 en digital enable/disable input. high level applied to en turns ic on and low level ? turns it off. for automatic startup, leave en uncon- nected. 08 ss soft start. ss is purposed to control the soft start period. to set soft start mode connect ss & gnd by capacitor. a 0.1f capacitor sets the soft-start period to 10ms. to disable the soft-start feature, leave ss unconnected. http://
IZ1583 ver.00/10.11.2008 2 in te r n a l regul a t o r s oscilator 40/385 khz c ur r ent lim i t e r m1 m2 5v s r q q 0, 7v 1u a pwm - c om par at or f r equenc y f ol dbac k c om par at or v cc en fb co m p bs sw gnd 0, 7 v 1,22v loc k out c om par at or 2,285/2,495v s hut dow n c o m parat or error am pl i f i er ss 1 , 8 v 100 k fig. 1 ? electric block diagram
IZ1583 ver.00/10.11.2008 3 table 2 ? maximum & absolute maximum ratings recommended operating conditions absolute maximum ratings norm norm param e ter, unit sym bol min. max. min. max. supply voltage, v u cc 4,75 23 -0,3 28 sw pin voltage, v u sw ? ? -1,0 u cc + 0,3 bs pin voltage, v u bs ? ? u sw ? 0,3 u sw + 6,0 junction tem p erature j - 40* 150 therm a l; resistance ?junction ? am bient?, o c/w r th j-a 150 am bient tem p erature, o c a - 40 85 note ? maxim u m perm issible power p tot , w , dissipated by ic in conditional package for am bi- ent tem p erature t a , , is calculated by form ula: a thj a tot r t p ? ? = 125 , (1) 125 ? is m a xim um perm issible operating junction tem perature, o c ; r th j-a - therm a l resistance junction-am bient of ic (without heatsink).
IZ1583 ver.00/10.11.2008 4 table 3 ? electric parameters of ic iz 1583 (on default u cc = 12 v, t a = 25 o c) norm parameter, unit symbol measurement mode min max shutdown supply current, ua i sd u en = 0 v 30 supply current, m a i s u en = 2,6 v u fb = 1,4 v 1,2 feedback voltage, v u fb 4,75 v u cc 23 v 1,194 1,250 error am plifier transconductance, ua/v s i comp = 10 ua 500 1120 output power switch leakage cur- rent, ua i leak u en = 0 v u sw = 0 v 10 operating frequency, khz f 335 435 short circuit oscillation frequency, khz f u fb = 0 v 25 55 m i n i mu m d u t y c y c l e , % min u fb = 1,5 v 0 en threshold voltage, v u en 0,9 1,5 bias current, ua i in u en = 0 v 1,1 2,5 table 4 ? typical parameters parameter, unit symbol mode typical value error amplifier voltage gain,v 400 power output switch on resistance, m o hm r1 100 pumping transistor on resistance, ohm r m2 10 current sense to comp transconductance, a/v s comp 3,8 maximum duty cycle, % max u fb = 1,0 v 90 under voltage lockout threshold hysteresis, mv u his 210 soft start period, ms t ss c ss = 10 uf 10 current limit, a i lim 5,5 thermal shutdown threshold, o c t s 160
IZ1583 ver.00/10.11.2008 5 fig 2 ? application diagram
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