ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 1 o f 8 5 f 03 n - rev. f00 2 fixed voltage re gulator adjustable voltage regulator notes 1.) c1 need if device is far from filter capacitors vout=v ref x(1+r2/r1)+i adj xr2 2.) c2 minimu m value required for stability. general description features the ec50117s series of positive adjustable and fixed regulators are designed to provide 1a with high efficiency. all internal circuitry is designed to operate down to 1.4v input to output differential. on - chip trimming adjusts the reference voltage to 1%. current limit the typical value of 1.5a allows t o minimizing the stress on both the regulator and the power source circuitry under overload conditions. adjustable or fixe d voltage . output current of 1a. low dropout voltage 1.2v (typ.) at 1 a output current. 0.04% line regulation 0.2 % load regulation 100% thermal limit burn - in fast transient response current - limit : 1a typ. at t j = 25c on - chip thermal limiting : 150c typ. applications efficiency linear regulators post regulators for switching supplies adjustable power supply pin assignment p a c k age : s o t 22 3 - 3l typical application circuits
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 2 o f 8 5 f 03 n - rev. f00 2 ordering information part number package marking marking information ec50117s xxb7nr sot223 - 3l 1117s xx llllllll ddt 1. 111 7 s absolute maximum ratings characteristics symbol maximum unit dc supply voltage v in 20 v operating junction temperature range t opr - 40 t o +125 c storage temperature range t s tg - 65 to 150 c lead temperature (soldering) 10 sec t lead 300 c electrostatic discharge sensitivity h.b.m 3 kv/min thermal resistance junction to ambient s o t 22 3 - 3l ja 135 c / w thermal resistance junction to cas e s o t 22 3 - 3l jc 27 c / w internal power dissipation s o t 22 3 - 3l p d 0.7 4 w caution: stresses above those listed in absolute maximum ratings may cause permanent damage to the device. this is a stre ss only rating and operation of the device at these or a ny other conditions above those indicated in the operational sections of this specification is not implied.
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 3 o f 8 5 f 03 n - rev. f00 2 electrical characteristics ( i load =0ma , tj=25 ) parameter test conditions min typ max units output vo ltage all fixed version v in = v out +1.5 v , variator from nominal v out - 1.5 1.5 % 1.5v Q in - v out Q load =0ma to 1a,variator from nominal v out ( Q in - v out Q load =0ma to 1a,variator from nominal v out ( d <2.25w 1.25 14.6 v reference voltage (note 1) ec50117s - ad j v in =+5v, i load =10ma 1.23 2 1.25 1.268 v 1.5v Q in - v out Q load =10ma to 1a( in =v out +1.5v, i load =10ma - 0 . 6 0 +0.6 % line regulation all 1.5v Q in - v out Q load =10ma ( in =v out +1.5v, i load =10ma to 1a ( in =+5v,v adj =0v( in =v out +1.5v i load =10ma to 1a( Q in - v out Q load =10ma ( a in - v out =1.5v( in - v out =2.5v, i load =1a 60 db dropout voltage (note 1,3) all i load =1a( in - v out =1.5v,i load =10ma( adj for adj=25uf) 3. out, ref =1%
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 4 o f 8 5 f 03 n - rev. f00 2 typical characteristics
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 5 o f 8 5 f 03 n - rev. f00 2
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 6 o f 8 5 f 03 n - rev. f00 2 application information output voltage the ec50117s develops a 1.25v reference voltage between the output a nd the adjust terminal. by placing a resistor between these two terminals, a constant current is caused to flow through r1 and down through r2 to set the overall output voltage. normally, this current is chosen to be the specified minimum load current of 10ma. for fixe d voltage devices r1 and r2 are included in the device. load regulation when the adjustable regulat or is used, load regulation will be limited by the resistance of the wire connecting the regulator to the load. the data sheet specification for load regulation is measured at the output pin of the device. best load regulation is ob tained when the top of the re sistor divider (r1) is tied directly to the output pin of the device not to the load. for fixed voltage, devices the top of r1 is internally connected to the output, and the ground pin can be connec ted to low side of the load. if r1 is connected to the load, rp is multiplied by the divider ratio, the effecti ve resistance between the regulator and the load would be: r p (1 + r2/r1), r p = parasitic line resistance
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 7 o f 8 5 f 03 n - rev. f00 2 input capacitor an input capacitor of 10f or greater is reco mmended. tantalum or aluminum electrolytic capacitors can be used for bypassing. larger values will improve ripple rejection by bypassing the input to the regulator. output capacitor the ec50117s requires an output capacitor to mainta in stability and improve transient response. proper capacitor selection is i mportant to ensure proper operation. the ec50117s output capacitor selection is dependent upon the esr ( equivalent series resistance) of the output capacitor to maintain stability. when the output capacitor is 10f o r greater, the output capacitor should have an esr less than 1. this will improve transient response as well as promote stability. a low - esr solid tantalum capacitor works extremely well and provides good transi ent response and stability over temperature. aluminum electrolytics can also be used, as long as the esr of the capacitor is <1. the value of the output capacitor can be increa sed without limit. higher capacitance values help to improve transient response and ripple rejection and reduce output noise. ripple rejection the curves for ripple re jection were generated using an adjustable device with the adjust pin by passed. with a 25f bypassing capacitor, 75db ripple rejection is obtainable at any output level. the impedance of the adjust pin capacitor, at the ripple frequency, should be < r1. r1 is normally in the range of 100w to 200w. the size o f the required adjus t pin capacitor is the function of the input ripple frequency. at 120hz, with r1=100, the adjust pin capacitor should be 13f. for fixed voltage devices and adjustable devices without an adjust pin capacit or, the out put ripple will increase as the ratio of the output voltage to the reference voltage (vout /vref).
ec50117s 1 a low dropout positive voltage regulator e - c m o s c o r p . ( ww w . e c m o s . c o m . t w ) p a g e 8 o f 8 5 f 03 n - rev. f00 2 mechanical dimensions o utline drawing sot 223 - 3l symbol dimensions in mm min max a 1.40 0 1.800 a1 0.000 0.120 b 3.300 3.700 b 0.600 0.840 b1 2.900 3.150 c 6.700 7.300 d 6.200 6.700 e 2.300 bsc h 0.230 0.350 l 1.500 2.000 l1 0.750 1.150
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