unisonic technologies co., ltd l11815a preliminary cmos ic www.unisonic.com.tw 1 of 6 copyright ? 2010 unisonic technologies co., ltd qw-r502-346.c 1.5a cmos ldo ? description the utc l11815a is a coms linear regulator. one of it?s feature is very low quiescent current typical as low as 45 a and its dropout voltage is extremely lo w with 1.5a output current. the internal circuit includes thermal shutdown and current fold-back mechanism to prevent device failure when the circuit is operated in the bad conditions. in application, the utc l11815a needs a low noise, regulated supply. for stable operation, t he output capacitance value should be 4.7 f or more. the utc l11815a is an ideal for battery applications, such as instrumentations, portable electronics, wireless devices, pc peripherals, and battery powered widgets. the output voltage values are set during manufacturing and the accuracy is tighten 1.5%. ? features * quiescent current (45 a typ.) * very low dropout voltage * guaranteed 1.5a output * accuracy : 1.5% * over-temperature shut down * with current limiting * short circuit current fold-back * low temperature coefficient ? ordering information pin assignment ordering number package 1 2 3 packing l11815ag-xx-aa3-d-r sot-223 i g o tape reel note: pin assignment: g:gnd o:v out i:v in xx: output voltage, refer to marking information.
l11815a preliminary cmos ic unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r502-346.c ? marking information package voltage code marking sot-223 15: 1.5v 19: 1.9v 25: 2.5v 28: 2.8v ? pin configuration 1 2 3 gnd v in v out ? pin description pin no. pin name description 1 v in input voltage pin. it should be decoupled with 1f or greater capacitor. 2 gnd ground connection pin. 3 v out ldo voltage regulator output pin. it should be decoupled with a 4.7f or greater value low esr ceramic capacitor.
l11815a preliminary cmos ic unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r502-346.c ? block diagram
l11815a preliminary cmos ic unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r502-346.c ? absolute maximum rating parameter symbol ratings unit input voltage v in -0.3 ~ +8 v output voltage v out gnd - 0.3 ~ v in + 0.3 v output current i out out in d v - v p ma power dissipation p d 900 mw junction temperature t j 150 c operating temperature t opr - 40 ~ + 85 c storage temperature t stg - 65 ~ +150 c note: absolute maximum ratings are those values be yond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? thermal data parameter symbol ratings unit junction to ambient ja 120 c/w junction to case (note) jc 25 c/w note: jc on center of molding compound if ic has on tab ? electrical characteristics ( v in = v o(nom) +2v , ta = 25c, unless otherwise specified .) parameter symbol test conditions min typ max unit input voltage v in note 7 v output voltage accuracy v out i o =1ma -1.5 1.5 % v out < 2.0v -0.15 0.15 % line regulation out out v v i out =1ma v in =v out +1~ v out +2 v out 2.0v -0.1 0.02 0.1 % load regulation out out v v i out =1ma ~ 1500ma -1 0.2 1 % output current i out 1500 ma current limit i limit 1500 2000 ma short circuit current i sc v in = v o(nom) +1v, v out < 0.4v 750 ma quiescent current i q i out =0ma 45 70 a ground pin current i gnd i out =1ma ~ 1500ma 45 a v o(nom) 2.0v 1300 mv dropout voltage v d i out =1.5a v out =v o(nom) -2.0% v o(nom) > 2.0v 800 mv over temperature shutdown ots 150 c over temperature hysteresis oth 30 c temperature coefficient of output voltage t c v o 30 ppm/c f=100hz 70 db f=1khz 50 db power supply rejection psrr i out =100ma, c o =4.7f f=10khz 20 db output voltage noise en f=10hz ~ 100khz, i out =10ma, co=4.7f 30 vrms note: v in(min) =v out +v d
l11815a preliminary cmos ic unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r502-346.c ? detailed descripation the utc l11815a of cmos regulators insist of a pmos pass tr ansistor, voltage referenc e, error amplifier, over-current protection, and thermal shutdown. the error amplifier, over-current shutdown, and thermal protection circuits provides data for p-channel pass transistor. the error amplifier takes output voltage for a precision referenc e in the normal operation and the normal operation is restored when the junction te mperature drops below 120c.over-curr ent and thermal shutdown circuits start to work when the junction temperature is higher than 150 c, or the current exceeds 2.2a. the output voltage stays low when the thermal shutdown is in active. the utc l11815a behaves like a current source when the load re aches 2.2a. but the current would fall back to 600ma to prevent excessive power loss when the load impedance value is below 0.3 ? .normal operation is restored when the load resistance value is higher than 0.75 ? . ? external capacitors the utc l11815a has an output capacitor to ground of 4.7 f or more in the stable operation. ceramic capacitors can provide the lowest esr wi th the best ac performance. aluminum el ectrolytic capacitors, in contrast, have the highest esr with poorest ac response. unfortu nately, large value ceramic capacitors are comparatively expensive. so we can parallel a 0.1 f ceramic capacitor with a 10 f aluminum electrolytic. the result is low esr, high capacitance, and low overall cost. a second capacitor is recommended between the input a nd ground to stabilize input voltage. to get an ideal effect the value of the input capacitor should be at least 0.1 f. all capacitors should be placed in close proximity to the pins. this can be achieved with a star connection.
l11815a preliminary cmos ic unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r502-346.c ? typical application circuit l11815a gnd v in v out v in v out c1=1f c2=4.7f utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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