unisonic technologies co., ltd ld3870 preliminary linear integrated circuit www.unisonic.com.tw 1 of 5 copyright ? 2011 unisonic technologies co., ltd qw-r105-028,da low dropout voltage regulator ? description the utc ld3870 is low dropout voltage regulator designed for cellular phone application. ? features * high ripple rejection: 56db rr(dcLD3870G-AF5-R sot-25 tape reel note: xx: output voltage, re fer to marking information.
ld3870 preliminary linear integrated circuit unisonic technologies co., ltd 2 of 5 www.unisonic.com.tw qw-r105-028,da ? marking information package voltage code marking sot-25 15:1.5v 18:1.8v 25:2.5v 27:2.7v 30:3.0v 33:3.3v 50:5.0v 12 3 4 5 mxx voltage code g: halogen free l: lead free ? pin configuration 2 1 3 5 4 v out gnd noise bypass cont v in ? block dagram
ld3870 preliminary linear integrated circuit unisonic technologies co., ltd 3 of 5 www.unisonic.com.tw qw-r105-028,da ? absolute maximum ratings (t a =25 , unless otherwise specified) parameter symbol ratings unit input voltage v in +14 v control voltage v cont +14(note 2) v power dissipation p d 200 mw operating temperature t opr -40 ~ +85 storage temperature t stg -40 ~ +125 note 1: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device operation is not implied. 2. when input voltage is less than +14v, the absolute maximum control vo ltage is equal to the input voltage. ? electrical characteristics (v in =v out +1v, c in =0.1 f, c out =4.7 f, cp=0.01 f, t a =25 ) parameter symbol test conditons min typ max unit output voltage v out i out =30ma -2% +2% v quiescent current i q i out =0ma, expect l cont 200 300 a quiescent current at control off i q(off) v cont =0v 100 na output current i out v out -0.3v 150 200 ma line regulation v out /v in v in =v out +1v ~ v out +6v, i out =30ma 0.10 %/v load regulation v out /i out i out =0 ~ 100ma 0.03 %/ma dropout voltage v d i out =60ma 0.12 0.2 v ripple rejection rr e in =200mvrms, f=1khz, i out =10ma, v in =v out +2v, v out =3v version 60 db average temperature coefficient of output voltage v out /t a t a =0~85 , i out =10ma, v out =3v version 0.2 mv/ output noise voltage e n f=10hz ~ 80khz, i out =10ma, v out =3v version 30 vrms control voltage on v cont ( on ) 1.6 v off v cont ( off ) 0.6 v note: the above specification is a common specification for all output voltages. t herefore, it may be different from the individual specificat ion for a specific output voltage.
ld3870 preliminary linear integrated circuit unisonic technologies co., ltd 4 of 5 www.unisonic.com.tw qw-r105-028,da ? test circuit
ld3870 preliminary linear integrated circuit unisonic technologies co., ltd 5 of 5 www.unisonic.com.tw qw-r105-028,da ? typical applicaton for on/off control is not required: v in v out control noise bypass gnd (ceramic or tantalum) (0~300k ) r v out 0.1 f cp=0.01 f 4.7 f utc ld3870 connect control terminal to v in terminal the quiescent current can be reduced by using a resist ance ?r?. instead, it incr eases the minimum operating voltage. for further information, please re fer to figure ?output volt age vs. control voltage?. for in use of on/off control: v in v out control noise bypass gnd (ceramic or tantalum) r v out v in utc ld3870 4.7 f cp=0.01 f 0.1 f state of control terminal: * ?h? ? output is enables. * ?l?or ?open? ? output is disabled. * noise bypass capacitance cp - noise bypass capacitance cp reduces noise generated by hand-gap reference circuit. - noise level and ripple rejection will be improved when larger cp is used. - use of smaller cp value may cause oscillation. - use the cp value of 0.01uf gr eater to avoid the problem. 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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