unisonic technologies co., ltd ld2127/a preliminary linear integrated circuit www.unisonic.com.tw 1 of 6 copyright ? 2013 unisonic technologies co., ltd qw-r102-054.a low drop fixed and adjustable positive voltage regulators ? description the utc ld2127/a is a low dropout, 3-terminal positive voltage regulator designed to provide output current up to 800ma/1a, there are adjustable versions (v ref =1.0v) and various fixed versions. ? features * low dropout voltage * suitable for scsi-2 active termination if v out set to 2.85v * output current up to 0.8a for 2127 and 1.0a for 2127a * built-in current limit and ov er temperature protection * ultra low adjustment current (7 a typ.) * ultra low minimum load (0.3ma typ.) * stable with low esr ceramic output capacitor (mlcc) sot-223 1 ? ordering information ordering number package ? pin assignment packing lead free halogen free ld2127 ? l-xx-aa3- ? -r ld2127 ? g-xx-aa3- ? -r sot-223 a: aoi b: oai c: aio d: iao tape reel note: pin assignment: i: v in o: v out a: adj (1) r: tape reel (2) refer to pin assignment (3) aa3: sot-223 (4) xx: refer to marking information (5) l: lead free, g: halogen free (6) blank: 800ma, a: 1a (1)packing type (2)pin assignment (3)package type (4)output voltage code (5)lead free (6)current code ld2127 1 l-xx-aa3- 2 - r
ld2127/a preliminary linear integrated circuit unisonic technologies co., ltd 2 of 6 www.unisonic.com.tw qw-r102-054.a ? marking information package voltage code marking sot-223 a d : a d j ld2127 xx 123 date code voltage code current code l: lead free g: halogen free pin code ? block diagram
ld2127/a preliminary linear integrated circuit unisonic technologies co., ltd 3 of 6 www.unisonic.com.tw qw-r102-054.a ? absolute maximum rating (t a =25c) parameter symbol ratings unit dc input voltage v in 18 v power dissipation p d internally limited w junction temperature t j +150 c storage temperature t stg -65 ~ +150 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? recommended operating ratings parameter symbol ratings unit input voltage v in 15 v operating junction temperature t j 0 ~ +125 c ? thermal data parameter symbol ratings unit junction to ambient ja 165 c/w junction to case jc 15 c/w ? electrical characteristics (t a =25c, refer to the test circuits, t j =0 ~ 125c, c o =10 f unless otherwise specified) for ld2127/a-adj parameter symbol test conditions min typ max unit reference voltage v ref v in -v out =2v, i out =10ma, t j =25c 0.98 1.0 1.02 v reference voltage v ref v in -v out =1.4~10v ld2127a : i out =10~1000ma 0.98 1.0 1.02 v line regulation ? v out v in -v out =1.5 ~ 13.75v, i out =10ma 0.5 % load regulation ? v out v in -v out =3v ld2127 : i out =10~800ma ld2127a : i out =10~1000ma 2.0 % temperature stability ? v out 0.50 % long term stability ? v out 1000 hrs, t j =125c 0.3 % operating input voltage v in 15 v adjustment pin current i adj v in ? 15v 7 10 a adjustment pin current change ? i adj v in -v out =1.4~10v, ld2127a : i out =10 ~ 1000ma 0.3 2 a minimum load current i o(min) v in =15v 0.3 1 ma current limit i limit v in -v out =5v, t j =25c ld2127 800 ma ld2127a 1000 output noise (%v o ) e n b=10hz ~ 10khz, t j =25c 0.003 % supply voltage rejection svr i out =40ma, f=120hz, t j =25c, v in -v out =3v, v ripple =1v pp 75 db dropout voltage v d i out =100ma 1.05 1.15 v i out =500ma 1.15 1.25 i out =800ma 1.18 1.28 i out =1a 1.22 1.35 thermal regulation t a =25c, 30ms pulse 0.01 0.10 %/w thermal shutdown otp 150 c
ld2127/a preliminary linear integrated circuit unisonic technologies co., ltd 4 of 6 www.unisonic.com.tw qw-r102-054.a ? application note of ld2127/a adjustable the ld2127/a adjustable has a reference voltage of between the out and adj pins. i adj is 7 a typ. (10 a max.) and ? i adj is 0.3 a typ. (2a max.). r 1 is normally fixed to 1.2k ? . from figure 1 we obtain: v out =v ref +r 2 (i adj +i r1 )=v ref + r 2 (i adj +v ref /r 1 )=v ref (1+r 2 /r 1 ) + r 2 i adj . usually r 2 value is in the range of few k ? , so the r 2 x i adj product could be negle cted; then the above expression becomes: v out =v ref (1+r 2 /r 1 ) for better load regulation, realize a good kelvin connection of r 1 and r 2 is important. particularly r 1 connection must be realized very close to out and adj pin, while r 2 ground connection must be placed as near as possible to the negative load pin. ripple rejecti on can be improved by introducing a 10 f electrolytic capacitor placed in parallel to the r 2 resistor (see fig. 2) the utc ld2127/a also supports mlcc. see fig.3 for adjustable output. in out adj utc ld2127/a + + 10f 10f r 1 1.2k ? v in v out v ref r 2 fig.1 adjustable output vo ltage application circuit fig.2 adjustable output voltage applic ation with improved ripple rejection.
ld2127/a preliminary linear integrated circuit unisonic technologies co., ltd 5 of 6 www.unisonic.com.tw qw-r102-054.a ? application note of ld2127/a adjustable(cont.) in out adj utc ld2127/a 10f 10f r 1 1.2k ? v in v out v ref r 2 fig.3 adjustable output volta ge application circuit for mlcc
ld2127/a preliminary linear integrated circuit unisonic technologies co., ltd 6 of 6 www.unisonic.com.tw qw-r102-054.a ? typical characteristics power (w) 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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