150 ma c-mos l.d.o. regulator LM1185SF features extremel y low su pp l y current ( 50 a,t yp . ) ver y low dro p out volta ge 150ma out p ut current hi g h out p ut volta g e accurac y +/- 1.4 % standard or custom out p ut volta g e s over currentand over tem p erature protection small in p ut/out p ut differential : 0.165v at 150ma moisture sensitivit y level 3 application s batter y o p erated s y stems portable com p uters portable cameras and video recorder s medical instruments instrumentation cellular/gsm/phs phones linear post-re g ulators for smps ordering information pa g er s (note : "xx" is output voltage for sot-25 pkg, 1.5v=ha15, 1.8v=ha18?.3.3v=ha33) description 2008 - ver 1.0 htc ? 1 ? package marking device lm1185 sf5 haxx sot-23-5l the lm1185 series is a low-dropout linear regulators. there are devices designed specifically for battery-operated s ystems. ground current is very small (2a - typ), that significantly extending battery life. low power consumption and high accuracy is achieved through cm os and programmable fuse technologies. output voltage: 1.5v to 6.0v. the lm1185 consists of a high-precision voltage reference, an e rror correction circuit, and a current limited output driver. with good transient responses, output r emains stable even during load changes. the shdn input enables the output to be turned off, resulting in reduced power consumption. also, the lm1185 having high ripple rejection ratios, the series can be u sed with power supply noise. a 470pf capacitor from the bypass input to ground reduces noise present on the internal reference, which in turn significantly reduces output noise. if output noise is not a concern, this input may be left unconn ected. larger capacitor values cbp be used, but results in a longer time period to rated output voltage whe n power is initially applied. the lm1185 incorporates both over-temperature and over-current protection. sot23-5 (300mw) and sot-89-5 (500mw) packages are available. sot-23-5l(sot-25) 1.vin 2.gnd 3. shdn 4.bypass 5.vout
150 ma c-mos l.d.o. regulator LM1185SF absolute maximum rating ( note 1 ) electrical characteristic s ( at ta = 25 , vin = vout+0.5v, unless otherwise noted ) htc ? 2 ? unit vin +6.5 v characteristic supply voltage symbol value output current iout 150 ma mw 300 output voltage vout vss-0.3 to vin+0.3 v 500 total power dissipation sot23-5ld sot89-5ld pd operating ambient temperature topr -40 ~ +85 c lead temperature (soldering, 5 sec) 260 c storage temperature tstg -40 ~ +125 c
150 ma c-mos l.d.o. regulator LM1185SF t yp ical a pp lication circuit detail description htc ? 3 ? 1. output capacitor 1uf(min) capacitor from v out to gnd is required. the output capacitor could have an effective series resistance greater than 0.1 ? and less than .0 ? . 1uf capacitor should be connected from vin to gnd if there is more than 10 inche sofwire between the regulator and the ac filter capacitor ,or if a battery is used as the power source. aluminum electrolytic or tantalum capacitor types can be used. (since many aluminum electrolytic capacitors freeze at approximately -30c, solid tantalums are recommended for applications operating below -25 c.) when operating from sources other than batteries,supply-noise rejection and transient response can be improved by increasing the value of the input and output capacitors and employing passive filtering techniques. 2. bypass input 470pf capacitor connected from the bypass input to ground reduces noise present on the internal reference, which in turn significantly reduces output noise. if output noise is not concern, this input maybe left unconnected. larger capacitor values maybe used, but results in a longer time period to rated output voltage when power is initially applied. 3. thermal considerations 3.1 thermal shutdown integrated thermal protection circuitry shuts the regulator off when die temperature exceeds150c. the regulator remains off until the die temperature drops to approxi mately 140c. 3.2 power dissipation the amount of power the regulator dissipate is primarily a function of input and output voltage, and output current. the following equation is used to calculate worst case actual power dissipation: vin (to cmos logic or tie to vin if unused) gnd bp + 1uf ? shdn vout + battery vout + 470pf reference bypass cap(optional) + 1uf ?
150 ma c-mos l.d.o. regulator LM1185SF equation 3-1: htc ? 4 ? the maximum allowable power dissipation (equation 3-2) is a function of the maximum ambient temperature(t amax ), the maximum allowable die temperature(t jmax ) and the thermal resistance from j unction-to-air( ja ). equation 3-2: 3.3 layout considerations : the primary path of heat conduction out of the package is via the package leads. therefore,layouts having a ground plane,wide traces at the pads,and wide power supply bus lines combine to lower ja and therefore increase the maximum allow able power dissipation limit. equation 3-1 can be used in conjunction with equation 4-2 to ensure regulator thermal operation is within limits.forexample:
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