features high accuracy output voltage guaranteed 100ma output very low quiescent current low dropout voltage extremely tight load and line regulation very low temperature coefficient needs only 1 m f for stability error flag warns of output dropout logic-controlled electronic shutdown output programmable from 1.24 to 29v applications battery powered systems cordless telephones radio control systems portable/palm top/notebook computers portable consumer equipment portable instrumentation avionics automotive electronics smps post-regulator voltage reference product description the lp2950-xx/LP2951-xx is a low power voltage regulator. this device excellent choice for use in battery powered application such as c ordless telephone, radio control systems, and portable computers. the lp2950-xx/LP2951-xx features very low quiescent current (75 m a typ.) and very low drop output voltage (typ. 40mv at light load and 380mv at 100ma). this includes a tight initial tolerance of 0.5% typ., extremely good load and line regulation of 0.05% typ., and very low output temperature coefficient, making the lp2950-xx/LP2951-xx useful as a low-power voltage reference. the error flag output feature is used as power-on reset for warn of a low output voltage, due to following batteries on input. other feature i s the logic-compatible shutdown input which enable the regulator to be switched on and off. the LP2951-xx is available in 8-pin plastic packages. the regulator output voltage may be pin-strapped for a -xx volt or programmed from 1.24 volt to 29 volts with external pair of resistors. the lp2950-xx is offered in 3-pin to-92 package compatible with other fixed regulator. absolute maximum ratings power dissipation internally limited lead temperature (soldering, 5 seconds) 260 c storage temperature range -65 c to+150 c operating junction temperature range -55 c to +150 c input supply voltage -0.3 to +30v feedback input voltage -1.5 to +30v shutdown input voltage -0.3 to +30v error comparator output -0.3 to +30v pin connection LP2951-xx top view to-92 plastic package (lp2950-xx only) bottom view device selection guide vout , v olts device 2.85* lp2950-2.85, LP2951-2.85 3.0 lp2950-3.0, LP2951-3.0 3.3 lp2950-3.3, LP2951-3.3 5.0 lp2950-5.0, LP2951-5.0 * - other versions are also available vout = 2.0v to 5.0v. please consult factory for more information figure 1. adjustable regulator lp2950/LP2951 100ma low drop out voltage regulators
electrical characteristics (at t a = 25 o c, v in = 15v; unless otherwise noted) parameter conditions ( note 2 ) min typ max units output voltage -25 c t j 85 c full operating temperature 0.985 |v 0 | 0.98 |v 0 | v 0 1.015 |v 0 | 1.02 |v 0 | v output voltage 100 m a i l 100ma, t j t jmax 0.976|v 0 | v 0 1.024 |v 0 | output voltage temperature coefficient (note 1) 50 150 ppm/ c line regulation (note 3) v 0 + 1v v in 30v (note 4) 0.04 0.4 % load regulation (note 3) 100 m a i l 100ma 0.1 0.3 % dropout voltage (note 5) i l =100 m a i l =100 ma 50 380 80 450 mv ground current i l =100 m a i l =100 ma 75 8 120 12 m a ma dropout ground current v in =v 0 - 0.5v, i l =100 m a 110 170 m a current limit vout=0 160 200 ma thermal regulation 0.05 0.2 %/w output noise, 10hz to 100khz c l =1 m f c l =200 m f c l =3.3 m f (bypass=0.01 m f pins 7 to 1 (LP2951-xx)) 430 160 100 m v rms 8-pin versions only reference voltage 1.21 1.235 1.26 v reference voltage over temperature (note 6) 1.185 1.285 feedback pin bias current 20 40 na reference voltage temperature coefficient (note 7) 50 ppm/ c feedback pin bias current temperature coefficient 0.1 na/ c error comparator output leakage current voh=30v 0.01 1.0 m a output low voltage vin=4.5v, i ol =400 m a 150 250 mv upper threshold voltage (note 8) 40 60 lower threshold voltage (note 8) 75 95 hysteresis (note 8) 15 shutdown input input logic voltage low (regulator on) high (regulator off) 2 1.3 0.7 v shut down pin input current v s =2.4v v s =30v 30 450 50 600 regulator output current in shutdown (note 9) v out = 5.0 v 3 10 m a 3.3v v out < 5.0 v 20 2.0v v out < 3.3 v 30 note 1: output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range. note 2: unless otherwise specified all limits guaranteed for t j = 25 c, vin = v 0 + 1v, i l = 100 m a and c l = 1 m f. additional conditions for the 8-pin versions are feedback tied to -xx v tap and output tied to output sense (v out = xx v) and v shutdown 0.8 v note 3: regulations is measured at constant junction temperature, using pulse testing with a low duty cycle. changes in output voltage due to heating effects are covered under the specification for thermal regulation. note 4: line regulation for LP2951-xx is tested at 150 c for i l = 1ma. for i l = 100 m a and t j = 125 c, line regulation is guaranteed by design to 0.2%. see typical performance characteristics for line regulation versus temperature and load current. note 5: dropout voltage is defined as the input to output differential at which the output voltage drops 100mv below its nominal value measured at 1v differential. at very low values of programmed output voltage, the minimum input supply voltage of 2v (2.3v over temperature) must be taken into account. note 6: vref vout (vin - 1v), 2.3v vin 30v, 100 m a i l 100ma, t j t jmax note 7: output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range note 8: comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at v 0 + 1v input. to express these thresholds in terms of output voltage change, multiply by the error amplifier gain = v out /v ref = (r1 + r2)/r2. for example, at a programmed output voltage of 5v, the error output is guaranteed to go low when the output drops by 95mv x 5v/ 1.235v=384mv. thresholds remain constant as a percent of vout as vout is varied , with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed. note 9: v shutdown 3 2v, vin 30v, vout = 0, feed-back pin tied to -xx v tap. lp2950/LP2951 100ma low drop out voltage regulators
block diagram and typical applications lp2950-xx LP2951-xx pad location LP2951-xx (for lp2950-xx fixed versions see note 1) chip size: 2.05 x 1.15 mm pad n pad name x ( m m) y ( m m) 1 output 440 110 2 sense 810 110 3 shutdown 1250 110 4 ground 1865 110 5 error 1865 950 6 xx v tap 935 950 7 feedback 735 950 8 input 440 950 note 1: for lp2950-xx: 8 - connected to input 1,2 - connected to output 4 - con nected to gnd lp2950/LP2951 100ma low drop out voltage regulators
|
