lt1118/lt1118-2.5 lt1118-2.85/lt1118-5 1 1118fd typical application description low i q , low dropout, 800ma, source and sink regulators adjustable and fixed 2.5v, 2.85v, 5v output the lt ? 1118 family of low dropout regulators has the unique capability of maintaining output regulation while sourcing or sinking load current. the 2.85v output voltage regulator is ideal for use as a boulay termination of up to 27 scsi data lines. the regulator maintains regulation while both sourcing and sinking current, enabling the use of active negation drivers for improved noise immunity on the data lines. regulation of output voltage is maintained for termpwr voltages as low as 4.0v. when unloaded, quiescent supply current is a low 600a, allowing continu- ous connection to the termpwr lines. an ultralow power shutdown mode is also available on the so-8 version. in shutdown the output is high impedance and supply cur- rent drops to less than 10a. current limits in both sourcing and sinking modes, plus on-chip thermal shutdown make the circuit tolerant of output fault conditions. the lt1118 is available in 3-lead sot-223 and 8-lead so packages. load transient response l , lt, ltc and ltm are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. features applications n regulates while sourcing or sinking current n provides termination for up to 27 scsi lines n 600a quiescent current n ultralow power shutdown mode n current limit and thermal shutdown protection n stable for any c load 0.22f n fast settling time n 1v dropout voltage n active negation scsi terminations n computers n disk drives n cd-rom n supply splitter lt1118-2.85 gnd 1118 ta01 in 2.2f 5v 1f ceramic i load out 0.2v 0v C0.2v 800ma 0ma C400ma 1118 ta02 $ v out i load
lt1118/lt1118-2.5/ lt1118-2.85/lt1118-5 2 1118fd absolute maximum ratings supply voltage (v cc ) ................................................15v input voltage (enable).................................C 0.2v to 7v output voltage ............................... C 0.2v to v cc + 0.5v short-circuit duration ..................................... inde? nite (note 1) 1 2 3 4 8 7 6 5 top view s8 package 8-lead plastic so gnd in out in gnd nc en fb t jmax = 125c, ja = 15c/w 1 2 3 4 8 7 6 5 top view s8 package 8-lead plastic so en gnd gnd nc in out gnd in t jmax = 125c, ja = 15c/w 3 2 1 front view tab is gnd in gnd out st package 3-lead plastic sot-223 t jmax = 125c, jc = 15c/w pin configuration order information lead free finish tape and reel part marking package description temperature range lt1118cs8#pbf lt1118cs8#trpbf 1118 8-lead plastic so 0c to 70c lt1118cs8-2.5#pbf lt1118cs8-2.5#trpbf 111825 8-lead plastic so 0c to 70c lt1118cs8-2.85#pbf lt1118cs8-2.85#trpbf 111828 8-lead plastic so 0c to 70c lt1118cs8-5#pbf lt1118cs8-5#trpbf 11185 8-lead plastic so 0c to 70c lt1118cst-2.5#pbf lt1118cst-2.5#trpbf 111825 3-lead plastic sot-223 0c to 70c lt1118cst-2.85#pbf lt1118cst-2.85#trpbf 111828 3-lead plastic sot-223 0c to 70c lt1118cst-5#pbf lt1118cst-5#trpbf 11185 3-lead plastic sot-223 0c to 70c lead based finish tape and reel part marking* package description temperature range lt1118cs8 lt1118cs8#tr 1118 8-lead plastic so 0c to 70c lt1118cs8-2.5 lt1118cs8-2.5#tr 111825 8-lead plastic so 0c to 70c lt1118cs8-2.85 lt1118cs8-2.85#tr 111828 8-lead plastic so 0c to 70c lt1118cs8-5 lt1118cs8-5#tr 11185 8-lead plastic so 0c to 70c lt1118cst-2.5 lt1118cst-2.5#tr 111825 3-lead plastic sot-223 0c to 70c lt1118cst-2.85 lt1118cst-2.85#tr 111828 3-lead plastic sot-223 0c to 70c lt1118cst-5 lt1118cst-5#tr 11185 3-lead plastic sot-223 0c to 70c consult ltc marketing for parts speci? ed with wider operating temperature ranges. for more information on lead free part marking, go to: http://www.linear.com/leadfree/ for more information on tape and reel speci? cations, go to: http://www.linear.com/tapeandreel/ operating temperature range...................... 0c to 70c storage temperature range ...................C 65c to 150c lead temperature (soldering, 10 sec) .................. 300c
lt1118/lt1118-2.5 lt1118-2.85/lt1118-5 3 1118fd electrical characteristics note 1: stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. exposure to any absolute maximum rating condition for extended periods may affect device reliability and lifetime. note 2: unless otherwide speci? ed, testing done at v cc = 5v (lt1118-2.5, lt1118-2.85) or v cc = 7v (lt1118-5). v en = v cc . output c load = 1f, i load = 0. parameter conditions min typ max units quiescent current (v in )v en = 5v l 0.6 1 ma quiescent current in shutdown (v in )v en = 0v l 110 a enable input thresholds input low level input high level l l 0.4 1.4 1.4 2 v v enable input current 0v v en 5v l C1 25 a feedback voltage no load (25c) (lt1118) all operating conditions (note 3) l 1.213 1.200 1.225 1.225 1.237 1.250 v v output voltage no load (25c) (lt1118-2.5) all operating conditions (note 3) l 2.47 2.45 2.5 2.5 2.53 2.55 v v no load (25c) (lt1118-2.85) all operating conditions (note 3) l 2.82 2.79 2.85 2.85 2.88 2.91 v v no load (25c) (lt1118-5) all operating conditions (note 3) l 4.95 4.90 5 5 5.05 5.10 v v line regulation (note 4) i l = 0ma, 4.2v v in 15v (lt1118) i l = 0ma, 4.2v v in 15v (lt1118-2.5) i l = 0ma, 4.75v v in 15v (lt1118-2.85) i l = 0ma, 6.5v v in 15v (lt1118-5) l l l l 6 6 6 10 mv mv mv mv load regulation (note 4) 0ma i l 800ma (lt1118) C 400ma i l 0ma l l 6 6 mv mv 0ma i l 800ma (lt1118-2.5) C 400ma i l 0ma l l 12 12 mv mv 0ma i l 800ma (lt1118-2.85) C 400ma i l 0ma l l 12 12 mv mv 0ma i l 800ma (lt1118-5) C 400ma i l 0ma l l 25 25 mv mv dropout voltage (note 5) i l = 100ma i l = 800ma 0.85 1 1.1 1.3 v v fb pin bias current lt1118 0.35 1 a minimum output voltage lt1118 l 2.1 v ripple rejection f ripple = 120hz, v in C v out = 2v v ripple = 0.5v p-p 60 80 db load transient settling time, v = 1% 0ma i l 800ma, c load = 1f C400ma i l 0ma, c load = 1f 5 5 s s output short-circuit current v out = 0v, sourcing v out = v in , sinking 800 1200 C700 C400 ma ma thermal shutdown junction temperature no load 170 c enable turn-on delay no load 50 s the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. (note 2) note 3: all operating conditions include the combined effects of load current, input voltage and temperature over each parameters full range. note 4: load and line regulation are tested at a constant junction temperature by low duty cycle pulse testing. note 5: dropout voltage is de? ned as the minimum input to output voltage measured while sourcing the speci? ed current.
lt1118/lt1118-2.5/ lt1118-2.85/lt1118-5 4 1118fd typical performance characteristics output impedance vs frequency feedback current vs temperature ripple rejection vs load current input current vs output sink current ground pin current vs output source current dropout voltage vs output current ripple rejection vs frequency ripple rejection vs frequency output current (ma) 0 200 400 600 800 dropout voltage (v) 1118 g01 1.4 1.2 1 0.8 0.6 0.4 0.2 0 t j = 75c t j = 25c t j = 125c frequency (hz) ripple rejection (db) 80 60 40 20 0 10 1k 10k 100k 1118 g02 100 sourcing current no load 800ma 10ma frequency (hz) ripple rejection (db) 80 60 40 20 0 10 1k 10k 100k 1118 g03 100 sinking current no load 400ma 10ma frequency (hz) 10 2 0.001 z out () 0.1 10 10 4 10 5 10 3 10 6 1118 g04 0.01 1 no current 10ma source 100ma source 10ma sink 100ma sink temperature (c) C55 C35 C15 5 25 45 65 85 105 125 current (na) 450 400 350 300 250 200 150 100 50 0 1118 g05 load current (ma) C400 ripple rejection (db) 80 60 40 20 0 C200 0 200 400 1118 g06 600 800 c in = c load = 1f output sink current (ma) 0 input current (a) 1000 1250 1500 400 1118 g07 750 500 0 100 200 300 250 2000 1750 50 150 250 350 output sourcing current (ma) 0 ground pin current (a) 400 500 600 800 1118 g08 300 200 0 200 400 600 100 800 700
lt1118/lt1118-2.5 lt1118-2.85/lt1118-5 5 1118fd pin functions in: input supply pin. this pin should be decoupled with a 1f or larger low esr capacitor. the two in pins on the so-8 package must be directly connected on the printed circuit board to prevent voltage drops between the two inputs. when used as a scsi active termination, in con- nects to term power. when used as a supply splitter, in is also the positive supply output. gnd: ground pin. the multiple gnd pins on the so-8 package are internally connected, but lowest load regulation errors will result if these pins are tightly connected on the printed circuit board. this will also aid heat dissipation at high power levels. en: ttl/cmos logic input. a high level allows normal operation. a low level reduces supply current to zero. this pin is internally connected to v in on 3-lead st packaged devices. out: regulated output voltage. output can source or sink current. current limit for sourcing and sinking current is provided to protect the device from fault conditons. the output must have a low esr output ? lter capacitor. c out 0.22f to guarantee stability. a 0.1f ceramic capacitor may be needed in parallel with c out if the esr of the main c out is too high. fb: feedback pin. the feedback pin is used to program the output voltage of the adjustable s8 part. the output voltage range that can be achieved is 2.1v to 6.5v. the output voltage is determined by the selection of feedback resistors de? ned by the following formula: v out = v fb (1 + r 1 /r 2 ) + i fb r 1 operation gnd in out en fb r 1 r 2 1f v in 1118 ta06 lt1118 1f r 1 r 2 1 + v out = v fb + i fb r 1 () lt1118 adjustable output capacitor the lt1118 family of voltage regulators require an output capacitor for stability. the regulators are stable with out- put capacitors larger than 0.2f. load transient response is very sensitive to output capacitor value and dielectric choice. low esr ceramic capacitors are the best choice for fast settling to load transients. output capacitors between 0.2f and 1f give good performance in most applications. larger tantalum output capacitors may be used to reduce load transient amplitudes. larger capaci- tors should be paralleled with a 0.1f ceramic capacitor to maintain quick settling time performance and to insure stability of the regulator control loop. capacitors larger than 10f may be safely used with the regulators, but little transient settling performance improvement results from their use. worst case transient response of the lt1118 regulators occurs at zero output current. in order to obtain the fastest transient settling performance, the regulator output may be preloaded with a small current. the preload current reduces the regulator output impedance, reducing output voltage settling time. thermal considerations the lt1118 regulators are packaged in plastic sot-223 and fused lead s8 packages. these small footprint packages are unable to convectively dissipate the heat generated when the regulator is operating at high current levels. in order to control die operating temperatures, the pc board layout should allow for maximum possible copper area at the ground pins of the lt1118. the ground pins and the tab on the sot-223 package are electrically and thermally
lt1118/lt1118-2.5/ lt1118-2.85/lt1118-5 6 1118fd operation scsi active terminator connected to the die substrate. table 1 shows measured thermal resistance from junction to ambient for the lt1118 connected to various sized pc board ground planes. the power dissipated in the lt1118 varies with input voltage and loading. when the regulator is sourcing current the power which must be dissipated by the package is: p d = (v in C v out ) ? i load when the regulator is sinking load current, power dissipa- tion is nearly independent of v in and can be calculated as: p d = v out ? i load heat sinking to the ic package must consider the worst case power dissipation which may occur. table 1. measured thermal resistance from junction to ambient for the lt1118 s8 package sot-223 free air 1 sq inch copper 120c/w 55c/w 95c/w 53c/w 4 sq inch copper 35c/w 38c/w typical applications power supply splitter lt1118-2.85 gnd in 27 lines 2.2f 5v 1f 110 110 1118 ta03 110 110 110 termpwr out ? ? ? ? ? ? ? ? + lt1118-2.5 gnd in 1f 1118 ta04 5v analog common 2.5v v in 5v out 1f
lt1118/lt1118-2.5 lt1118-2.85/lt1118-5 7 1118fd information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. package description st package 3-lead plastic sot-223 (reference ltc dwg # 05-08-1630) s8 package 8-lead plastic small outline (narrow 0.150) (reference ltc dwg # 05-08-1610) .016 ?.050 (0.406 ?1.270) .010 ?.020 (0.254 ?0.508) 45 0 ?8 typ .008 ?.010 (0.203 ?0.254) so8 0303 .053 ?.069 (1.346 ?1.752) .014 ?.019 (0.355 ?0.483) typ .004 ?.010 (0.101 ?0.254) .050 (1.270) bsc 1 2 3 4 .150 ?.157 (3.810 ?3.988) note 3 8 7 6 5 .189 ?.197 (4.801 ?5.004) note 3 .228 ?.244 (5.791 ?6.197) .245 min .160 .005 recommended solder pad layout .045 .005 .050 bsc .030 .005 typ inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm) .114 ?.124 (2.90 ?3.15) .248 ?.264 (6.30 ?6.71) .130 ?.146 (3.30 ?3.71) .264 ?.287 (6.70 ?7.30) .0905 (2.30) bsc .033 ?.041 (0.84 ?1.04) .181 (4.60) bsc .024 ?.033 (0.60 ?0.84) .071 (1.80) max 10 max .012 (0.31) min .0008 ?.0040 (0.0203 ?0.1016) 10 ?16 .010 ?.014 (0.25 ?0.36) 10 ?16 recommended solder pad layout st3 (sot-233) 0502 .129 max .059 max .059 max .181 max .039 max .248 bsc .090 bsc
lt1118/lt1118-2.5/ lt1118-2.85/lt1118-5 8 1118fd linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 1995 lt 0209 rev d ? printed in usa related parts typical application variable 2.1v to 6.5v regulator with digital control gnd in out en fb r 1 13.3k r 2 6.19k r 3 6.19k 0.22f v out v out gnd v ref v cc d in 1118 ta05 clk ltc1257 v dac 0.1f 12v lt1118 p load 1f r 1 r 2 || r 3 r 1 r 2 ( ) 1 + v out = 1.225 C v dac part number description comments lt1129 700ma, micropower, ldo v in : 4.2v to 30v, v out(min) = 3.8v, v do = 0.40v, i q = 50a, i sd = 16a; dd, sot-223, s8, to220-5 and tssop20 packages lt1206 250ma/60mhz current feedback ampli? er high output current drive capability, can sink/source lt1210 1.1a, 35mhz current feedback amplifer high output current drive capability, can sink/source lt1763 500ma, low noise micropower, ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.30v, i q = 30a, i sd = < 1a, low noise < 20v rms , s8 package lt1764/ lt1764a 3a, low noise, fast transient response, ldo v in : 2.7v to 20v, v out(min) = 1.21v, v do = 0.34v, i q = 1ma, i sd = < 1a, low noise < 40v rms , a version stable with ceramic capacitors, dd and to220-5 packages ltc1844 150ma, very low drop-out ldo v in : 1.6v to 6.5v, v out(min) = 1.25v, v do = 0.08v, i q = 35a, i sd = < 1a, low noise < 60v rms , thinsot? package lt1962 300ma, low noise micropower, ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.27v, i q = 30a, i sd = < 1a, low noise < 20v rms , ms8 package lt1963/ lt1963a 1.5a, low noise, fast transient response, ldo v in : 2.1v to 20v, v out(min) = 1.21v, v do = 0.34v, i q = 1ma, i sd = < 1a, low noise < 40v rms , a version stable with ceramic capacitors; dd, to220-5, sot-223 and s8 packages lt3021 500ma, low voltage v do , v in(min) = 0.9v, ldo v in : 0.9v to 10v, v out(min) = 0.20v, v do = 0.16v, i q = 120a, i sd = 3a, dfn and s8 packages lt3024 dual, 100ma/500ma, low noise micropower, ldo v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.30v, i q = 60a, i sd = < 1a, dfn and tssop packages lt3028 dual, 100ma/500ma, low noise micropower, ldo with independent inputs v in : 1.8v to 20v, v out(min) = 1.22v, v do = 0.30v, i q = 30a, i sd = < 1a, low noise < 20v rms , dfn and tssop packages lt3080/ lt3080-1 1.1a parallelable, low noise, low dropout linear regulator 300mv dropout voltage (2-supply operation), low noise: 40v rms , v in : 1.2v to 36v, v out : 0v to 35.7v, current-based reference with 1-resistor v out set; directly parallelable (no op amp required), stable with ceramic caps, to-220, sot-223, msop and 3mm 3mm dfn packages; lt3080-1 version has integrated internal ballast resistor lt3085 500ma, parallelable low noise low dropout linear regulator 275mv dropout voltage (2 supply operation), low noise: 40v rms , v in : 1.2v to 36v, v out : 0v to 35.7v, current reference, msop-8 and 2mm 3mm dfn-6 packages thinsot is a trademark of linear technology corporation
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