ltc1258 series 1 1258sfb typical application features applications description micropower low dropout references the ltc ? 1258/ltc1258-2.5/ltc1258-3/ltc1258-4.1/ ltc1258-5 are micropower bandgap references that combine high accuracy and low drift with very low sup- ply current and small package size. the combination of ultralow quiescent current and low dropout voltage of only 200mv maximum makes them ideal for battery-powered equipment. the output voltage is set by an external resistor divider for the adjustable ltc1258. this series of references uses curvature compensation to obtain low temperature coef? cient and trimmed thin-? lm resistors to achieve high output accuracy. these references can source up to 10ma and sink up to 2ma, making them ideal for precision regulator applications. they are stable without an output bypass capacitor, but are also stable with capacitance up to 1f. this feature is important in critical applications where pc board space is a premium and fast settling is demanded. the ltc1258 series references provide power dissipation advantages over shunt references. in addition to supply current, shunt references must also idle the entire load current to operate. the ltc1258 series is available in the 8-pin msop and so packages. 2.5v battery-powered reference n 200mv max dropout at 10ma output current n 4a typical quiescent current n 0.15% max initial accuracy (s8) n no output capacitor required n output sources 10ma, sinks 2ma n 40ppm/c max drift (s8) n voltage options: 2.5v, 3v, 4.1v, 5v and adjustable n available in small msop package n battery-powered systems n handheld instruments n precision power supplies n a/d and d/a converters l , lt, ltc and ltm are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. ltc1258-2.5 temperature drift temperature (c) C40 C20 0 20 40 60 80 100 reference voltage change (mv) 1258 ta02 4 3 2 1 C2 C1 C3 C4 0 ltc1258-2.5 out in gnd 4 2 2.7v to 12.6v 1 2.5v 1258 ta01 0.1f
ltc1258 series 2 1258sfb absolute maximum ratings supply voltage ..........................................................13v input voltages ............................................ C0.3v to 13v output voltages ......................................... C0.3v to 13v output short-circuit duration .......................... inde? nite (note 1) 1 2 3 4 out in **dnc/fb gnd 8 7 6 5 dnc* dnc* dnc* dnc* top view ms8 package 8-lead plastic msop t jmax = 125c, ja = 250c/w *connected internally. do not connect external circuitry to these pins **dnc for ltc1258-2.5/ltc1258-3/ltc1258-4.1/ltc1258-5, fb for ltc1258 1 2 3 4 8 7 6 5 top view dnc* dnc* dnc* dnc* out in **dnc/fb gnd s8 package 8-lead plastic so t jmax = 125c, ja = 190c/w *connected internally. do not connect external circuitry to these pins **dnc for ltc1258-2.5/ltc1258-3/ltc1258-4.1/ltc1258-5, fb for ltc1258 pin configuration order information lead free finish tape and reel part marking package description temperature range ltc1258cms8#pbf (obsolete) ltc1258cms8#trpbf ltel 8-lead plastic msop 0c to 70c ltc1258cms8-2.5#pbf ltc1258cms8-2.5#trpbf ltcf 8-lead plastic msop 0c to 70c ltc1258cms8-3#pbf ltc1258cms8-3#trpbf lteu 8-lead plastic msop 0c to 70c ltc1258cms8-4.1#pbf ltc1258cms8-4.1#trpbf lten 8-lead plastic msop 0c to 70c ltc1258cms8-5#pbf ltc1258cms8-5#trpbf ltem 8-lead plastic msop 0c to 70c ltc1258cs8#pbf (obsolete) ltc1258cs8#trpbf 1258 8-lead plastic so 0c to 70c ltc1258cs8-2.5#pbf ltc1258cs8-2.5#trpbf 12582 8-lead plastic so 0c to 70c ltc1258cs8-3#pbf ltc1258cs8-3#trpbf 12583 8-lead plastic so 0c to 70c ltc1258cs8-4.1#pbf ltc1258cs8-4.1#trpbf 125841 8-lead plastic so 0c to 70c ltc1258cs8-5#pbf ltc1258cs8-5#trpbf 12585 8-lead plastic so 0c to 70c consult ltc marketing for parts speci? ed with wider operating temperature ranges. consult ltc marketing for information on non-standard lead based ? nish parts. 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 (note 2).. C40c to 100c speci? ed temperature range ..................... 0c to 70c storage temperature range (note 3) ..... C65c to 150c lead temperature (soldering, 10 sec) .................. 300c
ltc1258 series 3 1258sfb 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. symbol parameter conditions min typ max units v in input voltage range l 12.6 v i in input current fb = out for ltc1258 l 4 6.5 8.5 a a v out output voltage (note 4) ltc1258 (s8), fb = out ltc1258-2.5 (s8) ltc1258-3 (s8) ltc1258-4.1 (s8) ltc1258-5 (s8) ltc1258 (ms8), fb = out ltc1258-2.5 (ms8) ltc1258-3 (ms8) ltc1258-4.1 (ms8) ltc1258-5 (ms8) 2.3755 2.4963 2.9955 4.090 4.9925 2.374 2.4948 2.994 4.0885 4.991 2.385 2.5 3 4.096 5 2.385 2.5 3 4.096 5 2.3945 2.5037 3.0045 4.102 5.0075 2.396 2.5052 3.006 4.1035 5.009 v v v v v v v v v v e n output voltage noise (note 5) 0.1hz f 10hz 8 ppm p-p tc output voltage temp coef? cient (note 6) t min t j t max (s8) t min t j t max (ms8) l l 15 40 60 ppm/c ppm/c v out /v in line regulation v in = (v out(nominal) + 0.2v) to 12.6v l 30 120 ppm/v v out /i out load regulation (note 7) sourcing 0ma to 10ma l 0.1 0.3 mv/ma sinking 0ma to 2ma l 1.75 4.0 6.5 mv/ma mv/ma i sc short-circuit output current v out shorted to gnd v out shorted to v in 20 2 40 4 ma ma v do dropout voltage (note 8) i out = 0, v out 0.1% i out = 10ma, v out 0.1% l l 100 200 mv mv v hyst output hysteresis (note 9) t = C40c to 85c t = 0c to 70c 200 50 ppm ppm i fb fb pin input current ltc1258, out = fb 10 na the l denotes the speci? cations which apply over the full operating temperature range, otherwise speci? cations are at t a = 25c. v in = v out(nominal) + 0.2v, i out = 0ma, fb = out for the ltc1258 unless otherwise noted. output voltage (v) temperature range (c) accuracy (%) temperature coefficent (ppm/c) package type so-8 (s8) msop-8 (ms8) order number part marking order number part marking 2.5 2.5 0 to 70 0 to 70 0.15 0.21 40 60 ltc1258cs8-2.5 12582 ltc1258cms8-2.5 ltcf 3 3 0 to 70 0 to 70 0.15 0.20 40 60 ltc1258cs8-3 12583 ltc1258cms8-3 lteu 4.096 4.096 0 to 70 0 to 70 0.15 0.18 40 60 ltc1258cs8-4.1 125841 ltc1258cms8-4.1 lten 5 5 0 to 70 0 to 70 0.15 0.18 40 60 ltc1258cs8-5 12585 ltc1258cms8-5 ltem obsolete adjustable adjustable 0 to 70 0 to 70 0.4 0.46 40 60 ltc1258cs8 1258 ltc1258cms8 ltel available options note 2: the ltc1258 is guaranteed functional over the operating temperature range of C40c to 100c. note 3: if the part is stored outside of the speci? ed operating temperature range, the output may shift due to hysteresis.
ltc1258 series 4 1258sfb note 4: esd (electrostatic discharge) sensitive device. extensive use of esd protection devices are used internal to the ltc1258, however, high electrostatic discharge can damage or degrade the device. use proper esd handling precautions. note 5: peak-to-peak noise is measured with a single pole highpass ? lter at 0.1hz and 2-pole lowpass ? lter at 10hz. note 6: temperature coef? cient is the change in output voltage divided by the nominal output voltage divided by the speci? ed temperature range. note 7: load regulation is measured on a pulse basis from no load to the speci? ed load current. output changes due to die temperature change must be taken into account separately. note 8: dropout voltage is (v in C v out ) when v out falls to 0.1% below its nominal value at v in = v out + 0.5v. note 9: hysteresis in output voltage is created by package stress that differs depending on whether the ic was previously at a higher or lower temperature. output voltage is always measured at 25c, but the ic is cycled hot or cold before successive measurements. hysteresis is not normally a problem for operational temperature excursions where the instrument might be stored at high or low temperature. electrical characteristics typical performance characteristics ltc1258-2.5* dropout voltage vs output source current ltc1258-2.5* input current vs temperature ltc1258 series output short- circuit current vs temperature ltc1258-2.5* output short- circuit vs input voltage ltc1258-2.5* output short- circuit current vs input voltage ltc1258 series load regulation output source current (ma) dropout voltage (mv) 100 90 80 70 60 50 40 30 20 10 0 0 1 10 100 1258 g01 0.1 t a = 25 o c temperature (c) C50 C25 input current (a) 150 1258 g02 025 50 75 100 125 8 7 6 5 4 3 2 1 0 v in = 2.7v temperature (c) C50 C25 output short-circuit current (ma) 150 1258 g03 025 50 75 100 125 70 60 50 40 30 20 10 5 0 t a = 25c v in = v out(nom) + 0.2v output shorted to v in output shorted to gnd input voltage (v) 2 output short-circuit current (ma) 25 20 15 10 5 0 4 6810 1258-g04 12 14 t a = 25c output shorted to v in input voltage (v) 2 output short-circuit current (ma) 42 41 4 6810 1258-g05 12 14 t a = 25c output shorted to gnd output current (ma) $ v out from no load (mv) 5 4 3 2 1 0 C1 C2 C3 C4 C5 0 1 10 100 1258 g06 0.1 t a = 25c v in = v out(nom) + 0.2v sinking sourcing *similar performance characteristics can be expected for all voltage options.
ltc1258 series 5 1258sfb typical performance characteristics ltc1258-2.5 output voltage vs input voltage ltc1258-2.5 input current vs input voltage ltc1258-2.5 psrr vs frequency ltc1258-2.5 0.1hz to 10hz noise ltc1258-5 input current vs input voltage in dropout ltc1258-2.5 input current vs input voltage in dropout input voltage (v) 2 output voltage (v) 2.5010 2.5005 2.5000 2.4995 4 6810 1258 g07 12 14 t a = 25c input voltage (v) 2 input current (a) 7 6 5 4 4 6810 1258 g08 12 14 t a = 25c frequency (hz) power supply rejection ratio (db) 60 50 40 30 20 10 0 10 1k 10k 1258 g09 100 v in = 2.7v 5v/div 1258 g10 1sec/div v in = 2.7v input voltage (v) 012345678910 input current (a) 1258 g11 1400 1200 1000 800 600 400 200 0 t a = C55c t a = 25c t a = 125c input voltage (v) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 input current (a) 1258 g12 250 200 150 100 50 0 t a = 25c t a = C55c t a = 125c pin functions out (pin 1): reference output. the output can source up to 10ma and sink up to 2ma. it is stable with output bypass capacitor ranging from 0f to 1f. in (pin 2): positive supply. bypassing with a 0.1f ca- pacitor is recommended if the output loading changes. (v out + 0.2v) v in 12.6v. dnc (pin 3): (ltc1258-2.5/ltc1258-3/ltc1258-4.1/ ltc1258-5) do not connect. connected internally for post package trim. this pin must be left unconnected. fb (pin 3): (lt1258) resistor divider feedback pin. con- nect a resistor divider from out to gnd and the center tap to fb. this pin sets the output potential. vv rr r out = + ? ? ? ? ? ? 2 385 12 2 .; r1 is connected from out to fb and r2 from fb to gnd. gnd (pin 4): negative supply or ground connection. dnc (pins 5, 6, 7, 8): do not connect. connected in- ternally for post package trim. these pins must be left unconnected.
ltc1258 series 6 1258sfb block diagram C + in 1 1258 bd 2 4 out 3 (ltc1258) fb 2.385v gnd r1 r2 note: r1 and r2 are not connected for ltc1258 applications information longer battery life series references have an advantage over shunt style references. to operate, shunt references require a resistor between the power supply and the output. this resistor must be chosen to supply the maximum current that is demanded by the circuit being regulated. when the circuit being controlled is not operating at this maximum current, the shunt reference must always sink this current, resulting in high power dissipation and short battery life. the ltc1258 series low dropout references do not require a current setting resistor and can operate with any supply voltage from (v out(nominal) + 0.2v) to 12.6v. when the circuitry being regulated does not demand current, the ltc1258 series reduces its dissipation and battery life is extended. if the reference is not delivering load current it dissipates only 10.8w when operating on a 2.7v supply for ltc1258-2.5, yet the same connection can deliver 10ma of load current when demanded. output bypass capacitor the ltc1258 series is designed to be stable with or without capacitive loads. with no capacitive load, the reference is ideal for fast settling applications, or where pc board space is at a premium. in applications with signi? cant output loading changes, an output bypass capacitor of up to 1f can be used to improve the output transient response. figure 1 shows the response of the reference to a 1ma to 0a load step with a 1f output capacitor. if more than 1f of output capacitance is required, a resistor in series with the capaci- tor is recommended to reduce the output ringing. figure 2 illustrates the use of a damping resistor for capacitive loads greater than 1f. figure 3 shows the resistor and capacitor values required to achieve critical damping. 1ma 0ma 10ms/div 1258 f01a i out v out 100mv/div 1ma 0ma 0.5ms/div 1258 f01b i out v out 100mv/div figure 1. reference output load transient response, 1f output capacitor
ltc1258 series 7 1258sfb 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 internal p-channel pass transistor the ltc1258 series features an internal p-channel mosfet pass transistor. this provides several advantages over similar designs using a pnp bipolar pass transistor. these references consume only 4a of quiescent current under light and heavy loads as well as in dropout; whereas, pnp-based references waste considerable amounts of current when the pass transistor is saturated. in addition, the ltc1258 series provides a lower dropout voltage (200mv max) than pnp-based references. ltc1258-5 out in gnd 4 2 5.2v to 12.6v 1 5v 1258 f02 0.1f c out >1f damping resistor <1k output capacitor value (f) 1 10 resistor value () 100 1k 10k 10 100 1000 1258 f03 figure 2. adding a damping resistor with output capacitors greater than 1f figure 3. damping resistance vs output capacitor value applications information ms8 package 8-lead plastic msop (reference ltc dwg # 05-08-1660 rev f) s8 package 8-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610) msop (ms8) 0307 rev f 0.53 p 0.152 (.021 p .006) seating plane note: 1. dimensions in millimeter/(inch) 2. drawing not to scale 3. dimension does not include mold flash, protrusions or gate burrs. mold flash, protrusions or gate burrs shall not exceed 0.152mm (.006") per side 4. dimension does not include interlead flash or protrusions. interlead flash or protrusions shall not exceed 0.152mm (.006") per side 5. lead coplanarity (bottom of leads after forming) shall be 0.102mm (.004") max 0.18 (.007) 0.254 (.010) 1.10 (.043) max 0.22 C 0.38 (.009 C .015) typ 0.1016 p 0.0508 (.004 p .002) 0.86 (.034) ref 0.65 (.0256) bsc 0 o C 6 o typ detail a detail a gauge plane 12 3 4 4.90 p 0.152 (.193 p .006) 8 7 6 5 3.00 p 0.102 (.118 p .004) (note 3) 3.00 p 0.102 (.118 p .004) (note 4) 0.52 (.0205) ref 5.23 (.206) min 3.20 C 3.45 (.126 C .136) 0.889 p 0.127 (.035 p .005) recommended solder pad layout 0.42 p 0.038 (.0165 p .0015) typ 0.65 (.0256) bsc .016 C .050 (0.406 C 1.270) .010 C .020 (0.254 C 0.508) s 45 o 0 o C 8 o typ .008 C .010 (0.203 C 0.254) so8 0303 .053 C .069 (1.346 C 1.752) .014 C .019 (0.355 C 0.483) typ .004 C .010 (0.101 C 0.254) .050 (1.270) bsc 1 2 3 4 .150 C .157 (3.810 C 3.988) note 3 8 7 6 5 .189 C .197 (4.801 C 5.004) note 3 .228 C .244 (5.791 C 6.197) .245 min .160 p .005 recommended solder pad layout .045 p .005 .050 bsc .030 p .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)
ltc1258 series 8 1258sfb linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2008 lt 0708 rev b ? printed in usa related parts typical applications micropower low dropout negative reference supply splitter + C 1 4 8 v ss = C4v v out = C3v 0.2v v cc 8.5v 3 2 ltc1258-3 1/2 ltc1542 out gnd 4 1 1258 ta03 in 2 0.1f ltc1258-2.5 out in gnd 4 2 v cc = 5v 1 2.5v virtual ground 1258 ta04 0.1f 0.1f low power, low voltage supply reference for ltc1069l ltc1258-3 ltc1096l mpu serial data link (microwire tm and spi compatible) out in gnd cs/ shdn +in Cin gnd v cc clk d out v ref analog input 0v to 3v range 1 2 3 4 8 7 6 5 4 2 v in 3.2v to 12.6v 1 1258 ta05 1f serial data link 0.1f part number description comments lt ? 1389 nanopower precision shunt voltage reference 800na quiescent current, 0.05% max, 10ppm/c max drift, 1.25v and 2.5v versions, so-8 package lt1634 micropower precision shunt voltage reference 0.05% max, 25ppm/c max drift, 1.25v, 2.5v, 4.096v and 5v outputs lt1460 micropower series reference 0.075% max, 10ppm/c max drift, 2.5v, 5v and 10v outputs lt1461 ldo micropower precision reference 0.04% max, 3ppm/c max drift in so-8 lt1790 sot-23, ldo micropower precision reference 0.05% max, 10ppm/c max
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