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1 lt1086 series sn1086 1086ffs applicatio s u features descriptio u typical applicatio u 3-terminal adjustable or fixed2.85v, 3.3v, 3.6v, 5v, 12v output current of 1.5a (0.5a for lt1086h) operates down to 1v dropout guaranteed dropout voltage at multiple current levels line regulation: 0.015% load regulation: 0.1% 100% thermal limit functional test ripple rejection >75db available in 3-pin to-220 and 3-pin dd packages the lt 1086 is designed to provide up to 1.5a output current. all internal circuitry is designed to operate downto 1v input-to-output differential and the dropout voltage is fully specified as a function of load current. dropout is guaranteed at several operating points up to a maximum of 1.5v at maximum output current. dropout decreases at lower load currents. on-chip trimming adjusts the refer- ence/ouput voltage to 1%. current limit is also trimmed, minimizing the stress on both the regulator and power source circuitry under overload conditions. the lt1086 is pin compatible with older 3-terminal adjust- able regulators. a minimum 10 m f output capacitor is required on these devices.the lt1086 offers excellent line and load regulation speci- fications and ripple rejection exceeds 75db even at the maximum load current of 1.5a. the lt1086 is floating architecture with a composite npn output stage. all of the quiescent current and the drive current for the output stage flows to the load increasing efficiency. the lt1086 is available in a 3-pin to-220 package and a space-saving surface mountable 3-pin dd package. 1.5a low dropout positive regulators adjustable and fixed 2.85v, 3.3v, 3.6v, 5v, 12v scsi-2 active terminator high efficiency linear regulators post regulators for switching supplies constant current regulators battery chargers microprocessor supply lt1086 dropout voltage output current (a) 0 0 minimum input/output differential (v) 1 2 0.5 1 lt1086 ?ta02 1.5 indicates guaranteed test point ?5 c t j 150 c 0 c t j 125 c t j = 55 c t j = 25 c t j = 150 c v in 3 4.75v 3.3v at 1.5a *may be omitted if input supply is well bypassed within 2" of the lt1086 lt1086-3.3 lt1086 ?ta01 10 f* tantalum 10 f tantalum in out gnd 5v to 3.3v regulator , ltc and lt are registered trademarks of linear technology corporation. downloaded from: http:///
2 lt1086 series sn1086 1086ffs preco n ditio n i n g u u u power dissipation ............................... internally limited input voltage* ......................................................... 30v operating input voltage adjustable devices ........................................... 25v 2.85v devices .................................................. 18v 3.3v, 3.6v, and 5v devices ............................... 20v 12v devices ...................................................... 25v operating junction temperature range ??grades control section ............................... 0 c to 125 c power transistor ............................. 0 c to 150 c ??grades control section .......................... 40 c to 125 c power transistor ........................ 40 c to 150 c ??grades control section .......................... 55 c to 150 c power transistor ........................ 55 c to 200 c storage temperature range ................. 65 c to 150 c lead temperature (soldering, 10 sec).................. 300 c absolute m axi m u m ratings w ww u 100% thermal shutdown functional test. package/order i n for m atio n w u u lt1086cmlt1086cm-3.3 lt1086cm-3.6 lt1086im lt1086im-3.3 order part number order part number lt1086chlt1086mh order part number order part number lt1086cklt1086ck-5 lt1086ck-12 lt1086ik lt1086ik-5 lt1086ik-12 lt1086mk lt1086mk-5 lt1086mk-12 q ja = 150 c/w 21 v in case is output adj (gnd)* k package 2-lead to-3 metal can bottom view q ja = 35 c/w ** with package soldered to 0.5in 2 copper area over backside ground plane or internal powerplane. q ja can vary from 20 c/w to > 40 c/w depending on mounting technique. v in v out adj(gnd) ? m package 3-lead plastic dd front view tab is output 32 1 t package 3-lead plastic to-220 front view tab is output 32 1 v in v out adj(gnd) ? q ja = 50 c/w lt1086ctlt1086ct-2.85 lt1086ct-3.3 lt1086it lt1086it-5 lt1086it-12 lt1086ct-3.6 lt1086ct-5 lt1086ct-12 q ja = 30 c/w** ? for fixed versions. bottom view v in v out (case) adj 13 2 h package 3-lead to-39 metal can (note 1) * although the device? maximum operating voltage is limited, (18v for a 2.85v device, 20v for a 5v device, and 25v for adjustable and12v devices) thedevices are guaranteed to withstand transient input voltages up to 30v. for input voltages greater than the maximum operating input voltage some degradation of specifications will occur. for fixed voltage devices operating at input/output voltage differentials greater than 15v, a minimum external load of 5ma is required to maintain regulation. consult ltc marketing for parts specified with wider operating temperature ranges. obsolete packages consider the t package for alternate source downloaded from: http:///
3 lt1086 series sn1086 1086ffs parameter conditions min typ max units reference voltage lt1086, lt1086h i out = 10ma, t j = 25 c, (v in ?v out ) = 3v 1.238 1.250 1.262 v (note 3) 10ma i out 1.5a, (0.5a for lt1086h), 1.5v (v in ?v out ) 15v 1.225 1.250 1.270 v output voltage lt1086-2.85 i out = 0ma, t j = 25 c, v in = 5v 2.82 2.85 2.88 v (note 3) 0v i out 1.5a, 4.35v v in 18v 2.79 2.85 2.91 v lt1086-3.3 v in = 5v, i out = 0ma, t j = 25 c 3.267 3.300 3.333 v 4.75v v in 18v, 0v i out 1.5a 3.235 3.300 3.365 v lt1086-3.6 v in = 5v, i out = 0ma, t j = 25 c 3.564 3.600 3.636 v 5v v in 18v, 0 i out 1.5a 3.500 3.672 v 4.75v v in 18v, 0 i out 1a, t j 3 0 c 3.500 3.672 v v in = 4.75v, i out = 1.5a, t j 3 0 c 3.300 3.672 v lt1086-5 i out = 0ma, t j = 25 c, v in = 8v 4.950 5.000 5.050 v 0 i out 1.5a, 6.5v v in 20v 4.900 5.000 5.100 v lt1086-12 i out = 0ma, t j = 25 c, v in = 15v 11.880 12.000 12.120 v 0 i out 1.5a, 13.5v v in 25v 11.760 12.000 12.240 v line regulation lt1086, lt1086h i load = 10ma, 1.5v (v in ?v out ) 15v, t j = 25 c 0.015 0.2 % 0.035 0.2 % lt1086-2.85 i out = 0ma, t j = 25 c, 4.35v v in 18v 0.3 6 mv 0.6 6 mv lt1086-3.3 4.5v v in 18v, i out = 0ma, t j = 25 c 0.5 10 mv 1.0 10 mv lt1086-3.6 4.75v v in 18v, i out = 0ma, t j = 25 c 0.5 10 mv 1.0 10 mv lt1086-5 i out = 0ma, t j = 25 c, 6.5v v in 20v 0.5 10 mv 1.0 10 mv lt1086-12 i out = 0ma, t j = 25 c, 13.5v v in 25v 1.0 25 mv 2.0 25 mv load regulation lt1086, lt1086h (v in ?v out ) = 3v, 10ma i out 1.5a, (0.5a for lt1086h) t j = 25 c (notes 2, 3) 0.1 0.3 % 0.2 0.4 % lt1086-2.85 v in = 5v, 0 i out 1.5a, t j = 25 c (notes 2, 3) 3 12 mv 62 0 m v lt1086-3.3 v in = 5v, 0 i out 1.5a, t j = 25 c (notes 2, 3) 3 15 mv 72 5 m v lt1086-3.6 v in = 5.25v, 0 i out 1.5a, t j = 25 c (notes 2, 3) 3 15 mv 62 5 m v v in = 5v, 0 i out 1a, t j = 25 c2 1 5 m v 42 5 m v lt1086-5 v in = 8v, 0 i out 1.5a, t j = 25 c (notes 2, 3) 5 20 mv 10 35 mv lt1086-12 v in = 15v, 0 i out 1.5a, t j = 25 c (notes 2, 3) 12 36 mv 24 72 mv dropout voltage lt1086/-2.85/-3.3/-3.6/-5/-12 d v out , d v ref = 1%, i out = 1.5a (note 4) 1.3 1.5 v (v in ?v out ) lt1086h d v ref = 1%, i out = 0.5a (note 4) 0.95 1.25 v electrical characteristics the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. downloaded from: http:///
4 lt1086 series sn1086 1086ffs parameter conditions min typ max units current limit lt1086/-2.85/-3.3/-3.6/-5/-12 (v in ?v out ) = 5v 1.50 2.00 a (v in ?v out ) = 25v 0.05 0.15 a lt1086h (v in ?v out ) = 5v 0.50 0.700 a (v in ?v out ) = 25v 0.02 0.075 a minimum load current lt1086/lt1086h (v in ?v out ) = 25v (note 5) 51 0 m a quiescient current lt1086-2.85 v in 18v 51 0 m a lt1086-3.3 v in 18v 51 0 m a lt1086-3.6 v in 18v 51 0 m a lt1086-5 v in 20v 51 0 m a lt1086-12 v in 25v 51 0 m a thermal regulation t a = 25 c, 30ms pulse 0.008 0.04 %/w ripple rejection f = 120hz, c out = 25 m f tantalum, i out = 1.5a, (i out = 0.5a for lt1086h) lt1086, lt1086h c adj = 25 m f, (v in ?v out ) = 3v 60 75 db lt1086-2.85 v in = 6v 60 72 db lt1086-3.3 v in = 6.3v 60 72 db lt1086-3.6 v in = 6.6v 60 72 db lt1086-5 v in = 8v 60 68 db lt1083-12 v in = 15v 54 60 db adjust pin current lt1086, lt1086h t j = 25 c5 5 m a 120 m a adjust pin current lt1086, lt1086h 10ma i out 1.5a (0.5a for lt1086h) change 1.5v (v in ?v out ) 15v 0.2 5 m a temperature stability 0.5 % long-term stability t a = 125 c, 1000 hrs. 0.3 1 % rms output noise t a = 25 c, 10hz = f 10khz 0.003 % (% of v out ) thermal resistance h package: control circuitry/power transistor 15/20 c/w junction-to-case k package: control circuitry/power transistor 1.7/4.0 c/w m package: control circuitry/power transistor 1.5/4.0 c/w t package: control circuitry/power transistor 1.5/4.0 c/w note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired.note 2: see thermal regulation specifications for changes in output voltage due to heating effects. line and load regulation are measured at aconstant junction temperature by low duty cycle pulse testing. load regulation is measured at the output lead ? 1/8" from the package. note 3: line and load regulation are guaranteed up to the maximum power dissipation of 15w (3w for the lt1086h). power dissipation is determined by the input/output differential and the output current. guaranteedmaximum power dissipation will not be available over the full input/output range. see short-circuit current curve for available output current. note 4: dropout voltage is specified over the full output current range of the device. test points and limits are shown on the dropout voltage curve.note 5: minimum load current is defined as the minimum output current required to maintain regulation. at 25v input/output differential the deviceis guaranteed to regulate if the output current is greater than 10ma. electrical characteristics the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. downloaded from: http:///
5 lt1086 series sn1086 1086ffs typical perfor m a n ce characteristics u w lt1086 maximum powerdissipation* temperature ( c) ?0 output voltage change (%) 0 1 150 lt1086 ? tpc04 ? ? 0 50 100 2 ?5 25 75 125 temperature stability temperature ( c) ?0 0 adjust pin current ( m a) 10 30 40 50 100 70 0 50 75 lt1086 ?tpc05 20 80 90 60 ?5 25 100 125 150 adjust pin currentlt1086 ripple rejection vs current lt1086 ripple rejection lt1086-5 ripple rejection output current (a) 0 0 ripple rejection (db) 20 30 40 50 60 70 0.25 0.5 0.75 1.0 lt1086 ?tpc08 1.25 80 90 100 10 1.5 f r = 120hz v ripple 3v p-p f r = 20khz v ripple 0.5v p-p v out = 5v c adj = 25 m f c out = 25 m f lt1086 short-circuit current input/output differential (v) 0 0 short-circuit current (a) 0.5 1.0 1.5 2.0 2.5 5 10 15 20 lt1086 ?tpc01 25 30 t j = 150 c t j = 25 c t j = 55 c guaranteed output current case temperature ( c) *as limited by maximum junction temperature 50 power (w) 15 20 130 lt1086 ?tpc06 10 50 70 90 110 150 120 60 80 100 140 lt1086mk lt1086ck lt1086ct frequency (hz) 20 ripple rejection (db) 40 50 60 80 100 10 30 70 90 10 1k 10k 100k lt1086 ?tpc07 0 100 v ripple 3v p-p (v in ?v out ) 3 3v (v in ?v out ) 3 v dropout v ripple 0.5v p-p c adj = 200 m f at frequencies < 60hz c adj = 25 m f at frequencies > 60hz i out = 1.5a frequency (hz) 20 ripple rejection (db) 40 50 70 80 10 1k 10k 100k lt1086 ?tpc09 0 100 6030 10 v ripple 3v p-p (v in ?v out ) 3 3v (v in ?v out ) 3 v dropout v ripple 0.5v p-p i out = 1.5a temperature ( c) ?0 0.20 output voltage deviation (%) 0.15 0.10 0.05 0 05 0 100 150 lt1086 ?tpc02 0.05 0.10 ?5 25 75 125 d i = 1.5a input/output differential (v) 0 0 minimum operating current (ma) 1 3 4 5 10 7 10 20 25 lt1086 ?tpc03 2 8 9 6 5 15 30 35 t j = 150 c t j = 25 c t j = 55 c minimum operating current(adjustable device) lt1086 load regulation downloaded from: http:///
6 lt1086 series sn1086 1086ffs typical perfor m a n ce characteristics u w lt1086h short-circuit current lt1086 line transient response time ( m s) 0 output voltage deviation (v) load current (a) 0.1 0.1 0.3 lt1086 ?tpc14 0.3 1.0 0.2 0 0.2 1.5 0.5 0 50 100 c adj = 0 c adj = 1 m f c in = 1 m f tantalum c out = 10 m f tantalum v out = 10v v in = 13v preload = 100ma lt1086 load transient responselt1086h load regulation lt1086h dropout voltage lt1086h ripple rejectionvs current output current (a) 0 minimum input/output differential (v) 2 0.4 lt1086 ?tpc16 10 0.1 0.2 0.3 0.5 ?5 c t j 150 c 0 c t j 125 c t j = 55 c t j = 25 c t j = 150 c indicates guaranteed test point temperature ( c) ?0 0.20 output voltage deviation (%) 0.15 0.10 0.05 0 05 0 100 150 lt1086 ?tpc17 0.05 0.10 ?5 25 75 125 d i = 0.5a output current (a) 0 0 ripple rejection (db) 20 30 40 50 60 70 0.1 0.2 0.3 0.4 lt1086 ?tpc18 80 90 100 10 0.5 f r = 20khz v ripple 0.5v p-p v out = 5v c adj = 25 m f c out = 25 m f f r = 120hz v ripple 3v p-p lt1086-5 ripple rejectionvs current output current (a) 0 0 ripple rejection (db) 20 30 40 50 60 70 0.25 0.5 0.75 1.0 lt1086 ?tpc10 1.25 80 90 100 10 1.5 f r = 120hz v ripple 3v p-p f r = 20khz v ripple 0.5v p-p v out = 5v c adj = 25 m f c out = 25 m f lt1086-12 ripple rejection lt1086-12 ripple rejectionvs current output current (a) 0 0 ripple rejection (db) 20 30 40 50 60 70 0.25 0.5 0.75 1.0 lt1086 ?tpc12 1.25 80 90 100 10 1.5 f r = 120hz v ripple 3v p-p f r = 20khz v ripple 0.5v p-p v out = 5v c adj = 25 m f c out = 25 m f input/output differential (v) 0 0 short-circuit current (a) 0.2 0.4 0.6 0.8 1.0 1.2 51 01 52 0 lt1086 ?tpc15 25 guaranteed output current frequency (hz) 20 ripple rejection (db) 40 50 70 80 10 1k 10k 100k lt1086 ?tpc11 0 100 6030 10 v ripple 3v p-p (v in ?v out ) 3 3v (v in ?v out ) 3 v dropout v ripple 0.5v p-p i out = 1.5a time ( m s) 0 output voltage deviation (mv) input voltage deviation (v) ?0 20 60 lt1086 ?tpc13 ?0 13 ?0 0 40 14 12 11 100 200 c adj = 1 m f c adj = 0 v out = 10v i out = 0.2a c in = 1 m f tantalum c out = 10 m f tantalum downloaded from: http:///
7 lt1086 series sn1086 1086ffs typical perfor m a n ce characteristics u w case temperature ( c) *as limited by maximum junction temperature 50 power (w) 4 5 130 lt1086 ?tpc20 32 1 0 70 90 110 150 120 60 80 100 140 lt1086mh lt1086h maximum powerdissipation* lt1086h ripple rejection block diagra m w + thermal limit v adj v out 1086 ?bd v in frequency (hz) 20 ripple rejection (db) 40 50 60 80 100 10 30 70 90 10 1k 10k 100k lt1086 ?tpc19 0 100 v ripple 3v p-p (v in ?v out ) 3 3v (v in ?v out ) 3 v dropout v ripple 0.5v p-p c adj = 200 m f at frequencies < 60hz c adj = 25 m f at frequencies > 60hz i out = 0.5a downloaded from: http:///
8 lt1086 series sn1086 1086ffs the lt1086 family of 3-terminal regulators is easy to useand has all the protection features that are expected in high performance voltage regulators. they are short-circuit protected and have safe area protection as well as thermal shutdown to turn off the regulator should the temperature exceed about 165 c at the sense point. these regulators are pin compatible with older 3-terminaladjustable devices, offer lower dropout voltage and more precise reference tolerance. further, the reference stabil- ity with temperature is improved over older types of regulators. the only circuit difference between using the lt1086 family and older regulators is that they require an output capacitor for stability. stability the circuit design used in the lt1086 family requires the use of an output capacitor as part of the device frequency compensation. for all operating conditions, the addition of 150 m f aluminum electrolytic or a 22 m f solid tantalum on the output will ensure stability. normally capacitors muchsmaller than this can be used with the lt1086. many different types of capacitors with widely varying charac- teristics are available. these capacitors differ in capacitor tolerance (sometimes ranging up to 100%), equivalent series resistance, and capacitance temperature coeffi-cient. the 150 m f or 22 m f values given will ensure stability. when using the lt1086 the adjustment terminal can bebypassed to improve ripple rejection. when the adjust- ment terminal is bypassed the requirement for an output capacitor increases. the values of 22 m f tantalum or 150 m f aluminum cover all cases of bypassing the adjustmentterminal. for fixed voltage devices or adjustable devices without an adjust pin bypass capacitor, smaller output capacitors can be used with equally good results. the table below shows approximately what size capacitors are needed to ensure stability. recommended capacitor values input output adjustment 10 m f1 0 m f tantalum, 50 m f aluminum none 10 m f2 2 m f tantalum, 150 m f aluminum 20 m f normally, capacitor values on the order of 100 m f are used in the output of many regulators to ensure good transient applicatio n s i n for m atio n wu u u response with heavy load current changes. output capaci-tance can be increased without limit and larger values of output capacitor further improve stability and transient response of the lt1086 regulators. another possible stability problem that can occur in mono- lithic ic regulators is current limit oscillations. these can occur because in current limit, the safe area protection exhibits a negative impedance. the safe area protection decreases the current limit as the input-to-output voltage increases.that is the equivalent of having a negitive resis- tance since increasing voltage causes current to decrease. negative resistance during current limit is not unique to the lt1086 series and has been present on all power ic regulators. the value of negative resistance is a function of how fast the current limit is folded back as input-to-output voltage increases. this negative resistance can react with capacitors or inductors on the input to cause oscillation during current limiting. depending on the value of series resistance, the overall circuitry may end up unstable. since this is a system problem, it is not necessarily easy to solve; however, it does not cause any problems with the ic regulator and can usually be ignored. protection diodes in normal operation the lt1086 family does not need any protection diodes. older adjustable regulators required protection diodes between the adjustment pin and the output and from the output to the input to prevent over- stressing the die. the internal current paths on the lt1086 adjustment pin are limited by internal resistors. therefore, even with capacitors on the adjustment pin, no protection diode is needed to ensure device safety under short-circuit conditions. diodes between input and output are usually not needed. the internal diode between the input and the output pins of the lt1086 family can handle microsecond surge currents of 10a to 20a. even with large output capaci- tances, it is very difficult to get those values of surge currents in normal operation. only with high value output capacitors such as 1000 m f to 5000 m f, and with the input pin instantaneously shorted to ground, can damage occur.a crowbar circuit at the input of the lt1086 can generate those kinds of currents and a diode from output to input is then recommended. normal power supply cycling or even downloaded from: http:///
9 lt1086 series sn1086 1086ffs plugging and unplugging in the system will not generatecurrent large enough to do any damage. the adjustment pin can be driven on a transient basis 25v, with respect to the output without any device degradation. of course as with any ic regulator, exceedingthe maximum input-to-output voltage differential causes the internal transistors to break down and none of the protection circuitry is functional. the power supply may need to be cycled down to zero andbrought up again to make the output recover. ripple rejection for the lt1086 the typical curves for ripple rejection reflect values for a bypassed adjust pin. this curve will be true for all values of output voltage. for proper bypassing and ripple rejection approaching the values shown, the impedance of the adjust pin capacitor at the ripple fre- quency should equal the value of r1, (normally 100 w to 120 w ). the size of the required adjust pin capacitor is a function of the input ripple frequency. at 120hz the adjustpin capacitor should be 13 m f if r1 = 100 w ; at 10khz only 0.16 m f is needed. for circuits without an adjust pin bypass capacitor theripple rejection will be a function of output voltage. the output ripple will increase directly as a ratio of the output voltage to the reference voltage (v out /v ref ). for ex- ample, with the output voltage equal to 5v and no adjustpin capacitor, the output ripple will be higher by the ratio of 5v/1.25v or four times larger. ripple rejection will be degraded by 12db from the value shown on the lt1086 curve. typical curves are provided for the 5v and 12v devices since the adjust pin is not available. output voltage the lt1086 develops a 1.25v reference voltage between the output and the adjust terminal (see figure 1). by placing resistor r1 between these two terminals, a con- stant current is caused to flow through r1 and down through r2 to set the overall output voltage. normally this current is chosen to be the specified minimum load current of 10ma. because i adj is very small and constant when compared with the current through r1, it repre-sents a small error and can usually be ignored. for fixed voltage devices r1 and r2 are included in the device. applicatio n s i n for m atio n wu u u v in v out lt1086 adj in out lt1086 ?ai01 c adj 10 f c out 150 f r1 d1 1n4002 (optional) r2 + + overload recoverylike any of the ic power regulators, the lt1086 has safe area protection. the safe area protection decreases the current limit as input-to-output voltage increases and keeps the power transistor inside a safe operating region for all values of input-to-output voltage. the lt1086 protection is designed to provide some output current at all values of input-to-output voltage up to the device breakdown. when power is first turned on, as the input voltage rises, the output follows the input, allowing the regulator to start up into very heavy loads. during the start-up, as the input voltage is rising, the input-to-output voltage differential remains small, allowing the regulator to supply large output currents. with high input voltage, a problem can occur wherein removal of an output short will not allow the output voltage to recover. older regulators such as the 7800 series also exhibited this phenomenon, so it is not unique to the lt1086. the problem occurs with a heavy output load when the input voltage is high and the output voltage is low, such as immediately after a removal of a short. the load line for such a load may intersect the output current curve at two points. if this happens there are two stable output operat- ing points for the regulator. with this double intersection figure 1. basic adjustable regulator r1 10 m f tantalum r2 in out i adj 50 m a adj v out lt1086 v in 1086 ?f01 v ref v out = v ref 1 + + i adj r2 r2r1 ( ) + downloaded from: http:///
10 lt1086 series sn1086 1086ffs applicatio n s i n for m atio n wu u u load regulationbecause the lt1086 is a 3-terminal device, it is not possible to provide true remote load sensing. load regu- lation will be limited by the resistance of the wire connect- ing the regulator to the load. the data sheet specification for load regulation is measured at the bottom of the package. negative side sensing is a true kelvin connec- tion, with the bottom of the output divider returned to the negative side of the load. although it may not be immedi- ately obvious, best load regulation is obtained when the top of the resistor divider r1 is connected directly to the case not to the load , as illustrated in figure 2. if r1 were connected to the load, the effective resistance between theregulator and the load would be: r p , r p = parasitic line resistance r2 + r1 r1 () thermal considerationsthe lt1086 series of regulators have internal power and thermal limiting circuitry designed to protect the device under overload conditions. for continuous normal load conditions however, maximum junction temperature rat- ings must not be exceeded. it is important to give careful consideration to all sources of thermal resistance from junction to ambient. this includes junction-to-case, case- to-heat sink interface and heat sink resistance itself. new thermal resistance specifications have been developed to more accurately reflect device temperature and ensure safe operating temperatures. the data section for these new regulators provides a separate thermal resistance and maximum junction temperature for both the control sec- tion and the power transistor . previous regulators, with a single junction-to-case thermal resistance specification,used an average of the two values provided here and therefore could allow excessive junction temperatures under certain conditions of ambient temperature and heat sink resistance. to avoid this possibility, calculations should be made for both sections to ensure that both thermal limits are met. for example, using a lt1086ck (to-3, commercial) and assuming: v in (max continuous) = 9v, v out = 5v, i out = 1a, t a = 75 c, q heat sink = 3 c/w, q case-to-heat sink = 0.2 c/ w for t package with thermal compound. power dissipation under these conditions is equal to: p d = (v in ?v out )(i out ) = 4w junction temperature will be equal to: t j = t a + p d ( q heat sink + q case-to-heat sink + q jc ) for the control section: t j = 75 c + 4w(3 c/w + 0.2 c/ w + 1.5 c/ w) = 94.6 c 95 c < 125 c = t jmax (control section commercial range) for the power transistor: t j = 75 c + 4w(3 c/ w + 0.2 c/ w + 4 c/ w) = 103.8 c 103.8 c < 150 c = t jmax (power transistor commercial range) lt1086 out in v in adj r p parasitic line resistance r1* *connect r1 to case connect r2 to load 1086 ?f02 r l r2* figure 2. connections for best load regulation connected as shown, r p is not multiplied by the divider ratio. r p is about 0.004 w per foot using 16-gauge wire. this translates to 4mv/ft at 1a load current, so it isimportant to keep the positive lead between regulator and load as short as possible and use large wire or pc board traces. note that the resistance of the package leads for the h package ? 0.06 w /inch. while it is usually not possible to connect the load directly to the package, it is possible toconnect larger wire or pc traces close to the case to avoid voltage drops that will degrade load regulation. for fixed voltage devices the top of r1 is internally kelvin connected and the ground pin can be used for negative side sensing. downloaded from: http:///
11 lt1086 series sn1086 1086ffs applicatio n s i n for m atio n wu u u in both cases the junction temperature is below themaximum rating for the respective sections, ensuring reliable operation. junction-to-case thermal resistance for the k and t pack- ages is specified from the ic junction to the bottom of the case directly below the die. this is the lowest resistance path for heat flow. while this is also the lowest resistance path for the h package, most available heat sinks for this package are of the clip-on type that attach to the cap of the package. the data sheet specification for thermal resis- tance for the h package is therefore written to reflect this. scsi-2 active termination typical applicatio n s u 5v, 1.5a regulator 10 m f tantalum 4.25vto 5.25v 1n5817 termpwr lt1086 ?ta03 10 m f tantalum 0.1 m f ceramic 18 total 110 w 2% 110 w 110 w 110 w 110 w 2% 110 w 2% lt1086-2.85 in out gnd + + v in 3 6.5v 5v at 1.5a *required for stability lt1086 lt1086 ?ai02 10 f* tantalum 121 w 1%365 w 1% 10 f in out adj + + in all cases proper mounting is required to ensure the bestpossible heat flow from the die to the heat sink. thermal compound at the case-to-heat sink interface is strongly recommended. in the case of the h package, mounting the device so that heat can flow out the bottom of the case will significantly lower thermal resistance ( ? a factor of 2). if the case of the device must be electrically isolated, athermally conductive spacer can be used as long as its added contribution to thermal resistance is considered. note that the case of all devices in this series is electrically connected to the output. downloaded from: http:///
12 lt1086 series sn1086 1086ffs typical applicatio n s u 1.2v to 15v adjustable regulator in v in out ttl adj 1k 1k 10 f 100 f 5v lt1086 2n3904 lt1086 ?ta05 + 121 w 1% 365 w 1% + 5v regulator with shutdown in out adj r25k c1*10 f v out ? v in lt1086 lt1086 ?ta04 + c2100 f + r1121 w *needed if device is far from filter capacitors ? v out = 1.25v 1 + r2r1 ( ) + lt1086 out in v in v in return adj r p (max drop 300mv) 121 w 365 w 25 w 10 m f 5 m f 100 m f lt1086 ?ta09 r l v out 5v return 25 w 2 6 7 1 8 100pf 3 4 + 1k lm301a + + remote sensing regulator with reference protected high current lamp driver v in > 11.5v 10v lt1086-5 lt1086 ?ta08 100 f lt1029 5v 10 f in out gnd + + battery charger v in v out r2 i f r s r1 lt1086 1.25v lt1086 ?ta06 r2r1 1 + v out ?1.25 () r2r1 1 + ?r s i f = () 1 r2r1 1 + ?r s = () di f dv out () in out adj adjusting output voltage of fixed regulators v in > 12v 5v to 10v *optional improves ripple rejection lt1086-5 lt1086 ?ta07 100 f 1k 10 f 10 f* in out gnd + + + ttl or cmos 15v 10k lt1086 adj in out lt1086 ?ta10 12v 1a downloaded from: http:///
13 lt1086 series sn1086 1086ffs typical applicatio n s u 12v1.5a 12v 1.5a lt1086 adj in out lt1086 ?ta12 10 f 1n4002 124 w * 1.07k* 470 f mur410 v in 470 f 10 f mur410 feedback path 5v output(typical) lt1086 switching regulator adj in out 10 f 1n4002 124 w * 1.07k* 470 f *1% film resistors mur410 10 f + + + + + + + high efficiency dual supply high efficiency dual linear supply 12v1.5a 12v 1.5a 124 w * lt1086 adj in out lt1086 ?ta11 1.07k* 100 m f d11n4002 2.4k 30k 20k* lt1004-2.5 30.1k* 2 8 7 4 3 510k 1000 m f l1 285 m h 1k mbr360 heat sink 2n6667 darlington heat sink 2n6667 darlington 10k + lt1011 4700 m f mda201 + 124 w * lt1086 adj in out 1.07k* 100 m f d21n4002 2.4k 30k 20k* lt1004-2.5 30.1k* 2 8 7 4 3 510k 1000 m f l1 285 m h 1k mbr360 130vac to 90vac stancorp-8685 10k + lt1011 4700 m f *1% film resistors mda = motorola l1 = pulse engineering, inc. #pe-92106 mda201 + q1q2 + + + + + + downloaded from: http:///
14 lt1086 series sn1086 1086ffs typical applicatio n s u improving ripple rejection package descriptio n u battery backed up regulated supply v in 5.2v line5v battery lt1086-5 lt1086 ?ta13 50 w 10 f select forcharge rate lt1086-5 100 f 10 f 6.5v in out gnd in out gnd + + + r1121 w 1% in out adj r2365 w 1% 10 f v in 3 6.5v lt1086 v out = 5v lt1086 ?ta14 + c110 f* 150 f + *c1 improves ripple rejection. x c should be ? r1 at ripple frequency automatic light control low dropout negative supply in v in out adj 10 f 100 f lt1086 lt1086 ?ta15 1.2k + in out gnd 10,000 f lt1086-12 lt1086 ?ta16 100 f v out = ?2v floating input v in + + 0.016 ?0.021** (0.406 ?0.533) dia 0.050 (1.270) max 0.165 ?0.185 (4.191 ?4.699) 0.500 (12.700) min 0.305 ?0.335 (7.747 ?8.509) 0.350 ?0.370 (8.890 ?9.398) 0.200 (5.080) typ 45 h3(to-39) 1098 0.100 (2.540) 0.100 (2.540) 0.029 ?0.045 (0.737 ?1.143) 0.028 ?0.034 (0.711 ?0.864) reference plane * lead diameter is uncontrolled between the reference plane and 0.045" below the reference plane for solder dip lead finish, lead diameter is 0.016 ?0.024 (0.406 ?0.610) * ** pin 1 h package 3-lead to-39 metal can (reference ltc dwg # 05-08-1330) obsolete package downloaded from: http:///
15 lt1086 series sn1086 1086ffs obsolete package m package 3-lead plastic dd pak (reference ltc dwg # 05-08-1460) k package 2-lead to-3 metal can (reference ltc dwg # 05-08-1310) package descriptio n u 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 represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. k2 (to-3) 1098 0.038 ?0.043 (0.965 ?1.09) 0.060 ?0.135 (1.524 ?3.429) 0.320 ?0.350 (8.13 ?8.89) 0.420 ?0.480 (10.67 ?12.19) 0.760 ?0.775 (19.30 ?19.69) 0.490 ?0.510 (12.45 ?12.95) r 0.167 ?0.177 (4.24 ?4.49) r 0.151 ?0.161 (3.86 ?4.09) dia, 2plcs 1.177 ?1.197 (29.90 ?30.40) 0.655 ?0.675 (16.64 ?17.15) 0.067 ?0.077 (1.70 ?1.96) 0.210 ?0.220 (5.33 ?5.59) 0.425 ?0.435 (10.80 ?11.05) m (dd3) 1098 0.050 (1.270) bsc 0.143 +0.012 0.020 () 3.632 +0.305 0.508 0.090 ?0.110 (2.286 ?2.794) 0.013 ?0.023 (0.330 ?0.584) 0.095 ?0.115 (2.413 ?2.921) 0.004 +0.008 0.004 () 0.102 +0.203 0.102 0.050 0.012 (1.270 0.305) 0.059 (1.499) typ 0.045 ?0.055 (1.143 ?1.397) 0.165 ?0.180 (4.191 ?4.572) 0.330 ?0.370 (8.382 ?9.398) 0.060 (1.524) typ 0.390 ?0.415 (9.906 ?10.541) 15 typ 0.300 (7.620) 0.075 (1.905) 0.183 (4.648) 0.060 (1.524) 0.060 (1.524) 0.256 (6.502) bottom view of dd pak hatched area is solder plated copper heat sink downloaded from: http:///
16 lt1086 series sn1086 1086ffs part number description comments lt1129 700ma, micropower, ldo v in = 4.2v to 30v, v out(min) = 3.75v, i q = 50 m a, i sd = 16 m a, dd, sot-223, s8, to-220, tssop-20 packages lt1528 3a ldo for microprocessor applications v in = 4v to 15v, v out(min) = 3.30v, i q = 400 m a, i sd = 125 m a, fast transient response, dd, to-220 packages lt1585 4.6a ldo , with fast transient response v in = 2.5v to 7v, v out(min) = 1.25v, i q = 8ma, fast transient response, dd, to-220 packages lt1761 100ma, low noise micropower, ldo v in = 1.8v to 20v, v out(min) = 1.22v, i q = 20 m a, i sd = <1 m a, low noise < 20 m v rms p-p , stable with 1 m f ceramic capacitors, thinsot tm package lt1762 150ma, low noise micropower, ldo v in = 1.8v to 20v, v out(min) = 1.22v, i q = 25 m a, i sd = <1 m a, low noise < 20 m v rms p-p , msop package lt1763 500ma, low noise micropower, ldo v in = 1.8v to 20v, v out(min) = 1.22v, i q = 30 m a, i sd = <1 m a, low noise < 20 m v rms p-p , s8 package lt1764/lt1764a 3a, low noise, fast transient response, ldos v in = 2.7v to 20v, v out(min) = 1.21v, i q = 1ma, i sd = <1 m a, low noise < 40 m v rms p-p , ??version stable with ceramic capacitor, dd, to-220 packages lt1962 300ma, low noise micropower, ldo v in = 1.8v to 20v, v out(min) = 1.22v, i q = 30 m a, i sd = <1 m a, low noise < 20 m v rms p-p , ms8 package lt1963/lt1963a 1.5a, low noise, fast transient response, ldos v in = 2.1v to 20v, v out(min) = 1.21v, i q = 1ma, i sd = <1 m a, low noise < 40 m v rms p-p ,??version stable with ceramic capacitor, dd, to-220, sot-223, s8 packages lt1964 200ma, low noise micropower, negative ldo v in = 0.9v to 20v, v out(min) = 1.21v, i q = 30 m a, i sd = 3 m a, low noise < 30 m v rms p-p , stable with ceramic capacitors, thinsot package package descriptio n u related parts 0.100 (2.540) bsc 0.028 ?0.038 (0.711 ?0.965) t3 (to-220) 1098 0.045 ?0.055 (1.143 ?1.397) 0.165 ?0.180 (4.191 ?4.572) 0.095 ?0.115 (2.413 ?2.921) 0.013 ?0.023 (0.330 ?0.584) 0.520 ?0.570 (13.208 ?14.478) 0.980 ?1.070 (24.892 ?27.178) 0.218 ?0.252 (5.537 ?6.401) 0.050 (1.270) typ 0.147 ?0.155 (3.734 ?3.937) dia 0.390 ?0.415 (9.906 ?10.541) 0.330 ?0.370 (8.382 ?9.398) 0.460 ?0.500 (11.684 ?12.700) 0.570 ?0.620 (14.478 ?15.748) 0.230 ?0.270 (5.842 ?6.858) ? linear technology corporation 1988 lt/tp 0703 1k rev f ? printed in usa linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com t package 3-lead plastic to-220 (reference ltc dwg # 05-08-1420) thinsot is a trademark of linear technology corporation. downloaded from: http:///

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