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1 lt 1072 1072fc 1 .25a high efficiency switching regulator available in minidip, to-220, and to-3 packages wide input voltage range 3v to 60v low quiescent current?ma internal 1.25a switch very few external parts required self-protected against overloads operates in nearly all switching topologies shutdown mode draws only 50 a supply current flyback-regulated mode has fully floating outputs can be externally synchronized the lt 1072 is a monolithic high power switching regulator. it can be operated in all standard switching configurations including buck, boost, flyback, forward, inverting and ?uk? a high current, high efficiency switch is included on the die along with all oscillator, control, and protection circuitry. integration of all functions allows the lt1072 to be built in a standard 5-pin to-3 or to-220 power package as well as the 8-pin minidlp. this makes it extremely easy to use and provides ?ust proof?operation similar to that obtained with 3-pin linear regulators. the lt1072 operates with supply voltages from 3v to 60v, and draws only 6ma quiescent current. it can deliver load power up to 20 watts with no external power devices. by utilizing current-mode switching techniques, it provides excellent ac and dc load and line regulation. the lt1072 has many unique features not found even on the vastly more difficult to use low power control chips presently available. it uses an adaptive anti-sat switch drive to allow very wide ranging load currents with no loss in efficiency. an externally activated shutdown mode reduces total supply current to 50 a typical for standby operation. totally isolated and regulated outputs can be generated by using the optional ?lyback regulation mode built into the lt1072, without the need for optocouplers or extra transformer windings. user note: this data sheet is only intended to provide specifications, graphs, and a general functional description of the lt1072. application circuits are included to show the capability of the lt1072. a complete design manual (an-19) should be obtained to assist in developing new designs. this manual contains a comprehensive discussion of both the lt1070 and the external components used with it, as well as complete formulas for calculating the values of these components. the manual can also be used for the lt1072 by factoring in the lower switch current rating. , ltc and lt are registered trademarks of linear technology corporation. features descriptio u boost converter (5v to 12v) typical applicatio u 10.7k 1.24k l t1072 gnd v c v in v sw fb 1k 1 f 470 f 12v, 0.25a *required if input leads 2 **pulse engineering 52626 220 h** 5v + c3 25 f* + lt1072 ?ta01 + maximum output power* lt1072 ?ta02 input voltage (v) 0 *rough guide only. buck mode p out = 1a x v out . minidip output power may be limited by package temperature rise at high input voltages or high duty cycles power (w) 15 20 25 10 5 0 10 20 30 40 50 buck-boost v o = 5v buck-boost v o = 30v flyback isolated boost logic supply 5v at 2.5a 5v logic to 15v op amp supply offline converter up to 50w battery upconverter power lnverter (+ to ? or (?to +) fully floating multiple outputs driver for high current supplies applicatio s u
2 lt 1072 1072fc supply voltage lt1072hv (see note 1) ......................................... 60v lt1072 (see note 1) ............................................. 40v switch output voltage lt1072hv ............................................................. 75v lt1072 .................................................................. 65v lt1072s8 .............................................................. 60v feedback pin voltage (transient, 1ms) ................. 15v operating junction temperature range lt1072hvm, lt1072m (obsolete) .... 55 c to 150 c lt1072hvc, lt1072c (oper.)* ............ 0 c to 100 c lt1072hvc, lt1072c (sh. ckt.)* ........ 0 c to 125 c lt1072hvi ....................................... 40 c to 125 c storage temperature range ............... 65 c to 150 c lead temperature (soldering, 10 sec) ............... 300 c *includes lt1072s8 (note 1) consult ltc marketing for parts specified with wider operating temperature ranges. note 1: minimum switch ?n?time for the lt1072 in current limit is 0.7 sec. this limits the maximum input voltage during short-circuit conditions, in the buck and inverting modes only, to 40v. normal (unshorted) conditions are not affected. if the lt1072 is being operated in the buck or inverting mode at high input voltages and short-circuit conditions are expected, a resistor must be placed in series with the inductor, as follows: the value of the resistor is given by: r = r l (t) (f) (v in ) ?v f i (limit) t = minimum ?n?time of lt1072 in current limit, 0.7 s f = operating frequency (40khz) v f = forward voltage of external catch diode at i (limit) i (limit) = current limit of lt1072 (2a) r l = internal series resistance of inductor obsolete package obsolete package consider the s8 or n8 packages for alternate source t package 5-lead to-220 t jmax = 100 c/w, jc = 8 c/w, ja = 50 c/w v in v c gnd fb v sw front view 5 4 3 2 1 n package 8-lead pdip t jmax = 100 c, ja = 130 c/w j package 8-lead ceramic dip t jmax = 150 c, ja = 100 c/w 1 2 3 4 8 7 6 5 top view gnd v c fb nc e2 v sw e1 v in 1 2 3 4 5 6 7 8 sw package 16-lead plastic so wide t jmax = 100 c, jc = 130 c/w 16 15 14 13 12 11 10 9 nc nc gnd v c fb nc nc nc nc nc e2 v sw e1 v in nc nc top view bottom view k package 4-lead to-3 metal can t jmax = 150 c, jc = 8 c/w, ja = 35 c/w t jmax = 100 c*, jc = 8 c/w, ja = 35 c/w case is gnd v c 1 4 2 3 fb v sw v in lt1072hvmk lt1072mk lt1072hvck lt1072ck order part number order part number order part number order part number lt1072ct lt1072hvct lt1072hvit lt1072cn8 lt1072cs8 lt1072mj8 lt1072cj8 lt1072csw lt1072 ?poi01 1 2 3 4 8 7 6 5 top view e2 v sw e1 v in gnd v c fb nc s8 package 8-lead plastic so t jmax = 100 c, ja = 130 c/w s8 part marking 1072 absolute axi u rati gs w ww u package/order i for atio uu w
3 lt 1072 1072fc symbol parameter conditlons min typ max units v ref reference voltage measured at feedback pin 1.224 1.244 1.264 v v c = 0.8v 1.214 1.244 1.274 v i b feedback input current v fb = v ref 350 750 na 1100 na gm error amplifier ? i c = 25 a 3000 4400 6000 mho transconductance 2400 7000 mho error amplifier source or v c = 1.5v 150 200 350 a sink current 120 400 a error amplifier clamp hi clamp, v fb = 1v 1.8 2.3 v voltage lo clamp, v fb = 1.5v 0.25 0.38 0.52 v reference voltage line 3v v in v max 0.03 %/v regulation v c = 0.8v %/v a v error amplifier voltage gain 0.9v v c 1.4v 500 800 v/v minimum input voltage 2.6 3.0 v i q supply current 3v v in v max , v c = 0.6v 6 9 ma control pin threshold duty cycle = 0 0.8 0.9 1.08 v 0.6 1.25 v normal/flyback threshold on feedback pin 0.4 0.45 0.54 v v fb flyback reference voltage l fb = 50 a1 5 16.3 17.6 v 14 18 v change in flyback reference voltage 0.05 i fb 1ma 4.5 6.8 8.5 v flyback reference voltage l fb = 50 a 0.01 0.03 %/v line regulation 3v v in v max (note 4) %/v flyback amplifier transconductance (gm) ? i c = 10 a 150 300 650 mho flyback amplifier source v c = 0.6v source 15 32 70 a and sink current i fb = 50 a sink 25 40 70 a bv output switch breakdown 3v v in v max lt1072 65 90 v voltage i sw = 1.5ma lt1072hv 75 90 v lt1072s8 60 80 v v sat output switch on resistance (note 2) i sw = 1.25a 0.6 1 ? control voltage to switch current transconductance 2 a/v i lim switch current limit duty cycle = 50% t j 25 c 1.25 3 a duty cycle = 50% t j < 25 c 1.25 3.5 a duty cycle = 80% (note 3) 1 2.5 a ? i in supply current increase 25 35 ma/a ? i sw during switch on time f switching frequency 35 40 45 khz 33 47 khz dc (max) maximum switch duty cycle 90 92 97 % flyback sense delay time 1.5 s shutdown mode 3v v in v max 100 250 a supply current v c = 0.05v shutdown mode 3v v in v max 100 150 250 mv threshold voltage 50 300 mv the denotes specifications which apply over the full operating temperature range. unless otherwise specified, v in = 15v, v c = 0.5v, v fb = v ref , output pin open. note 1: absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: measured with v c in hi clamp, v fb = 0.8v. note 3: for duty cycles (dc) between 50% and 80%, minimum guaranteed switch current is given by i lim = 0.833 (2 ?dc). note 4: v max = 55v for lt1072hv to avoid switch breakdown. electrical characteristics
4 lt 1072 1072fc switch current limit vs duty cycle maximum duty cycle flyback blanking time duty cycle (%) 0 switch current (a) 4 3 2 1 0 80 lt1072 ?tpc01 20 40 60 100 70 10 30 50 90 ?5 c 125 c 25 c junction temperature ( c) ?5 90 duty cycle (%) 91 93 94 95 ?5 25 50 150 lt1072 ?tpc02 92 ?0 0 75 100 125 96 junction temperature ( c) ?5 1.0 time ( s) 1.2 1.6 1.8 2.0 ?5 25 50 150 lt1072 ?tpc03 1.4 ?0 0 75 100 125 2.2 minimum input voltage switch saturation voltage isolated mode flyback reference voltage temperature ( c) ?5 2.3 minimum input voltage (v) 2.4 2.6 2.7 2.8 ?5 25 50 150 lt1072 ?tpc04 2.5 ?0 0 75 100 125 2.9 switch current = 1.25a switch current = 0a switch current (a) 0 switch saturation voltage (v) 0.8 1.2 2 lt1072 ?tpc05 0.4 0 0.5 1 1.5 0.25 0.75 1.25 1.75 1.6 0.6 1.0 0.2 1.4 150 c 100 c ?5 c 25 c temperature (c ) ?5 flyback voltage (v) 19 20 21 125 lt1072 ?tpc06 18 17 15 ?5 25 75 ?0 150 0 50 100 16 23 22 r feedback = 500 ? r feedback = 1k ? r feedback = 10k ? line regulation reference voltage and switching frequency vs temperature feedback bias current vs temperature input voltage (v) 0 ? reference voltage change (mv) ? ? 1 10 20 30 40 lt1072 ?tpc07 50 3 5 ? ? 0 2 4 60 t j = 150 c t j = 55 c t j = 25 c temperature ( c) ?5 reference voltage (v) frequency (khz) 1.242 1.244 1.246 125 lt1072 ?tpc08 1.240 1.238 1.234 ?5 25 75 ?0 150 0 50 100 1.236 1.250 1.248 38 39 40 37 36 34 35 42 41 reference voltage switching frequency temperature ( c) ?5 feedback bias current (na) 400 500 600 125 lt1072 ?tpc09 300 200 0 ?5 25 75 ?0 150 0 50 100 100 800 700 typical perfor a ce characteristics uw
5 lt 1072 1072fc driver current* vs switch current supply current vs input voltage* supply current vs supply voltage (shutdown mode) normal/flyback mode threshold on feedback pin shutdown mode supply current error amplifier transconductance shutdown thresholds idle supply current vs temperature feedback pin clamp voltage switch current (a) 0 *average lt1072 power supply current is found by multiplying driver current by duty cycle, then adding quiescent current driver current (ma) 80 70 60 50 40 30 20 10 0 1.6 lt1072 ?tpc10 0.4 0.8 1.2 2 1.4 0.2 0.6 1 1.8 *under very low output current conditions, duty cycle for most circuits will approach 10% or less input voltage (v) 0 5 supply current (ma) 7 9 11 10 20 30 40 lt1072 ?tpc11 50 13 15 6 8 10 12 14 60 t j = 25 c note that this current does not include driver current, which is a function of load current and duty cycle. 90% duty cycle 50% duty cycle 10% duty cycle 0% duty cycle supply voltage (v) 0 supply current ( a) 60 80 100 30 50 lt1072 ?tpc12 40 20 0 10 20 40 120 140 160 60 t j = 25 c v c = 50mv v c = 0v temperature ( c) ?0 400 feedback pin voltage (mv) feedback pin current ( a) 410 430 440 450 500 470 0 50 75 lt1072 ?tpc13 420 480 490 460 ? ? ?0 ?2 ?4 ?4 ?8 ? ?0 ?2 ?6 ?5 25 100 125 150 feedback pin voltage (at threshold) feedback pin current (at threshold) v c pin voltage (mv) 0 supply current ( a) 120 160 200 80 lt1072 ?tpc14 80 40 100 140 180 60 20 0 20 10 40 30 60 70 90 50 100 t j = 150 c ?5 c t j 125 c temperature (c ) ?5 0 transconductance ( mho) 500 1500 2000 2500 5000 3500 ?5 25 50 150 lt1072 ?tpc15 1000 4000 4500 3000 ?0 0 75 100 125 g m = ? i ? v (v c pin) (fb pin) temperature ( c) ?5 v c pin voltage (mv) v c pin voltage ( a) 200 250 300 125 lt1072 ?tpc16 150 100 0 ?5 25 75 ?0 150 050 100 50 400 350 ?00 ?50 ?00 ?50 ?00 0 ?0 400 ?50 current (out of v c pin) voltage v c voltage is reduced until regulator current drops below 300 a temperature ( c) ?5 1 idle supply current (ma) 2 4 5 6 11 8 ?5 25 50 150 lt1072 ?tpc17 3 9 10 7 ?0 0 75 100 125 v c = 0.6v v supply = 60v v supply = 3v feedback current (ma) 0 feedback voltage (mv) 300 400 500 0.8 lt1072 ?tpc18 200 100 250 350 450 150 50 0 0.2 0.1 0.4 0.3 0.6 0.7 0.9 0.5 1 ?5 c 25 c 150 c typical perfor a ce characteristics uw
6 lt 1072 1072fc transconductance of error amplifier v c pin characteristics switch ?ff?characteristics frequency (hz) 1000 transconductance ( mho) phase ( ) 3000 4000 6000 7000 1k 100k 1m 10m lt1072 ?tpc19 ?000 10k 5000 2000 0 150 90 60 0 ?0 210 30 120 180 g m v c pin voltage (v) 0 400 v c pin current ( a) ?00 ?00 ?00 300 100 0.5 1.0 200 0 1.5 2.0 2.5 lt1072 ?tpc20 v fb = 1.5v (current into v c pin) v fb = 0.8v (current out of v c pin) t j = 25 c switch voltage (v) 0 switch current ( a) 600 800 1000 80 lt1072 ?tpc21 400 200 500 700 900 300 100 0 20 10 40 30 60 70 90 50 100 v supply = 55v v supply = 40v v supply = 15v v supply = 3v + 2.3v reg 40khz osc fb v c shutdown circuit 0.15v 0.16 ? gain 6 gnd mode select logic comp v in flyback error amp driver anti- sat switch out 16v + 0.16 ? e1* * always connect e1 to ground pin on minidip and surface mount packages. emitters tied to ground on to-3 and to-220 packages e2 1.24v ref error amp current amp lt1072 ?bd01 typical perfor a ce characteristics uw block diagra w
7 lt 1072 1072fc the lt1072 is a current mode switcher. this means that switch duty cycle is directly controlled by switch current rather than by output voltage. referring to the block diagram, the switch is turned ?n?at the start of each oscillator cycle. it is turned ?ff?when switch current reaches a predetermined level. control of output voltage is obtained by using the output of a voltage sensing error amplifier to set current trip level. this technique has several advantages. first, it has immediate response to input voltage variations, unlike ordinary switchers which have notoriously poor line transient response. second, it reduces the 90 phase shift at midfrequencies in the energy storage inductor. this greatly simplifies closed loop fre- quency compensation under widely varying input voltage or output load conditions. finally, it allows simple pulse- by-pulse current limiting to provide maximum switch protection under output overload or short conditions. a low-dropout internal regulator provides a 2.3v supply for all internal circuitry on the lt1072. this low-dropout design allows input voltage to vary from 3v to 60v with virtually no change in device performance. a 40khz oscillator is the basic clock for all internal timing. it turns ?n?the output switch via the logic and driver circuitry. special adaptive antisat circuitry detects onset of saturation in the power switch and adjusts driver current instantaneously to limit switch saturation. this minimizes driver dissipation and provides very rapid turn-off of the switch. a 1.2v bandgap reference biases the positive input of the error amplifier. the negative input is brought out for output voltage sensing. this feedback pin has a second function; when pulled low with an external resistor, it programs the lt1072 to disconnect the main error amplifier output and connects the output of the flyback amplifier to the comparator input. the lt1072 will then regulate the value of the flyback pulse with respect to the supply voltage. this flyback pulse is directly proportional to output voltage in the traditional transformer coupled flyback topology regulator. by regulating the amplitude of the flyback pulse, the output voltage can be regulated with no direct connection between input and output. the output is fully floating up to the breakdown voltage of the transformer windings. multiple floating outputs are easily obtained with additional windings. a special delay network inside the lt1072 ignores the leakage inductance spike at the leading edge of the flyback pulse to improve output regulation. the error signal developed at the comparator input is brought out externally. this pin (v c ) has four different functions. it is used for frequency compensation, current limit adjustment, soft starting, and total regulator shutdown. during normal regulator operation this pin sits at a voltage between 0.9v (low output current) and 2.0v (high output current). the error amplifiers are current output (gm) types, so this voltage can be externally clamped for adjusting current limit. likewise, a capacitor coupled external clamp will provide soft start. switch duty cycle goes to zero if the v c pin is pulled to ground through a diode, placing the lt1072 in an idle mode. pulling the v c pin below 0.15v causes total regulator shutdown, with only 50 a supply current for shutdown circuitry biasing. see an-19 for full application details. extra pins on the minidip and surface mount packages the 8 and 16-pin versions of the lt1072 have the emitters of the power transistor brought out separately from the ground pin. this eliminates errors due to ground pin voltage drops and allows the user to reduce switch current limit 2:1 by leaving the second emitter (e2) disconnected. the first emitter (e1) should always be connected to the ground pin. note that switch ?n?resistance doubles when e2 is left open, so efficiency will suffer somewhat when switch currents exceed 100ma. also, note that chip dissipation will actually increase with e2 open during normal load operation, even though dissipation in current limit mode will decrease. see ?hermal considerations. thermal considerations when using small packages the low supply current and high switch efficiency of the lt1072 allow it to be used without a heat sink in most applications when the to-220 or to-3 package is selected. these packages are rated at 50 c/w and 35 c/w respectively. the small packages, however, are rated at greater than 100 c/w. care should be taken with these packages to ensure that the worse case input voltage and load current conditions do not cause excessive die temperatures. the following formulas can be used as a lt1072 operatio u
8 lt 1072 1072fc rough guide to calculate lt1072 power dissipation. for more details, the reader is referred to application note 19 (an19), ?fficiency calculations?section. average supply current (including driver current) is: i in 6ma + i sw (0.004 + dc/40) i sw = switch current dc = switch duty cycle switch power dissipation is given by: p sw = (i sw ) 2 ?r sw ?dc r sw = lt1072 switch ?n?resistance (1 ? maximum) total power dissipation is the sum of supply current times input voltage plus switch power: p tot = (l ln )(v in ) + p sw in a typical example, using a boost converter to generate 12v @ 0.12a from a 5v input, duty cycle is approximately 60%, and switch current is about 0.65a, yielding: l ln = 6ma + 0.65(0.004 + dc/40) = 18ma p sw = (0.65) 2 ?1 ? ?(0.6) = 0.25w p tot = (5v)(0.018a) + 0.25 = 0.34w temperature rise in a plastic minidip would be 130 c/w times 0.34w, or approximately 44 c. the maximum ambient temperature would be limited to 100 c (commercial temperature limit) minus 44 c, or 56 c. in most applications, full load current is used to calculate die temperature. however, if overload conditions must also be accounted for, four approaches are possible. first, if loss of regulated output is acceptable under overload conditions, the internal thermal limit of the lt1072 will protect the die in most applications by shutting off switch current. thermal limit is not a tested parameter, however, and should be considered only for non-critical applications with temporary overloads. a second approach is to use the larger to-220 (t) or to-3 (k) package which, even without a heat sink, may limit die temperatures to safe levels under overload conditions. in critical situations, heat sinking of these packages is required; especially if overload conditions must be tolerated for extended periods of time. the third approach for lower current applications is to leave the second switch emitter open. this increases switch ?n?resistance by 2:1, but reduces switch current limit by 2:1 also, resulting in a net 2:1 reduction in i 2 r switch dissipation under current limit conditions. the fourth approach is to clamp the v c pin to a voltage less than its internal clamp level of 2v. the lt1072 switch current limit is zero at approximately 1v on the v c pin and 2a at 2v on the v c pin. peak switch current can be externally clamped between these two levels with a diode. see an-19 for details. lt1072 synchronizing the lt1072 can be externally synchronized in the frequency range of 48khz to 70khz. this is accomplished as shown in the accompanying figures. synchronizing occurs when the v c pin is pulled to ground with an external transistor. to avoid disturbing the dc characteristics of the internal error amplifier, the width of the synchronizing pulse should be under 1 s. c2 sets the pulse width at 0.35 s. the effect of a synchronizing pulse on the lt1072 amplifier offset can be calculated from: kt = 26mv at 25 c q t s = pulse width f s = pulse frequency i c = lt1072 v c source current ( 200 a) v c = lt1072 operating v c voltage (1v to 2v) r3 = resistor used to set mid-frequency ?ero?in lt1072 frequency compensation network. with t s = 0.35 s, f s = 50khz, v c = 1.5v, and r3 = 2k ? , offset voltage shift is 2.2mv. this is not particularly bothersome, but note that high offsets could result if r3 were reduced to a much lower value. also, the synchronizing transistor must sink higher currents with low values of r3, so larger drives may have to be used. the transistor must be capable of pulling the v c pin to within 200mv of ground to ensure synchronizing. lt1072 operatio u ? v os = (t s )(f s ) i c + i c kt q (( ( v c r3 (
9 lt 1072 1072fc totally isolated converter synchronizing with bipolar transistor synchronizing with mos transistor from 5v logic r1 3k r2 2.2k c2 68pf v in v c gnd lt1072 2n2369 r3 c1 lt1072 ?op01 from 5v logic *siliconix or equivalent r2 2.2k d2 1n4158 c2 200pf d1 1n4158 v in v c gnd lt1072 r3 c1 vn2222* lt1072 ?op02 lt1072 operatio u c5 25 f* r4 2.7k c3 0.47 f c2 0.01 f 1:n d1 com 15v l1 10 h optional output filter n n v in 5v 500 ? r2 *required if input leads 2 n = 0.875 = 7:8 for v out = 15v 5k c1 200 f c5 200 f c6 200 f c4 200 f ?5v l2 10 h v in v sw fb v c gnd lt1072 switch voltage v out + v f (v f = diode forward voltage) t off t on v in 0 0v secondary voltage n ?v in 16v lt1072 ?ta03 + + + + + typical applicatio s u
10 lt 1072 1072fc flyback converter negative to positive buck-boost converter external current limit r1 1k v in note that the lt1072 gnd pin is no longer common to v in (? lt1072 ?ta06 c1 1000pf c2 r s r2 + v in v sw fb v c gnd lt1072 q1 c3 0.47 f v out 5v 1.5a d2 d1 optional filter 1 1 3 n* n* = c2 0.15 f c4 25 f* v in 20 to 30v r3 1.5k required if input leads 2" optional to replace r4 and c3 * ** c1 500 f r4 1k ** r1 3.74k r2 1.24k v in v sw fb v c gnd lt1072 l2 10 h c4 200 f v snub v out + v f i pri i pri i pri (i pri ) (l l ) v snub i pri n ? i v in 0v 0v 0 0 0 0 clamp turn-on spike primary flyback voltage = lt1072 switch voltage area ??= area ??to maintain zero dc volts across primary secondary voltage area ??= area ??to maintain zero dc volts across secondary primary current secondary current lt1070 switch current snubber diode current v out + v f n n ?v in t = a b c d lt1072 ?ta04 + + v in v sw fb v c gnd lt1072 c2 1000 f c1 0.22 f c4 25 f* r2 1.24k r3 2.2k r1 11.3k v out 12v, 0.5a v in ?2v d1 l1** 220 h q1 * ** required if input leads 2" pulse engineering 52626 optional input filter l3 optional output filter l2 c3 lt1072 ?ta05 + + typical applicatio s u
11 lt 1072 1072fc positive to negative buck-boost converter external current limit lt1072 ?ta08 d1 r1 500 ? r2 2v v x v c gnd lt1072 voltage boosted boost converter lt1072 ?ta09 d2 d1 total inductance = 8mh interleave primary and secondary for low leakage inductance 1 l1 n = 5 + c2 0.047 f r3 10k v in 15v c1 200 f r4 1.5k 1/2w c3 0.68 r1 98k v out 100v at 75ma r2 1.24k v in v sw fb v c gnd lt1072 + c c5 100 f* v in 10 to 30v *required if input leads 2" **pulse engineering 92113 ? to avoid start-up problems for input voltages below 10v, connect anode of d3 to v in , and remove r5. c1 may be reduced for lower output currents. c1 (500 f)(i out ). for 5v outputs, reduce r3 to 1.5k, increase c2 to 0.3 f, and reduce r6 to 100 ? lt1072 ?ta07 r4 47 ? d1 d2 1n914 c1 ? 1000 f c c3 2 f r5 ? 470 ? , 1w c c2 0.1 f d3 ? 1n4001 c4 5 f r6 470 ? r2 1.24k l1** 200 h r3 5k v out ?2v at 2a r1 10.7k v in v sw fb v c gnd lt1072 + + + typical applicatio s u
12 lt 1072 1072fc negative buck converter lt1072 ?ta11 r3 c3 25 f* v in ?0v r2 1.24k q1 2n3906 r1 4.64k c2 500 f d1 l1** 220 h c1 v in v sw fb v c gnd lt1072 load 5.2v at 1a optional output filter l2 4 h c4 200 f optional input filter l3 required if input leads 2" pulse engineering 52626 * ** + + + positive buck converter driving high voltage fet (for offline applications, see an-25) lt1072 ?ta10 + 10 to 20v v in v sw gnd lt1072 d1 gd q1 lt1072 ?ta12 c1 1 f r3 470 ? optional output filter required if input leads 2" pulse engineering 52626 * ** d1 r d2 l2 4 h 1n914 v in v sw fb v c gnd lt1072 r2 1.24k r4 10 ? 100ma minimum 5v, 1a c3 2.2 f c2 1 f d3 v in r1 3.74k l1** 220 h c4 500 f c5* 25 f c5 200 f + + + + typical applicatio s u
13 lt 1072 1072fc j8 0801 .014 ?.026 (0.360 ?0.660) .200 (5.080) max .015 ?.060 (0.381 ?1.524) .125 3.175 min .100 (2.54) bsc .300 bsc (7.62 bsc) .008 ?.018 (0.203 ?0.457) 0 ?15 .005 (0.127) min .405 (10.287) max .220 ?.310 (5.588 ?7.874) 12 3 4 87 65 .025 (0.635) rad typ .045 ?.068 (1.143 ?1.650) full lead option .023 ?.045 (0.584 ?1.143) half lead option corner leads option (4 plcs) .045 ?.065 (1.143 ?1.651) note: lead dimensions apply to solder dip/plate or tin plate leads negative boost regulator j8 package 8-lead cerdip (narrow .300 inch, hermetic) (reference ltc dwg # 05-08-1110) lt1072 ?ta13 *required if input leads 2" c2 0.22 f r3 3.3k c4 470 f* v in ?5v c3 10 f c1 1000 f r1 27k r2 1.24k r 0 (minimum load) d2 d1 v out ?8v at 0.25a l1 200 h v in v sw fb v c gnd lt1072 + + + obsolete package typical applicatio s u u package descriptio
14 lt 1072 1072fc k package 4-lead to-3 metal can (reference ltc dwg # 05-08-1311) obsolete package k4(to-3) 1098 72 18 0.490 ?0.510 (12.45 ?12.95) r 0.470 tp p.c.d. 0.167 ?0.177 (4.24 ?4.49) r 0.151 ?0.161 (3.84 ?4.09) dia 2 plc 0.655 ?0.675 (16.64 ?19.05) 1.177 ?1.197 (29.90 ?30.40) 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) n8 package 8-lead pdip (narrow .300 inch) (reference ltc dwg # 05-08-1510) n8 1002 .065 (1.651) typ .045 ?.065 (1.143 ?1.651) .130 .005 (3.302 0.127) .020 (0.508) min .018 .003 (0.457 0.076) .120 (3.048) min 12 3 4 87 6 5 .255 .015* (6.477 0.381) .400* (10.160) max .008 ?.015 (0.203 ?0.381) .300 ?.325 (7.620 ?8.255) .325 +.035 ?015 +0. 889 ?. 381 8.255 () note: 1. dimensions are inches millimeters *these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .010 inch (0.254mm) .100 (2.54) bsc u package descriptio
15 lt 1072 1072fc 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. sw package 16-lead plastic small outline (wide .300 inch) (reference ltc dwg # 05-08-1620) s8 package 8-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610) u package descriptio .016 ?.050 (0.406 ?1.270) .010 ?.020 (0.254 ?0.508) 45 0 ?8 typ .008 ?.010 (0.203 ?0.254) so8 0502 .053 ?.069 (1.346 ?1.752) .014 ?.019 (0.355 ?0.483) typ .004 ?.010 (0.101 ?0.254) .050 (1.270) bsc 1 n 2 3 4 n/2 .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 n 123 n/2 .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) s16 (wide) 0502 note 3 .398 ?.413 (10.109 ?10.490) note 4 16 15 14 13 12 11 10 9 1 n 23 4 5 6 78 n/2 .394 ?.419 (10.007 ?10.643) .037 ?.045 (0.940 ?1.143) .004 ?.012 (0.102 ?0.305) .093 ?.104 (2.362 ?2.642) .050 (1.270) bsc .014 ?.019 (0.356 ?0.482) typ 0 ?8 typ note 3 .009 ?.013 (0.229 ?0.330) .005 (0.127) rad min .016 ?.050 (0.406 ?1.270) .291 ?.299 (7.391 ?7.595) note 4 45 .010 ?.029 (0.254 ?0.737) inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. pin 1 ident, notch on top and cavities on the bottom of packages are the manufacturing options. the part may be supplied with or without any of the options 4. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm) .420 min .325 .005 recommended solder pad layout .045 .005 n 123 n/2 .050 bsc .030 .005 typ
16 lt 1072 1072fc lw/tp 1102 1k rev c ?printed in usa ? l inear technology corporation 1988 linear technology corporation 1 630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com part number description comments lt1070/hv 5a i sw , 40khz, high efficiency switching regulator v in =3v to 40/60v, v out up to 65/75v, i q =6ma, i sd <50 a, to220-5 package lt1071/hv 2.5a i sw , 40khz, high efficiency switching regulator v in =3v to 40/60v, v out up to 65/75v, i q =6ma, i sd <50 a,to220-5 package lt1082 1a i sw , 60khz, high efficiency switching regulator v in =3v to 75v, v out up to 100v, i q =4.5ma, i sd <120 a, dd, n8, to220-5 packages lt1170/hv 5a i sw , 100khz, high efficiency switching regulator v in =3v to 40/60v, v out up to 65/75v, i q =6ma, i sd <50 a, dd, n8, s16, to220-5 packages lt1171/hv 2.5a i sw , 100khz, high efficiency switching v in =3v to 40/60v, v out up to 65/75v, i q =6ma, i sd <50 a, dd, n8, s16, regulator to220-5 packages lt1172/hv 1.25a i sw , 100khz, high efficiency switching v in =3v to 40/60v, v out up to 65/75v, i q =6ma, i sd <50 a, dd, n8, s16, regulator to220-5 packages lt1307/lt1307b 600ma i sw , 600khz, high efficiency switching v in =1v to 12v, v out up to 28v, i q =50 a/1ma, i sd <1 a, ms8, n8, s8 regulator packages lt1317/lt1317b 600ma i sw , 600khz, high efficiency switching v in =1.5v to 12v, v out up to 28v, i q =100 a/4.8ma, i sd <30 a/28 a, ms8, regulator s8 packages lt1370/hv 6a isw, 500khz, high efficiency switching regulator v in =2.7v to 30v, v out up to 35/42v, i q =4.5ma, i sd <12 a, dd, t0220-7 packages lt1371/hv 3a isw, 500khz, high efficiency switching regulator v in =2.7v to 30v, v out up to 35/42v, i q =4ma, i sd <12 a, dd, s20, t0220-7 packages t package 5-lead plastic to-220 (standard) (reference ltc dwg # 05-08-1421) u package descriptio related parts t5 (to-220) 0801 .028 ?.038 (0.711 ?0.965) .067 (1.70) .135 ?.165 (3.429 ?4.191) .700 ?.728 (17.78 ?18.491) .045 ?.055 (1.143 ?1.397) .095 ?.115 (2.413 ?2.921) .013 ?.023 (0.330 ?0.584) .620 (15.75) typ .155 ?.195* (3.937 ?4.953) .152 ?.202 (3.861 ?5.131) .260 ?.320 (6.60 ?8.13) .165 ?.180 (4.191 ?4.572) .147 ?.155 (3.734 ?3.937) dia .390 ?.415 (9.906 ?10.541) .330 ?.370 (8.382 ?9.398) .460 ?.500 (11.684 ?12.700) .570 ?.620 (14.478 ?15.748) .230 ?.270 (5.842 ?6.858) bsc seating plane * measured at the seating plane

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