View LTM4644_8967854.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

1 for more information www.linear.com/ltm4650 typical application description dual 25a or single 50a dc/dc module regulator the lt m ? 4650 is a dual 25a or single 50a output switch - ing mode step-down dc /dc module ? ( power module) regulator . included in the package are the switching controllers, power fets, inductors, and all supporting components. operating from an input voltage range of 4.5v to 15v, the ltm4650 supports two outputs each with an output voltage range of 0.6 v to 1.8v, each set by a single external resistor. its high efficiency design delivers up to 25a continuous current for each output. only a few input and output capacitors are needed. the ltm4650 is pin compatible with the ltm4620 (dual 13a, single 26a) and the ltm4630 (dual 18a, single 36a). the device supports frequency synchronization, multi - phase operation, burst mode operation and output voltage tracking for supply rail sequencing and has an onboard temperature diode for device temperature monitoring . high switching frequency and a current mode architecture enable a very fast transient response to line and load changes without sacrificing stability. fault protection features include overvoltage and overcurrent protection . the ltm4650 is offered in a 16mm? ?16mm 5.01mm bga package. features applications n dual 25a or single 50a output n input voltage range: 4.5v to 15v n output voltage range: 0.6v to 1.8v n 1.5% maximum total dc output error over line, load and temperature n differential remote sense amplifer n current mode control/fast transient response n adjustable switching frequency n frequency synchronization n overcurrent foldback protection n multiphase parallel current sharing with multiple ltm4650s up to 300a n internal temperature monitor n pin compatible with the ltm4620 (dual 13a, single 26a) and ltm4630 (dual 18a, single 36a) n selectable burst mode ? operation n soft-start/voltage tracking n output overvoltage protection n 16mm 16mm 5.01mm bga package n processor, asic and fpga core power n telecom and networking equipment n storage and atca cards n industrial equipment l, lt , lt c , lt m , linear technology, the linear logo, module, burst mode and polyphase are registered trademarks of linear technology corporation. all other trademarks are the property of their respective owners. protected by u.s. patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066 and 6580258. other patents pending. 50a, 1.2v output dc/dc module regulator 1.2v out efficiency vs i out v in = 5v v in = 12v * 4650 ta01a ltm4650 v in 220f ceramic 4v 8 470pf v out1 v fb1 v fb2 v outs2 comp2 v out2 1.2v 50a mode_pllin sgnd phasmd gnd comp1 v out2 diffp diffn diffout 60.4k 121k v in 4.5v to 15v 120k 0.1f 22f 25v 4 4.7f temp run1 run2 track1 track2 intv cc pgood1 pgood2 f set pins not used in this circuit: clkout extv cc sw1 sw2 v outs1 10k ltm 4650 4650fb 70 75 80 85 90 95 efficiency (%) 4650 ta01b f sw = 500khz load current (a) 0 10 20 30 40 50 65
2 for more information www.linear.com/ltm4650 pin configuration absolute maximum ratings v in .............................................................. C 0.3 v to 16 v v sw 1 , v sw 2 .................................................... C1 v to 16 v pgood 1, pgood2, run 1, run 2, intv cc , extv cc .......................................... C 0.3 v to 6v mode _ pllin , f set , track 1, track 2, diffout , phasmd ............................... C 0. 3 v to intv cc v out 1 , v out 2 , v outs 1 , v outs 2 ..................... C 0.3 v to 6v diffp , diffn ......................................... C 0.3 v to intv cc comp 1, comp 2, v fb 1 , v fb 2 ( note 5) ........ C 0.3 v to 2.7 v intv cc peak output current ................................ 10 0 ma internal operating temperature range ( no te 2) ............................................. C 4 0 c to 125 c storage temperature range .................. C 5 5 c to 125 c peak package body temperature .......................... 24 5 c (note 1) bga package 144-lead (16mm 16mm 5.01mm) top view temp clkout sw1 phasmd extv cc 1 2 3 4 5 6 7 8 109 11 12 l k j h g f e d c b m a sw2 pgood1 pgood2 run2 track2 intv cc v outs2 diffp diffout diffn run1 track1 mode_pllin v fb1 v outs1 f set sgnd comp1 comp2 sgnd v fb2 v out2 gnd gnd sgnd gnd t jmax = 125c, ja = 7c/w, jcbottom = 1.5c/w, jctop = 3.7c/w, jb + jba ? 7c/w values defined per jesd 51-12 weight = 3.2g part number pad or ball finish part marking* package type msl rating temperature range (note 2) device finish code lt m 4650ey#pbf sac305 (rohs) lt m 4650y e1 bga 3 C40c to 125c lt m 4650iy#pbf sac305 (rohs) lt m 4650y e1 bga 3 C40c to 125c lt m 4650iy snpb (63/37) lt m 4650y e0 bga 3 C40c to 125c consult marketing for parts specified with wider operating temperature ranges. * device temperature grade is indicated by a label on the shipping container. pad or ball finish code is per ipc/jedec j-std-609. ? terminal finish part marking: www.linear.com/leadfree ? recommended lga and bga pcb assembly and manufacturing procedures: www.linear.com/umodule/pcbassembly ? lga and bga package and tray drawings: www.linear.com/packaging order information (http://www .linear.com/product/ltm4650#orderinfo) ltm 4650 4650fb
3 for more information www.linear.com/ltm4650 electrical characteristics the l denotes the specifications which apply over the specified internal operating temperature range. specified as each individual output channel. t a = 25c (note 2), v in = 12v and v run1 , v run2 at 5v unless otherwise noted. per the typical application in figure 22. symbol parameter conditions min typ max units v in input dc voltage l 4.5 15 v v out output dc voltage l 0.6 1.8 v v out1(dc) , v out2(dc) output voltage, total variation with line and load (note 7) c in = 22f 3, c out = 100f 2 ceramic, 470f poscap v out = 1.2v, i out = 0a to 25a l 1.182 1.2 1.218 v input specifications v run1 , v run2 run pin on/off threshold run rising 1.1 1.25 1.40 v v run1hys , v run2hys run pin on hysteresis 150 mv i inrush(vin) input inrush current at start-up i out = 0a, c in = 22f 3, c ss = 0.01f, c out = 100f 3, v out1 = 1.5v, v out2 = 1.5v 1 a i q(vin) input supply bias current v in = 12v, v out = 1.2v, burst mode operation v in = 12v, v out = 1.2v, pulse-skipping mode v in = 12v, v out = 1.2v, switching continuous shutdown, run = 0, v in = 12v 4.5 25 240 35 ma ma ma a i s(vin) input supply current v in = 4.5v, v out = 1.2v, i out = 25a v in = 12v, v out = 1.2v, i out = 25a 8.4 3.2 a a output specifications i out1(dc) , i out2(dc) output continuous current range v in = 12v, v out = 1.2v (note 6) 0 25 a v out1(line) /v out1 v out2(line) /v out2 line regulation accuracy v out = 1.2v, v in from 4.5v to 15v i out = 0a for each output, l 0.01 0.1 %/v v out1 /v out1 v out2 /v out2 load regulation accuracy for each output, v out = 1.2v, 0a to 25a v in = 12v (note 6) l 0.5 0.75 % v out1(ac) , v out2(ac) output ripple voltage for each output, i out = 0a, c out = 100f 3 ceramic, 470f poscap, v in = 12v, v out = 1.2v, frequency = 500khz 15 mv p-p f s (each channel) output ripple voltage frequency v in = 12v, v out = 1.2v, f set = 1.25v (note 4) 500 khz f sync (each channel) sync capture range 400 780 khz v outstart (each channel) turn-on overshoot c out = 100f ceramic, 470f poscap, v out ?= 1.2v, i out = 0a v in = 12v 10 mv t start (each channel) t urn-on t ime c out = 100f ceramic, 470f poscap, no load, track/ss with 0.01f to gnd, v in = 12v 5 ms v out(ls) (each channel) peak deviation for dynamic load load : 0% to 50% to 0% of full load c out = 22f 3 ceramic, 470f poscap v in ?=?12v, v out = 1.5v 30 mv t settle (each channel) settling t ime for dynamic load step load: 0% to 50% to 0% of full load, v in = 12v, c out = 100f, 470f poscap 20 s ltm 4650 4650fb
4 for more information www.linear.com/ltm4650 electrical characteristics the l denotes the specifications which apply over the specified internal operating temperature range. specified as each individual output channel. t a = 25c (note 2), v in = 12v and v run1 , v run2 at 5v unless otherwise noted. per the typical application in figure 22. symbol parameter conditions min typ max units i out(pk) (each channel) output current limit v in = 12v, v out = 1.2v 35 a control section v fb1 , v fb2 voltage at v fb pins i out = 0a, v out = 1.2v l 0.594 0.600 0.606 v i fb (note 5) C5 C20 na v ovl feedback overvoltage lockout l 0.64 0.66 0.68 v track1 (i), track2 (i) t rack pin soft-start pull-up current track1 (i),track2 (i) start at 0v 1 1.25 1.5 a uvlo undervoltage lockout (falling) 3.3 v uvlo hysteresis 0.6 v t on(min) minimum on-time (note 5) 90 ns r fbhi1 , r fbhi2 resistor between v outs1 , v outs2 and v fb1 , v fb2 pins for each output 60.05 60.4 60.75 k? v pgood1 , v pgood2 low pgood v oltage low i pgood = 2ma 0.1 0.3 v i pgood pgood leakage current v pgood = 5v 5 a v pgood pgood trip level v fb with respect to set output voltage v fb ramping negative v fb ramping positive C10 10 % % intv cc linear regulator v intvcc internal v cc voltage 6v < v in < 15v 4.8 5 5.2 v v intvcc load regulation int v cc load regulation i cc = 0ma to 50ma 0.75 2 % v extvcc extv cc switchover voltage extv cc ramping positive 4.5 4.7 v v extvcc(drop) extv cc dropout i cc = 20ma, v extvcc = 5v 50 100 mv v extvcc(hyst) extv cc hysteresis 220 mv oscillator and phase-locked loop frequency nominal nominal frequency f set = 1.2v 450 500 550 khz frequency low lowest frequency f set = 0.93v 400 khz frequency high highest frequency f set > 2.4v, up to intv cc 780 khz f set frequency set current 9 10 11 a r mode_pllin mode_pllin input resistance 250 k clkout phase (relative to v out1 ) phasmd = gnd phasmd = float phasmd = intv cc 60 90 120 deg deg deg clk high clk low clock high output voltage clock low output voltage 2 0.2 v v ltm 4650 4650fb
5 for more information www.linear.com/ltm4650 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: the ltm4650 is tested under pulsed load conditions such that t j t a . the ltm4650e is guaranteed to meet specifications from 0c to 125c internal temperature. specifications over the C40c to 125c internal operating temperature range are assured by design, characterization and correlation with statistical process controls. the ltm4650i is guaranteed over the full C40c to 125c internal operating temperature range. note that the maximum ambient temperature consistent with these specifications is determined by specific operating conditions in conjunction with board layout, the rated package thermal impedance and other environmental factors. note 3: two outputs are tested separately and the same testing condition is applied to each output. note 4: ltm4650 device is designed to operate from 400khz to 750khz. note 5: these parameters are tested at wafer sort. note 6: see output current derating curves for different v in , v out and t a . note 7: total dc output voltage error includes all errors over temperature: line and load regulation as well as the tolerance of the integrated top feedback resistor. symbol parameter conditions min typ max units differential amplifier a v differential amplifier gain 1 v/v r in input resistance measured at diffp input 80 k? v os input offset voltage v diffp = v diffout = 1.5v, i diffout = 100a 3 mv psrr differential amplifier power supply rejection ratio 5v < v in < 15v 90 db i cl maximum output current 3 ma v out(max) maximum output voltage i diffout = 300a intv cc C 1.4 v gbw gain bandwidth product 3 mhz v temp diode connected pnp i = 100a 0.6 v tc temperature coefficient l C2.2 mv/c the l denotes the specifications which apply over the specified internal operating temperature range. specified as each individual output channel. t a = 25c (note 2), v in = 12v and v run1 , v run2 at 5v unless otherwise noted. per the typical application in figure 22. ltm 4650 4650fb
6 for more information www.linear.com/ltm4650 burst mode and pulse-skip mode efficiency v in =12v, v out = 1.2v, f s = 500khz 1v dual phase single output load transient response 1.2v dual phase single output load transient response load current (a) 0.01 0 10 20 30 efficiency (%) 90 80 70 60 50 40 100 1 10 0.1 4650 g04 pulse-skip mode burst mode operation ccm 50s/div v out(ac) 20mv/div load step 10a/div 4650 g05 12v in , 1v out , 500khz, 12.5a load step, 10a/s step-up and step-down c out = 8 220f ceramic c ff = 470pf 50s/div v out(ac) 20mv/div load step 10a/div 4650 g06 12v in , 1.2v out , 500khz, 12.5a load step, 10a/s step-up and step-down c out = 8 220f ceramic c ff = 470pf typical performance characteristics efficiency vs output current, v in = 5v efficiency vs output current, v in = 12v dual phase single output efficiency vs output current, v in = 12v, f s = 500khz 1.5v out , 600khz 1.8v out , 600khz 1.2v out , 500khz 1.0v out , 500khz 0.8v out , 400khz 1.5v out , 600khz 1.8v out , 600khz 1.2v out , 500khz 1.0v out , 500khz 0.8v out , 400khz load current (a) 0 65 efficiency (%) 90 85 80 75 70 95 20 30 40 50 10 4650 g03 1.5v out , 600khz 1.8v out , 600khz 1.2v out , 500khz 1.0v out , 500khz 0.8v out , 400khz ltm 4650 4650fb 70 75 80 85 90 95 efficiency (%) 4650 g01 load current (a) 0 load current (a) 5 10 15 20 25 65 70 75 80 85 0 90 95 efficiency (%) 4650 g02 5 10 15 20 25 65
7 for more information www.linear.com/ltm4650 typical performance characteristics single phase short circuit protection with 25a single phase start-up with 25a single phase short circuit protection with no load 1.5v dual phase single output load transient response 1.8v dual phase single output load transient response single phase start-up with no load 20ms/div v sw 10v/div v out 0.5v/div i in 0.2a/div 4650 g09 12v in , 1.2v out , 500khz c out = 1 470f poscap + 2 100f ceramic, c ss = 0.1f 50s/div v sw 10v/div v out 0.5v/div i in 1a/div 4650 g10 12v in , 1.2v out , 500khz c out = 1 470f poscap + 2 100f ceramic, c ss = 0.1f 20ms/div v sw 10v/div v out 0.5v/div i in 1a/div 4650 g11 12v in , 1.2v out , 500khz c out = 1 470f poscap + 2 100f ceramic, c ss = 0.1f 50s/div v sw 10v/div v out 0.5v/div i in 2a/div 4650 g12 12v in , 1.2v out , 500khz c out = 1 470f poscap + 2 100f ceramic 50s/div v out(ac) 20mv/div load step 10a/div 4650 g07 12v in , 1.5v out , 600khz, 12.5a load step, 10a/s step-up and step-down c out = 8 220f ceramic c ff = 470pf 50s/div v out(ac) 20mv/div load step 10a/div 4650 g08 12v in , 1.8v out , 600khz, 12.5a load step, 10a/s step-up and step-down c out = 8 220f ceramic c ff = 470pf ltm 4650 4650fb
8 for more information www.linear.com/ltm4650 pin functions v out1 (a1-a5, b1-b5, c1-c4): power output pins. apply output load between these pins and gnd pins. recommend placing output decoupling capacitance directly between these pins and gnd pins. review table 4. gnd (a6-a7, b6-b7, d1-d4, d9-d12, e1-e4, e10-e12, f1-f3, f10-f12, g1, g3, g10, g12, h1-h7, h9-h12, j1, j5, j8, j12, k1, k5-k8, k12, l1, l12, m 1 , m12): power ground pins for both input and output returns. v out2 (a8-a12, b8-b12, c9-c12): power output pins. apply output load between these pins and gnd pins. rec - ommend placing output decoupling capacitance directly between these pins and gnd pins . review t able 4. v outs1 , v outs2 (c5, c8): this pin is connected to the top of the internal top feedback resistor for each output. the pin can be directly connected to its specific output, or connected to diffout when the remote sense amplifier is used. in paralleling modules, one of the v outs pins is connected to the diffout pin in remote sensing or directly to v out with no remote sensing. it is very important to connect these pins to either the diffout or v out since this is the feedback path, and cannot be left open. see the applications information section. f set (c6): frequency set pin. a 10 a current is sourced from this pin . a resistor from this pin to ground sets a voltage that in turn programs the operating frequency. alternatively, this pin can be driven with a dc voltage that can set the operating frequency. see the applications information section. sgnd (c7, d6, g6-g7, f6-f7): signal ground pin. return ground path for all analog and low power circuitry . tie a single connection to the output capacitor gnd in the ap - plication. see layout guidelines in figure 11. v fb1 , v fb2 (d5, d7): the negative input of the error amplifier for each channel. internally, this pin is con - nected to v outs1 or v outs2 with a 60.4k? precision resistor. different output voltages can be programmed with an additional resistor between v fb and gnd pins. in polyphase ? operation, tying the v fb pins together allows for parallel operation. see the applications information section for details. track1, track 2 (e5, d8): output voltage tracking pin and soft-start inputs . each channel has a 1.3a pull-up current source . when one channel is configured to be master of the two channels, then a capacitor from this pin to ground will set a soft-start ramp rate. the remaining channel can be set up as the slave, and have the masters output applied through a voltage divider to the slave out - puts track pin. this voltage divider is equal to the slave output s feedback divider for coincidental tracking . see the applications information section. comp1, comp 2 (e6, e7): current control threshold and error amplifier compensation point for each channel. the current comparator threshold increases with this control voltage. tie the comp pins together for parallel operation. the device is internal compensated. diffp (e8): positive input of the remote sense amplifier . this pin is connected to the remote sense point of the output voltage. see the applications information section. diffn (e9): negative input of the remote sense amplifier. this pin is connected to the remote sense point of the output gnd. see the applications information section. mode_pllin (f4): force continuous mode , burst mode operation, or pulse-skipping mode selection pin and external synchronization input to phase detector pin. connect this pin to sgnd to force both channels into force continuous mode of operation . connect to intv cc to enable pulse-skipping mode of operation. leaving the pin floating will enable burst mode operation. a clock on the pin will force both channels into continuous mode of operation and synchronized to the external clock applied to this pin. (recommended to use test points to monitor signal pin connections.) package row and column labeling may vary among module products. review each package layout carefully. ltm 4650 4650fb
9 for more information www.linear.com/ltm4650 pin functions run1, run 2 (f5, f9): run control pin. a voltage above 1.25v will turn on each channel in the module. a voltage below 1.25 v on the run pin will turn off the related chan - nel. each run pin has a 1a pull-up current, once the run pin reaches 1.2 v an additional 4.5a pull-up current is added to this pin. diffout (f8): internal remote sense amplifier output. connect this pin to v outs1 or v outs2 depending on which output is using remote sense . in parallel operation con - nect one of the v outs pin to diffout for remote sensing. sw1, sw 2 (g2, g11): switching node of each channel that is used for testing purposes. also an r-c snubber network can be applied to reduce or eliminate switch node ringing, or otherwise leave floating. see the applications information section. phasmd (g4): connect this pin to sgnd, intv cc , or float- ing this pin to select the phase of clkout to 60 degrees, 120 degrees, and 90 degrees respectively. clkout (g5): clock output with phase control using the phasmd pin to enable multiphase operation between devices. see the applications information section. pgood1, pgood 2 (g 9, g 8): output voltage power good indicator. open drain logic output that is pulled to ground when the output voltage is not within 10% of the regulation point. intv cc (h8): internal 5v regulator output. the control circuits and internal gate drivers are powered from this voltage. decouple this pin to pgnd with a 4.7 f low esr tantalum or ceramic. intv cc is activated when either run1 or run2 is activated. temp (j6): temperature monitor . an internal diode con - nected npn transistor between this pin and sgnd with 10nf filtering capacitor . see the applications information section. extv cc (j7): external power input that is enabled through a switch to intv cc whenever extv cc is greater than 4.7v. do not exceed 6v on this input, and connect this pin to v in when operating v in on 5v. an efficiency increase will occur that is a function of the (v in C intv cc ) multiplied by power mosfet driver current. typical current requirement is 30ma. v in must be applied before extv cc , and extv cc must be removed before v in . v in (m2-m11, l2-l11, j2-j4, j9-j11, k2-k4, k9-k11): power input pins. apply input voltage between these pins and gnd pins. recommend placing input decoupling capacitance directly between v in pins and gnd pins. heat sink ( top exposed metal): the top exposed metal is electrically unconnected. (recommended to use test points to monitor signal pin connections.) ltm 4650 4650fb
10 for more information www.linear.com/ltm4650 simplified block diagram decoupling requirements symbol parameter conditions min typ max units c in1, c in2 external input capacitor requirement (v in1 = 4.5v to 15v, v out1 = 1.5v) (v in2 = 4.5v to 15v, v out2 = 1.0v) i out1 = 25a i out2 = 25a 44 44 66 66 f f c out1 c out2 external output capacitor requirement (v in1 = 4.5v to 15v, v out1 = 1.5v) (v in2 = 4.5v to 15v, v out2 = 1.0v) i out1 = 25a i out2 = 25a 600 600 800 800 f f t a = 25c. use figure 1 configuration. figure 1. simplified ltm4650 block diagram 4650 f01 temp clkout run1 mode_pllin phasemd track1 = 100a or temp monitors 4.7f 0.22f ss cap 1f c in1 22f 25v 3 v in v in r fb2 60.4k mtop1 mbot1 power control 0.22f 0.12h 60.4k c out1 r fb1 40.2k + v out1 1.5v 25a v out2 1.2v 25a v fb1 gnd gnd v in 4.5v to 15v gnd gnd sw2 sw1 pgood2 pgood1 internal comp internal comp internal filter 1f c in2 22f 25v 3 mtop2 mbot2 0.22f 0.12h c out2 + + ? 60.4k v out1 v out2 v fb2 v outs2 v outs1 r fset v in r t v in r t ss cap diffout diffn diffp comp1 sgnd track2 intv cc extv cc run2 comp2 f set sgnd ltm 4650 4650fb
11 for more information www.linear.com/ltm4650 operation power module description the ltm4650 is a dual-output standalone nonisolated switching mode dc/dc power supply. it can provide two 25a outputs with few external input and output capacitors and setup components. this module provides precisely regulated output voltages programmable via external resistors from 0.6v dc to 1.8v dc over 4.5v to 15v input voltages. the typical application schematic is shown in figure 22. the ltm4650 has dual integrated constant-frequency cur - rent mode regulators and built-in power mosfet devices with fast switching speed . the typical switching frequency is from 400khz to 600khz depending on output voltage. for switching-noise sensitive applications , it can be externally synchronized from 400khz to 780khz. a resistor can be used to program a free run frequency on the fset pin. see the applications information section. with current mode control and internal feedback loop compensation, the ltm4650 module has sufficient stabil - ity margins and good transient performance with a wide range of output capacitors , even with all ceramic output capacitors. current mode control provides cycle-by-cycle fast current limit and foldback current limit in an overcurrent condition . internal overvoltage and undervoltage comparators pull the open-drain pgood outputs low if the output feedback voltage exits a 10% window around the regulation point. as the output voltage exceeds 10% above regulation, the bottom mosfet will turn on to clamp the output voltage . the top mosfet will be turned off. this overvoltage protect is feedback voltage referred. pulling the run pins below 1.1 v forces the regulators into a shutdown state, by turning off both mosfets . the track pins are used for programming the output voltage ramp and voltage tracking during start-up or used for soft-starting the regulator. see the applications information section. the ltm4650 is internally compensated to be stable over all operating conditions. table 4 provides a guide line for input and output capacitances for several operating conditions. the linear technology module power design tool will be provided for transient and stability analysis. the v fb pin is used to program the output voltage with a single external resistor to ground . a differential remote sense amplifier is available for sensing the output voltage accurately on one of the outputs at the load point, or in parallel operation sensing the output voltage at the load point. multiphase operation can be easily employed with the mode_ pllin, phasmd, and clkout pins. up to 12? phases can be cascaded to run simultaneously with respect to each other by programming the phasmd pin to different levels. see the applications information section. high efficiency at light loads can be accomplished with selectable burst mode operation or pulse-skipping opera - tion using the mode_pllin pin. these light load features will accommodate batter y operation . efficiency graphs are provided for light load operation in the typical performance characteristics section. see the applications information section for details. a general purpose temperature diode is included inside the module to monitor the temperature of the module. see the applications information section for details. the switch pins are available for functional operation monitoring and a resistor-capacitor snubber circuit can be careful placed on the switch pin to ground to dampen any high frequency ringing on the transition edges. see the applications information section for details. ltm 4650 4650fb
12 for more information www.linear.com/ltm4650 the typical ltm4650 application circuit is shown in figure? 22. external component selection is primarily determined by the maximum load current and output voltage. refer to table 4 for specific external capacitor requirements for particular applications. v in to v out step-down ratios there are restrictions in the maximum v in and v out step- down ratio that can be achieved for a given input voltage. each output of the ltm4650 is capable of 98% duty cycle, but the v in to v out minimum dropout is still shown as a function of its load current and will limit output current capability related to high duty cycle on the top side switch . minimum on-time t on(min) is another consideration in operating at a specified duty cycle while operating at a certain frequency due to the fact that t on(min) < d /f sw , where d is duty cycle and f sw is the switching frequency. t on(min) is specified in the electrical parameters as 90ns. output voltage programming the pwm controller has an internal 0.6v reference voltage. as shown in the block diagram, a 60.4 k? internal feedback resistor connects between the v outs1 to v fb1 and v outs2 to v fb2 . it is very important that these pins be connected to their respective outputs for proper feedback regulation. overvoltage can occur if these v outs1 and v outs2 pins are left floating when used as individual regulators, or at least one of them is used in paralleled regulators. the output voltage will default to 0.6v with no feedback resistor on either v fb1 or v fb2 . adding a resistor r fb from v fb pin to gnd programs the output voltage: v out = 0.6v ? 60.4k + r fb r fb table 1. v fb resistor table vs various output voltages v out 0.6v 0.8v 0.9v 1.0v 1.2v 1.5v 1.8v r fb open 182k 121k 90.9k 60.4k 40.2k 30.2k for parallel operation of multiple channels the same feed - back setting resistor can be used for the parallel design. this is done by connecting the v outs1 to the output as shown in figure 2, thus tying one of the internal 60.4k resistors to the output. all of the v fb pins tie together with one programming resistor as shown in figure 2. applications information in parallel operation, the v fb pins have an i fb current of 20na maximum each channel. to reduce output voltage error due to this current , an additional v outs pin can be tied to v out , and an additional r fb resistor can be used to lower the total thevenin equivalent resistance seen by this current . for example in figure 2, the total thevenin equivalent resistance of the v fb pin is (60.4k//r fb ), which is 30.2k where r fb is equal to 60.4k for a 1.2v output. four phases connected in parallel equates to a worse case feedback current of 4 ? i fb = 80 na maximum. the voltage error is 80na ? 30.2k = 2.4mv. if v outs2 is connected, as shown in figure 2, to v out , and another 60.4k resistor is connected from v fb2 to ground, then the voltage error is reduced to 1.2mv. if the voltage error is acceptable then no additional connections are necessary . the onboard 60.4k resistor is 0.5% accurate and the v fb resistor can be chosen by the user to be as accurate as needed. all comp pins are tied together for current sharing between the phases. the track/ss pins can be tied together and a single soft-start capacitor can be used to soft-start the regulator. the soft-start equation will need to have the soft-start current parameter increased by the number of paralleled channels. see output voltage tracking section. figure 2. 4-phase parallel configurations 4650 f02 60.4k track1 track2 v out1 v outs1 v fb1 v fb2 comp1 4 paralleled outputs for 1.2v at 100a optional connection comp2 v outs2 v out2 60.4k 60.4k track1 track2 0.1f v out1 v outs1 v fb1 v fb2 comp1 comp2 v outs2 v out2 60.4k ltm4650 ltm4650 r fb 60.4k optional r fb 60.4k use to lower total equivalent resistance to lower i fb voltage error ltm 4650 4650fb
13 for more information www.linear.com/ltm4650 applications information input capacitors the ltm4650 module should be connected to a low ac- impedance dc source . for the regulator input two 22f input ceramic capacitors are required for each channel for rms ripple current. a 47f to 100 f surface mount aluminum electrolytic bulk capacitor can be used for more input bulk capacitance . this bulk input capacitor is only needed if the input source impedance is compromised by long inductive leads, traces or not enough source capaci - tance. if low impedance power planes are used, then this bulk capacitor is not needed. for a buck converter , the switching duty cycle can be estimated as: d = v out v in without considering the inductor current ripple, for each output, the rms current of the input capacitor can be estimated as: i cin(rms) = i out(max) % ? d ? 1 ? d ( ) in the above equation, % is the estimated efficiency of the power module. the bulk capacitor can be a switcher- rated electrolytic aluminum capacitor , polymer capacitor. output capacitors the ltm4650 is designed for low output voltage ripple noise and good transient response. the bulk output capacitors defined as c out are chosen with low enough effective series resistance (esr) to meet the output volt - age ripple and transient requirements. c out can be a low esr tantalum capacitor, the low esr polymer capacitor or ceramic capacitor. the typical output capacitance range for each output is from 400f to 600f. additional output filtering may be required by the system designer, if further reduction of output ripples or dynamic transient spikes is required. table 4 shows a matrix of different output voltages and output capacitors to minimize the voltage droop and overshoot during a 12.5a (25%) load step transient. the table optimizes total equivalent esr and total bulk capacitance to optimize the transient performance . stability criteria are considered in the table 4 matrix, and the linear technology ltpowercad design tool will be provided for stability analysis. multiphase operation will reduce effective output ripple as a function of the num - ber of phases . application note 77 discusses this noise reduction versus output ripple current cancellation, but the output capacitance should be considered carefully as a function of stability and transient response. the linear technology module power design tool can calculate the output ripple reduction as the number of implemented phases increases by n times . a small value 10? to 50? resistor can be place in series from v out to the v outs pin to allow for a bode plot analyzer to inject a signal into the control loop and validate the regulator stability. the same resistor could be place in series from v out to diffp and a bode plot analyzer could inject a signal into the control loop and validate the regulator stability. burst mode operation the ltm4650 is capable of burst mode operation on each regulator in which the power mosfets operate intermit - tently based on load demand, thus saving quiescent cur - rent. for applications where maximizing the efficiency at ver y light loads is a high priority , burst mode operation should be applied . burst mode operation is enabled with the mode_pllin pin floating. during this operation, the peak current of the inductor is set to approximately one third of the maximum peak current value in normal opera - tion even though the voltage at the comp pin indicates a lower value. the voltage at the comp pin drops when the inductors average current is greater than the load requirement. as the comp voltage drops below 0.5v, the burst comparator trips, causing the internal sleep line to go high and turn off both power mosfets. in sleep mode, the internal circuitry is partially turned off, reducing the quiescent current to about 450a for each output. the load current is now being supplied from the output capacitors. when the output voltage drops, caus - ing comp to rise above 0.5v, the internal sleep line goes low , and the ltm4650 resumes normal operation. the next oscillator cycle will turn on the top power mosfet and the switching cycle repeats . either regulator can be configured for burst mode operation. ltm 4650 4650fb
14 for more information www.linear.com/ltm4650 applications information pulse-skipping mode operation in applications where low output ripple and high effi - ciency at intermediate currents are desired, pulse-skipping mode should be used . pulse-skipping operation allows the ltm4650 to skip cycles at low output loads, thus increasing efficiency by reducing switching loss. tying the mode_pllin pin to intv cc enables pulse-skipping operation. at light loads the internal current comparator may remain tripped for several cycles and force the top mosfet to stay off for several cycles, thus skipping cycles. the inductor current does not reverse in this mode. this mode will maintain higher effective frequencies thus lower output ripple and lower noise than burst mode operation. either regulator can be configured for pulse-skipping mode. forced continuous operation in applications where fixed frequency operation is more critical than low current efficiency, and where the lowest output ripple is desired, forced continuous operation should be used. forced continuous operation can be enabled by tying the mode_pllin pin to gnd. in this mode, inductor current is allowed to reverse during low output loads, the comp voltage is in control of the current comparator threshold throughout, and the top mosfet always turns on with each oscillator pulse. during start-up, forced continuous mode is disabled and inductor current is prevented from reversing until the ltm4650s output voltage is in regulation. either regulator can be configured for force continuous mode. multiphase operation for output loads that demand more than 25a of current, two outputs in ltm4650 or even multiple ltm4650s can be paralleled to run out of phase to provide more output current without increasing input and output voltage ripples. the mode_pllin pin allows the ltm4650 to synchronize to an external clock (between 400khz and 780khz) and the internal phase-locked-loop allows the ltm4650 to lock onto incoming clock phase as well. the clkout signal can be connected to the mode_pllin pin of the following stage to line up both the frequency and the phase of the entire system. tying the phasmd pin to intv cc , sgnd, or ( floating ) generates a phase difference ( between mode_pllin and clkout) of 120 degrees , 60 degrees , or 90 degrees respectively. a total of 12 phases can be cascaded to run simultaneously with respect to each other by programming the phasmd pin of each ltm4650 chan - nel to different levels. figure 3 shows a 2-phase design, 4 -phase design and a 6-phase design example for clock phasing with the phasmd table. a multiphase power supply significantly reduces the amount of ripple current in both the input and output ca - pacitors. the rms input ripple current is reduced by, and the effective ripple frequency is multiplied by , the number of phases used (assuming that the input voltage is greater than the number of phases used times the output voltage). the output ripple amplitude is also reduced by the number of phases used when all of the outputs are tied together to achieve a single high output current design. the ltm4650 device is an inherently current mode con - trolled device, so parallel modules will have very good current sharing . this will balance the thermals on the design. figure 26 shows an example of parallel operation and pin connection. input rms ripple current cancellation application note 77 provides a detailed explanation of multiphase operation. the input rms ripple current cancel - lation mathematical derivations are presented, and a graph is displayed representing the rms ripple current reduction as a function of the number of interleaved phases . figure 4 shows this graph. frequency selection and phase-lock loop (mode_pllin and f set pins) the ltm4650 device is operated over a range of frequencies to improve power conversion efficiency. it is recommended to operate the module at 400khz for output voltage below 1.0v, 500 khz for output voltage between 1.0v to 1.5v and 600 khz for output voltage above 1.5v, for the best efficiency and inductor current ripple. the ltm4650 switching frequency can be set with an external resistor from the f set pin to sgnd. an accurate 10 a current source into the resistor will set a voltage that programs the frequency or a dc voltage can be ltm 4650 4650fb
15 for more information www.linear.com/ltm4650 figure 4. input rms current ratios to dc load current as a function of duty cycle duty factor (v out /v in ) 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 4650 f04 rms input ripple current dc load current 6-phase 4-phase 3-phase 2-phase 1-phase applications information figure 3. examples of 2-phase, 4-phase, and 6-phase operation with phasmd table 4650 f03 v out2 180 phase 0 phase mode_pllin v out1 phasmd clkout 2-phase design 4-phase design 6-phase design 90 degree float v out2 180 phase 0 phase float mode_pllin v out1 phasmd clkout v out2 270 phase 90 phase float mode_pllin v out1 phasmd clkout 60 degree 60 degree v out2 180 phase 0 phase sgnd mode_pllin v out1 phasmd clkout v out2 240 phase 60 phase sgnd mode_pllin v out1 phasmd clkout v out2 300 phase 120 phase float mode_pllin v out1 phasmd clkout phasmd sgnd controller1 controller2 clkout float intv cc 0 0 0 180 180 240 60 90 120 ltm 4650 4650fb
16 for more information www.linear.com/ltm4650 applications information applied. figure 5 shows a graph of frequency setting verses programming voltage. an external clock can be applied to the mode_pllin pin from 0 v to intv cc over a frequency range of 400khz to 780khz. the clock input high threshold is 1.6v and the clock input low threshold is 1v. the ltm4650 has the pll loop filter components on board. the frequency setting resistor should always be present to set the initial switching frequency before locking to an external clock. both regulators will operate in continuous mode while being externally clock. the output of the pll phase detector has a pair of comple - mentary current sources that charge and discharge the internal filter network . when the external clock is applied then the f set frequency resistor is disconnected with an internal switch , and the current sources control the frequency adjustment to lock to the incoming external clock. when no external clock is applied, then the internal switch is on, thus connecting the external f set frequency set resistor for free run operation. low duty cycle applications may approach this minimum on-time limit and care should be taken to ensure that: v out v in ? freq > t on(min) if the duty cycle falls below what can be accommodated by the minimum on-time, the controller will begin to skip cycles. the output voltage will continue to be regulated, but the output ripple and current will increase. the on-time can be increased by lowering the switching frequency. a good rule of thumb is to keep on-time longer than 110ns. output voltage tracking output voltage tracking can be programmed externally using the track pins. the output can be tracked up and down with another regulator. the master regulators output is divided down with an external resistor divider that is the same as the slave regulators feedback divider to implement coincident tracking. the ltm4650 uses an accurate 60.4 k resistor internally for the top feedback resistor for each channel. figure 6 shows an example of coincident tracking. equations: slave = 1 + 60.4k r ta ? ? ? ? ? ? ? v track v track is the track ramp applied to the slaves track pin. v track has a control range of 0v to 0.6v, or the internal reference voltage. when the masters output is divided down with the same resistor values used to set the slave s output, then the slave will coincident track with the master until it reaches its final value. the master will continue to its final value from the slave s regulation point. voltage tracking is disabled when v track is more than 0.6v. r ta in figure 6 will be equal to the r fb for coincident tracking . figure 7 shows the coincident tracking waveforms. the track pin of the master can be controlled by a capacitor placed on the master regulator track pin to ground. a 1.3 a current source will charge the track pin up to the reference voltage and then proceed up figure 5. operating frequency vs f set pin voltage f set pin voltage (v) 0 frequency (khz) 900 800 600 400 100 200 700 500 300 0 2 4650 f05 2.5 1 1.5 0.5 minimum on-time minimum on-time t on is the smallest time duration that the ltm4650 is capable of turning on the top mosfet on either channel . it is determined by internal timing delays, and the gate charge required turning on the top mosfet. ltm 4650 4650fb
17 for more information www.linear.com/ltm4650 applications information figure 7. output coincident tracking waveform figure 6. example of output tracking application circuit time master output slave output output voltage 4650 f07 to intv cc . after the 0.6v ramp, the track pin will no longer be in control, and the internal voltage reference will control output regulation from the feedback divider. foldback current limit is disabled during this sequence of turn-on during tracking or soft-starting. the track pins are pulled low when the run pin is below 1.2v. the total soft-start time can be calculated as: t soft-start = c ss 1.3a ? ? ? ? ? ? ? 0.6 regardless of the mode selected by the mode_pllin pin, the regulator channels will always start in pulse-skipping mode up to track = 0.5v. between track = 0.5v and 0.54v, it will operate in forced continuous mode and revert to the selected mode once track > 0.54v. in order to track with another channel once in steady state operation , the ltm4650 is forced into continuous mode operation as soon as v fb is below 0.54v regardless of the setting on the mode_pllin pin. ratiometric tracking can be achieved by a few simple cal - culations and the slew rate value applied to the masters track pin. as mentioned above, the track pin has a control range from 0 to 0.6v. the masters track pin slew rate is directly equal to the masters output slew rate in volts/time. the equation: mr sr ? 60.4k = r tb where mr is the master s output slew rate and sr is the slave s output slew rate in volts /time. when coincident 4650 f06 ltm4650 v in temp run1 run2 track1 track2 f set c8 470f 6.3v r fb 60.4k r2 10k c6 100f 6.3v phasmd v out1 v outs1 sw1 v fb1 v fb2 comp1 comp2 v outs2 v out2 sw2 pgood2 mode_pllin clkout intv cc extv cc pgood1 pgood1 intv cc sgnd gnd v out1 1.5v ramp time t softstart = (c ss /1.3a) 0.6 diffp diffn diffout 40.2k pgood2 v out2 (slave) 1.2v at 25a v out1 (master) 1.5v at 25a c7 470f 6.3v c5 100f 6.3v r4 121k r tb 60.4k 4.5v to 15v intermediate bus r6 100k c ss 0.1f c1 22f 25v 4 r ta 60.4k c10 4.7f r9 10k intv cc intv cc v in ltm 4650 4650fb
18 for more information www.linear.com/ltm4650 applications information tracking is desired, then mr and sr are equal, thus r tb is equal the 60.4k. r ta is derived from equation: r ta = 0.6v v fb 60.4k + v fb r fb ? v track r tb where v fb is the feedback voltage reference of the regula - tor, and v track is 0.6v. since r tb is equal to the 60.4k top feedback resistor of the slave regulator in equal slew rate or coincident tracking, then r ta is equal to r fb with v fb = v track . therefore r tb = 60.4k, and r ta = 60.4 k in figure 6. in ratiometric tracking, a different slew rate maybe desired for the slave regulator. r tb can be solved for when sr is slower than mr. make sure that the slave supply slew rate is chosen to be fast enough so that the slave output voltage will reach it final value before the master output. for example, mr = 1.5v/1ms, and sr = 1.2v/1ms. then r tb = 76.8k. solve for r ta to equal to 49.9k. each of the track pins will have the 1.3 a current source on when a resistive divider is used to implement tracking on that specific channel. this will impose an offset on the track pin input . smaller values resistors with the same ratios as the resistor values calculated from the above equation can be used . for example, where the 60.4 k is used then a 6.04k can be used to reduce the track pin offset to a negligible value. power good the pgood pins are open drain pins that can be used to monitor valid output voltage regulation. this pin monitors a 10% window around the regulation point. a resistor can be pulled up to a particular supply voltage no greater than 6v maximum for monitoring. stability compensation the module has already been internally compensated for all output voltages. table 4 is provided for most ap - plication requirements . the linear technology module power design t ool will be provided for other control loop optimization. run enable the run pins have an enable threshold of 1.4v maximum, typically 1.25 v with 150mv of hysteresis. they control the turn on each of the channels and intv cc . these pins can be pulled up to v in for 5 v operation, or a 5 v zener diode can be placed on the pins and a 10k to 100k resistor can be placed up to higher than 5v input for enabling the channels. the run pins can also be used for output voltage sequencing. in parallel operation the run pins can be tie together and controlled from a single control . see the typical applica - tion circuits in figure 22. int v cc and extv cc the ltm4650 module has an internal 5v low dropout regulator that is derived from the input voltage. this regu - lator is used to power the control circuitry and the power mosfet drivers . this regulator can source up to 70ma, and typically uses ~30ma for powering the device at the maximum frequency. this internal 5v supply is enabled by either run1 or run2. extv cc allows an external 5 v supply to power the ltm4650 and reduce power dissipation from the internal low dropout 5v regulator. the power loss savings can be calculated by: ( v in C 5v) ? 30ma = ploss extv cc has a threshold of 4.7v for activation, and a maximum rating of 6v. when using a 5 v input, connect this 5 v input to extv cc also to maintain a 5v gate drive level. extv cc must sequence on after v in , and extv cc must sequence off before v in . differential remote sense amplifier an accurate differential remote sense amplifier is provided to sense low output voltages accurately at the remote load points. this is especially true for high current loads. the amplifier can be used on one of the two channels, or on a single parallel output. it is very important that the diffp and diffn are connected properly at the output, and diffout is connected to either v outs1 or v outs2 . in parallel operation, the diffp and diffn are connected properly at the output, and diffout is connected to one of the v outs pins. review the parallel schematics in figure 23 and review figure 2. ltm 4650 4650fb
19 for more information www.linear.com/ltm4650 applications information sw pins the sw pins are generally for testing purposes by moni - toring these pins . these pins can also be used to dampen out switch node ringing caused by lc parasitic in the switched current paths . usually a series r-c combina - tion is used called a snubber circuit . the resistor will dampen the resonance and the capacitor is chosen to only affect the high frequency ringing across the resistor . if the stray inductance or capacitance can be measured or approximated then a somewhat analytical technique can be used to select the snubber values. the inductance is usually easier to predict. it combines the power path board inductance in combination with the mosfet interconnect bond wire inductance. first the sw pin can be monitored with a wide bandwidth scope with a high frequency scope probe. the ring fre - quency can be measured for its value. the impedance z can be calculated : zl = 2fl, where f is the resonant frequency of the ring , and l is the total parasitic inductance in the switch path. if a resistor is selected that is equal to z, then the ringing should be dampened. the snubber capacitor value is chosen so that its impedance is equal to the resistor at the ring frequency . calculated by: zc = 1/(2 fc). these values are a good place to start with. modification to these components should be made to attenuate the ringing with the least amount of power loss. temperature monitoring measuring the absolute temperature of a diode is pos - sible due to the relationship between current, voltage and temperature described by the classic diode equation : i d = i s ? e v d ? v t ? ? ? ? ? ? or v d = ? v t ?in i d i s where i d is the diode current , v d is the diode voltage , is the ideality factor (typically close to 1.0) and i s (satura- tion current) is a process dependent parameter. v t can be broken out to: v t = k ? t q where t is the diode junction temperature in kelvin , q is the electron charge and k is boltzmanns constant. v t is approximately 26 mv at room temperature (298k) and scales linearly with kelvin temperature. it is this linear temperature relationship that makes diodes suitable tem - perature sensors. the i s term in the previous equation is the extrapolated current through a diode junction when the diode has zero volts across the terminals. the i s term varies from process to process, varies with temperature, and by definition must always be less than i d . combining all of the constants into one term: k d = ?k q where k d = 8.62 ? 10 ?5 , and knowing ln(i d /i s ) is always positive because i d is always greater than i s , leaves us with the equation that: v d = t kelvin ( ) ?k d ?in i d i s where v d appears to increase with temperature. it is com - mon knowledge that a silicon diode biased with a current sour ce has an approximate C2mv/c temperature rela - tionship ( figure 8), which is at odds with the equation. in fact, the i s term increases with temperature, reducing the ln(i d /i s ) absolute value yielding an approximate C2mv/c composite diode voltage slope. to obtain a linear voltage proportional to temperature we cancel the i s variable in the natural logarithm term to remove the i s dependency from the equation 1. this is accomplished by measuring the diode voltage at two cur - rents i 1 , and i 2 , where i 1 = 10 ? i 2 ) and subtracting we get: v d = t(kelvin)?k d ?in i 1 i s C t(kelvin)?k d ?in i 2 i s ltm 4650 4650fb
20 for more information www.linear.com/ltm4650 applications information thermal considerations and output current derating the thermal resistances reported in the pin configuration section of the data sheet are consistent with those param- eters defined by jesd51-9 and are intended for use with finite element analysis (fea) software modeling tools that leverage the outcome of thermal modeling, simulation, and correlation to hardware evaluation performed on a module package mounted to a hardware test board also defined by jesd 51-9 ( test boards for area array surface mount package thermal measurements). the motivation for providing these thermal coefficients is found in jesd 51-12 ( guidelines for reporting and using electronic package thermal information). many designers may opt to use laboratory equipment and a test vehicle such as the demo board to anticipate the module regulator s thermal performance in their ap - plication at various electrical and environmental operating conditions to compliment any fea activities . without fea software, the thermal resistances reported in the pin con - figuration section are in-and-of themselves not relevant to providing guidance of thermal per formance ; instead, the derating curves provided in the data sheet can be used in a manner that yields insight and guidance pertaining to ones application-usage, and can be adapted to correlate thermal performance to ones own application. the pin configuration section typically gives four thermal coefficients explicitly defined in jesd 51-12; these coef - ficients are quoted or paraphrased below: 1. ja , the thermal resistance from junction to ambient, is the natural convection junction-to-ambient air thermal resistance measured in a one cubic foot sealed enclo - sure. this environment is sometimes referred to as still air although natural convection causes the air to move. this value is determined with the part mounted to a jesd 51-9 defined test board , which does not reflect an actual application or viable operating condition. 2. jcbottom , the thermal resistance from junction to the bottom of the product case , is the junction-to-board thermal resistance with all of the component power dissipation flowing through the bottom of the package. in the typical module, the bulk of the heat flows out combining like terms, then simplifying the natural log terms yields: v d = t(kelvin) ? k d ? ln(10) and redefining constant k' d = k d ?in(10) = 198v k yields v d = k' d ? t(kelvin) solving for temperature: t(kelvin) = v d k' d ( celsius) = t(kelvin)C 273.15 where 300 k = 27c means that is we take the difference in voltage across the diode measured at two currents with a ratio of 10, the resulting voltage is 198v per kelvin of the junction with a zero intercept at 0 kelvin. the diode connected pnp transistor at the temp pin can be used to monitor the internal temperature of the ltm4650. see figure 23 for an example. figure 8. diode voltage v d vs temperature t(c) temperature (c) ?50 ?25 0.3 diode voltage (v) 0.5 0.8 0 50 75 0.4 0.7 0.6 25 100 4650 f08 125 ltm 4650 4650fb
21 for more information www.linear.com/ltm4650 applications information the bottom of the package, but there is always heat flow out into the ambient environment. as a result, this thermal resistance value may be useful for comparing packages but the test conditions dont generally match the users application. 3. jctop , the thermal resistance from junction to top of the product case, is determined with nearly all of the component power dissipation flowing through the top of the package. as the electrical connections of the typical module are on the bottom of the package, it is rare for an application to operate such that most of the heat flows from the junction to the top of the part. as in the case of jcbottom , this value may be useful for comparing packages but the test conditions dont generally match the users application. 4. jb , the thermal resistance from junction to the printed circuit board , is the junction-to-board thermal resistance where almost all of the heat flows through the bottom of the module and into the board, and is really the sum of the jcbottom and the thermal resistance of the bottom of the part through the solder joints and through a por - tion of the board. the board temperature is measured a specified distance from the package , using a two sided, two layer board. this board is described in jesd 51-9. a graphical representation of the aforementioned ther - mal resistances is given in figure 9; blue resistances are contained within the module regulator, whereas green resistances are external to the module. as a practical matter, it should be clear to the reader that no individual or sub-group of the four thermal resistance parameters defined by jesd 51-12 or provided in the pin configuration section replicates or conveys normal operating conditions of a module. for example, in normal board-mounted applications, never does 100% of the devices total power loss (heat) thermally conduct exclu - sively through the top or exclusively through bottom of the module as the standard defines for jctop and jcbottom , respectively. in practice, power loss is thermally dissipated in both directions away from the package granted, in the absence of a heat sink and airflow , a majority of the heat flow is into the board. within a sip (system-in-package) module, be aware there are multiple power devices and components dissipating power, with a consequence that the thermal resistances relative to different junctions of components or die are not exactly linear with respect to total package power loss. to reconcile this complication without sacrificing modeling simplicitybut also, not ignoring practical realitiesan approach has been taken using fea software modeling along with laboratory testing in a controlled-environment chamber to reasonably define and correlate the thermal resistance values supplied in this data sheet : (1) initially, fea software is used to accurately build the mechanical geometry of the module and the specified pcb with all of the correct material coefficients along with accurate power loss source definitions ; (2) this model simulates a software-defined jedec environment consistent with jsed51-9 to predict power loss heat flow and temperature figure 9. graphical representation of jesd51-12 thermal coefficients 4650 f09 module device junction-to-case (top) resistance junction-to-board resistance junction-to-ambient resistance (jesd 51-9 defined board) case (top)-to-ambient resistance board-to-ambient resistance junction-to-case (bottom) resistance junction ambient case (bottom)-to-board resistance ltm 4650 4650fb
22 for more information www.linear.com/ltm4650 readings at different interfaces that enable the calculation of the jedec-defined thermal resistance values ; (3) the model and fea software is used to evaluate the module with heat sink and airflow ; (4) having solved for and analyzed these thermal resistance values and simulated various operating conditions in the software model, a thorough laboratory evaluation replicates the simulated conditions with thermocouples within a controlled-environment chamber while operating the device at the same power loss as that which was simulated. an outcome of this process and due-diligence yields a set of derating curves provided in other sections of this data sheet. after these laboratory test have been performed and correlated to the module model, then the jb and ba are summed together to cor - relate quite well with the module model with no airflow or heat sinking in a properly define chamber . this jb + ba value is shown in the pin configuration section and should accurately equal the ja value because approximately 100% of power loss flows from the junction through the board into ambient with no airflow or top mounted heat sink. each system has its own thermal characteristics, therefore thermal analysis must be performed by the user in a particular system. applications information the ltm4650 module has been designed to effectively remove heat from both the top and bottom of the pack - age. the bottom substrate material has very low thermal resistance to the printed cir cuit board . an external heat sink can be applied to the top of the device for excellent heat sinking with airflow. figure 10 shows a temperature plot of the ltm4650 with 12v input , 1.0v output at 50a without heat sink and a no airflow condition. safety considerations the ltm4650 modules do not provide isolation from v in to v out . there is no internal fuse. if required, a slow blow fuse with a rating twice the maximum input current needs to be provided to protect each unit from catastrophic failure. the device does support over current protection. a temperature diode is provided for monitoring internal temperature, and can be used to detect the need for thermal shutdown that can be done by controlling the run pin. figure 10. thermal image 12v to 1v, 50a with no air flow and no heat sink (based on 4-layer 101mm 114mm pcb board containing 2oz copper on the top , bottom and all internal layers) ltm 4650 4650fb
23 for more information www.linear.com/ltm4650 power derating the 0.9 v and 1.5 v power loss curves in figures 12 and 13 can be used in coordination with the load current derating curves in figures 14 to 21 for calculating an approximate ja thermal resistance for the ltm4650 with various heat sinking and airflow conditions . the power loss curves are taken at room temperature , and are increased with a 1.2 multiplicative factor at 120c. the derating curves are plotted with ch 1 and ch2 in parallel single output operation starting at 50a of load with low ambient temperature. the output voltages are 0.9v and 1.5v. these are chosen to include the lower and higher output voltage ranges for correlating the thermal resistance. thermal models are derived from several temperature measurements in a controlled temperature chamber along with thermal modeling analysis. the junction temperatures are monitored while ambient temperature is increased with and without airflow . the power loss increase with ambient temperature change is factored into the derating curves . the junctions are maintained at ~120c maximum while lowering output current or power while increasing ambient temperature. the decreased output current will decrease the internal module loss as ambient temperature is increased. the monitored junction temperature of 120c minus the ambient operating temperature specifies how much module temperature rise can be allowed. as an example in figure 15, the load current is derated to ~35a at ~90c with 200 lfm air but not heat sink and the power loss for the 12 v to 0.9v at 35a output is a ~5.6w loss. the 5.6w loss is calculated with the ~4.7w room temperature loss from the 12v to 0.9 v power loss curve at 35a, and the 1.20 multiplying factor at 120 c junction temperature. if the 90 c ambient temperature is subtracted from the 120c junction temperature, then the difference of 30c divided 5.5w equals a 5.4c/w ja thermal resistance. table 2 specifies a 5.5c/w value which is pretty close. tables 2 and 3 provide equivalent thermal resistances for 0.9 v and 1.5v outputs with and without airflow and heat sinking. the derived thermal resistances in tables 2 and 3 for the various conditions can be multiplied by the calculated power loss as a function of ambient temperature to derive temperature rise above ambient, thus maximum junction temperature. room temperature power loss can be derived from the efficiency curves and adjusted with the above ambient temperature multiplicative factors. the printed circuit board is a 1.6mm thick 4 -layer board with 2 oz? copper on each layer. the pcb dimensions are 101mm 114mm. the bga heat sinks are listed in table 3. layout checklist/example the high integration of ltm4650 makes the pcb board layout very simple and easy . however, to optimize its electrical and thermal performance , some layout consid - erations are still necessary. ? use large pcb copper areas for high current paths, including v in , gnd, v out1 and v out2 . it helps to mini - mize the pcb conduction loss and thermal stress. ? place high frequency ceramic input and output capaci - tors next to the v in , pgnd and v out pins to minimize high frequency noise. ? place a dedicated power ground layer underneath the unit. ? to minimize the via conduction loss and reduce module thermal stress, use multiple vias for interconnection between top layer and other power layers. ? do not put via directly on the pad, unless they are capped or plated over. ? use a separated sgnd ground copper area for com - ponents connected to signal pins. connect the sgnd to gnd underneath the unit . ? for parallel modules, tie the v out , v fb , and comp pins together. use an internal layer to closely connect these pins together. the track pin can be tied a common capacitor for regulator soft-start. ? bring out test points on the signal pins for monitoring. figure 11 gives a good example of the recommended layout. lga and bga pcb layouts are identical with the exception of circle pads for bga (see package description). applications information ltm 4650 4650fb
24 for more information www.linear.com/ltm4650 applications information figure 11. recommended pcb layout gnd gnd gnd sgnd cntrl cntrl v out1 c out1 c out2 v out2 v in c in1 c in2 1 2 3 4 5 6 7 8 109 11 12 l k j h g f e d c b m a 4650 f11 table 2. 0.9v output derating curve v in (v) power loss curve airflow (lfm) heat sink ja (c/w) figures 14, 15 5, 12 figure 12 0 none 7.5 figures 14, 15 5, 12 figure 12 200 none 5.5 figures 14, 15 5, 12 figure 12 400 none 5 figures 16, 17 5, 12 figure 12 0 bga heat sink 7 figures 16, 17 5, 12 figure 12 200 bga heat sink 4.5 figures 16, 17 5, 12 figure 12 400 bga heat sink 4 table 3. 1.5v output derating curve v in (v) power loss curve airflow (lfm) heat sink ja (c/w) figures 18, 19 5, 12 figure 13 0 none 7.5 figures 18, 19 5, 12 figure 13 200 none 5.5 figures 18, 19 5, 12 figure 13 400 none 5 figures 19, 20 5, 12 figure 13 0 bga heat sink 7 figures 19, 20 5, 12 figure 13 200 bga heat sink 4.5 figures 19, 20 5, 12 figure 13 400 bga heat sink 4 heat sink manufacturer part number website wakefield lt n 20069-t5 wakefield-vette.com ltm 4650 4650fb
25 for more information www.linear.com/ltm4650 applications information figure 12. 0.9v output power loss curve figure 13. 1.5v output power loss curve figure 14. 5v to 0.9v derating curve, no heat sink load current (a) 0 0 powe loss (w) 4 3 2 1 5 9 8 7 6 10 40 50 10 20 4650 f12 30 v in = 5v v in = 12v load current (a) 0 0 powe loss (w) 4 3 2 1 5 9 8 7 6 10 40 50 10 20 4650 f13 30 v in = 5v v in = 12v ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f14 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm table 4. two-phase single output (see figure 24) c in (ceramic) c out (ceramic) vendors part number value vendors part number value bulk sun electronics 25ce150ax 150f, 25v panasonic etpf470m5h 470f, 2.5v, 5m? ceramic murata grm21br61e106ka73l 10f, 25v, 0805, x5r murata grm32er60j227m 220f, 4v, 1206, x5r taiyo yuden tmk212bbj106kg-t 10f, 25v, 0805, x5r taiyo yuden amk325abj227mm-t 220uf, 4v, 1210, x5r murata grm31cr61e226ke15l 22f, 25v, 1206, x5r taiyo yuden tmk316bbj226ml-t 22f, 25v, 1206, x5r 25% load step (0 to 12.5a), ceramic output cap only solutions v in v out c in * (bulk) c in (ceramic) c out (bulk) c out (ceramic) c ff (feed- forward cap) pkCpk deviation (v pkCpk ) settling time (t settle ) load step load step slew rate rfb freq 12v 1.0v 150f 22f 2 none 220f 8 470pf 47mv 30s 12.5a 10a/s 90.9k? 500khz 12v 1.2v 150f 22f 2 none 220f 8 470pf 49mv 30s 12.5a 10a/s 60.4k? 500khz 12v 1.5v 150f 22f 2 none 220f 8 470pf 50mv 30s 12.5a 10a/s 40.2k? 600khz 12v 1.8v 150f 22f 2 none 220f 8 470pf 53mv 30s 12.5a 10a/s 30.2k? 600khz 25% load step (0 to 12.5a), bulk + ceramic output cap solutions v in v out c in * (bulk) c in (ceramic) c out (bulk) c out (ceramic) c ff (feed- forward cap) pkCpk deviation (v pkCpk ) settling time (t settle ) load step load step slew rate rfb freq 12v 1.0v 150f 22f 2 470f 2 220f 3 none 58mv 20s 12.5a 10a/s 90.9k? 500khz 12v 1.2v 150f 22f 2 470f 2 220f 3 none 58mv 20s 12.5a 10a/s 60.4k? 500khz 12v 1.5v 150f 22f 2 470f 2 220f 3 none 61mv 30s 12.5a 10a/s 40.2k? 600khz 12v 1.8v 150f 22f 2 470f 2 220f 3 none 64mv 50s 12.5a 10a/s 30.2k? 600khz ltm 4650 4650fb
26 for more information www.linear.com/ltm4650 applications information figure 15.12v to 0.9v derating curve, no heat sink figure 16. 5v to 0.9v derating curve, bga heat sink figure 17. 12v to 0.9v derating curve, bga heat sink figure 18. 5v to 1.5v derating curve, no heat sink figure 19. 12v to 1.5v derating curve, no heat sink figure 20. 5v to 1.5v derating curve, bga heat sink figure 21. 12v to 1.5v derating curve, bga heat sink ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f15 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f16 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f17 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f18 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f19 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f20 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ambient temperature (c) 25 output current (a) 20 30 40 105 4650 f21 10 0 45 65 85 35 115 55 75 95 60 50 0lfm 200lfm 400lfm ltm 4650 4650fb
27 for more information www.linear.com/ltm4650 figure 22. typical 4.5v in to 15v in , 1.5v and 1.2v at 25a outputs applications information 4650 f22 ltm4650 v in temp run1 run2 track1 track2 f set r fb2 60.4k r2 10k phasmd v out1 v outs1 sw1 v fb1 v fb2 comp1 comp2 v outs2 v out2 sw2 pgood2 mode_pllin clkout intv cc extv cc pgood1 pgood1 intv cc sgnd gnd track1 track2 diffn diffp diffout r fb1 40.2k pgood2 v out2 1.2v at 25a c out3 100f 6.3v c out4 470f 6.3v r4 121k r7 100k c5 0.1f c9 0.1f c1 22f 25v 4 c10 4.7f v out1 1.5v at 25a r3 10k intv cc + c in (opt) v in 4.5v to 15v intv cc + c out1 100f 6.3v c out2 470f 6.3v + ltm 4650 4650fb
28 for more information www.linear.com/ltm4650 typical applications figure 23. ltm4650 2-phase, 1v at 50a design figure 24. 25%, 12.5a load step transient waveform of figure 23 circuit 4650 f23 ltm4650 v in temp run1 run2 run monitor temp track1 track track2 f set r5 90.9k c out1 220f 4v 8 phasmd v out1 v out2 v outs1 sw1 v fb1 v fb2 comp1 comp2 v out2 v outs2 sw2 pgood2 pgood mode_pllin clkout intv cc extv cc pgood1 pgood r2 10k intv cc sgnd gnd diffn diffp diffout r4 121k c9 0.1f c in 22f 25v 4 c10 4.7f intv cc v in 4.5v to 15v v out 1v 50a *see table 4 470pf 50s/div v out(ac) 20mv/div load step 10a/div 4650 f24 54mv ltm 4650 4650fb
29 for more information www.linear.com/ltm4650 typical applications figure 25. ltm4650 1.2v and 1v output tracking 4650 f25 ltm4650 v in temp run1 run2 track1 track2 f set c out2 470f 6.3v r8 90.9k r2 10k c out1 100f 6.3v 2 phasmd v out1 v outs1 sw1 v fb1 v fb2 comp1 comp2 v outs2 v out2 sw2 pgood2 mode_pllin clkout intv cc extv cc pgood1 pgood1 intv cc intv cc sgnd gnd v out1 1.2v diffp diffn diffout r5 60.4k pgood2 v out2 1v at 25a c out2 470f 6.3v c out1 100f 6.3v 2 r4 121k r9 60.4k r6 100k c5 0.1f r7 90.9k c in 22f 25v 4 c10 4.7f + + r3 10k v out1 1.2v 25a v in 4.5v to 15v intv cc ltm 4650 4650fb
30 for more information www.linear.com/ltm4650 typical applications figure 26. ltm4650 4-phase, 1.2v at 100a 4650 f26 ltm4650 v in temp run1 run2 track1 track track2 f set c out2 470f 6.3v r5 60.4k r2 5k c out1 100f 6.3v phasmd v out1 v outs1 sw1 v fb1 v fb2 comp1 comp2 comp v out2 v outs2 sw2 pgood2 pgood mode_pllin clkout clk1 clk1 intv cc extv cc pgood1 pgood sgnd gnd diffp diffn diffout c out2 470f 6.3v c out1 100f 6.3v r4 121k r6 100k c in1 22f 25v 3 c10 4.7f + + ltm4650 v in temp run1 run2 track1 track2 f set c out2 470f 6.3v c out1 100f 6.3v v in 4.5v to 15v phasmd v out1 v outs1 sw1 v fb1 v fb2 comp1 v fb comp comp2 v outs2 v out2 sw2 pgood2 pgood mode_pllin clkout intv cc extv cc pgood1 pgood sgnd gnd diffp diffn diffout c out2 470f 6.3v c out1 100f 6.3v r10 121k r9 100k c19 0.22f c in2 22f 25v 3 c16 4.7f + + intv cc track v fb intv cc v out 1.2v 100a intv cc run run ltm 4650 4650fb
31 for more information www.linear.com/ltm4650 ltm4650 component bga pinout package description pin id function pin id function pin id function pin id function pin id function pin id function a1 v out1 b1 v out1 c1 v out1 d1 gnd e1 gnd f1 gnd a2 v out1 b2 v out1 c2 v out1 d2 gnd e2 gnd f2 gnd a3 v out1 b3 v out1 c3 v out1 d3 gnd e3 gnd f3 gnd a4 v out1 b4 v out1 c4 v out1 d4 gnd e4 gnd f4 mode_pllin a5 v out1 b5 v out1 c5 v out1s d5 v fb1 e5 track1 f5 run1 a6 gnd b6 gnd c6 f set d6 sgnd e6 comp1 f6 sgnd a7 gnd b7 gnd c7 sgnd d7 v fb2 e7 comp2 f7 sgnd a8 v out2 b8 v out2 c8 v out2s d8 track2 e8 diffp f8 diffout a9 v out2 b9 v out2 c9 v out2 d9 gnd e9 diffn f9 run2 a10 v out2 b10 v out2 c10 v out2 d10 gnd e10 gnd f10 gnd a11 v out2 b11 v out2 c11 v out2 d11 gnd e11 gnd f11 gnd a12 v out2 b12 v out2 c12 v out2 d12 gnd e12 gnd f12 gnd pin id function pin id function pin id function pin id function pin id function pin id function g1 gnd h1 gnd j1 gnd k1 gnd l1 gnd m1 gnd g2 sw1 h2 gnd j2 v in k2 v in l2 v in m2 v in g3 gnd h3 gnd j3 v in k3 v in l3 v in m3 v in g4 phasemd h4 gnd j4 v in k4 v in l4 v in m4 v in g5 clkout h5 gnd j5 gnd k5 gnd l5 v in m5 v in g6 sgnd h6 gnd j6 temp k6 gnd l6 v in m6 v in g7 sgnd h7 gnd j7 extv cc k7 gnd l7 v in m7 v in g8 pgood2 h8 intv cc j8 gnd k8 gnd l8 v in m8 v in g9 pgood1 h9 gnd j9 v in k9 v in l9 v in m9 v in g10 gnd h10 gnd j10 v in k10 v in l10 v in m10 v in g11 sw2 h11 gnd j11 v in k11 v in l11 v in m11 v in g12 gnd h12 gnd j12 gnd k12 gnd l12 gnd m12 gnd ltm 4650 4650fb
32 for more information www.linear.com/ltm4650 package description please refer to http://www .linear.com/product/ltm4650#packaging for the most recent package drawings. bga package 144-lead (16mm 16mm 5.01mm) (reference ltc dwg # 05-08-1523 rev ?) package top view 4 pin ?a1? corner x y aaa z aaa z package bottom view 3 see notes d e b e e b f g bga 144 1215 rev ? tray pin 1 bevel package in tray loading orientation component pin ?a1? ltmxxxxxx module detail a pin 1 l k j h g f e d c b m a 1 2 3 4 5 6 7 8 10 9 11 12 suggested pcb layout top view 0.0000 0.0000 0.630 0.025 ? 144x 0.6350 0.6350 1.9050 1.9050 3.1750 3.1750 4.4450 4.4450 5.7150 5.7150 6.9850 6.9850 6.9850 5.7150 5.7150 4.4450 4.4450 3.1750 3.1750 1.9050 1.9050 0.6350 0.6350 6.9850 detail a ?b (144 places) a detail b package side view z m x yzddd m zeee a2 detail b substrate a1 b1 ccc z mold cap symbol a a1 a2 b b1 d e e f g h1 h2 aaa bbb ccc ddd eee min 4.81 0.50 4.31 0.60 0.60 0.36 3.95 nom 5.01 0.60 4.41 0.75 0.63 16.00 16.00 1.27 13.97 13.97 0.41 4.00 max 5.21 0.70 4.51 0.90 0.66 0.46 4.05 0.15 0.10 0.20 0.30 0.15 notes dimensions total number of balls: 144 // bbb z z h2 h1 notes: 1. dimensioning and tolerancing per asme y14.5m-1994 2. all dimensions are in millimeters ball designation per jesd ms-028 and jep95 5. primary datum -z- is seating plane 6. solder ball composition is 96.5% sn/3.0% ag/0.5% cu 4 3 details of pin #1 identifier are optional, but must be located within the zone indicated. the pin #1 identifier may be either a mold or marked feature 7 package row and column labeling may vary among module products. review each package layout carefully ! 7 see notes ltm 4650 4650fb
33 for more information www.linear.com/ltm4650 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 . revision history rev date description page number a 05/16 updated package drawing 32 b 12/16 changed v out specs and condition from v out = 1.5v to 1.2v added note 7 3 3, 5 ltm 4650 4650fb
34 for more information www.linear.com/ltm4650 ? linear technology corporation 2016 lt 1216 rev b ? printed in usa linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax : (408) 434-0507 www.linear.com/ltm4650 related parts package photo design resources subject description module design and manufacturing resources design: ? selector guides ? demo boards and gerber files ? free simulation tools manufacturing: ? quick start guide ? pcb design, assembly and manufacturing guidelines ? package and board level reliability module regulator products sear ch 1. sort table of products by parameters and download the result as a spread sheet. 2. search using the quick power sear ch parametric table. techclip videos quick videos detailing how to bench test electrical and thermal performance of module products. digital power system management linear technologys family of digital power supply management ics are highly integrated solutions that offer essential functions, including power supply monitoring, supervision, margining and sequencing, and feature eeprom for storing user configurations and fault logging. bga part number description comments ltm4630 lower current than ltm4650; dual 18a or single 36a pin compatible with ltm4650; 4.5v v in 15v, 0.6v v out 1.8v, 15mm 15mm 4.41mm lga and 15mm 15mm 5.01mm bga packages ltm 4630a lower current and higher v out than ltm4650; up to 5.3v out , dual 18a or single 26a pin compatible with ltm4650; 4.5v v in 15v, 0.6v v out 5.3v, 15mm 15mm 4.41mm lga package ltm 4630-1 lower current than ltm4650 with external compensation and 0.8% (-1a) or 1.5% (-1b) v out accuracy pin compatible with ltm4650; 4.5v v in 15v, 0.6v v out 1.8v, 15mm 15mm 5.01mm bga package ltm 4620 lower current than ltm4650; dual 13a or single 26a. pin compatible with ltm4650; 4.5v v in 16v, 0.6v v out 5.3v, 15mm 15mm 4.41mm lga and 15mm 15mm 5.01mm bga packages ltm 4620a lower current and higher v out than ltm4650; up to 5.3v out , dual 13a or single 26a. pin compatible with ltm4650; 4.5v v in 16v, 0.6v v out 2.5v, 15mm 15mm 4.41mm lga and 15mm 15mm 5.01mm bga packages ltm 4628 lower current, higher v in and v out than ltm4650; dual 8a or single 16a pin compatible with ltm4650; 4.5v v in 26.5v, 0.6v v out 5.5v, 15mm 15mm 4.32mm lga and 15mm 15mm 4.92mm bga packages ltm4677 dual 18a or single 36a with psm 4.5v v in 16 v, 0.5v v out 1.8 v. 16mm 16mm 5.01mm bga package LTM4644 quad 4a 4v v in 14v, 0.6v v out 5.5v. 9mm 15mm 5.01mm bga package ltm4639 lower v in (2.375v v in 7v), 20a 0.6v v out 5.5v. 15mm 15mm 4.92mm bga package ltm 4650 4650fb

▲Up To Search▲

Price & Availability of LTM4644

	To Download LTM4644 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .