LTM4603HV

LTM4603HV LINER | Alldatasheet

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6A, 28VIN DC/DC µModule with PLL, Output Tracking and Margining ■ Telecom and Networking Equipment ■ Servers ■ Industrial Equipment ■ Point of Load Regulation ■ Complete Switch Mode Power Supply ■ Wide Input Voltage Range: 4.5V to 28V ■ 6A DC Typical, 8A Peak Output Current ■ 0.6V to 5V Output Voltage ■ Output Voltage Tracking and Margining ■ Remote Sensing for Precision Regulation ■ Typical Operating Frequency: 1MHz ■ PLL Frequency Synchronization ■ 1.5% Regulation ■ Current Foldback Protection (Disabled at Start-Up) ■ Pin Compatible with the LTM4601/LTM4601HV/ LTM4603 ■ Ultrafast Transient Response ■ Current Mode Control ■ Up to 93% Effi ciency at 5VIN, 3.3VOUT ■ Programmable Soft-Start ■ Output Overvoltage Protection ■ Pb-Free (e4) RoHS Compliant Package with Gold Finish Pads ■ Small Footprint, Low Profi le (15mm × 15mm × 2.8mm) Surface Mount LGA Package 2.5V/6A with 4.5V to 28V Input μModule Regulator APPLICATIO SU FEATURES DESCRIPTIO U TYPICAL APPLICATIO U Effi ciency vs Load Current with 24VIN The LTM®4603HV is a complete 6A step-down switch mode DC/DC power supply with onboard switching controller, MOSFETs, inductor and all support components. The μModule TM is housed in a small surface mount 15mm × 15mm × 2.8mm LGA package. Operating over an input voltage range of 4.5 to 28V, the LTM4603HV supports an output voltage range of 0.6V to 5V as well as output voltage tracking and margining. The high effi ciency design deliv- ers 6A continuous current (8A peak). Only bulk input and output capacitors are needed to complete the design. The low profi le (2.8mm) and light weight (1.7g) package easily mounts on the unused space on the back side of PC boards for high density point of load regulation. The μModule can be synchronized with an external clock for reducing undesirable frequency harmonics and allows PolyPhase ® operation for high load currents. A high switching frequency and adaptive on-time current mode architecture deliver a very fast transient response to line and load changes without sacrifi cing stability. An onboard remote sense amplifi er can be used to accurately regulate an output voltage independent of load current. , LT, LTC, LTM and PolyPhase are registered trademarks of Linear Technology Corporation. μModule is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. VOUT VFB MARG0 MARG1 VOUT_LCL DIFFVOUT VOSNS+ VOSNS– PGOOD RUN COMP INTV CC DRVCC MPGM TRACK/SSPLLIN LTM4603HV ON/OFF 392k 19.1k MARGIN CONTROL COUT 4603HV TA01a VOUT 2.5V CLOCK SYNC TRACK/SS CONTROL 100pF CIN VIN fSETPGNDSGND 5% MARGIN VIN 4.5V TO 28V LOAD CURRENT (A) EFFICIENCY (%) 100 4603HV G03 12 46 7 24VIN, 1.8VOUT 24VIN, 2.5VOUT 24VIN, 3.3VOUT 24VIN, 5VOUT

INTVCC, DRVCC, VOUT_LCL, VOUT (VOUT ≤ 3.3V PLLIN, TRACK/SS, MPGM, MARG0, MARG1, CC + 0.3V V Operating Temperature Range (Note 2) ... –40°C to 85°C (Note 1) The ● denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. Per typical application (front page) confi guration.

ELECTRICAL CHARACTERISTICS

ABSOLUTE AXI U RATI GSW WW U SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN(DC) Input DC Voltage ● 4.5 28 V VOUT(DC) Output Voltage CIN = 10μF ×2, COUT = 2×, 100μF/X5R/ Ceramic V IN = 5V, VOUT = 1.5V, IOUT = 0A V IN = 12V, VOUT = 1.5V, IOUT = 0A 1.478 1.478 1.5 1.5 1.522 1.522 V V Input Specifi cations V IN(UVLO) Undervoltage Lockout Threshold I OUT = 0A 3.2 4 V IINRUSH(VIN) Input Inrush Current at Startup I OUT = 0A. VOUT = 1.5V V IN = 5V V IN = 12V 0.6 0.7 A A I Q(VIN,NOLOAD) Input Supply Bias Current VIN = 12V, VOUT = 1.5V, No Switching VIN = 12V, VOUT = 1.5V, Switching Continuous V IN = 5V, VOUT = 1.5V, No Switching VIN = 5V, VOUT = 1.5V, Switching Continuous Shutdown, RUN = 0, V IN = 12V 3.8 2.5 mA mA mA mA μA PIN CONFIGURATION MARG1 DRVCC VFB PGOOD SGND V OSNS+ DIFFVOUT VOUT_LCL VOSNS– VIN PGND VOUT fSET MARG0 RUN COMP MPGM PLLIN INTVCC TRACK/SS LGA PACKAGE 118-LEAD (15mm /KB4 15mm /KB4 2.8mm) TOP VIEW TJMAX = 125°C, θJA = 15°C/W, θJC = 6°C/W θJA DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS, WEIGHT = 1.7g ORDER INFORMATION LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTM4603HVEV#PBF LTM4603HVV 118-Lead (15mm × 15mm × 2.8mm) LGA –40°C to 85°C LTM4603HVIV#PBF LTM4603HVV 118-Lead (15mm × 15mm × 2.8mm) LGA –40°C to 85°C Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://linear.com/packaging/

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IS(VIN) Input Supply Current V IN = 12V, VOUT = 1.5V, IOUT = 6A VIN = 12V, VOUT = 3.3V, IOUT = 6A VIN = 5V, VOUT = 1.5V, IOUT = 6A 0.85 1.78 2.034 A A A INTV CC VIN = 12V, RUN > 2V No Load 4.7 5 5.3 V Output Specifi cations I OUTDC Output Continuous Current Range (See Output Current Derating Curves for Different V IN, VOUT and TA) VIN = 12V, VOUT = 1.5V 0 6 A ΔVOUT(LINE) VOUT Line Regulation Accuracy V OUT = 1.5V, IOUT = 0A, VIN = 4.5V to 28V ● 0.3 % ΔVOUT(LOAD) VOUT Load Regulation Accuracy V OUT = 1.5V, IOUT = 0A to 6A, VIN = 12V ● 0.25 % VOUT(AC) Output Ripple Voltage I OUT = 0A, COUT = 2×, 100μF/X5R/Ceramic VIN = 12V, VOUT = 1.5V VIN = 5V, VOUT = 1.5V mVP-P mVP-P fS Output Ripple Voltage Frequency I OUT = 3A, VIN = 12V, VOUT = 1.5V 1000 kHz ΔVOUT(START) Turn-On Overshoot, TRACK/SS = 10nF COUT = 2×, 100μF/X5R/Ceramic, VOUT = 1.5V, IOUT = 0A VIN = 12V VIN = 5V mV mV tSTART Turn-On Time, TRACK/SS = Open C OUT = 2×, 100μF/X5R/Ceramic, VOUT = 1.5V, IOUT = 1A Resisitive Load VIN = 12V VIN = 5V 0.5 0.7 ms ms ΔVOUTLS Peak Deviation for Dynamic Load Load: 0% to 50% to 0% of Full Load, COUT = 2 × 22μF/Ceramic, 470μF, 4V Sanyo POSCAP V IN = 12V VIN = 5V mV mV tSETTLE Settling Time for Dynamic Load Step Load: 0% to 50% to 10% of Full Load VIN = 12V 25 μs IOUTPK Output Current Limit C OUT = 2×, 100μF/X5R/Ceramic VIN = 12V, VOUT = 1.5V VIN = 5V, VOUT = 1.5V A A Remote Sense Amp (Note 3) VOSNS+, VOSNS– CM Range Common Mode Input Voltage Range V IN = 12V, RUN > 2V 0 INTV CC – 1 V DIFFVOUT Range Output Voltage Range V IN = 12V, DIFFVOUT Load = 100k 0 INTV CC V VOS Input Offset Voltage Magnitude 1.25 mV AV Differential Gain 1 V/V GBP Gain Bandwidth Product 3 MHz SR Slew Rate 2 V/μs RIN Input Resistance V OSNS+ to GND 20 k Ω CMRR Common Mode Rejection Ratio 100 dB The ● denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. Per typical application (front page) confi guration.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Control Stage V FB Error Amplifi er Input Voltage Accuracy IOUT = 0A, VOUT = 1.5V ● 0.594 0.6 0.606 V VRUN RUN Pin On/Off Threshold 1 1.5 1.9 V ISS/TRACK Soft-Start Charging Current V SS/TRACK = 0V –1 –1.5 –2 μA tON(MIN) Minimum On Time (Note 4) 50 100 ns tOFF(MIN) Minimum Off Time (Note 4) 250 400 ns RPLLIN PLLIN Input Resistance 50 k Ω IDRVCC Current into DRVCC Pin V OUT = 1.5V, IOUT = 1A, Frequency = 1MHz, DRVCC = 5V 18 25 mA RFBHI Resistor Between VOUT_LCL and VFB 60.098 60.4 60.702 k Ω VMPGM Margin Reference Voltage 1.18 V VMARG0, VMARG1 MARG0, MARG1 Voltage Thresholds 1.4 V PGOOD Output ΔV FBH PGOOD Upper Threshold V FB Rising 7 10 13 % ΔVFBL PGOOD Lower Threshold V FB Falling –7 –10 –13 % ΔVFB(HYS) PGOOD Hysteresis V FB Returning 1.5 3 % VPGL PGOOD Low Voltage I PGOOD = 5mA 0.15 0.4 V The ● denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. Per typical application (front page) confi guration. 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 LTM4603HVEV is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM4603HVIV is guaranteed over the –40°C to 85°C temperature range. Note 3: Remote sense amplifi er recommended for ≤3.3V output. Note 4: 100% tested at die level only.

Effi ciency vs Load Current with 5VIN TYPICAL PERFOR A CE CHARACTERISTICSUW Effi ciency vs Load Current with 12VIN Effi ciency vs Load Current with 24V IN 1.2V Transient Response 1.5V Transient Response 2.5V Transient Response 3.3V Transient Res ponse (See Figure 20 for all curves) 1.8V Transient Response LOAD CURRENT (A) EFFICIENCY (%) 100 2 4 5 4603HV G01 1 3 6 7 5VIN, 0.6VOUT 5VIN, 1.2VOUT 5VIN, 1.5VOUT 5VIN, 1.8VOUT 5VIN, 2.5VOUT 5VIN, 3.3VOUT LOAD CURRENT (A) EFFICIENCY (%) 100 4603HV G03 12 46 7 24VIN, 1.8VOUT 24VIN, 2.5VOUT 24VIN, 3.3VOUT 24VIN, 5VOUT LOAD CURRENT (A) EFFICIENCY (%)60 100 2 4 5 4603HV G02 1 3 6 7 12VIN, 1.2VOUT 12VIN, 1.5VOUT 12VIN, 1.8VOUT 12VIN, 2.5VOUT 12VIN, 3.3VOUT 12VIN, 5VOUT LOAD STEP 1A/DIV VOUT 50mV/DIV 25μs/DIV 4603HV G04 1.2V AT 3A/μs LOAD STEP COUT: 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP LOAD STEP 1A/DIV VOUT 50mV/DIV 25μs/DIV 4603HV G05 1.5V AT 3A/μs LOAD STEP COUT: 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP LOAD STEP 1A/DIV VOUT 50mV/DIV 25μs/DIV 4603HV G06 1.8V AT 3A/μs LOAD STEP COUT: 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP LOAD STEP 1A/DIV VOUT 50mV/DIV 25μs/DIV 4603HV G07 2.5V AT 3A/μs LOAD STEP COUT: 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP LOAD STEP 1A/DIV VOUT 50mV/DIV 25μs/DIV 4603HV G08 3.3V AT 3A/μs LOAD STEP COUT: 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP

INPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 3.0 4.0 5.5 5.0 4603HV G13 2.0 1.0 2.5 3.5 4.5 1.5 0.5 4 8 12 2820 24 3.3V OUTPUT WITH 82.5k FROM VOUT TO fSET 5V OUTPUT WITH 150k RESISTOR ADDED FROM fSET TO GND 5V OUTPUT WITH NO RESISTOR ADDED FROM fSET TO GND 2.5V OUTPUT 1.8V OUTPUT 1.5V OUTPUT 1.2V OUTPUT TYPICAL PERFOR A CE CHARACTERISTICSUW (See Figure 20 for all curves) Start-Up, IOUT = 6A (Resistive Load)Start-Up, IOUT = 0A VIN to VOUT Step-Down Ratio Short-Circuit Protection, IOUT = 0A Short-Circuit Protection, IOUT = 6A VOUT 0.5V/DIV IIN 0.5A/DIV 1ms/DIV 4603HV G09 VIN = 12V VOUT = 1.5V COUT = 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP SOFT-START = 3.9nF VOUT 0.5V/DIV IIN 0.5A/DIV 1ms/DIV 4603HV G10 VIN = 12V VOUT = 1.5V COUT = 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP SOFT-START = 3.9nF VOUT 0.5V/DIV IIN 2A/DIV 100μs/DIV 4603HV G11 VIN = 12V VOUT = 1.5V COUT = 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP SOFT-START = 3.9nF VOUT 0.5V/DIV IIN 2A/DIV 100μs/DIV

4603 G12

VIN = 12V VOUT = 1.5V COUT = 1x 22μF, 6.3V CERAMIC 1x 330μF, 4V SANYO POSCAP SOFT-START = 3.9nF

(See Package Description for Pin Assignment) VIN (Bank 1): Power Input Pins. Apply input voltage be- tween these pins and PGND pins. Recommend placing input decoupling capacitance directly between V IN pins and PGND pins. VOUT (Bank 3): Power Output Pins. Apply output load between these pins and PGND pins. Recommend placing output decoupling capacitance directly between these pins and PGND pins. Review the fi gure below. PGND (Bank 2): Power ground pins for both input and output returns. V OSNS– (Pin M12): (–) Input to the Remote Sense Amplifi er. This pin connects to the ground remote sense point. The remote sense amplifi er is used for V OUT ≤3.3V. VOSNS+ (Pin J12): (+) Input to the Remote Sense Amplifi er. This pin connects to the output remote sense point. The remote sense amplifi er is used for V OUT ≤3.3V. DIFFVOUT (Pin K12): Output of the Remote Sense Ampli- fi er. This pin connects to the VOUT_LCL pin. DRVCC (Pin E12): This pin normally connects to INTVCC for powering the internal MOSFET drivers. This pin can be biased up to 6V from an external supply with about 50mA capability, or an external circuit shown in Figure 16. This improves effi ciency at the higher input voltages by reducing power dissipation in the modules. INTV CC (Pin A7): This pin is for additional decoupling of the 5V internal regulator. PLLIN (Pin A8): External Clock Synchronization Input to the Phase Detector. This pin is internally terminated to SGND with a 50k resistor. Apply a clock above 2V and below INTVCC. See Applications Information. TRACK/SS (Pin A9): Output Voltage Tracking and Soft- Start Pin. When the module is confi gured as a master output, then a soft-start capacitor is placed on this pin to ground to control the master ramp rate. A soft-start capacitor can be used for soft-start turn on as a stand alone regulator. Slave operation is performed by putting a resistor divider from the master output to the ground, and connecting the center point of the divider to this pin. See Applications Information. MPGM (Pin A12): Programmable Margining Input. A re- sistor from this pin to ground sets a current that is equal to 1.18V/R. This current multiplied by 10k Ω will equal a value in millivolts that is a percentage of the 0.6V refer- ence voltage. See Applications Information. To parallel LTM4603HVs, each requires an individual MPGM resistor. Do not tie MPGM pins together. f SET (Pin B12): Frequency Set Internally to 1MHz. An external resistor can be placed from this pin to ground to increase frequency. This pin can be decoupled with a 1000pF capacitor. See Applications Information for fre- quency adjustment. V FB (Pin F12): The Negative Input of the Error Ampli- fi er. Internally, this pin is connected to VOUT_LCL with a 60.4k precision resistor. Different output voltages can be programmed with an additional resistor between V FB and SGND pins. See Applications Information. MARG1 DRVCC VFB PGOOD SGND V OSNS+ DIFFVOUT VOUT_LCL VOSNS– VIN BANK 1 PGND BANK 2 A B C D E F G H J K L M V OUT BANK 3 fSET MARG0 RUN COMP MPGM PLLIN INTVCC TRACK/SS 1234567 TOP VIEW 8 9 10 11 12

Figure 1. Simplifi ed LTM4603HV Block Diagram 50k. See Applications Information. 50k. See Applications Information. PGND at output capacitor point. sense voltage (zero current). PGOOD (Pin G12): Output Voltage Power Good Indicator. after a 25μs power bad mask timer expires. a 5.1V zener to ground. Maximum pin voltage is 5V. to this pin when remote sense amplifi er is used.

W UDECOUPLI G REQUIRE E TSU SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS CIN External Input Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V) IOUT = 6A 20 μF COUT External Output Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V) IOUT = 6A 100 200 μF T A = 25°C, VIN = 12V. Use Figure 1 confi guration. OPERATIOU Power Module Description The LTM4603HV is a standalone nonisolated switching mode DC/DC power supply. It can deliver up to 6A of DC output current with few external input and output capaci- tors. This module provides precisely regulated output volt- age programmable via one external resistor from 0.6V DC to 5.0VDC over a 4.5V to 28V wide input voltage. The typical application schematic is shown in Figure 20. The LTM4603HV has an integrated constant on-time current mode regulator, ultralow R DS(ON) FETs with fast switching speed and integrated Schottky diodes. The typi- cal switching frequency is 1MHz at full load. With current mode control and internal feedback loop compensation, the LTM4603HV module has suffi cient stability margins and good transient performance under a wide range of operating conditions and with a wide range of output capacitors, even all ceramic output capacitors. Current mode control provides cycle-by-cycle fast current limit. Besides, foldback current limiting is provided in an overcurrent condition while V FB drops. Internal overvoltage and undervoltage comparators pull the open-drain PGOOD output low if the output feedback voltage exits a ±10% window around the regulation point. Furthermore, in an overvoltage condition, internal top FET Q1 is turned off and bottom FET Q2 is turned on and held on until the overvoltage condition clears. Pulling the RUN pin below 1V forces the controller into its shutdown state, turning off both Q1 and Q2. At low load current, the module works in continuous current mode by default to achieve minimum output voltage ripple. When DRV CC pin is connected to INTV CC an integrated 5V linear regulator powers the internal gate drivers. If a 5V external bias supply is applied on the DRV CC pin, then an effi ciency improvement will occur due to the reduced power loss in the internal linear regulator. This is especially true at the higher input voltage range. The LTM4603HV has a very accurate differential remote sense amplifi er with very low offset. This provides for very accurate remote sense voltage measurement. The MPGM pin, MARG0 pin and MARG1 pin are used to sup- port voltage margining, where the percentage of margin is programmed by the MPGM pin, and the MARG0 and MARG1 select margining. The PLLIN pin provides frequency synchronization of the device to an external clock. The TRACK/SS pin is used for power supply tracking and soft-start programming.

Figure 20. External component selection is primarily requirements for a particular application. down ratio that can be achieved for a given input voltage. The PWM controller has an internal 0.6V reference voltage. Table 1. Standard 1% Resistor Values PGM resistor on the MPGM pin programs the current. The output margining will be ± margining of the value. by long inductive leads or traces.

APPLICATIO S I FOR ATIOWU UU the ramp of the internal reference and the output voltage. The total soft-start time can be calculated as: tV V V C µSOFTSTART OUT MARGIN When the RUN pin falls below 1.5V, then the TRACK/SS pin is reset to allow for proper soft-start control when the regulator is enabled again. Current foldback and force continuous mode are disabled during the soft-start pro- cess. The soft-start function can also be used to control the output ramp up time, so that another regulator can be easily tracked to it. Output Voltage Tracking Output voltage tracking can be programmed externally using the TRACK/SS pin. The output can be tracked up and down with another regulator. The master regulator’s output is divided down with an external resistor divider that is the same as the slave regulator’s feedback divider. Figure 5 shows an example of coincident tracking. Ratiometric modes of tracking can be achieved by selecting different resistor values to change the output tracking ratio. The master output must be greater than the slave output for the tracking to work. Figure 6 shows the coincident output tracking characteristics. Run Enable The RUN pin is used to enable the power module. The pin has an internal 5.1V zener to ground. The pin can be driven with a logic input not to exceed 5V. The RUN pin can also be used as an undervoltage lock out (UVLO) function by connecting a resistor divider from the input supply to the RUN pin: V RR R VUVLO = +12 2 15. Power Good The PGOOD pin is an open-drain pin that can be used to monitor valid output voltage regulation. This pin monitors a ±10% window around the regulation point and tracks with margining. COMP Pin This pin is the external compensation pin. The module has already been internally compensated for most output voltages. Table 2 is provided for most application require- ments. A spice model will be provided for other control loop optimization. PLLIN The power module has a phase-locked loop comprised of an internal voltage controlled oscillator and a phase detector. This allows the internal top MOSFET turn-on to be locked Figure 5 Figure 6 VOUT VFB MARG0 MARG1 VOUT_LCL DIFFVOUT VOSNS+ VOSNS– PGOOD MPGM RUN COMP INTV CC DRVCC TRACK/SS TRACK CONTROL PLLIN LTM4603HV RSET 40.2k 100k 40.2k MASTER OUTPUT 60.4k C OUT SLAVE OUTPUT 4603HV F05 60.4k FROM VOUT TO VFB CIN VIN fSETPGNDSGND VIN OUTPUT VOLTAGE TIME 4603HV F06 MASTER OUTPUT SLAVE OUTPUT

range is ±30% around the operating frequency of 1MHz. of the clock has to be at least 400ns and 2V in amplitude. n is the number of paralleled modules. maintained at 100°C or below for the derating curves. to a total of 124°C at the junction of the device.

Figure 10. BGA Heat Sink Figure 11. No Heat Sink Figure 12. BGA Heat Sink Figure 13. No Heat Sink Figure 14. BGA Heat Sink Figure 15. No Heat Sink Figure 16. BGA Heat Sink

1635 G24

Table 2. Output Voltage Response Versus Component Matrix (Refer to Figure 20)

Table 4. 3.3V Output Table 3. 1.5V Output

APPLICATIO S I FOR ATIOWU UU Example for 5V Output LTM4603HV minimum on-time = 100ns; t ON = ((4.8 • 10pf)/IfSET) LTM4603HV minimum off-time = 400ns; t OFF = t– tON, where t = 1/Frequency Duty Cycle = t ON/t or VOUT/VIN Equations for setting frequency: I fSET = (VIN/(3 • RfSET)), for 28V input operation, I fSET = 281μA, tON = ((4.8 • 10pF)/IfSET), tON = 171ns, where the internal RfSET is 33.2k. Frequency = (VOUT/(VIN • tON)) = (5V/(28 • 171ns)) ~ 1MHz. The inductor ripple current begins to get high at the higher input voltages due to a larger voltage across the inductor. This is shown in the “Inductor Ripple Current vs Duty Cycle” graph as ~4A at 25% duty cycle. The inductor ripple current can be lowered at the higher input voltages by adding an external resistor from f SET to ground to increase the switching frequency. A 3A ripple current is chosen, and the total peak current is equal to 1/2 of the 3A ripple current plus the output current. The 5V output current is limited to 5A, so total peak current is less than 6.5A. This is below the 8A peak specified value. A 150k resistor is placed from f SET to ground, and the parallel combination of 150k and 33.2k equates to 27.2k. The I fSET calculation with 27.2k and 28V input voltage equals 343μA. This equates to a tON of 140ns. This will increase the switching frequency from 1MHz to ~1.28MHz for the 28V to 5V conversion. The minimum on time is above 100ns at 28V input. Since the switching frequency is approximately constant over input and output conditions, then the lower input voltage range is limited to 10V for the 1.28MHz operation due to the 400ns minimum off time. Equation: t ON = (VOUT/VIN) • (1/Frequency) equates to a 382ns on time, and a 400ns off time. The “V IN to VOUT Step-Down Ratio” curve refl ects an operating range of 10V to 28V for 1.28MHz operation with a 150k resistor to ground (shown in Figure 18), and an 8V to 16V operating range for f SET fl oating. These modifi cations are made to provide wider input voltage ranges for the 5V output designs while limiting the inductor ripple current, and maintaining the 400ns minimum off time. Example for 3.3V Output LTM4603HV minimum on-time = 100ns; t ON = ((3.3 • 10pF)/IfSET) LTM4603HV minimum off-time = 400ns; t OFF = t – tON, where t = 1/Frequency Duty Cycle (DC) = t ON/t or VOUT/VIN Equations for setting frequency: I fSET = (VIN/(3 • RfSET)), for 28V input operation, I fSET = 281μA, tON = ((3.3 • 10pf)/IfSET), tON = 117ns, where the internal RfSET is 33.2k. Frequency = (V OUT/(VIN • tON)) = (3.3V/(28 • 117ns)) ~ 1MHz. The minimum on-time and minimum-off time are within specifi cation at 118ns and 882ns. But the 4.5V minimum input for converting 3.3V output will not meet the minimum off-time specifi cation of 400ns. t ON = 733ns, Frequency = 1MHz, tOFF = 267ns. Solution Lower the switching frequency at lower input voltages to allow for higher duty cycles, and meet the 400ns mini- mum off-time at 4.5V input voltage. The off-time should be about 500ns with 100ns guard band. The duty cycle for (3.3V/4.5) = ~73%. Frequency = (1 – DC)/t OFF or (1 – 0.73)/500ns = 540kHz. The switching frequency needs to be lowered to 540kHz at 4.5V input. t ON = DC/frequency, or 1.35μs. The fSET pin voltage compliance is 1/3 of VIN, and the I fSET current equates to 45μA with the internal 33.2k. The I fSET current needs to be 24μA for 540kHz operation. A resistor can be placed from V OUT to fSET to lower the effective IfSET current out of the fSET pin to 24μA. The fSET pin is 4.5V/3 =1.5V and V OUT = 3.3V, therefore an 82.5k resistor will source 21μA into the fSET node and lower the IfSET current to 24μA. This enables the 540kHz operation and the 4.5V to 28V input operation for down converting to 3.3V output as shown in Figure 19. The frequency will scale from 540kHz to 1.27MHz over this input range. This provides for an effective output current of 5A over the input range.

Figure 21. 2-Phase, Parallel 2.5V at 12A Design Figure 20. Typical 4.5V-28VIN, 1.5V at 6A Design

4603 F18

118-Lead (15mm × 15mm) (Reference LTM DWG # 05-05-1801 Rev Ø) PACKAGE DESCRIPTIO U NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS LAND DESIGNATION PER JESD MO-222, SPP-010 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. THE TOTAL NUMBER OF PADS: 118 DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE SYMBOL aaa bbb eee TOLERANCE 0.10 0.10 0.03 2.72 – 2.92 DETAIL BDETAIL A DETAIL B SUBSTRATE MOLD CAP 0.27 – 0.37 2.45 – 2.55 bbb Z Z BSC TOP VIEW BSC PAD 1 CORNER X Y aaa Z aaa Z 13.97 BSC 1.27 BSC 13.97 BSC 0.12 – 0.28 23 45 678 9 1 0 1 1 BOTTOM VIEW C(0.30) PAD 1 PADS SEE NOTES1 SUGGESTED SOLDER PAD LAYOUT TOP VIEW A B C D E F G H K J L M DETAIL A 0.60 – 0.66 0.60 – 0.66 M YXeee 0.0000 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 0.0000 6.9850 LGA 118 0306 REV Ø 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.

© LINEAR TECHNOLOGY CORPORATION 2007 LT 0607 • PRINTED IN USA Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC2900 Quad Supply Monitor with Adjustable Reset Timer Monitors Four Supplies; Adjustable Reset Timer LTC2923 Power Supply Tracking Controller Tracks Both Up and Down; Power Supply Sequencing LT3825/LT3837 Synchronous Isolated Flyback Controllers No Optocoupler Required; 3.3V, 12A Output; Simple Design LTM4600 10A DC/DC μModule Fast Transient Response LTM4601 12A DC/DC μModule with PLL, Output Tracking and Margining, LTM4603HV Pin Compatible LTM4602 6A DC/DC μModule Pin Compatible with the LTM4600 LTM4603 6A DC/DC μModule with Tracking PLL/Margining Pin Compatible with the LTM4601