LTM4600HVEV#PBF资料

FEATURES

■ ■ ■ ■LTM4600HV10A, 28VIN High Effi ciency DC/DC µModuleDESCRIPTIO

The LTM®4600HV is a complete 10A, DC/DC step down power supply with up to 28V input operation. Included in the package are the switching controller, power FETs, inductor, and all support components. Operating over an input voltage range of 4.5V to 28V, the LTM4600HV supports an output voltage range of 0.6V to 5V, set by a single resistor. This high effi ciency design delivers 10A continuous current (12A peak), needing no heat sinks or airfl ow to meet power specifi cations. Only bulk input and output capacitors are needed to fi nish the design.The low profi le package (2.8mm) enables utilization of unused space on the bottom of PC boards for high density point of load regulation. High switching frequency and an adaptive on-time current mode architecture enables a very fast transient response to line and load changes without sacrifi cing stability. Fault protection features include integrated overvoltage and short circuit protection with a defeatable shutdown timer. A built-in soft-start timer is adjustable with a small capacitor.The LTM4600HV is packaged in a thermally enhanced, compact (15mm × 15mm) and low profi le (2.8mm) over-molded Land Grid Array (LGA) package suitable for auto-mated assembly by standard surface mount equipment. The LTM4600HV is Pb-free and RoHS compliant., LTC, LT and LTM 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.

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APPLICATIOS

■Complete Switch Mode Power SupplyWide Input Voltage Range: 4.5V to 28V10A DC, 12A Peak Output CurrentParallel Two μModule™ DC/DC Converters for 20A Output Current■ 0.6V to 5V Output Voltage■ 1.5% Output Voltage Regulation■ Ultrafast Transient Response■ Current Mode Control■ –55°C to 125°C Operating Temperature Range (LTM4600HVMPV)■ Pb-Free (e4) RoHS Compliant Package Gold-Pad Finish■ Up to 92% Effi ciency■ Programmable Soft-Start■ Output Overvoltage Protection■ Optional Short-Circuit Shutdown Timer■ Small Footprint, Low Profi le (15mm × 15mm × 2.8mm) LGA Package Telecom and Networking Equipment■ Military and Avionics Systems■ Industrial Equipment■ Point of Load Regulation■ ServersTYPICAL APPLICATIO

VIN

4.5V TO 28VABSMAX

Effi ciency vs Load Current with 24VIN (FCB = 0)1009080EFFICIENCY (%)7060504030

1.8VOUT2.5VOUT3.3VOUT5VOUT0

2

6

LOAD CURRENT (A)

4

8

10

4600HV TA01b

10A μModule Power Supply with 4.5V to 28V InputVINCINVOUTCOUTVOUT2.5V*10A

LTM4600HVVOSETPGNDSGND31.6k4600hv TA01a*REVIEW DE-RATING CURVE AT THE HIGHER INPUT VOLTAGE

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LTM4600HVABSOLUTE AXIU RATIGS

(Note 1)fADJSVINEXTVCCVOSETCOMPSGNDRUN/SSFCBPGOODPGNDFCB, EXTVCC, PGOOD, RUN/SS, VOUT ..........–0.3V to 6VVIN, SVIN, fADJ ............................................–0.3V to 28VVOSET, COMP .............................................–0.3V to 2.7VOperating Temperature Range (Note 2) E and I Grades .....................................–40°C to 85°C MP Grade ...........................................–55°C to 125°CJunction Temperature ...........................................125°CStorage Temperature Range ...................–55°C to 125°CORDER INFORMATION

LEAD FREE FINISHLTM4600HVEV#PBFLTM4600HVIV#PBFLTM4600HVMPV#PBFTAPE AND REELLTM4600HVEV#TRPBFLTM4600HVIV#TRPBFLTM4600HVMPV#TRPBFPART MARKINGLTM4600HVEVLTM4600HVIVLTM4600HVMPVPACKAGE DESCRIPTION104-Lead (15mm × 15mm × 2.8mm)104-Lead (15mm × 15mm × 2.8mm)104-Lead (15mm × 15mm × 2.8mm)TEMPERATURE RANGE–40°C to 85°C–40°C to 85°C–55°C to 125°CConsult LTC Marketing for parts specifi ed with wider operating temperature ranges.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/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. External CIN = 120μF, COUT = 200μF/Ceramic per typical application (front page) confi guration.SYMBOLVIN(DC)VOUT(DC)PARAMETERInput DC VoltageOutput VoltageCONDITIONSAbsMax 28V for Tolerance on 24V InputsFCB = 0V VIN = 5V or 12V, VOUT = 1.5V, IOUT = 0A● The ● denotes the specifi cations which apply over the full operating ELECTRICAL CHARACTERISTICS

Input Specifi cationsVIN(UVLO)IINRUSH(VIN)Under Voltage Lockout ThresholdInput Inrush Current at StartupIOUT = 0AIOUT = 0A, VOUT = 1.5V, FCB = 0 VIN = 5V VIN = 12V VIN = 24VIOUT = 0A, EXTVCC Open VIN = 12V, VOUT = 1.5V, FCB = 5V VIN = 12V, VOUT = 1.5V, FCB = 0V VIN = 24V, VOUT = 2.5V, FCB = 5V VIN = 24V, VOUT = 2.5V, FCB = 0V Shutdown, RUN = 0.8V, VIN = 12V3.40.60.70.81.2421.83635100400Input Supply Current VIN = 12V, VOUT = 1.5V, IOUT = 10AVIN = 12V, VOUT = 3.3V, IOUT = 10AVIN = 5V, VOUT = 1.5V, IOUT = 10AVIN = 24V to 3.3V at 10A, EXTVCC = 5V1.523.133.1.VAAAmAmAmAmAμAnsnsAAAA4600hvfcIQ(VIN)Input Supply Bias CurrentMin On TimeMin Off TimeIS(VIN)2

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PIN CONFIGURATIONTOP VIEWVINVOUTLGA PACKAGE104-LEAD (15mm × 15mm × 2.8mm)TJMAX = 125°C, θJA = 15°C/W, θJC = 6°C/W,θJA DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS, WEIGHT = 1.7gMIN4.51.4781.470TYPMAX281.5221.530UNITSVV●1.501.5075元器件交易网www.cecb2b.com

LTM4600HVtemperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V. External CIN = 120μF, COUT = 200μF/Ceramic per typical application (front page) confi guration.SYMBOLPARAMETEROutput Specifi cationsIOUTDCΔVOUT(LINE) VOUT The ● denotes the specifi cations which apply over the full operating ELECTRICAL CHARACTERISTICS

CONDITIONSVIN = 12V, VOUT = 1.5VVIN = 24V, VOUT = 2.5V (Note 3)VOUT = 1.5V. FCB = 0V, IOUT = 0A,VIN = 4.5V to 28VVOUT = 1.5V. FCB = 0V, IOUT = 0A to 10A VIN = 5V VIN = 12V (Note 4)VIN = 12V, VOUT = 1.5V, FCB = 0V, IOUT = 0AFCB = 0V, IOUT = 5A, VIN = 12V, VOUT = 1.5V●MIN00TYPMAX1010UNITSAA%Output Continuous Current Range(See Output Current Derating Curves for Different VIN, VOUT and TA)Line Regulation Accuracy0.150.3ΔVOUT(LOAD)Load Regulation Accuracy VOUTVOUT(AC)fstSTARTΔVOUTLStSETTLEIOUTPKOutput Ripple VoltageOutput Ripple Voltage FrequencyTurn-On Time●108500.50.736±1±1.515%%mVP-PkHzmsmsmVVOUT = 1.5V, IOUT = 1A VIN = 12V VIN = 5VVoltage Drop for Dynamic Load StepVOUT = 1.5V, Load Step: 0A/μs to 5A/μsCOUT = 3 • 22μF 6.3V, 470μF 4V POSCAP, See Table 2Settling Time for Dynamic Load Step VIN = 12VLoad: 10% to 90% to 10% of Full LoadOutput Current LimitOutput Voltage in Foldback VIN = 24V, VOUT = 2.5V VIN = 12V, VOUT = 1.5V VIN = 5V, VOUT = 1.5VIOUT = 0A, VOUT = 1.5V●251717170.5910.5940.8–0.50.80.60.61.5–1.21.8100161000.570.6–17.5–7.510–1020.150.40.63–212.5–12.50.6090.6062–33μsAAAVVVμAμAmVmAkΩVμA%%%VControl StageVOSETVRUN/SSIRUN(C)/SSIRUN(D)/SSVIN – SVINIEXTVCCRFBHIVFCBIFCBΔVOSETHΔVOSETLΔVOSET(HYS)VPGLCurrent into EXTVCC PinResistor Between VOUT and VOSET PinsForced Continuous ThresholdForced Continuous Pin CurrentPGOOD Upper ThresholdPGOOD Lower ThresholdPGOOD HysteresisPGOOD Low VoltageVFCB = 0.6VVOSET RisingVOSET FallingVOSET ReturningIPGOOD = 5mAVoltage at VOSET PinRUN ON/OFF ThresholdSoft-Start Charging CurrentSoft-Start Discharging CurrentVRUN/SS = 0VVRUN/SS = 4VEXTVCC = 0V, FCB = 0VEXTVCC = 5V, FCB = 0V, VOUT = 1.5V, IOUT = 0APGOOD OutputNote 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 LTM4600HVE 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 LTM46000HVMP is guaranteed and tested over the –55°C to 125°C temperature range. For output current derating at high temperature, please refer to Thermal Considerations and Output Current Derating discussion.Note 3: Refer to current de-rating curves and thermal application note.Note 4: Test assumes current derating versus temperature.4600hvfc

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LTM4600HVTYPICAL PERFOR A CE CHARACTERISTICS(See Figure 21 for all curves)Effi ciency vs Load Current with 5VIN (FCB = 0)1009080EFFICIENCY (%)7060504030

EFFICIENCY (%)10090807060504030

0.6VOUT1.2VOUT1.5VOUT2.5VOUT3.3VOUT0

2

6

LOAD CURRENT (A)

4

8

10

4600hv G02

EFFICIENCY (%)02

LOAD CURRENT (A)

Effi ciency vs Load Current with Different FCB Settings908070EFFICIENCY (%)60

FCB = GND504030200.1

VIN = 12VVOUT = 1.5V1

LOAD CURRENT (A)

10

4600hv G04

FCB > 0.7VVOUT = 50mV/DIV1.8V Transient Response4600hv G07 25μs/DIV 1.8V AT 5A/μs LOAD STEPCOUT = 3 • 22μF 6.3V CERAMICS470μF 4V SANYO POSCAPC3 = 100pF4

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0.6VOUT1.2VOUT1.5VOUT2.5VOUT8

Effi ciency vs Load Current with 12VIN(FCB = 0)10090807060504030

Effi ciency vs Load Current with 24VIN (FCB = 0)1.8VOUT2.5VOUT3.3VOUT5VOUT0

2

6

LOAD CURRENT (A)

4

8

10

4600hv G03

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4600hv G01

1.2V Transient Response1.5V Transient ResponseIOUT = 5A/DIV4600hv G05 25μs/DIV 1.2V AT 5A/μs LOAD STEPCOUT = 3 • 22μF 6.3V CERAMICS470μF 4V SANYO POSCAPC3 = 100pF4600hv G06 25μs/DIV 1.5V AT 5A/μs LOAD STEPCOUT = 3 • 22μF 6.3V CERAMICS470μF 4V SANYO POSCAPC3 = 100pF2.5V Transient Response3.3V Transient Response4600hv G08 25μs/DIV 2.5V AT 5A/μs LOAD STEPCOUT = 3 • 22μF 6.3V CERAMICS470μF 4V SANYO POSCAPC3 = 100pF4600hv G09 25μs/DIV 3.3V AT 5A/μs LOAD STEPCOUT = 3 • 22μF 6.3V CERAMICS470μF 4V SANYO POSCAPC3 = 100pF4600hvfc

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LTM4600HVTYPICAL PERFOR A CE CHARACTERISTICS(See Figure 21 for all curves)Start-Up, IOUT = 0AVOUT(0.5V/DIV)IIN(0.5A/DIV)4600hv G10 200μs/DIV VIN = 12VVOUT = 1.5VCOUT = 200μFNO EXTERNAL SOFT-START CAPACITORShort-Circuit Protection, IOUT = 0AVOUT(0.5V/DIV)IIN(0.2A/DIV)VOUT (V)4600hv G12 20μs/DIV VIN = 12VVOUT = 1.5VCOUT = 2× 200μF/X5RNO EXTERNAL SOFT-START CAPACITORVOSET vs Temperature0.610

0.605VOSET(V)0.600

0.595

VIN = 12VVOUT = 1.5VIOUT = 10A

–25

53565TEMPERATURE (°C)

95

125

400μs/DIV

4600HV G16

0.590

–55

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Start-Up, IOUT = 10A (Resistive Load)VOUT(0.5V/DIV)IIN(0.5A/DIV)4600hv G11 200μs/DIV VIN = 12VVOUT = 1.5VCOUT = 200μFNO EXTERNAL SOFT-START CAPACITORShort-Circuit Protection, IOUT = 10A5.55.0

VOUT(0.5V/DIV)IIN(0.5A/DIV)4.54.03.53.02.52.01.51.00.50

VIN to VOUT Stepdown RatiofADJ = OPEN5V3.3V2.5V1.8V1.5V1.2V0.6V0

5

1015VIN (V)

20

24

4600hv G13 20μs/DIV VIN = 12VVOUT = 1.5VCOUT = 2× 200μF/X5RNO EXTERNAL SOFT-START CAPACITORSEE FREQUENCY ADJUSTMENT DISCUSSIONFOR 12VIN TO 5VOUT AND 5VIN TO 3.3VOUTCONVERSION

4600HV G14

Start-Up Waveform, TA = –55°C4600HV G15

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LTM4600HVPI FUCTIOS

VIN (Bank 1): Power Input Pins. Apply input voltage between these pins and GND pins. Recommend placing input decoupling capacitance directly between VIN pins and GND pins.fADJ (Pin A15): A 110k resistor from VIN to this pin sets the one-shot timer current, thereby setting the switching frequency. The LTM4600HV switching frequency is typically 850kHz. An external resistor to ground can be selected to reduce the one-shot timer current, thus lower the switching frequency to accommodate a higher duty cycle step down requirement. See the applications section.SVIN (Pin A17): Supply Pin for Internal PWM Controller. Leave this pin open or add additional decoupling capacitance.EXTVCC (Pin A19): External 5V supply pin for controller. If left open or grounded, the internal 5V linear regulator will power the controller and MOSFET drivers. For high input voltage applications, connecting this pin to an external 5V will reduce the power loss in the power module. The EXTVCC voltage should never be higher than VIN.VOSET (Pin A21): The Negative Input of The Error Amplifi er. Internally, this pin is connected to VOUT with a 100k precision resistor. Different output voltages can be programmed with additional resistors between the VOSET and SGND pins.COMP (Pin B23): Current Control Threshold and Error Amplifi er Compensation Point. The current comparator threshold increases with this control voltage. The voltage ranges from 0V to 2.4V with 0.8V corresponding to zero sense voltage (zero current).EXTVCC18213459610147111617VOSET192021SVINfADJ6

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(See Package Description for Pin Assignment)SGND (Pin D23): Signal Ground Pin. All small-signal components should connect to this ground, which in turn connects to PGND at one point.RUN/SS (Pin F23): Run and Soft-Start Control. Forcing this pin below 0.8V will shut down the power supply. Inside the power module, there is a 1000pF capacitor which provides approximately 0.7ms soft-start time with 200μF output capacitance. Additional soft-start time can be achieved by adding additional capacitance between the RUN/SS and SGND pins. The internal short-circuit latchoff can be disabled by adding a resistor between this pin and the VIN pin. This resistor must supply a minimum 5μA pull up current.FCB (Pin G23): Forced Continuous Input. Grounding this pin enables forced continuous mode operation regardless of load conditions. Tying this pin above 0.63V enables discontinuous conduction mode to achieve high effi ciency operation at light loads. There is an internal 4.75K resistor between the FCB and SGND pins.PGOOD (Pin J23): Output Voltage Power Good Indicator. When the output voltage is within 10% of the nominal voltage, the PGOOD is open drain output. Otherwise, this pin is pulled to ground.PGND (Bank 2): Power ground pins for both input and output returns.VOUT (Bank 3): Power Output Pins. Apply output load between these pins and GND pins. Recommend placing High Frequency output decoupling capacitance directly between these pins and GND pins.TOP VIEW

AC

BD

COMPSGNDRUN/SSFCBPGOOD

VINBANK 1

81312253215222324EFGJ

26333950614051624152634253273443546528354455662935566730374657683138475869485970496071HK

PGNDBANK 2

LMN

7273849574859675869776879877781007990101809110281921038293104PRT23VOUTBANK 3

83941234567101112131415161718192021224600hv PN01

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LTM4600HVSI PLIFIEDBLOCK DIAGRA

SVINRUN/SS1000pFPGOODQ1COMPFCBCOUT4.75kfADJSGNDEXTVCCVOSETR631.6k100k0.5%10ΩQ2PGNDCONTROLLER15μF6.3VINTCOMPVOUT, 2.5V/10A MAX1.5μFLTM4600HVVIN, 4.5V TO 28V ABS MAX CINFigure 1. Simplifi ed LTM4600HV Block DiagramDECOUPLI G REQUIRE E TS SYMBOLCINCOUTPARAMETERExternal Input Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V)External Output Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V)W

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4600hv F01TA = 25°C, VIN = 12V. Use Figure 1 confi guration.MIN20100200TYPMAXUNITSμFμFCONDITIONSIOUT = 10A, 2x 10μF 35V Ceramic Taiyo Yuden GDK316BJ106MLIOUT = 10A, Refer to Table 2 in the Applications Information Section4600hvfc

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LTM4600HVU

OPERATIO

μModule DescriptionThe LTM4600HV is a standalone non-isolated synchronous switching DC/DC power supply. It can deliver up to 10A of DC output current with only bulk external input and output capacitors. This module provides a precisely regulated output voltage programmable via one external resistor from 0.6VDC to 5.0VDC. The input voltage range is 4.5V to 28V. A simplifi ed block diagram is shown in Figure 1 and the typical application schematic is shown in Figure 21.The LTM4600HV contains an integrated LTC constant on-time current-mode regulator, ultra-low RDS(ON) FETs with fast switching speed and integrated Schottky diode. The typical switching frequency is 850kHz at full load. With current mode control and internal feedback loop compensation, the LTM4600HV 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 (X5R or X7R for extended temperature range).Current mode control provides cycle-by-cycle fast current limit. In addition, foldback current limiting is provided in an over-current condition while VOSET drops. Also, the LTM4600HV has defeatable short circuit latch off. 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/SS pin low forces the controller into its shutdown state, turning off both Q1 and Q2. Releasing the pin allows an internal 1.2μA current source to charge up the softstart capacitor. When this voltage reaches 1.5V, the controller turns on and begins switching.At low load current the module works in continuous cur-rent mode by default to achieve minimum output voltage ripple. It can be programmed to operate in discontinuous current mode for improved light load effi ciency when the FCB pin is pulled up above 0.8V and no higher than 6V. The FCB pin has a 4.75k resistor to ground, so a resistor to VIN can set the voltage on the FCB pin.When EXTVCC pin is grounded or open, an integrated 5V linear regulator powers the controller and MOSFET gate drivers. If a minimum 4.7V external bias supply is ap-plied on the EXTVCC pin, the internal regulator is turned off, and an internal switch connects EXTVCC to the gate driver voltage. This eliminates the linear regulator power loss with high input voltage, reducing the thermal stress on the controller. The maximum voltage on EXTVCC pin is 6V. The EXTVCC voltage should never be higher than the VIN voltage. Also EXTVCC must be sequenced after VIN. Recommended for 24V operation to lower temperature in the μModule.4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

The typical LTM4600HV application circuit is shown in Figure 21. External component selection is primarily determined by the maximum load current and output voltage.Output Voltage Programming and MarginingThe PWM controller of the LTM4600HV has an internal 0.6V±1% reference voltage. As shown in the block diagram, a 100k/0.5% internal feedback resistor connects VOUT and VOSET pins. Adding a resistor RSET from VOSET pin to SGND pin programs the output voltage: VO=0.6V•

100k+RSET

RSET

Table 1 shows the standard values of 1% RSET resistor for typical output voltages:Table 1.RSET(kΩ)VO(V)Open0.61001.266.51.549.91.843.2231.62.522.13.313.75Voltage margining is the dynamic adjustment of the output voltage to its worst case operating range in production testing to stress the load circuitry, verify control/protec-tion functionality of the board and improve the system reliability. Figure 2 shows how to implement margining function with the LTM4600HV. In addition to the feedback resistor RSET, several external components are added. Turn off both transistor QUP and QDOWN to disable the margining. When QUP is on and QDOWN is off, the output LTM4600HVVOUTRDOWN100kQDOWN

VOSETPGNDSGNDRSET2N7002RUPQUP2N70024600hv F02Figure 2. LTM4600HV Margining Implementation U

voltage is margined up. The output voltage is margined down when QDOWN is on and QUP is off. If the output voltage VO needs to be margined up/down by ±M%, the resistor values of RUP and RDOWN can be calculated from the following equations:(RSETRUP)•VO•(1+M%)

=0.6V

(RR)+100kΩSETUP RSET•VO•(1–M%)

=0.6V

R+(100kΩR)SETDOWN Input CapacitorsThe LTM4600HV μModule should be connected to a low ac-impedance DC source. High frequency, low ESR input capacitors are required to be placed adjacent to the mod-ule. In Figure 21, the bulk input capacitor CIN is selected for its ability to handle the large RMS current into the converter. For a buck converter, the switching duty-cycle can be estimated as: D=

VOVIN

Without considering the inductor current ripple, the RMS current of the input capacitor can be estimated as: ICIN(RMS)=

IO(MAX)

•D•(1−D)η%

In the above equation, η% is the estimated effi ciency of the power module. C1 can be a switcher-rated electrolytic aluminum capacitor, OS-CON capacitor or high volume ceramic capacitors. Note the capacitor ripple current ratings are often based on only 2000 hours of life. This makes it advisable to properly derate the input capacitor, or choose a capacitor rated at a higher temperature than required. Always contact the capacitor manufacturer for derating requirements over temperature.In Figure 21, the input capacitors are used as high fre-quency input decoupling capacitors. In a typical 10A output application, 1-2 pieces of very low ESR X5R or X7R (for extended temperature range), 10μF ceramic capacitors are recommended. This decoupling capacitor 4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

should be placed directly adjacent the module input pins in the PCB layout to minimize the trace inductance and high frequency AC noise.Output CapacitorsThe LTM4600HV is designed for low output voltage ripple. The bulk output capacitors COUT is chosen with low enough effective series resistance (ESR) to meet the output voltage ripple and transient requirements. COUT can be low ESR tantalum capacitor, low ESR polymer capacitor or ceramic capacitor (X5R or X7R). The typical capacitance is 200μF if all ceramic output capacitors are used. The internally optimized loop compensation provides suffi cient stability margin for all ceramic capacitors applications. Additional output fi ltering may be required by the system designer, if further reduction of output ripple or dynamic transient spike is required. Refer to Table 2 for an output capaci-tance matrix for each output voltage Droop, peak to peak deviation and recovery time during a 5A/μs transient with a specifi c output capacitance.Fault Conditions: Current Limit and Over current FoldbackThe LTM4600HV has a current mode controller, which inherently limits the cycle-by-cycle inductor current not only in steady state operation, but also in transient.To further limit current in the event of an over load condi-tion, the LTM4600HV provides foldback current limiting. If the output voltage falls by more than 50%, then the maximum output current is progressively lowered to about one sixth of its full current limit value.10

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Soft-Start and Latchoff with the RUN/SS pinThe RUN/SS pin provides a means to shut down the LTM4600HV as well as a timer for soft-start and over-current latchoff. Pulling the RUN/SS pin below 0.8V puts the LTM4600HV into a low quiescent current shutdown (IQ ≤ 75μA). Releasing the pin allows an internal 1.2μA current source to charge up the timing capacitor CSS. Inside LTM4600HV, there is an internal 1000pF capaci-tor from RUN/SS pin to ground. If RUN/SS pin has an external capacitor CSS_EXT to ground, the delay before starting is about: tDELAY=

1.5V

•(CSS_EXT+1000pF)1.2μA

When the voltage on RUN/SS pin reaches 1.5V, the LTM4600HV internal switches are operating with a clamp-ing of the maximum output inductor current limited by the RUN/SS pin total soft-start capacitance. As the RUN/SS pin voltage rises to 3V, the soft-start clamping of the inductor current is released.VIN to VOUT Stepdown RatiosThere are restrictions in the maximum VIN to VOUT step down ratio that can be achieved for a given input voltage. These contraints are shown in the Typical Performance Characteristics curves labeled “VIN to VOUT Stepdown Ratio”. Note that additional thermal de-rating may apply. See the Thermal Considerations and Output Current De-Rating sections of this data sheet.4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

TYPICAL MEASURED VALUESCOUT1 VENDORSTDKTAIYO YUDENTAIYO YUDENTAIYO YUDENTable 2. Output Voltage Response Versus Component Matrix *(Refer to Figure 21)PART NUMBERC4532X5R0J107MZ (100μF,6.3V)JMK432BJ107MU-T ( 100μF, 6.3V)JMK316BJ226ML-T501 ( 22μF, 6.3V)JMK316BJ226ML-T501 ( 22μF, 6.3V)COUT2(BULK)470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V470μF 2.5V330μF 6.3VNONE470μF 4V330μF 6.3V470μF 4VNONE470μF 4V470μF 4V330μF 6.3VNONE470μF 6.3V470μF 6.3V330μF 6.3V470μF 4V470μF 4VNONE470μF 4V470μF 4V330μF 6.3VNONE470μF 6.3VNONENONECCOMPNONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONENONECOUT2 VENDORSSANYO POSCAPSANYO POSCAPSANYO POSCAPSANYO POSCAPC3100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pF100pFVIN(V)5555121212125555121212125555121212125555121212122424777712121212241520DROOP(mV)353540493535404936374461363744544044466240444462485657604851567056506682100527674188159PART NUMBER6TPE330MIL (330μF, 6.3V)2R5TPE470M9 (470μF, 2.5V)4TPE470MCL (470μF, 4V)6TPD470M (470μF, 6.3V)PEAK TO PEAK(mV)687080986870809875798411875791088181128818591125103113116115103102113159112100126132166200106129126144149375320RECOVERY TIME(μs)252020202520202025202020252020203020202030202020303030253030302530303030352530353025302525LOAD STEP(A/μs)5555555555555555555555555555555555555555555554600hvfc

VOUTCINCINCOUT1(V)(CERAMIC)(BULK)(CERAMIC)1.22 × 10μF 35V150μF 35V3 × 22μF 6.3V1.22 × 10μF 35V150μF 35V1 × 100μF 6.3V1.22 × 10μF 35V150μF 35V2 × 100μF 6.3V1.22 × 10μF 35V150μF 35V4 × 100μF 6.3V1.22 × 10μF 35V150μF 35V3 × 22μF 6.3V1.22 × 10μF 35V150μF 35V1 × 100μF 6.3V1.22 × 10μF 35V150μF 35V2 × 100μF 6.3V1.22 × 10μF 35V150μF 35V4 × 100μF 6.3V1.52 × 10μF 35V150μF 35V3 × 22μF 6.3V1.52 × 10μF 35V150μF 35V1 × 100μF 6.3V1.52 × 10μF 35V150μF 35V2 × 100μF 6.3V1.52 × 10μF 35V150μF 35V4 × 100μF 6.3V1.52 × 10μF 35V150μF 35V3 × 22μF 6.3V1.52 × 10μF 35V150μF 35V1 × 100μF 6.3V1.52 × 10μF 35V150μF 35V2 × 100μF 6.3V1.52 × 10μF 35V150μF 35V4 × 100μF 6.3V1.82 × 10μF 35V150μF 35V3 × 22μF 6.3V1.82 × 10μF 35V150μF 35V1 × 100μF 6.3V1.82 × 10μF 35V150μF 35V2 × 100μF 6.3V1.82 × 10μF 35V150μF 35V4 × 100μF 6.3V1.82 × 10μF 35V150μF 35V3 × 22μF 6.3V1.82 × 10μF 35V150μF 35V1 × 100μF 6.3V1.82 × 10μF 35V150μF 35V2 × 100μF 6.3V1.82 × 10μF 35V150μF 35V4 × 100μF 6.3V2.52 × 10μF 35V150μF 35V1 × 100μF 6.3V2.52 × 10μF 35V150μF 35V2 × 100μF 6.3V2.52 × 10μF 35V150μF 35V3 × 22μF 6.3V2.52 × 10μF 35V150μF 35V4 × 100μF 6.3V2.52 × 10μF 35V150μF 35V1 × 100μF 6.3V2.52 × 10μF 35V150μF 35V3 × 22μF 6.3V2.52 × 10μF 35V150μF 35V2 × 100μF 6.3V2.52 × 10μF 35V150μF 35V4 × 100μF 6.3V2.52 × 10μF 35V150μF 35V3 × 22μF 6.3V2.82 × 10μF 35V150μF 35V3 × 22μF 6.3V3.32 × 10μF 35V150μF 35V2 × 100μF 6.3V3.32 × 10μF 35V150μF 35V1 × 100μF 6.3V3.32 × 10μF 35V150μF 35V3 × 22μF 6.3V3.32 × 10μF 35V150μF 35V4 × 100μF 6.3V3.32 × 10μF 35V150μF 35V1 × 100μF 6.3V3.32 × 10μF 35V150μF 35V3 × 22μF 6.3V3.32 × 10μF 35V150μF 35V2 × 100μF 6.3V3.32 × 10μF 35V150μF 35V4 × 100μF 6.3V3.32 × 10μF 35V150μF 35V3 × 22μF 6.3V52 × 10μF 35V150μF 35V4 × 100μF 6.3V52 × 10μF 35V150μF 35V4 × 100μF 6.3V*X7R is recommended for extended temperature range.UWUU

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LTM4600HVAPPLICATIOS IFORATIO

After the controller has been started and given adequate time to charge up the output capacitor, CSS is used as a short-circuit timer. After the RUN/SS pin charges above 4V, if the output voltage falls below 75% of its regulated value, then a short-circuit fault is assumed. A 1.8μA current then begins discharging CSS. If the fault condition persists until the RUN/SS pin drops to 3.5V, then the controller turns off both power MOSFETs, shuting down the converter permanently. The RUN/SS pin must be actively pulled down to ground in order to restart operation.The over-current protection timer requires the soft-start timing capacitor CSS be made large enough to guarantee that the output is in regulation by the time CSS has reached the 4V threshold. In general, this will depend upon the size of the output capacitance, output voltage and load current characteristic. A minimum external soft-start capacitor can be estimated from:–3[F/V])C+1000pF>C•V(10SS_EXTOUTOUTS Generally 0.1μF is more than suffi cient.Since the load current is already limited by the current mode control and current foldback circuitry during a shortcircuit, over-current latchoff operation is NOT always needed or desired, especially the output has large amount of capacitance or the load draw huge current during start up. The latchoff feature can be overridden by a pull-up current greater than 5μA but less than 80μA to the RUN/SS pin. The additional current prevents the discharge of CSS during a fault and also shortens the soft-start period. Us-ing a resistor from RUN/SS pin to VIN is a simple solution 12

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to defeat latchoff. Any pull-up network must be able to maintain RUN/SS above 4V maximum latchoff threshold and overcome the 4μA maximum discharge current. Figure 3 shows a conceptual drawing of VRUN during startup and short circuit.VRUN/SS4V3.5V3V1.5VSHORT-CIRCUITLATCH ARMEDtSOFT-STARTCLAMPINGOF IL RELEASEDVO75%VOOUTPUTOVERLOADHAPPENSSHORT-CIRCUITLATCHOFFSWITCHINGSTARTS

t4600hv F03

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Figure 3. RUN/SS Pin Voltage During Startup and Short-Circuit ProtectionVINRRUN/SSVINLTM4600HVRUN/SSPGNDSGNDRECOMMENDED VALUES FOR RUN/SS

VIN4.5V TO 5.5V10.8V TO 13.8V24V TO 28V

RRUN/SS50k150k500k

4600hv F04Figure 4. Defeat Short-Circuit Latchoff with a Pull-Up Resistor to VIN4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

EnableThe RUN/SS pin can be driven from logic as shown in Figure 5. This function allows the LTM4600HV to be turned on or off remotely. The ON signal can also control the sequence of the output voltage.RUN/SSON

LTM4600HVPGNDSGND2N70024600hv F05Figure 5. Enable Circuit with External LogicOutput Voltage TrackingFor the applications that require output voltage tracking, several LTM4600HV modules can be programmed by the power supply tracking controller such as the LTC2923. Figure 6 shows a typical schematic with LTC2923. Coin-cident, ratiometric and offset tracking for VO rising and falling can be implemented with different sets of resistor values. See the LTC2923 data sheet for more details.VIN5VDC/DCQ13.3VVINVINRONBRONAVCCONLTC2923RAMPBUFRTB1TRACK1RTA1RTB2TRACK2RTA2GNDFB2SDOSTATUSGATERAMPFB1LTM4600HVVOSETVOUT49.9k1.8VVINVINLTM4600HVVOSETVOUT66.5k4600hv F06Figure 6. Output Voltage Tracking with the LTC2923 ControllerU

EXTVCC ConnectionAn internal low dropout regulator produces an internal 5V supply that powers the control circuitry and FET drivers. Therefore, if the system does not have a 5V power rail, the LTM4600HV can be directly powered by VIN. The gate driver current through LDO is about 18mA. The internal LDO power dissipation can be calculated as:PLDO_LOSS = 18mA • (VIN – 5V)The LTM4600HV also provides an external gate driver voltage pin EXTVCC. If there is a 5V rail in the system, it is recommended to connect EXTVCC pin to the external 5V rail. Whenever the EXTVCC pin is above 4.7V, the in-ternal 5V LDO is shut off and an internal 50mA P-channel switch connects the EXTVCC to internal 5V. Internal 5V is supplied from EXTVCC until this pin drops below 4.5V. Do not apply more than 6V to the EXTVCC pin and ensure that EXTVCC < VIN. The following list summaries the possible connections for EXTVCC:1. EXTVCC grounded. Internal 5V LDO is always powered from the internal 5V regulator. 2. EXTVCC connected to an external supply. Internal LDO is shut off. A high effi ciency supply compatible with the MOSFET gate drive requirements (typically 5V) can im-prove overall effi ciency. With this connection, it is always required that the EXTVCC voltage can not be higher than VIN pin voltage.3. EXTVCC is recommended for VIN > 20VDiscontinuous Operation and FCB PinThe FCB pin determines whether the internal bottom MOSFET remains on when the current reverses. There is an internal 4.75k pull-down resistor connecting this pin to ground. The default light load operation mode is forced continuous (PWM) current mode. This mode provides minimum output voltage ripple.1.5V4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

In the application where the light load effi ciency is im-portant, tying the FCB pin above 0.6V threshold enables discontinuous operation where the bottom MOSFET turns off when inductor current reverses. Therefore, the conduc-tion loss is minimized and light load effi ciency is improved. The penalty is that the controller may skip cycle and the output voltage ripple increases at light load.Paralleling Operation with Load SharingTwo or more LTM4600HV modules can be paralleled to provide higher than 10A output current. Figure 7 shows the necessary interconnection between two paralleled modules. The OPTI-LOOP™ current mode control en-sures good current sharing among modules to balance the thermal stress. The new feedback equation for two or more LTM4600HVs in parallel is:100k

+RSET

VOUT=0.6V•NRSET

where N is the number of LTM4600HVs in parallel.VIN

VINLTM4600HVPGNDCOMPVOSETSGNDRSETVOUTVOUT

(20AMAX)

COMPVOSETSGNDVINPGND4600hv F07LTM4600HVVOUTFigure 7. Parallel Two μModules with Load SharingThermal Considerations and Output Current DeratingThe power loss curves in Figures 8 and 15 can be used in coordination with the load current derating curves in Figures 9 to 14, and Figures 16 to 19 for calculating an approximate θJA for the module with various heatsink-ing methods. Thermal models are derived from several temperature measurements at the bench, and thermal modeling analysis. Application Note 103 provides a detailed OPTI-LOOP is a trademark of Linear Technology Corporation.14

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explanation of the analysis for the thermal models, and the derating curves. Tables 3 and 4 provide a summary of the equivalent θJA for the noted conditions. These equivalent θJA parameters are correlated to the measure values, and improved with air-fl ow. The case temperature is maintained at 100°C or below for the derating curves. This allows for 4W maximum power dissipation in the total module with top and bottom heatsinking, and 2W power dissipation through the top of the module with an approximate θJC between 6°C/W to 9°C/W. This equates to a total of 124°C at the junction of the device.Safety ConsiderationsThe LTM4600HV modules do not provide isolation from VIN to VOUT. There is no internal fuse. If required, a slow blow fuse with a rating twice the maximum input current should be provided to protect each unit from catastrophic failure.Layout Checklist/ExampleThe high integration of the LTM4600HV makes the PCB board layout very simple and easy. However, to optimize its electrical and thermal performance, some layout con-siderations are still necessary.• Use large PCB copper areas for high current path, in-cluding VIN, PGND and VOUT. It helps to minimize the PCB conduction loss and thermal stress• Place high frequency ceramic input and output capaci-tors next to the VIN, PGND and VOUT 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 vias directly on pad unless they are capped.• Use a separated SGND ground copper area for com-ponents connected to signal pins. Connect the SGND to PGND underneath the unitFigure 20 gives a good example of the recommended layout.4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

4.54.0

MAXIMUM LOAD CURRENT (A)3.5POWER LOSS (W)3.02.52.01.51.00.500

2

468OUTPUT CURRENT (A)

10

4600hv F08

VOUT = 1.5V10987654

0 LFM200 LFM400 LFM50

18V LOSSMAXIMUM LOAD CURRENT (A)12V LOSS5V LOSSFigure 8. 1.5V Power Loss Curves vs Load Current10MAXIMUM LOAD CURRENT (A)987654

0 LFM200 LFM400 LFM50

55

606570758085AMBIENT TEMPERATURE (°C)

90

VIN = 12VVOUT = 1.5VMAXIMUM LOAD CURRENT (A)109876543

VIN = 12VVOUT = 1.5VMAXIMUM LOAD CURRENT (A)50

4600hv F11

Figure 11. No Heatsink10MAXIMUM LOAD CURRENT (A)VIN = 18VVOUT = 1.5V5.04.5

MAXIMUM LOAD CURRENT (A)8

POWER LOSS (W)4.03.53.02.52.01.51.00.5

100

4600hv F14

6

4

2

0

0 LFM200 LFM400 LFM50

80906070

AMBIENT TEMPERATURE (°C)

00

2

468OUTPUT CURRENT (A)

10

4600hv F15

Figure 14. BGA HeatsinkFigure 15. 3.3V Power Loss Curves vs Load CurrentU

VIN = 5VVOUT = 1.5V10987654

0 LFM200 LFM400 LFM50

60708090AMBIENT TEMPERATURE (°C)

100

4600hv F10

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VIN = 5VVOUT = 1.5V608070

AMBIENT TEMPERATURE (°C)

90

4600hv F09

Figure 9. No HeatsinkFigure 10. BGA Heatsink10987654321

100

4600hv F12

VIN = 18VVOUT = 1.5V0 LFM200 LFM400 LFM60708090AMBIENT TEMPERATURE (°C)

0

0 LFM200 LFM400 LFM40

60805070

AMBIENT TEMPERATURE (°C)

90

4600hv F13

Figure 12. BGA Heatsink10987654321040

Figure 13. No HeatsinkVIN = 12VVOUT = 3.3V24V LOSS12V LOSS0 LFM200 LFM400 LFM50608070

AMBIENT TEMPERATURE (°C)

90

4600hv F16

Figure 16. No Heatsink4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

10MAXIMUM LOAD CURRENT (A)987654

0 LFM200 LFM400 LFM40

6070809050

AMBIENT TEMPERATURE (°C)

100

4600hv F17

VIN = 12VVOUT = 3.3VMAXIMUM LOAD CURRENT (A)10

8

MAXIMUM LOAD CURRENT (A)6

4

2

0

50

Figure 17. BGA HeatsinkTable 3. 1.5V OutputDERATING CURVEFigures 9, 11, 13Figures 9, 11, 13Figures 9, 11, 13Figures 10, 12, 14Figures 10, 12, 14Figures 10, 12, 14VIN (V)5, 12, 185, 12, 185, 12, 185, 12, 185, 12, 185, 12, 18POWER LOSS CURVEFigure 8Figure 8Figure 8Figure 8Figure 8Figure 8AIR FLOW (LFM)02004000200400HEATSINKNoneNoneNoneBGA HeatsinkBGA HeatsinkBGA HeatsinkθJA (°C/W)15.2141213.911.310.25Table 4. 3.3V OutputDERATING CURVEFigures 16, 18Figures 16, 18Figures 16, 18Figures 17, 19Figures 17, 19Figures 17, 19VIN (V)12, 2412, 2412, 2412, 2412, 2412, 24POWER LOSS CURVEFigure 15Figure 15Figure 15Figure 15Figure 15Figure 15AIR FLOW (LFM)02004000200400HEATSINKNoneNoneNoneBGA HeatsinkBGA HeatsinkBGA HeatsinkθJA (°C/W)15.214.613.413.911.110.516

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VIN = 24VVOUT = 3.3V TEMPERATUREDE-RATING109876

5VIN = 24VVOUT = 3.3V TEMPERATUREDE-RATING4

60708050

AMBIENT TEMPERATURE (°C)

0 LFM200 LFM400 LFM0 LFM200 LFM400 LFM608070

AMBIENT TEMPERATURE (°C)

90

90

4600hv F18.eps

4600hv F19.eps

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Figure 18. No HeatsinkFigure 19. BGA Heatsink4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

VINCIN

PGNDVOUT4600hv F20LOADTOP LAYERFigure 20. Recommended PCB LayoutLTM4600HV Frequency Adjustment The LTM4600HV is designed to typically operate at 850kHz across most input and output conditions. The control ar-chitecture is constant on time valley mode current control. The fADJ pin is typically left open or decoupled with an optional 1000pF capacitor. The switching frequency has been optimized to maintain constant output ripple over the operating conditions. The equations for setting the operat-ing frequency are set around a programmable constant on time. This on time is developed by a programmable current into an on board 10pF capacitor that establishes a ramp that is compared to a voltage threshold equal to the output voltage up to a 2.4V clamp. This ION current is equal to: ION = (VIN – 0.7V)/110k, with the 110k onboard resistor from VIN to fADJ. The on time is equal to tON = (VOUT/ION) • 10pF and tOFF = ts – tON. The frequency is equal to: Freq. = DC/tON. The ION current is proportional to VIN, and the regulator duty cycle is inversely proportional to VIN, there-fore the step-down regulator will remain relatively constant frequency as the duty cycle adjustment takes place with lowering VIN. The on time is proportional to VOUT up to a 2.4V clamp. This will hold frequency relatively constant with different output voltages up to 2.4V. The regulator switching period is comprised of the on time and off time as depicted in the following waveform. The on time is equal to tON = (VOUT/ION) • 10pF and tOFF = ts – tON. The frequency is equal to: Frequency = DC/tON).U

t

(DC) DUTY CYCLE = ON

tstOFFtONVt

DC = ON= OUT

tsVINDC

FREQ =

tON

4602 F25

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PERIOD tsThe LTM4600HV has a minimum (tON) on time of 100 nanoseconds and a minimum (tOFF) off time of 400 nanoseconds. The 2.4V clamp on the ramp threshold as a function of VOUT will cause the switching frequency to increase by the ratio of VOUT/2.4V for 3.3V and 5V outputs. This is due to the fact the on time will not increase as VOUT increases past 2.4V. Therefore, if the nominal switch-ing frequency is 850kHz, then the switching frequency will increase to ~1.2MHz for 3.3V, and ~1.7MHz for 5V outputs due to Frequency = (DC/tON) When the switching frequency increases to 1.2MHz, then the time period tS is reduced to ~833 nanoseconds and at 1.7MHz the switching period reduces to ~588 nanoseconds. When higher duty cycle conversions like 5V to 3.3V and 12V to 5V need to be accommodated, then the switching frequency can be lowered to alleviate the violation of the 400ns minimum off time. Since the total switching period is tS = tON + tOFF, tOFF will be below the 400ns minimum off time. A resistor from the fADJ pin to ground can shunt current away from the on time generator, thus allowing for a longer on time and a lower switching frequency. 12V to 5V and 5V to 3.3V derivations are explained in the data sheet to lower switching frequency and accommodate these step-down conversions.Equations for setting frequency for 12V to 5V: ION = (VIN – 0.7V)/110k; ION = 103μA frequency = (ION/[2.4V • 10pF]) • DC = 1.79MHz; DC = duty cycle, duty cycle is (VOUT/VIN) tS = tON + tOFF, tON = on-time, tOFF = off-time of the switching period; tS = 1/frequencytOFF must be greater than 400ns, or tS – tON > 400ns. tON = DC • tS1MHz frequency or 1μs period is chosen for 12V to 5V.4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

tON = 0.41 • 1μs ≅ 410ns tOFF = 1μs – 410ns ≅ 590nstON and tOFF are above the minimums with adequate guard band.Using the frequency = (ION/[2.4V • 10pF]) • DC, solve for ION = (1MHz • 2.4V • 10pF) • (1/0.41) ≅ 58μA. ION current calculated from 12V input was 103μA, so a resistor from fADJ to ground = (0.7V/15k) = 46μA. 103μA – 46μA = 57μA, sets the adequate ION current for proper frequency range for the higher duty cycle conversion of 12V to 5V. Input voltage range is limited to 9V to 16V. Higher input voltages can be used without the 15k on fADJ. The inductor ripple current gets too high above 16V, and the 400ns minimum off-time is limited below 9V.Using the frequency = (ION/[2.4V • 10pF]) • DC, solve for ION = (450kHz • 2.4V • 10pF) • (1/0.66) ≅ 16μA. ION current calculated from 5V input was 39μA, so a resistor from fADJ to ground = (0.7V/30.1k) = 23μA. 39μA – 23μA = 16μA, sets the adequate ION current for proper frequency range Equations for setting frequency for 5V to 3.3V:for the higher duty cycle conversion of 5V to 3.3V. Input ION = (VIN – 0.7V)/110k; ION = 39μAvoltage range is limited to 4.5V to 7V. Higher input voltages frequency = (ION/[2.4V • 10pF]) • DC = 1.07MHz; can be used without the 30.1k on fADJ. The inductor ripple current gets too high above 7V, and the 400ns minimum DC = duty cycle, duty cycle is (VOUT/VIN)off-time is limited below 4.5V. tS = tON + tOFF, tON = on-time, tOFF = off-time of the switching period; tS = 1/frequency5V to 3.3V at 8A4.5V TO 7VC310μF25VC110μF25VEXTVCCFCBLTM4600HVRUN/SOFT-STARTRUN/SSCOMPSGNDSVINPGOODPGND4600 F225V TO 3.3V AT 8A WITH fADJ = 30.1kLTM4600HV MINIMUM ON-TIME = 100nsLTM4600HV MINIMUM OFF-TIME = 400ns

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tOFF must be greater than 400ns, or tS – tON > 400ns. tON = DC • tS~450kHz frequency or 2.22μs period is chosen for 5V to 3.3V. Frequency range is about 450kHz to 650kHz from 4.5V to 7V input. tON = 0.66 • 2.22μs ≅ 1.46μs tOFF = 2.22μs – 1.46μs ≅ 760nstON and tOFF are above the minimums with adequate guard band.R130.1kC5100pF3.3V AT 8AVOUTVOSETR222.1k1%OPEN DRAINEFFICIENCY = 94%C222μFVINfADJWUU

+C4330μF6.3VC1, C3: TDK C3216X5R1E106MTC2: TAIYO YUDEN, JMK316BJ226MLC4: SANYO POSCAP, 6TPE330MIL

4600hvfc

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LTM4600HVAPPLICATIOS IFORATIO

12V to 5V at 8A9V TO 16VC310μF25VC110μF25VEXTVCCFCBLTM4600HVRUN/SOFT-STARTRUN/SSCOMPSGNDSVINPGOODPGND4600 F23R115kC5100pF5V AT 8AVOUTVOSETR213.7k1%OPEN DRAINEFFICIENCY = 94%VINfADJVOUT (V)12V TO 5V AT 8A WITH fADJ = 15k

LTM4600HV MINIMUM ON-TIME = 100nsLTM4600HV MINIMUM OFF-TIME = 400nsC1, C3: TDK C3216X5R1E106MTC2: TAIYO YUDEN, JMK316BJ226MLC4: SANYO POSCAP, 6TPE330MIL

TYPICAL APPLICATIO

VIN5V TO 24VGND

+CIN (BULK)150μFCIN (CER)10μF2xEXTVCCC3100pFVOUTSVINfADJVOSETCOMPFCBPGOODSGNDC4OPTR166.5kREFER TOTABLE 14600HV F21Figure 21. Typical Application, 5V to 24V Input, 0.6V to 5V Output, 10A MaxU

VIN to VOUT Stepdown Ratio for 12V to 5V and 5V to 3.3V5.0

3.3V: fADJ = 30.1k4.55V: fADJ = 15k4.0

C222μFW

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+3.53.02.52.01.51.00.501

3

5

7

911VIN (V)

3.3V AT 8A5V AT 8A13

15

17

4600 F24

C4330μF6.3VVIN(MULTIPLE PINS)VOUT(MULTIPLE PINS)VOUT

COUT1+22μF6.3V×3REFER TOTABLE 2COUT2470μFREFER TOTABLE 2LTM4600HVRUN/SSPGND(MULTIPLE PINS)0.6V TO 5VREFER TO STEP DOWNRATIO GRAPHGND

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LTM4600HVTYPICAL APPLICATIO

C810μF35VC710μF35VEXTVCCFCBRUN/SOFT-STARTC310μF35VC110μF35VEXTVCCFCBINDIVIDUAL SHARE20

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Parallel Operation and Load Sharing4.5V TO 24VVINfADJVOUTVOSETLTM4600HVRUNCOMPSGNDSVINPGOODPGND2.5V AT 20AR415.8k1%C922μFx3VOUT = 0.6V • ([100k/N] + RSET)/RSETWHERE N = 2 +C10470μF4VVINfADJVOUTVOSETC4220pF2.5VC222μFx3R1100k+LTM4600HVRUNCOMPSGNDSVINPGOODPGND4600hv TA02C5470μF4VC1, C3, C7, C8: TAIYO YUDEN, GDK316BJ106MLC2, C9: TAIYO YUDEN, JMK316BJ226ML-T501C5, C10: SANYO POSCAP, 4TPE470MCLCurrent Sharing Between Two LTM4600HV Modules12

12VIN2.5VOUT1020AMAX820

IOUT2IOUT105

10

TOTAL LOAD

1520

4600hv TA03

4600hvfc

LGA Package104-Lead (15mm × 15mm)(Reference LTM DWG # 05-05-1800)1.90420.00004.44426.9865

19201011211422232824354455566770687169585966576045484749363738293031156.94215.71584.4458

3.17581.9058

0.63580.63423.17426.98886167171823456.547515.76502.72 – 2.92aaa Z15BSCXY95.277584.4950134.0075122.73754PAD 1CORNER25元器件交易网www.cecb2b.com

2.360026271.4675321.09003334PACKAGE DESCRIPTIO

1.2700505152535415BSC2.5400616263654.4450819293809172777879808273747576MOLDCAPSUBSTRATE5.71500.27 – 0.379910410010110210383848586876.98502.45 – 2.55DETAIL B0.31750.31751.27003.81006.3500bbb ZZ94959697983.81006.35005.08002.54001.27002.54000.00005.0800aaa ZSUGGESTED SOLDER PAD LAYOUTTOP VIEW12.70BSC991049382887781787980909192100101102103TOP VIEWDETAIL B0.11 – 0.279495969798PADSSEE NOTEST3RPNOTES:1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-19942. ALL DIMENSIONS ARE IN MILLIMETERS3 LAND DESIGNATION PER JESD MO-222, SPP-010483848586877273747576615559484944352423363738454756575860626371656667686970NMLKH5051525354DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL,BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.THE PAD #1 IDENTIFIER IS A MARKED FEATURE OR ANOTCHED BEVELED PAD5. PRIMARY DATUM -Z- IS SEATING PLANE6. THE TOTAL NUMBER OF PADS: 10413.97BSC394041424332282930313334JGFEDCBAeeeMXY25221421102067161718191115262712138SYMBOLTOLERANCE0.15aaa0.10bbb0.15eee912345C(0.30)PAD 1111213.93BSC141618201315171921135792322LTM4600HV21

2468104600 02-184600hvfc

BOTTOM VIEWU

0.31750.00000.317539404142435.7142元器件交易网www.cecb2b.com

LTM4600HVPACKAGE DESCRIPTIO

PIN NAMEA1 -A2 -A3 VINA4 -A5 VINA6 -A7 VINA8 -A9 VINA10 -A11 VINA12 -A13 VINA14 -A15 fADJA16 -A17 SVINA18 -A19 EXTVCCA20 -A21 VOSETA22 -A23 -PIN NAMEJ1 PGNDJ2 -J3 -J4 -J5 -J6 -J7 -J8 -J9 -J10 -J11 -J12 -J13 -J14 -J15 -J16 -J17 -J18 -J19 -J20 -J21 -J22 -J23 PGOODPIN NAMEB1 VINB2 -B3 -B4 -B5 -B6 -B7 -B8 -B9 -B10 -B11 -B12 -B13 -B14 -B15 -B16 -B17 -B18 -B19 -B20 -B21 -B22 -B23 COMPPIN NAMEK1 -K2 -K3 -K4 -K5 -K6 -K7 PGNDK8K9 PGNDK10K11 PGNDK12 -K13 PGNDK14 -K15 PGNDK16 -K17 PGNDK18 -K19 -K20 -K21 -K22 -K23 -PIN NAMEC1 -C2 -C3 -C4 -C5 -C6 -C7 -C8 -C9 -C10 VINC11 -C12 VINC13 -C14 VINC15 -C16 -C17 -C18 -C19 -C20 -C21 -C22 -C23 -PIN NAMEL1 -L2 PGNDL3 -L4 PGNDL5 -L6 PGNDL7 -L8 PGNDL9 -L10 PGNDL11 -L12 PGNDL13 -L14 PGNDL15 -L16 PGNDL17 -L18 PGNDL19 -L20 PGNDL21 -L22 PGNDL23 -22

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Pin Assignment Tables(Arranged by Pin Number)PIN NAMED1 VIND2 -D3 -D4 -D5 -D6 -D7 -D8 -D9 -D10 -D11 -D12 -D13 -D14 -D15 -D16 -D17 -D18 -D19 -D20 -D21 -D22 -D23 SGNDPIN NAMEM1 -M2 PGNDM3 -M4 PGNDM5 -M6 PGNDM7 -M8 PGNDM9 -M10 PGNDM11 -M12 PGNDM13 -M14 PGNDM15 -M16 PGNDM17 -M18 PGNDM19 -M20 PGNDM21 -M22 PGNDM23 -PIN NAMEE1 -E2 -E3 -E4 -E5 -E6 -E7 -E8 -FE9 -FFE10 VINFE11 -FFE12 VINFE13 -FFE14 VINE15 -FE16 -FE17 -FE18 -FE19 -FFE20 -FE21 -FFE22 -FE23 -FPIN NAMEN1 -N2 PGNDN3 -N4 PGNDN5 -N6 PGNDN7 -N8 PGNDN9 -N10 PGNDN11 -N12 PGNDN13 -N14 PGNDN15 -N16 PGNDN17 -N18 PGNDN19 -N20 PGNDN21 -N22 PGNDN23 -PIN NAME1 VIN2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 -17 -18 -19 -20 -21 -22 -23 RUN/SSPIN NAMEG1 PGNDG2 -G3 -G4 -G5 -G6 -G7 -G8 -FG9 -G10 -G11 -G12 -G13 -G14 -G15 -G16 -G17 -G18 -G19 -G20 -G21 -G22 -G23 CBPIN NAMER1 -R2 VOUTR3 -R4 VOUTR5 -R6 VOUTR7 -R8 VOUTR9 -R10 VOUTR11 -R12 VOUTR13 -R14 VOUTR15 -R16 VOUTR17 -R18 VOUTR19 -R20 VOUTR21 -R22 VOUTR23 -PIN NAMEH1 -H2 -H3 -H4 -H5 -H6 -H7 PGNDH8 -H9 PGNDH10 -H11 PGNDH12 -H13 PGNDH14 -H15 PGNDH16 -H17 PGNDH18 -H19 -H20 -H21 -H22 -H23 -PIN NAMET1 -T2 VOUTT3 -T4 VOUTT5 -T6 VOUTT7 -T8 VOUTT9 -T10 VOUTT11 -T12 VOUTT13 -T14 VOUTT15 -T16 VOUTT17 -T18 VOUTT19 -T20 VOUTT21 -T22 VOUTT23 -4600hvfc

PIN NAMEP1 -P2 VOUTP3 -P4 VOUTP5 -P6 VOUTP7 -P8 VOUTP9 -P10 VOUTP11 -P12 VOUTP13 -P14 VOUTP15 -P16 VOUTP17 -P18 VOUTP19 -P20 VOUTP21 -P22 VOUTP23 -元器件交易网www.cecb2b.com

LTM4600HVPACKAGE DESCRIPTIO

PIN NAMEG1H7H9H11H13H15H17J1K7K9K11K13K15K17L2L4L6L8L10L12L14L16L18L20L22M2M4M6M8M10M12M14M16M18M20M22N2N4N6N8N10N12N14N16N18N20N22PGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDPGNDP2P4P6P8P10P12P14P16P18P20P22R2R4R6R8R10R12R14R16R18R20R22T2T4T6T8T10T12T14T16T18T20T22Information 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.U

Pin Assignment Tables(Arranged by Pin Number)PIN NAMEVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTVOUTA3A5A7A9A11A13B1C10C12C14D1E10E12E14F1PIN NAMEVINVINVINVINVINVINVINVINVINVINVINVINVINVINVINA15A17A19A21B23D23F23G23J23PIN NAMEfADJSVINEXTVCCVOSETCOMPSGNDRUN/SSFCBPGOOD4600hvfc

23

元器件交易网www.cecb2b.com

LTM4600HVTYPICAL APPLICATIO

C210μF35V4.5V TO 22VC110μF35VEXTVCCFCBLTM4600HVRUNCOMPSGNDSVINPGOODPGND4600hv TA04RELATED PARTS

PART NUMBERLTC2900LTC2923LT3825/LT3837LTM4600LTM4601LTM4602LTM4603DESCRIPTIONQuad Supply Monitor with Adjustable Reset TimerPower Supply Tracking ControllerSynchronous Isolated Flyback Controllers10A DC/DC μModule12A DC/DC μModule with PLL, Output Tracking/ Margining and Remote Sensing6A DC/DC μModuleCOMMENTSMonitors Four Supplies; Adjustable Reset TimerTracks Both Up and Down; Power Supply SequencingNo Optocoupler Required; 3.3V, 12A Output; Simple DesignBasic 10A DC/DC μModuleSynchronizable, PolyPhase Operation to 48A, LTM4601-1 Version has no Remote SensingPin Compatible with the LTM46006A DC/DC μModule with PLL and Outpupt Tracking/Synchronizable, PolyPhase Operation to 48A, LTM4601-1 Version has no Margining and Remote SensingRemote Sensing, Pin Compatible with the LTM460124

Linear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com© LINEAR TECHNOLOGY CORPORATION 2005

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1.8V, 10A RegulatorC5100pFVOUTVOSET1.8V AT 10AC322μFx3VINfADJ+R1100kC4470μF4VPGOODR249.9k1%C1, C2: TAIYO YUDEN, GDK316BJ106MLC3: TAIYO YUDEN, JMK316BJ226ML-T501C4: SANYO POSCAP, 4TPE470MCLThis product contains technology licensed from Silicon Semiconductor Corporation.®4600hvfc

LT 0707 REV C • PRINTED IN USA