LTM4600HV 10A, 28VIN High Efficiency DC/DC Module Features n n n n n n n n n n n n n n Complete Switch Mode Power Supply Wide Input Voltage Range: 4.5V to 28V 10A DC, 12A Peak Output Current Parallel Two ModuleTM DC/DC Converters for 20A Output Current 0.6V to 5V Output Voltage 1.5% Output Voltage Regulation Ultrafast Transient Response Current Mode Control -55C to 125C Operating Temperature Range (LTM4600HVMPV) RoHS Compliant Package with Gold Pad Finish (e4) Up to 92% Efficiency Programmable Soft-Start Output Overvoltage Protection Optional Short-Circuit Shutdown Timer Small Footprint, Low Profile (15mm x 15mm x 2.82mm) LGA Package Applications n n n n n The LTM(R)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 efficiency design delivers 10A continuous current (12A peak), needing no heat sinks or airflow to meet power specifications. Only bulk input and output capacitors are needed to finish the design. The low profile package (2.82mm) 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 sacrificing 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 compact (15mm x 15mm) and low profile (2.82mm) over-molded Land Grid Array (LGA) package suitable for automated assembly by standard surface mount equipment. The LTM4600HV is RoHS compliant. Telecom and Networking Equipment Military and Avionics Systems Industrial Equipment Point of Load Regulation Servers L, LT, LTC, LTM, Module and OPTI-LOOP are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Efficiency vs Load Current with 24VIN (FCB = 0) 100 10A Module Power Supply with 4.5V to 28V Input VIN 4.5V TO 28V ABSMAX CIN VIN VOUT LTM4600HV VOUT 2.5V* 10A COUT VOSET PGND SGND *REVIEW DE-RATING CURVE AT THE HIGHER INPUT VOLTAGE 90 EFFICIENCY (%) n Description 80 70 60 31.6k 50 4600hv TA01a 40 30 1.8VOUT 2.5VOUT 3.3VOUT 5VOUT 0 2 4 6 LOAD CURRENT (A) 8 10 4600HV TA01b 4600hvfe For more information www.linear.com/LTM4600HV 1 LTM4600HV Absolute Maximum Ratings Pin Configuration (Note 1) TOP VIEW fADJ SVIN EXTVCC VOSET FCB, EXTVCC, PGOOD, RUN/SS, VOUT.......... -0.3V to 6V VIN, SVIN, fADJ............................................. -0.3V to 28V VOSET, COMP............................................. -0.3V to 2.7V Operating Temperature Range (Note 2) E and I Grades......................................-40C to 85C MP Grade............................................ -55C to 125C Junction Temperature............................................ 125C Storage Temperature Range................... -55C to 125C Peak Solder Reflow Body Temperature.................. 245C COMP SGND RUN/SS FCB VIN PGOOD PGND VOUT LGA PACKAGE 104-LEAD (15mm x 15mm x 2.82mm) TJMAX = 125C, JA = 15C/W, JC = 6C/W, JA DERIVED FROM 95mm x 76mm PCB WITH 4 LAYERS, WEIGHT = 1.7g Order Information PART MARKING PART NUMBER PAD OR BALL FINISH LTM4600HVEV#PBF LTM4600HVIV#PBF LTM4600HVMPV#PBF DEVICE FINISH CODE PACKAGE TYPE MSL RATING e4 LGA 3 LTM4600HVEV Au (RoHS) LTM4600HVIV TEMPERATURE RANGE (SEE NOTE 2) -40C to 85C LTM4600HVMPV -40C to 85C -55C to 125C * Consult Marketing for parts specified with wider operating temperature ranges. *Pad or ball finish code is per IPC/JEDEC J-STD-609. * Recommended LGA and BGA PCB Assembly and Manufacturing Procedures: www.linear.com/umodule/pcbassembly * Terminal Finish Part Marking: www.linear.com/leadfree * LGA and BGA Package and Tray Drawings: www.linear.com/packaging 2 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C, VIN = 12V. External CIN = 120F, COUT = 200F/Ceramic per typical application (front page) configuration. SYMBOL VIN(DC) PARAMETER Input DC Voltage CONDITIONS Abs Max 28V for Tolerance on 24V Inputs VOUT(DC) Output Voltage FCB = 0V VIN = 5V or 12V, VOUT = 1.5V, IOUT = 0A MIN 4.5 TYP l MAX 28 UNITS V l 1.478 1.470 1.50 1.50 1.522 1.530 V V 3.4 4 V Input Specifications VIN(UVLO) Under Voltage Lockout Threshold IOUT = 0A IINRUSH(VIN) Input Inrush Current at Startup IQ(VIN) Input Supply Bias Current IOUT = 0A, VOUT = 1.5V, FCB = 0 VIN = 5V VIN = 12V VIN = 24V IOUT = 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 = 12V Min On Time Min Off Time IS(VIN) Input Supply Current VIN = 12V, VOUT = 1.5V, IOUT = 10A VIN = 12V, VOUT = 3.3V, IOUT = 10A VIN = 5V, VOUT = 1.5V, IOUT = 10A VIN = 24V to 3.3V at 10A, EXTVCC = 5V 0.6 0.7 0.8 A A A 1.2 42 1.8 36 35 100 mA mA mA mA A ns 75 400 ns 1.52 3.13 3.64 1.6 A A A A Output Specifications IOUTDC VOUT(LINE) Output Continuous Current Range (See Output Current Derating Curves for Different VIN, VOUT and TA) Line Regulation Accuracy VOUT VOUT(LOAD) Load Regulation Accuracy VIN = 12V, VOUT = 1.5V VIN = 24V, VOUT = 2.5V (Note 3) VOUT = 1.5V. FCB = 0V, IOUT = 0A, VIN = 4.5V to 28V VOUT(AC) Output Ripple Voltage VOUT = 1.5V. FCB = 0V, IOUT = 0A to 10A VIN = 5V VIN = 12V (Notes 4, 5) VIN = 12V, VOUT = 1.5V, FCB = 0V, IOUT = 0A fs Output Ripple Voltage Frequency FCB = 0V, IOUT = 5A, VIN = 12V, VOUT = 1.5V tSTART Turn-On Time VOUT tSETTLE VOUT = 1.5V, IOUT = 1A VIN = 12V VIN = 5V Voltage Drop for Dynamic Load Step VOUT = 1.5V, Load Step: 0A/s to 5A/s COUT = 3 * 22F 6.3V, 470F 4V POSCAP, See Table 2 Settling Time for Dynamic Load Step VIN = 12V Load: 10% to 90% to 10% of Full Load IOUTPK Output Current Limit Output Voltage in Foldback VIN = 24V, VOUT = 2.5V VIN = 12V, VOUT = 1.5V VIN = 5V, VOUT = 1.5V VOSET Voltage at VOSET Pin IOUT = 0A, VOUT = 1.5V VRUN/SS RUN ON/OFF Threshold VOUTLS 0 0 l 10 10 A A 0.15 0.3 % % % 10 1 1.5 15 l mVP-P 850 kHz 0.5 0.7 36 ms ms mV 25 s 17 17 17 A A A Control Stage l 0.591 0.594 0.8 0.6 0.6 1.5 0.609 0.606 2 V V V 4600hvfe For more information www.linear.com/LTM4600HV 3 LTM4600HV Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C, VIN = 12V. External CIN = 120F, COUT = 200F/Ceramic per typical application (front page) configuration. SYMBOL IRUN(C)/SS PARAMETER Soft-Start Charging Current IRUN(D)/SS Soft-Start Discharging Current VIN - SVIN IEXTVCC Current into EXTVCC Pin RFBHI Resistor Between VOUT and VOSET Pins VFCB Forced Continuous Threshold IFCB Forced Continuous Pin Current CONDITIONS VRUN/SS = 0V MIN -0.5 VRUN/SS = 4V 0.8 TYP -1.2 MAX -3 1.8 3 UNITS A A EXTVCC = 0V, FCB = 0V 100 mV EXTVCC = 5V, FCB = 0V, VOUT = 1.5V, IOUT = 0A 16 mA 100 k 0.57 VFCB = 0.6V 0.6 0.63 V -1 -2 A PGOOD Output VOSETH PGOOD Upper Threshold VOSET Rising 7.5 10 12.5 % VOSETL PGOOD Lower Threshold VOSET Falling -7.5 -10 -12.5 % VOSET(HYS) PGOOD Hysteresis VOSET Returning VPGL PGOOD Low Voltage IPGOOD = 5mA 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 LTM4600HVE is guaranteed to meet performance specifications from 0C to 85C. Specifications over the -40C to 85C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM4600HVI 4 2 0.15 % 0.4 V is guaranteed over the -40C to 85C temperature range. The LTM46000HVMP is guaranteed and tested over the -55C to 125C temperature range. Note 3: For output current derating at high temperature, please refer to Thermal Considerations and Output Current Derating discussion. Note 4: Test assumes current derating versus temperature. Note 5: Guaranteed by correlation. 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Typical Performance Characteristics 100 Efficiency vs Load Current with 12VIN (FCB = 0) 100 90 90 80 80 80 70 60 50 40 30 0 2 8 6 4 LOAD CURRENT (A) 70 60 0.6VOUT 1.2VOUT 1.5VOUT 2.5VOUT 3.3VOUT 50 0.6VOUT 1.2VOUT 1.5VOUT 2.5VOUT 40 10 30 0 2 4 6 LOAD CURRENT (A) 4600hv G01 Efficiency vs Load Current with Different FCB Settings EFFICIENCY (%) 90 EFFICIENCY (%) EFFICIENCY (%) 100 Efficiency vs Load Current with 5VIN (FCB = 0) (See Figure 21 for all curves) 8 Efficiency vs Load Current with 24VIN (FCB = 0) 70 60 50 1.8VOUT 2.5VOUT 3.3VOUT 5VOUT 40 10 30 0 2 4 6 LOAD CURRENT (A) 4600hv G02 1.2V Transient Response 8 10 4600hv G03 1.5V Transient Response 90 FCB > 0.7V 80 VOUT = 50mV/DIV EFFICIENCY (%) 70 60 FCB = GND 50 IOUT = 5A/DIV 40 30 20 0.1 25s/DIV VIN = 12V VOUT = 1.5V 1 LOAD CURRENT (A) 10 4600HV G05 25s/DIV 1.2V AT 5A/s LOAD STEP COUT = 3 * 22F 6.3V CERAMICS 470F 4V SANYO POSCAP C3 = 100pF 1.5V AT 5A/s LOAD STEP COUT = 3 * 22F 6.3V CERAMICS 470F 4V SANYO POSCAP C3 = 100pF 2.5V Transient Response 3.3V Transient Response 4600HV G06 4600hv G04 1.8V Transient Response 25s/DIV 1.8V AT 5A/s LOAD STEP COUT = 3 * 22F 6.3V CERAMICS 470F 4V SANYO POSCAP C3 = 100pF 4600HV G07 25s/DIV 4600HV G08 2.5V AT 5A/s LOAD STEP COUT = 3 * 22F 6.3V CERAMICS 470F 4V SANYO POSCAP C3 = 100pF 25s/DIV 4600HV G09 3.3V AT 5A/s LOAD STEP COUT = 3 * 22F 6.3V CERAMICS 470F 4V SANYO POSCAP C3 = 100pF 4600hvfe For more information www.linear.com/LTM4600HV 5 LTM4600HV Typical Performance Characteristics (See Figure 21 for all curves) Start-Up, IOUT = 10A (Resistive Load) Start-Up, IOUT = 0A VOUT (0.5V/DIV) VOUT (0.5V/DIV) IIN (0.5A/DIV) IIN (0.5A/DIV) 4600HV G11 200s/DIV VIN = 12V VOUT = 1.5V COUT = 200F NO EXTERNAL SOFT-START CAPACITOR 4600HV G10 200s/DIV VIN = 12V VOUT = 1.5V COUT = 200F NO EXTERNAL SOFT-START CAPACITOR Short-Circuit Protection, IOUT = 0A Short-Circuit Protection, IOUT = 10A 5.5 fADJ = OPEN 5.0 VOUT (0.5V/DIV) VOUT (0.5V/DIV) VIN to VOUT Step-Down Ratio 5V 4.5 4.0 IIN (0.2A/DIV) IIN (0.5A/DIV) 4600HV G12 200s/DIV VIN = 12V VOUT = 1.5V COUT = 2x 200F/X5R NO EXTERNAL SOFT-START CAPACITOR 3.3V VOUT (V) 3.5 3.0 2.5V 2.5 1.8V 2.0 4600HV G13 20s/DIV VIN = 12V VOUT = 1.5V COUT = 2x 200F/X5R NO EXTERNAL SOFT-START CAPACITOR 1.5V 1.5 1.0 1.2V 0.5 0 0.6V 0 5 10 20 15 VIN (V) 24 SEE FREQUENCY ADJUSTMENT DISCUSSION FOR 12VIN TO 5VOUT AND 5VIN TO 3.3VOUT CONVERSION 4600HV G14 VOSET vs Temperature 12V Input Load Regulation vs Temperature Start-Up Waveform, TA = -55C 0.00 0.610 -0.05 -0.10 LOAD REGULATION % VOSET(V) 0.605 0.600 0.595 0.590 -55 -0.20 -0.25 25C -0.30 100C -0.35 -25 5 35 65 TEMPERATURE (C) 95 125 VIN = 12V VOUT = 1.5V IOUT = 10A 400s/DIV 4600HV G16 -45C -0.40 -0.45 0 5 LOAD CURRENT 10 4600HV G17 4600HV G15 6 -0.15 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Pin Functions (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. 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. 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 200F 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 5A pull up current. The RUN/SS pin has an internal 6V Zener to ground. 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. 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 efficiency operation at light loads. There is an internal 4.75K resistor between the FCB and SGND pins. VOSET (Pin A21): The Negative Input of The Error Amplifier. 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. 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. COMP (Pin B23): Current Control Threshold and Error Amplifier 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). 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. 5 6 VOSET 4 EXTVCC 3 SVIN 2 fADJ TOP VIEW 16 17 18 19 7 1 VIN BANK 1 9 10 8 13 14 32 PGND BANK 2 VOUT BANK 3 1 26 27 28 29 30 31 33 34 35 36 37 38 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 2 4 6 7 8 9 10 11 12 C 22 E 24 40 5 21 23 39 3 A 15 12 25 20 11 13 14 15 16 17 18 19 20 21 22 G J B COMP D SGND F RUN/SS H K FCB PGOOD L M N P R T 23 For more information www.linear.com/LTM4600HV 4600hv PN01 4600hvfe 7 LTM4600HV Simplified Block Diagram SVIN RUN/SS LTM4600HV VIN, 4.5V TO 28V ABS MAX 1000pF CIN 1.5F PGOOD Q1 COMP INT COMP VOUT, 2.5V/10A MAX FCB 4.75k COUT 15F 6.3V CONTROLLER fADJ SGND PGND Q2 10 EXTVCC 100k 0.5% VOSET R6 31.6k 4600hv F01 Figure 1. Simplified LTM4600HV Block Diagram Decoupling Requirements TA = 25C, VIN = 12V. Use Figure 1 configuration. SYMBOL PARAMETER CONDITIONS CIN External Input Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V) IOUT = 10A, 2x 10F 35V Ceramic Taiyo Yuden GDK316BJ106ML 20 COUT External Output Capacitor Requirement (VIN = 4.5V to 28V, VOUT = 2.5V) IOUT = 10A, Refer to Table 2 in the Applications Information Section 100 8 MIN TYP MAX UNITS F 200 F 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Operation Module Description The 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 simplified 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 sufficient 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 1.2A current source to charge up the soft-start capacitor. When this voltage reaches 1.5V, the controller turns on and begins switching. At low load current the module works in continuous current mode by default to achieve minimum output voltage ripple. It can be programmed to operate in discontinuous current mode for improved light load efficiency 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 applied 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 Module. 4600hvfe For more information www.linear.com/LTM4600HV 9 LTM4600HV Applications Information 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 Margining The PWM controller of the LTM4600HV has an internal 0.6V1% 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. RSET (k) Open 100 66.5 49.9 43.2 31.6 22.1 13.7 VO (V) 0.6 1.2 1.5 1.8 2 2.5 3.3 5 Voltage 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/protection 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 voltage is margined up. The output voltage is margined VOUT RDOWN 100k QDOWN 2N7002 VOSET PGND SGND RSET RUP QUP 2N7002 4600hv F02 Figure 2. LTM4600HV Margining Implementation 10 (RSET RUP ) * VO * (1+M%) = 0.6V (RSET RUP )+ 100k RSET * VO * (1- M%) = 0.6V RSET +(100k RDOWN ) Input Capacitors Table 1 shows the standard values of 1% RSET resistor for typical output voltages: LTM4600HV 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: The LTM4600HV Module should be connected to a low ac-impedance DC source. High frequency, low ESR input capacitors are required to be placed adjacent to the module. 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= VO VIN Without considering the inductor current ripple, the RMS current of the input capacitor can be estimated as: ICIN(RMS) = IO(MAX) % * D * (1-D) In the above equation, % is the estimated efficiency 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 frequency input decoupling capacitors. In a typical 10A output application, 1-2 pieces of very low ESR X5R or X7R (for extended temperature range), 10F ceramic capacitors are recommended. This decoupling capacitor should be placed directly adjacent the module input pins 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV applications information in the PCB layout to minimize the trace inductance and high frequency AC noise. Output Capacitors The 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 200F if all ceramic output capacitors are used. The internally optimized loop compensation provides sufficient stability margin for all ceramic capacitors applications. Additional output filtering 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 capacitance matrix for each output voltage droop, peak to peak deviation and recovery time during a 5A/s transient with a specific output capacitance. Fault Conditions: Current Limit and Over current Foldback The 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 condition, 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. VIN to VOUT Step-Down Ratios There are restrictions in the maximum VIN to VOUT step down ratio that can be achieved for a given input voltage. These constraints are shown in VIN to VOUT Step-Down Ratio in the Typical Performance Characteristics section. Note that additional thermal derating may apply. See the Thermal Considerations and Output Current Derating sections of this data sheet. Soft-Start and Latchoff with the RUN/SS pin The RUN/SS pin provides a means to shut down the LTM4600HV as well as a timer for soft-start and overcurrent latchoff. Pulling the RUN/SS pin below 0.8V puts the LTM4600HV into a low quiescent current shutdown (IQ 75A). Releasing the pin allows an internal 1.2A current source to charge up the timing capacitor CSS. Inside LTM4600HV, there is an internal 1000pF capacitor 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) 1.2A When the voltage on RUN/SS pin reaches 1.5V, the LTM4600HV internal switches are operating with a clamping 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. 4600hvfe For more information www.linear.com/LTM4600HV 11 LTM4600HV Applications Information Table 2. Output Voltage Response Versus Component Matrix *(Refer to Figure 21) TYPICAL MEASURED VALUES COUT1 VENDORS TDK TAIYO YUDEN TAIYO YUDEN TAIYO YUDEN PART NUMBER C4532X5R0J107MZ (100F,6.3V) JMK432BJ107MU-T ( 100F, 6.3V) JMK316BJ226ML-T501 ( 22F, 6.3V) JMK316BJ226ML-T501 ( 22F, 6.3V) VOUT CIN CIN COUT1 (V) (CERAMIC) (BULK) (CERAMIC) 2 x 10F 35V 1.2 150F 35V 3 x 22F 6.3V 1.2 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.2 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.2 2 x 10F 35V 150F 35V 4 x 100F 6.3V 1.2 2 x 10F 35V 150F 35V 3 x 22F 6.3V 1.2 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.2 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.2 2 x 10F 35V 150F 35V 4 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 3 x 22F 6.3V 1.5 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 4 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 3 x 22F 6.3V 1.5 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.5 2 x 10F 35V 150F 35V 4 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 3 x 22F 6.3V 1.8 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 4 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 3 x 22F 6.3V 1.8 2 x 10F 35V 150F 35V 1 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 2 x 100F 6.3V 1.8 2 x 10F 35V 150F 35V 4 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 1 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 2 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 3 x 22F 6.3V 2.5 2 x 10F 35V 150F 35V 4 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 1 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 3 x 22F 6.3V 150F 35V 2 x 100F 6.3V 2.5 2 x 10F 35V 2.5 2 x 10F 35V 150F 35V 4 x 100F 6.3V 2.5 2 x 10F 35V 150F 35V 3 x 22F 6.3V 2.8 2 x 10F 35V 150F 35V 3 x 22F 6.3V 3.3 2 x 10F 35V 150F 35V 2 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 1 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 3 x 22F 6.3V 3.3 2 x 10F 35V 150F 35V 4 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 1 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 3 x 22F 6.3V 3.3 2 x 10F 35V 150F 35V 2 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 4 x 100F 6.3V 3.3 2 x 10F 35V 150F 35V 3 x 22F 6.3V 5 2 x 10F 35V 150F 35V 4 x 100F 6.3V 5 2 x 10F 35V 150F 35V 4 x 100F 6.3V *X7R is recommended for extended temperature range. 12 COUT2 (BULK) 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 470F 2.5V 330F 6.3V NONE 470F 4V 330F 6.3V 470F 4V NONE 470F 4V 470F 4V 330F 6.3V NONE 470F 6.3V 470F 6.3V 330F 6.3V 470F 4V 470F 4V NONE 470F 4V 470F 4V 330F 6.3V NONE 470F 6.3V NONE NONE COUT2 VENDORS SANYO POSCAP SANYO POSCAP SANYO POSCAP SANYO POSCAP CCOMP C3 NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE NONE 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF 100pF VIN (V) 5 5 5 5 12 12 12 12 5 5 5 5 12 12 12 12 5 5 5 5 12 12 12 12 5 5 5 5 12 12 12 12 24 24 7 7 7 7 12 12 12 12 24 15 20 DROOP (mV) 35 35 40 49 35 35 40 49 36 37 44 61 36 37 44 54 40 44 46 62 40 44 44 62 48 56 57 60 48 51 56 70 56 50 64 66 82 100 52 64 64 76 74 188 159 PART NUMBER 6TPE330MIL (330F, 6.3V) 2R5TPE470M9 (470F, 2.5V) 4TPE470MCL (470F, 4V) 6TPD470M (470F, 6.3V) PEAK TO PEAK (mV) 68 70 80 98 68 70 80 98 75 79 84 118 75 79 89 108 81 88 91 128 81 85 91 125 103 113 116 115 103 102 113 159 112 100 126 132 166 200 106 129 126 144 149 375 320 RECOVERY TIME (s) 25 20 20 20 25 20 20 20 25 20 20 20 25 20 20 20 30 20 20 20 30 20 20 20 30 30 30 25 30 30 30 25 30 30 30 30 35 25 30 35 30 25 30 25 25 LOAD STEP (A/s) 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV applications information 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 1.8A 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, shutting 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: CSS _ EXT + 1000pF > COUT * VOUT 10kV Generally 0.1F is more than sufficient. Since the load current is already limited by the current mode control and current foldback circuitry during a short-circuit, 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 5A but less than 80A to the RUN/ SS pin. The additional current prevents the discharge of CSS during a fault and also shortens the soft-start period. Using a resistor from RUN/SS pin to VIN is a simple solution to defeat latchoff. Any pull-up network must be able to maintain RUN/SS above 4V maximum latchoff threshold and overcome the 4A maximum discharge current. With a pull-up resistor, the delay before starting is approximately: VRUN/SS 4V 3.5V 3V 1.5V SHORT-CIRCUIT LATCH ARMED SOFT-START CLAMPING OF IL RELEASED OUTPUT OVERLOAD HAPPENS t SHORT-CIRCUIT LATCHOFF VO 75%VO t SWITCHING STARTS 4600hv F03 Figure 3. RUN/SS Pin Voltage During Startup and Short-Circuit Protection VIN VIN RRUN/SS RECOMMENDED VALUES FOR RUN/SS LTM4600HV RUN/SS PGND SGND VIN RRUN/SS 4.5V TO 5.5V 10.8V TO 13.8V 24V TO 28V 50k 150k 500k 4600hv F04 Figure 4. Defeat Short-Circuit Latchoff with a Pull-Up Resistor to VIN tDELAY = -RRUN/SS * (CSS _ EXT + 1000pF ) 1.5V * ln 1- V + 1.2A * R ( ) IN RUN/SS Figure 3 shows a conceptual drawing of VRUN during startup and short-circuit. 4600hvfe For more information www.linear.com/LTM4600HV 13 LTM4600HV Applications Information Enable EXTVCC Connection The 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. An 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: RUN/SS PLDO_LOSS = 18mA * (VIN - 5V) LTM4600HV ON PGND SGND 2N7002 4600hv F05 Figure 5. Enable Circuit with External Logic Output Voltage Tracking For 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. Coincident, 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. VIN 5V Q1 DC/DC 3.3V VIN RONB VCC GATE RAMP ON RONA FB1 STATUS RTA1 SDO VIN FB2 LTM4600HV VOSET VOUT RTB2 TRACK2 RTA2 GND 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 efficiency supply compatible with the MOSFET gate drive requirements (typically 5V) can improve overall efficiency. 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 > 20V Discontinuous Operation and FCB Pin VIN RTB1 TRACK1 1.8V 49.9k LTC2923 RAMPBUF VIN LTM4600HV VOSET VOUT 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 internal 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: 1.5V 66.5k 4600hv F06 The 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. Figure 6. Output Voltage Tracking with the LTC2923 Controller 14 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV applications information In the application where the light load efficiency is important, tying the FCB pin above 0.6V threshold enables discontinuous operation where the bottom MOSFET turns off when inductor current reverses. Therefore, the conduction loss is minimized and light load efficiency is improved. The penalty is that the controller may skip cycle and the output voltage ripple increases at light load. Paralleling Operation with Load Sharing Two 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-LOOPTM current mode control ensures good current sharing among modules to balance the thermal stress. The new feedback equation for two or more LTM4600HVs in parallel is: VOUT 100k +RSET N = 0.6V * RSET VIN VOUT LTM4600HV VOUT (20AMAX) PGND COMP VOSET SGND RSET The 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. LTM4600HV The high integration of the LTM4600HV makes the PCB board layout very simple and easy. However, to optimize its electrical and thermal performance, some layout considerations are still necessary. * Use large PCB copper areas for high current path, including VIN, PGND and VOUT. It helps to minimize the PCB conduction loss and thermal stress * Place high frequency ceramic input and output capacitors next to the VIN, PGND and VOUT pins to minimize high frequency noise COMP VOSET SGND VIN Safety Considerations Layout Checklist/Example where N is the number of LTM4600HVs in parallel. VIN explanation of the analysis for the thermal models, and the derating curves. Tables 3 and 4 provide a summary of the equivalent qJA for the noted conditions. These equivalent qJA parameters are correlated to the measure values, and improved with air-flow. The case temperature is maintained at 100C or below for the derating curves. This allows for 4W maximum power dissipation in the total module with top and bottom heat sinking, and 2W power dissipation through the top of the module with an approximate qJC between 6C/W to 9C/W. This equates to a total of 124C at the junction of the device. VOUT PGND 4600hv F07 Figure 7. Parallel Two Modules with Load Sharing Thermal Considerations and Output Current Derating The 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 qJA for the module with various heat sinking methods. Thermal models are derived from several temperature measurements at the bench, and thermal modeling analysis. Application Note 103 provides a detailed * 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 components connected to signal pins. Connect the SGND to PGND underneath the unit Figure 20 gives a good example of the recommended layout. 4600hvfe For more information www.linear.com/LTM4600HV 15 LTM4600HV Applications Information 18V LOSS 3.0 2.5 12V LOSS 2.0 1.5 5V LOSS 1.0 0.5 0 2 0 4 6 8 OUTPUT CURRENT (A) 9 8 7 6 5 4 10 0 LFM 200 LFM 400 LFM 50 60 80 70 AMBIENT TEMPERATURE (C) 4600hv F08 6 5 0 LFM 200 LFM 400 LFM 50 55 60 65 70 75 80 85 AMBIENT TEMPERATURE (C) 9 POWER LOSS (W) MAXIMUM LOAD CURRENT (A) 4 6 5 0 LFM 200 LFM 400 LFM 4 50 8 7 6 5 4 3 2 0 LFM 200 LFM 400 LFM 1 60 70 80 90 AMBIENT TEMPERATURE (C) 0 100 40 100 10 4.5 9 3.5 24V LOSS 3.0 2.5 2.0 12V LOSS 1.5 0 VIN = 12V VOUT = 3.3V 8 7 6 5 4 3 2 0 LFM 200 LFM 400 LFM 1 0 2 4 6 8 OUTPUT CURRENT (A) 4600hv F14 Figure 14. BGA Heat Sink 90 4600hv F13 5.0 0.5 80 90 60 70 AMBIENT TEMPERATURE (C) 60 80 50 70 AMBIENT TEMPERATURE (C) Figure 13. No Heat Sink 1.0 0 LFM 200 LFM 400 LFM 100 VIN = 18V VOUT = 1.5V Figure 12. BGA Heat Sink 6 60 70 80 90 AMBIENT TEMPERATURE (C) 9 4.0 16 50 4600hv F12 VIN = 18V VOUT = 1.5V 50 0 LFM 200 LFM 400 LFM 10 7 3 90 8 0 5 Figure 10. BGA Heat Sink 8 Figure 11. No Heat Sink 2 6 4600hv F10 VIN = 12V VOUT = 1.5V 4600hv F11 10 7 4 90 MAXIMUM LOAD CURRENT (A) 7 4 10 MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) 8 8 Figure 9. No Heat Sink VIN = 12V VOUT = 1.5V 9 9 VIN = 5V VOUT = 1.5V 4600hv F09 Figure 8. 1.5V Power Loss Curves vs Load Current 10 10 VIN = 5V VOUT = 1.5V MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) 3.5 POWER LOSS (W) 10 VOUT = 1.5V 4.0 MAXIMUM LOAD CURRENT (A) 4.5 10 0 40 50 60 80 70 AMBIENT TEMPERATURE (C) 90 4600hv F15 Figure 15. 3.3V Power Loss Curves vs Load Current 4600hv F16 Figure 16. No Heat Sink 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV applications information 8 7 6 5 4 0 LFM 200 LFM 400 LFM 40 60 70 80 90 50 AMBIENT TEMPERATURE (C) 100 VIN = 24V VOUT = 3.3V TEMPERATURE DE-RATING 8 6 4 2 0 0 LFM 200 LFM 400 LFM 50 60 80 70 AMBIENT TEMPERATURE (C) 4600hv F17 Figure 17. BGA Heat Sink 90 10 MAXIMUM LOAD CURRENT (A) 9 10 VIN = 12V VOUT = 3.3V MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) 10 0 LFM 200 LFM 400 LFM 9 8 7 6 5 VIN = 24V VOUT = 3.3V TEMPERATURE DE-RATING 4 60 70 80 50 AMBIENT TEMPERATURE (C) 4600hv F18.eps 90 4600hv F19.eps Figure 18. No Heat Sink Figure 19. BGA Heat Sink Table 3. 1.5V Output DERATING CURVE VIN (V) POWER LOSS CURVE AIR FLOW (LFM) HEAT SINK qJA (C/W) Figures 9, 11, 13 5, 12, 18 Figure 8 0 None 15.2 Figures 9, 11, 13 5, 12, 18 Figure 8 200 None 14 Figures 9, 11, 13 5, 12, 18 Figure 8 400 None 12 Figures 10, 12, 14 5, 12, 18 Figure 8 0 BGA Heat Sink 13.9 Figures 10, 12, 14 5, 12, 18 Figure 8 200 BGA Heat Sink 11.3 Figures 10, 12, 14 5, 12, 18 Figure 8 400 BGA Heat Sink 10.25 DERATING CURVE VIN (V) POWER LOSS CURVE AIR FLOW (LFM) HEAT SINK qJA (C/W) Figures 16, 18 12, 24 Figure 15 0 None 15.2 Figures 16, 18 12, 24 Figure 15 200 None 14.6 Figures 16, 18 12, 24 Figure 15 400 None 13.4 Table 4. 3.3V Output Figures 17, 19 12, 24 Figure 15 0 BGA Heat Sink 13.9 Figures 17, 19 12, 24 Figure 15 200 BGA Heat Sink 11.1 Figures 17, 19 12, 24 Figure 15 400 BGA Heat Sink 10.5 4600hvfe For more information www.linear.com/LTM4600HV 17 LTM4600HV Applications Information VIN t (DC) DUTY CYCLE = ON ts tOFF CIN tON t V DC = ON = OUT ts VIN DC FREQ = tON 4602 F25 PERIOD ts PGND VOUT 4600hv F20 LOAD TOP LAYER Figure 20. Recommended PCB Layout LTM4600HV Frequency Adjustment The LTM4600HV is designed to typically operate at 850kHz across most input and output conditions. The control architecture 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 operating 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, therefore 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). 18 The 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 switching 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 = 103A 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/frequency tOFF must be greater than 400ns, or tS - tON > 400ns. tON = DC * tS 1MHz frequency or 1s period is chosen for 12V to 5V. 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV applications information tOFF must be greater than 400ns, or tS - tON > 400ns. tON = 0.41 * 1s @ 410ns tON = DC * tS tOFF = 1s - 410ns @ 590ns tON 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) @ 58A. ION current calculated from 12V input was 103A, so a resistor from fADJ to ground = (0.7V/15k) = 46A. 103A - 46A = 57A, 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. Equations for setting frequency for 5V to 3.3V: ION = (VIN - 0.7V)/110k; ION = 39A frequency = (ION/[2.4V * 10pF]) * DC = 1.07MHz; DC = duty cycle, duty cycle is (VOUT/VIN) tS = tON + tOFF, tON = on-time, tOFF = off-time of the switching period; tS = 1/frequency ~450kHz frequency or 2.22s period is chosen for 5V to 3.3V. Frequency range is about 450kHz to 650kHz from 4.5V to 7V input. tON = 0.66 * 2.22s @ 1.46s tOFF = 2.22s - 1.46s @ 760ns tON and tOFF are above the minimums with adequate guard band. Using the frequency = (ION/[2.4V * 10pF]) * DC, solve for ION = (450kHz * 2.4V * 10pF) * (1/0.66) @ 16A. ION current calculated from 5V input was 39A, so a resistor from fADJ to ground = (0.7V/30.1k) = 23A. 39A - 23A = 16A, sets the adequate ION current for proper frequency range for the higher duty cycle conversion of 5V to 3.3V. Input voltage range is limited to 4.5V to 7V. Higher input voltages can be used without the 30.1k on fADJ. The inductor ripple current gets too high above 7V, and the 400ns minimum off-time is limited below 4.5V. 5V to 3.3V at 8A R1 30.1k 4.5V TO 7V C3 10F 25V C1 10F 25V VIN C5 100pF fADJ EXTVCC 3.3V AT 8A VOUT FCB VOSET R2 22.1k 1% LTM4600HV RUN/SOFT-START RUN/SS SVIN PGOOD COMP SGND EFFICIENCY = 94% C2 22F + C4 330F 6.3V OPEN DRAIN PGND 4600 F22 5V TO 3.3V AT 8A WITH fADJ = 30.1k LTM4600HV MINIMUM ON-TIME = 100ns LTM4600HV MINIMUM OFF-TIME = 400ns C1, C3: TDK C3216X5R1E106MT C2: TAIYO YUDEN, JMK316BJ226ML C4: SANYO POSCAP, 6TPE330MIL 4600hvfe For more information www.linear.com/LTM4600HV 19 LTM4600HV Applications Information 12V to 5V at 8A R1 15k 9V TO 16V C1 10F 25V VIN 5.0 fADJ EXTVCC VOSET RUN/SS SVIN SGND + C4 330F 6.3V 3.5 2.5 2.0 1.0 PGND 3.3V AT 8A 5V AT 8A 0.5 4600 F23 12V TO 5V AT 8A WITH fADJ = 15k LTM4600HV MINIMUM ON-TIME = 100ns LTM4600HV MINIMUM OFF-TIME = 400ns 3.0 1.5 OPEN DRAIN PGOOD COMP EFFICIENCY = 94% C2 22F R2 13.7k 1% LTM4600HV RUN/SOFT-START 4.0 5V AT 8A VOUT FCB 3.3V: fADJ = 30.1k 4.5 5V: fADJ = 15k C5 100pF VOUT (V) C3 10F 25V VIN to VOUT Step-Down Ratio for 12V to 5V and 5V to 3.3V 0 C1, C3: TDK C3216X5R1E106MT C2: TAIYO YUDEN, JMK316BJ226ML C4: SANYO POSCAP, 6TPE330MIL 1 3 5 7 9 11 VIN (V) 13 15 17 4600 F24 Typical Applications VIN + 5V TO 24V CIN (BULK) 150F CIN (CER) 10F 2x GND EXTVCC C3 100pF SVIN VIN (MULTIPLE PINS) VOUT (MULTIPLE PINS) fADJ VOSET VOUT COMP LTM4600HV FCB COUT1 + 22F 6.3V x3 REFER TO TABLE 2 RUN/SS PGOOD VOUT COUT2 470F REFER TO TABLE 2 0.6V TO 5V SGND C4 OPT REFER TO STEP DOWN RATIO GRAPH PGND (MULTIPLE PINS) R1 66.5k REFER TO TABLE 1 GND 4600HV F21 Figure 21. Typical Application, 5V to 24V Input, 0.6V to 5V Output, 10A Max 20 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Typical Applications Parallel Operation and Load Sharing 4.5V TO 24V C8 10F 35V C7 10F 35V VOUT = 0.6V * ([100k/N] + RSET)/RSET WHERE N = 2 VIN fADJ EXTVCC VOUT FCB C9 22F x3 VOSET LTM4600HV RUN R4 15.8k 1% SVIN + C10 470F 4V PGOOD COMP SGND PGND 2.5V AT 20A RUN/SOFT-START C1 10F 35V VIN C4 220pF fADJ EXTVCC 2.5V VOUT FCB C2 22F x3 VOSET LTM4600HV RUN + C5 470F 4V R1 100k SVIN PGOOD COMP SGND PGND C1, C3, C7, C8: TAIYO YUDEN, GDK316BJ106ML C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501 C5, C10: SANYO POSCAP, 4TPE470MCL 4600hv TA02 Current Sharing Between Two LTM4600HV Modules 12 12VIN 2.5VOUT 10 20AMAX INDIVIDUAL SHARE C3 10F 35V IOUT2 8 IOUT1 6 4 2 0 0 5 10 TOTAL LOAD 15 20 4600hv TA03 4600hvfe For more information www.linear.com/LTM4600HV 21 5.7150 2.5400 0.3175 0.3175 2.7375 For more information www.linear.com/LTM4600HV C(0.30) PAD 1 13.97 BSC 0.11 - 0.27 6.9850 4.4450 1.2700 0.0000 1.4675 4.0075 1 6.9421 1 1 8 12 25 32 32 25 12 8 94 83 72 61 50 39 5.7158 2 3 4 40 3 5 6 41 34 27 7 8 89 78 67 56 45 100 88 77 66 55 44 36 29 15 11 99 35 28 14 10 7 98 87 76 65 54 43 13 9 6 0.0000 37 30 16 10 9 13 43 54 65 76 87 98 11 6 28 35 13 7 29 36 13.93 BSC 12 10 14 44 55 66 77 88 99 12.70 BSC 14 11 15 45 56 67 78 89 100 15 16 30 37 BOTTOM VIEW 9 5 27 26 4 34 33 42 53 52 51 86 97 64 85 96 63 50 1.9058 5 91 102 90 80 69 58 47 101 79 68 57 46 38 31 17 3.1742 18 16 46 57 68 79 90 101 17 17 31 38 18 47 58 69 80 91 102 19 18 SUGGESTED SOLDER PAD LAYOUT TOP VIEW 62 61 97 86 75 64 53 42 75 73 72 96 85 74 63 52 41 33 26 4.4950 5.7650 4 3.1758 74 84 83 2 95 84 73 62 51 40 1.0900 95 39 4.4458 2.3600 94 6.3500 5.2775 3.8100 6.5475 5.0800 0.6358 1.2700 1.9042 0.3175 0.3175 0.0000 3 2.5400 0.6342 1.2700 2 2.5400 4.4442 3.8100 6.9888 103 92 81 70 59 48 104 93 82 71 60 49 20 48 59 21 22 49 60 71 70 93 104 82 19 19 5.7142 81 92 103 5.0800 23 20 21 22 23 24 24 23 22 21 20 6.9865 6.3500 2.45 - 2.55 A C E G J L M N P R B D F H K 4600 02-18 eee M X Y 7 SEE NOTES PADS SEE NOTES T 3 DETAIL B MOLD CAP DETAIL B 4 PAD 1 CORNER aaa Z DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER IS A MARKED FEATURE OR A NOTCHED BEVELED PAD 4 7 15 BSC TOP VIEW LGA 104 1112 REV C PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG Module PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULLY SYMBOL TOLERANCE aaa 0.15 bbb 0.10 eee 0.15 ! 6. THE TOTAL NUMBER OF PADS: 104 5. PRIMARY DATUM -Z- IS SEATING PLANE LAND DESIGNATION PER JESD MO-222, SPP-010 3 2. ALL DIMENSIONS ARE IN MILLIMETERS NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 0.27 - 0.37 SUBSTRATE 2.72 - 2.92 (Reference LTM DWG # 05-05-1800 Rev C) Z 22 bbb Z LGA Package 104-Lead (15mm x 15mm x 2.82mm) X 15 BSC Y aaa Z LTM4600HV Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 4600hvfe LTM4600HV package description Pin Assignment Tables (Arranged by Pin Number) PIN NAME A1 A2 A3 VIN A4 A5 VIN A6 A7 VIN A8 A9 VIN A10 A11 VIN A12 A13 A14 A15 A16 A17 A18 A19 A20 A21 A22 A23 VIN fADJ SVIN EXTVCC VOSET - PIN NAME J1 PGND J2 J3 J4 J5 J6 J7 J8 J9 J10 J11 J12 J13 J14 J15 J16 J17 J18 J19 J20 J21 J22 J23 PGOOD PIN NAME B1 VIN B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 - PIN NAME C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 VIN C11 - PIN NAME D1 VIN D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 - PIN NAME E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 VIN E11 - PIN NAME F1 VIN F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 - PIN NAME G1 PGND G2 G3 G4 G5 G6 G7 G8 G9 G10 G11 - PIN NAME H1 H2 H3 H4 H5 H6 H7 PGND H8 H9 PGND H10 H11 PGND B12 B13 B14 B15 B16 B17 B18 B19 B20 B21 B22 B23 C12 C13 C14 C15 C16 C17 C18 C19 C20 C21 C22 C23 D12 D13 D14 D15 D16 D17 D18 D19 D20 D21 D22 D23 E12 E13 E14 E15 E16 E17 E18 E19 E20 E21 E22 E23 F12 F13 F14 F15 F16 F17 F18 F19 F20 F21 F22 F23 G12 G13 G14 G15 G16 G17 G18 G19 G20 G21 G22 G23 H12 H13 H14 H15 H16 H17 H18 H19 H20 H21 H22 H23 COMP PIN NAME K1 K2 K3 K4 K5 K6 K7 PGND K8 K9 PGND K10 K11 PGND K12 K13 PGND K14 K15 PGND K16 K17 PGND K18 K19 K20 K21 K22 K23 - VIN VIN - PIN NAME L1 L2 PGND L3 L4 PGND L5 L6 PGND L7 L8 PGND L9 L10 PGND L11 L12 PGND L13 L14 PGND L15 L16 PGND L17 L18 PGND L19 L20 PGND L21 L22 PGND L23 - SGND PIN NAME M1 M2 PGND M3 M4 PGND M5 M6 PGND M7 M8 PGND M9 M10 PGND M11 M12 PGND M13 M14 PGND M15 M16 PGND M17 M18 PGND M19 M20 PGND M21 M22 PGND M23 - VIN VIN - PIN NAME N1 N2 PGND N3 N4 PGND N5 N6 PGND N7 N8 PGND N9 N10 PGND N11 N12 PGND N13 N14 PGND N15 N16 PGND N17 N18 PGND N19 N20 PGND N21 N22 PGND N23 - RUN/SS PIN NAME P1 P2 VOUT P3 P4 VOUT P5 P6 VOUT P7 P8 VOUT P9 P10 VOUT P11 P12 VOUT P13 P14 VOUT P15 P16 VOUT P17 P18 VOUT P19 P20 VOUT P21 P22 VOUT P23 - FCB PIN NAME R1 R2 VOUT R3 R4 VOUT R5 R6 VOUT R7 R8 VOUT R9 R10 VOUT R11 R12 VOUT R13 R14 VOUT R15 R16 VOUT R17 R18 VOUT R19 R20 VOUT R21 R22 VOUT R23 - PGND PGND PGND - PIN NAME T1 T2 VOUT T3 T4 VOUT T5 T6 VOUT T7 T8 VOUT T9 T10 VOUT T11 T12 VOUT T13 T14 VOUT T15 T16 VOUT T17 T18 VOUT T19 T20 VOUT T21 T22 VOUT T23 4600hvfe For more information www.linear.com/LTM4600HV 23 LTM4600HV package description Pin Assignment Tables (Arranged by Pin Number) PIN NAME 24 G1 PGND H7 H9 H11 H13 H15 H17 PGND PGND PGND PGND PGND PGND J1 PGND K7 K9 K11 K13 K15 K17 PGND PGND PGND PGND PGND PGND L2 L4 L6 L8 L10 L12 L14 L16 L18 L20 L22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND M2 M4 M6 M8 M10 M12 M14 M16 M18 M20 M22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND N2 N4 N6 N8 N10 N12 N14 N16 N18 N20 N22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PIN NAME P2 P4 P6 P8 P10 P12 P14 P16 P18 P20 P22 VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT R2 R4 R6 R8 R10 R12 R14 R16 R18 R20 R22 VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT T2 T4 T6 T8 T10 T12 T14 T16 T18 T20 T22 VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT PIN NAME PIN NAME A3 A5 A7 A9 A11 A13 VIN VIN VIN VIN VIN VIN B1 VIN C10 C12 C14 VIN VIN VIN D1 VIN E10 E12 E14 VIN VIN VIN F1 VIN A15 fADJ A17 SVIN A19 EXTVCC A21 VOSET B23 COMP D23 SGND F23 RUN/SS G23 FCB J23 PGOOD 4600hvfe For more information www.linear.com/LTM4600HV LTM4600HV Revision History (Revision history begins at Rev E) REV DATE DESCRIPTION E 5/14 Added reflow temperature. PAGE NUMBER 2 Updated the Order Table. 2 Updated Notes. 4 Updated the Soft-Start and Latchoff section. 11, 13 4600hvfe 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 representation that the interconnection of information its circuits as described herein will not infringe on existing patent rights. For more www.linear.com/LTM4600HV 25 LTM4600HV Typical Application 1.8V, 10A Regulator 4.5V TO 22V C2 10F 35V C1 10F 35V VIN C5 100pF fADJ EXTVCC 1.8V AT 10A VOUT FCB VOSET R1 100k LTM4600HV RUN SVIN SGND PGND 4600hv TA04 + C4 470F 4V PGOOD PGOOD COMP C3 22F x3 R2 49.9k 1% C1, C2: TAIYO YUDEN, GDK316BJ106ML C3: TAIYO YUDEN, JMK316BJ226ML-T501 C4: SANYO POSCAP, 4TPE470MCL Related Parts PART NUMBER DESCRIPTION COMMENTS LTM4649 16VIN, 10A Step-Down Module Regulator 4.5V VIN 16V, 0.6V VOUT 3.3V, PLL Input, Remote Sense Amplifier, VOUT tracking, 9mm x 15mm x 4.92mm BGA LTM4641 38VIN, 10A Step-Down Module Regulator with Advanced Input & Load Protection 4.5V VIN 38V, 0.6V VOUT 6V, Adjustable Protection Trip Thresholds for Many Faults: (Output Overvoltage, Input Overvoltage, Input Undervoltage, Overtemperature), 15mm x 15mm x 5.01mm BGA LTM4633 Triple 10A, 16VIN Step-Down DC/DC Module 4.7V VIN 16V, 0.8V VOUT1,2 1.8V, 0.8V VOUT3 5.5V, PLL input, VOUT Soft-Start Regulator and Tracking, PGOOD, Internal Temperature Monitor, 15mm x 15mm x 5.01mm BGA LTM4627 20VIN, 15A DC/DC Step-Down Module Regulator LTM4611 1.5VIN(MIN), 15A DC/DC Step-Down Module 1.5V VIN 5.5V, 0.8V VOUT 5V, PLL Input, Remote Sense Amplifier, VOUT Tracking, Regulator 15mm x 15mm x 4.32mm LGA LTM4613 36VIN, 8A EN55022 Class B DC/DC Step-Down Module Regulator LTM8061 32V, 2A Step-Down Module Battery Charger Compatible with Single Cell or Dual Cell Li-Ion or Li-Poly Battery Stacks (4.1V, 4.2V, with Programmable Input Current Limit 8.2V, or 8.4V), 4.95V VIN 32V, C/10 or Adjustable Timer Charge Termination, NTC Resistor Monitor Input, 9mm x 15mm x 4.32mm LGA LTM8045 Inverting or SEPIC Module DC/DC Converter with Up to 700mA Output Current LTM8048 1.5W, 725VDC Galvanically Isolated Module 3.1V VIN 32V, 2.5V VOUT 12V, 1mVP-P Output Ripple, Internal Isolated Transformer, 9mm x 11.25mm x 4.92mm BGA Converter with LDO Post Regulator LTC2977 8-Channel PMBus Power System Manager 0.25% TUE 16-Bit ADC, Voltage/Temperature Monitoring and Supervision LTC2974 4-Channel PMBus Power System Manager 0.25% TUE 16-Bit ADC, Voltage/Current/Temperature Monitoring and Supervision 4.5V VIN 20V, 0.6V VOUT 5V, PLL Input, VOUT Tracking, Remote Sense Amplifier, 15mm x 15mm x 4.32mm LGA or 15mm x 15mm x 4.92mm BGA 5V VIN 36V, 3.3V VOUT 15V, PLL Input, VOUT Tracking and Margining, 15mm x 15mm x 4.32mm LGA 2.8V VIN 18V, 2.5V VOUT 15V, Synchronizable, No Derating or Logic Level Shift for Control Inputs When Inverting, 6.25mm x 11.25mm x 4.92mm BGA This product contains technology licensed from Silicon Semiconductor Corporation. 26 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTM4600HV (408) 432-1900 FAX: (408) 434-0507 www.linear.com/LTM4600HV (R) 4600hvfe LT 0514 REV E * PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2005