LTM4609 36VIN, 34VOUT High Efficiency Buck-Boost DC/DC µModule Regulator Description Features Single Inductor Architecture Allows VIN Above, Below or Equal to VOUT n Wide V Range: 4.5V to 36V IN n Wide V OUT Range: 0.8V to 34V nI OUT : 4A DC (10A DC in Buck Mode) n Up to 98% Efficiency n Current Mode Control n Power Good Output Signal n Phase-Lockable Fixed Frequency: 200kHz to 400kHz n Ultrafast Transient Response n Current Foldback Protection n Output Overvoltage Protection n RoHS Compliant with Pb-Free Finish: Gold Finish LGA (e4) or SAC 305 BGA (e1) n Small Surface Mount Footprint, Low Profile (15mm × 15mm × 2.82mm) LGA and (15mm × 15mm × 3.42mm) BGA Packages The LTM®4609 is a high efficiency switching mode buckboost power supply. Included in the package are the switching controller, power FETs and support components. Operating over an input voltage range of 4.5V to 36V, the LTM4609 supports an output voltage range of 0.8V to 34V, set by a resistor. This high efficiency design delivers up to 4A continuous current in boost mode (10A in buck mode). Only the inductor, sense resistor, bulk input and output capacitors are needed to finish the design. n The low profile package enables utilization of unused space on the bottom of PC boards for high density point of load regulation. The high switching frequency and current mode architecture enable a very fast transient response to line and load changes without sacrificing stability. The LTM4609 can be frequency synchronized with an external clock to reduce undesirable frequency harmonics. Fault protection features include overvoltage and foldback current protection. The DC/DC µModule® regulator is offered in small thermally enhanced 15mm × 15mm × 2.82mm LGA and 15mm × 15mm × 3.42mm BGA packages. The LTM4609 is RoHS compliant with Pb-free finish. Applications Telecom, Servers and Networking Equipment Industrial and Automotive Equipment n High Power Battery-Operated Devices n n L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule, Burst Mode and PolyPhase are registered trademarks and No RSENSE is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Efficiency and Power Loss vs Input Voltage 30V/2A Buck-Boost DC/DC µModule Regulator with 6.5V to 36V Input RUN PLLIN V OUT FCB LTM4609 10µF 50V 5.6µH SW1 SW2 RSENSE SENSE+ 0.1µF SS SGND SENSE– PGND + 330µF 50V VOUT 30V 2A 98 R2 15mΩ ×2 VFB 4609 TA01a 4 96 95 3 94 2 93 92 91 2.74k 5 97 POWER LOSS (W) ON/OFF VIN 6 99 CLOCK SYNC 10µF 50V EFFICIENCY (%) VIN 6.5V TO 36V EFFICIENCY POWER LOSS 8 12 16 24 20 VIN (V) 28 32 36 1 0 4609 TA01b 4609fc 1 LTM4609 Absolute Maximum Ratings (Note 1) VIN.............................................................. –0.3V to 36V VOUT.............................................................. 0.8V to 36V INTVCC, EXTVCC, RUN, SS, PGOOD............... –0.3V to 7V SW1, SW2 (Note 7)....................................... –5V to 36V VFB, COMP................................................. –0.3V to 2.4V FCB, STBYMD........................................ –0.3V to INTVCC PLLIN......................................................... –0.3V to 5.5V Pin Configuration TOP VIEW PLLFLTR..................................................... –0.3V to 2.7V Operating Temperature Range (Note 2) E- and I-grades.....................................–40°C to 85°C MP-grade............................................ –55°C to 125°C Junction Temperature............................................ 125°C Storage Temperature Range....................–55°C to 125°C Solder Temperature (Note 3).................................. 245°C (See Table 6 Pin Assignment) TOP VIEW SW2 (BANK 2) M M L L SW1 (BANK 4) VOUT (BANK 5) INTVCC EXTVCC PGND (BANK 6) PGOOD VFB SW2 (BANK 2) VIN (BANK 1) K SW1 (BANK 4) J J H H RSENSE (BANK 3) G F VOUT (BANK 5) INTVCC EXTVCC F E E D PGND (BANK 6) B COMP PLLFLTR PLLIN SENSE – SS SGND RUN FCB A 1 2 3 4 5 6 7 8 9 SENSE+ 10 11 PGOOD VFB RSENSE (BANK 3) G D C VIN (BANK 1) K C B COMP PLLFLTR PLLIN SENSE – SS SGND RUN FCB A 1 12 2 3 4 SENSE+ STBYMD 5 6 7 8 9 10 11 12 STBYMD BGA PACKAGE 141-LEAD (15mm × 15mm × 3.42mm) LGA PACKAGE 141-LEAD (15mm × 15mm × 2.82mm) TJMAX = 125°C, θJCbottom = 4°C/W, WEIGHT = 1.7g TJMAX = 125°C, θJCbottom = 4°C/W, WEIGHT = 1.5g Order Information LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE (NOTE 2) LTM4609EV#PBF LTM4609V 141-Lead (15mm × 15mm × 2.82mm) LGA –40°C to 85°C LTM4609IV#PBF LTM4609V 141-Lead (15mm × 15mm × 2.82mm) LGA –40°C to 85°C LTM4609MPV#PBF LTM4609V 141-Lead (15mm × 15mm × 2.82mm) LGA –55°C to 125°C LTM4609EY#PBF LTM4609Y 141-Lead (15mm × 15mm × 3.42mm) BGA –40°C to 85°C LTM4609IY#PBF LTM4609Y 141-Lead (15mm × 15mm × 3.42mm) BGA –40°C to 85°C LTM4609MPY#PBF LTM4609Y 141-Lead (15mm × 15mm × 3.42mm) BGA –55°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear.com/packaging/ 4609fc 2 LTM4609 Electrical Characteristics The l denotes the specifications which apply over the specified operating temperature range (Note 2), otherwise specifications are at TA = 25°C, VIN = 12V, per typical application (front page) configuration. SYMBOL PARAMETER Input Specifications VIN(DC) Input DC Voltage VIN(UVLO) Undervoltage Lockout Threshold IQ(VIN) Input Supply Bias Current Normal Standby Shutdown Supply Current Output Specifications Output Continuous Current Range IOUTDC (See Output Current Derating Curves for Different VIN, VOUT and TA) Reference Voltage Line Regulation ΔVFB/VFB(NOM) Accuracy Load Regulation Accuracy ΔVFB/VFB(LOAD) Switch Section M1 tr Turn-On Time (Note 5) M1 tf Turn-Off Time M3 tr Turn-On Time M3 tf Turn-Off Time M2, M4 tr Turn-On Time M2, M4 tf Turn-Off Time t1d M1 Off to M2 On Delay (Note 5) t2d M2 Off to M1 On Delay t3d M3 Off to M4 On Delay t4d M4 Off to M3 On Delay Mode Transition 1 M2 Off to M4 On Delay Mode Transition 2 M4 Off to M2 On Delay M1 RDS(ON) Static Drain-to-Source On-Resistance Static Drain-to-Source M2 RDS(ON) On-Resistance Static Drain-to-Source M3 RDS(ON) On-Resistance Static Drain-to-Source M4 RDS(ON) On-Resistance Oscillator and Phase-Locked Loop fNOM Nominal Frequency fLOW Lowest Frequency CONDITIONS MIN l VIN Falling (–40°C to 85°C) VIN Falling (–55°C to 125°C) TYP MAX 3.4 3.4 36 4 4.5 V V V 60 mA mA µA 4.5 l l VRUN = 0V, VSTBYMD > 2V VRUN = 0V, VSTBYMD = Open 2.8 1.6 35 VIN = 32V, VOUT = 12V VIN = 6V, VOUT = 12V 10 4 VIN = 4.5V to 36V, VCOMP = 1.2V (Note 4) VCOMP = 1.2V to 0.7V VCOMP = 1.2V to 1.8V (Note 4) l l Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Drain to Source Voltage VDS = 12V, Bias Current ISW = 10mA Bias Current ISW = 3A UNITS A A 0.002 0.02 %/V 0.15 –0.15 0.5 –0.5 % % 50 ns 40 ns 25 ns 20 ns 20 ns 20 ns 50 ns 50 ns 50 ns 50 ns 220 ns 220 ns 10 mΩ Bias Current ISW = 3A 14 20 mΩ Bias Current ISW = 3A 14 20 mΩ Bias Current ISW = 3A 14 20 mΩ 300 200 330 220 kHz kHz VPLLFLTR = 1.2V VPLLFLTR = 0V 260 170 4609fc 3 LTM4609 Electrical Characteristics The l denotes the specifications which apply over the specified operating temperature range (Note 2), otherwise specifications are at TA = 25°C, VIN = 12V, per typical application (front page) configuration. SYMBOL fHIGH RPLLIN IPLLFLTR PARAMETER Highest Frequency PLLIN Input Resistance Phase Detector Output Current CONDITIONS VPLLFLTR = 2.4V Control Section VFB Feedback Reference Voltage VCOMP = 1.2V(–40°C to 85°C) VCOMP = 1.2V (–55°C to 125°C) RUN Pin ON/OFF Threshold Soft-Start Charging Current Start-Up Threshold Keep-Active Power On Threshold Forced Continuous Threshold Forced Continuous Pin Current Burst Inhibit (Constant Frequency) Threshold Maximum Duty Factor DF(BOOST, MAX) DF(BUCK, MAX) Maximum Duty Factor tON(MIN, BUCK) Minimum On-Time for Synchronous Switch in Buck Operation RFBHI Resistor Between VOUT and VFB Pins Internal VCC Regulator INTVCC Internal VCC Voltage Internal VCC Load Regulation ΔVLDO/VLDO VEXTVCC EXTVCC Switchover Voltage EXTVCC Switchover Hysteresis ΔVEXTVCC(HYS) EXTVCC Switch Drop Voltage ΔVEXTVCC Current Sensing Section VSENSE(MAX) Maximum Current Sense Threshold VRUN ISS VSTBYMD(START) VSTBYMD(KA) VFCB IFCB VBURST VSENSE(MIN, BUCK) ISENSE PGOOD ΔVFBH ΔVFBL ΔVFB(HYS) VPGL IPGOOD TYP 400 50 –15 15 MAX 440 UNITS kHz kΩ µA µA 0.792 0.785 1 1 0.4 0.8 0.8 1.6 1.7 0.7 1.25 0.8 –0.2 5.3 0.808 0.815 2.2 0.84 –0.1 5.5 V V V µA V V V µA V 99 99 200 250 % % ns 99.5 100 100.5 kΩ l 5.7 6.3 2 l 5.4 6 0.3 5.6 300 60 V % V mV mV fPLLIN < fOSC fPLLIN > fOSC l l VRUN = 2.2V VSTBYMD Rising VSTBYMD Rising, VRUN = 0V 0.76 –0.3 VFCB = 0.85V Measured at FCB Pin % Switch M4 On % Switch M1 On Switch M1 (Note 6) VIN > 7V, VEXTVCC = 5V ICC = 0mA to 20mA, VEXTVCC = 5V ICC = 20mA, VEXTVCC Rising ICC = 20mA, VEXTVCC = 6V Minimum Current Sense Threshold Sense Pins Total Source Current Boost Mode Buck Mode Discontinuous Mode VSENSE– = VSENSE+ = 0V PGOOD Upper Threshold PGOOD Lower Threshold PGOOD Hysteresis PGOOD Low Voltage PGOOD Leakage Current VFB Rising VFB Falling VFB Returning IPGOOD = 2mA VPGOOD = 5V 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 LTM4609 is tested under pulsed load conditions such that TJ ≈ TA. The LTM4609E is guaranteed to meet performance specifications from 0°C to 85°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM4609I is guaranteed over the –40°C to 85°C operating temperature range. The LTM4609MP is guaranteed and tested over the –55°C to 125°C operating temperature range. For output current derating at high temperature, please refer to 4 MIN 340 l l –95 5.5 –5.5 150 160 –130 –6 –380 190 –150 mV mV mV µA 7.5 –7.5 2.5 0.2 10 –10 % % % V µA 0.3 1 Thermal Considerations and Output Current Derating discussion. High junction temperatures degrade operating lifetimes; operating lifetime is derated for junction temperatures greater than 125°C. Note 3: See Application Note 100. Note 4: The LTM4609 is tested in a feedback loop that servos VCOMP to a specified voltage and measures the resultant VFB. Note 5: Turn-on and turn-off time are measured using 10% and 90% levels. Transition delay time is measured using 50% levels. Note 6: 100% test at wafer level only. Note 7: Absolute Maximum Rating of –5V on SW1 and SW2 is under transient condition only. 4609fc LTM4609 Typical Performance Characteristics 100 Efficiency vs Load Current 12VIN to 12VOUT Efficiency vs Load Current 32VIN to 12VOUT 100 90 90 80 80 80 70 70 70 60 50 40 30 20 0 0.01 0.1 1 LOAD CURRENT (A) 60 50 40 30 0 0.01 0.1 1 LOAD CURRENT (A) 4609 G01 0 0.01 10 100 99 70 99 98 1 2 3 4 5 6 7 LOAD CURRENT (A) 8 9 96 95 94 93 28VIN to 20VOUT 32VIN to 20VOUT 36VIN to 20VOUT 91 10 90 0 1 2 4 5 3 6 LOAD CURRENT (A) 96 7 Efficiency vs Load Current 3.3µH Inductor 8 93 0 1 3 2 4 LOAD CURRENT (A) 100 6 5 4609 G06 Transient Response from 12VIN to 12VOUT Transient Response from 6VIN to 12VOUT 95 30VIN to 30VOUT 32VIN to 30VOUT 36VIN to 30VOUT 94 4609 G05 4609 G04 EFFICIENCY (%) 97 95 92 12VIN TO 5VOUT 24VIN TO 5VOUT 32VIN TO 5VOUT 0 98 97 EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 95 80 100 Efficiency vs Load Current 8µH Inductor 100 100 85 0.1 1 10 LOAD CURRENT (A) 4609 G03 Efficiency vs Load Current 5.6µH Inductor 90 SKIP CYCLE DCM CCM 10 4609 G02 Efficiency vs Load Current 3.3µH Inductor 75 50 40 20 BURST DCM CCM 10 10 60 30 20 BURST DCM CCM 10 EFFICIENCY (%) 90 EFFICIENCY (%) EFFICIENCY (%) 100 Efficiency vs Load Current 6VIN to 12VOUT (Refer to Figure 18) IOUT 2A/DIV IOUT 2A/DIV VOUT 200mV/DIV VOUT 200mV/DIV 90 85 80 200µs/DIV 70 LOAD STEP: 0A TO 3A AT CCM OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 15mΩ SENSING RESISTORS 5VIN to 16VOUT 5VIN to 24VOUT 5VIN to 30VOUT 75 0 0.5 1.5 1 2 LOAD CURRENT (A) 2.5 4609 G08 200µs/DIV 4609 G09 LOAD STEP: 0A TO 3A AT CCM OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 15mΩ SENSING RESISTORS 3 4609 G07 4609fc 5 LTM4609 Typical Performance Characteristics Transient Response from 32VIN to 12VOUT Start-Up with 6VIN to 12VOUT at IOUT = 4A IOUT 2A/DIV VOUT 100mV/DIV 200µs/DIV Start-Up with 32VIN to 12VOUT at IOUT = 5A IL 5A/DIV IL 5A/DIV IIN 5A/DIV IIN 2A/DIV VOUT 10V/DIV VOUT 10V/DIV 4609 G10 50ms/DIV 4609 G11 10ms/DIV 4609 G12 LOAD STEP: 0A TO 5A AT CCM OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 12mΩ SENSING RESISTORS 0.1µF SOFT-START CAP OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 12mΩ SENSING RESISTORS 0.1µF SOFT-START CAP OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 12mΩ SENSING RESISTORS Short Circuit with 6VIN to 12VOUT at IOUT = 4A Short Circuit with 32VIN to 12VOUT at IOUT = 5A Short Circuit with 12VIN to 34VOUT at IOUT = 2A VOUT 10V/DIV VOUT 5V/DIV IIN 2A/DIV VOUT 5V/DIV IIN 5A/DIV 50µs/DIV 4609 G13 OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 12mΩ SENSING RESISTORS IIN 5A/DIV 50µs/DIV 4609 G14 OUTPUT CAPS: 4x 22µF CERAMIC CAPS AND 2x 180µF ELECTROLYTIC CAPS 2x 12mΩ SENSING RESISTORS 20µs/DIV 4607 G15 OUTPUT CAPS: 2x 10µF 50V CERAMIC CAPS AND 2x 47µF 50V ELECTROLYTIC CAPS 2x 15mΩ SENSING RESISTORS 4609fc 6 LTM4609 Pin Functions VIN (Bank 1): Power Input Pins. Apply input voltage between these pins and PGND pins. Recommend placing input decoupling capacitance directly between VIN pins and PGND pins. VOUT (Bank 5): Power Output Pins. Apply output load between these pins and PGND pins. Recommend placing output decoupling capacitance directly between these pins and PGND pins. PGND (Bank 6): Power Ground Pins for Both Input and Output Returns. SW1, SW2 (Bank 4, Bank 2): Switch Nodes. The power inductor is connected between SW1 and SW2. RSENSE (Bank 3): Sensing Resistor Pin. The sensing resistor is connected from this pin to PGND. SENSE+ (Pin A4): Positive Input to the Current Sense and Reverse Current Detect Comparators. SENSE– (Pin A5): Negative Input to the Current Sense and Reverse Current Detect Comparators. EXTVCC (Pin F6): External VCC Input. When EXTVCC exceeds 5.7V, an internal switch connects this pin to INTVCC and shuts down the internal regulator so that the controller and gate drive power is drawn from EXTVCC. Do not exceed 7V at this pin and ensure that EXTVCC < VIN INTVCC (Pin F5): Internal 6V Regulator Output. This pin is for additional decoupling of the 6V internal regulator. Do not source more than 40mA from INTVCC. PLLIN (Pin B9): External Clock Synchronization Input to the Phase Detector. This pin is internally terminated to SGND with a 50k resistor. The phase-locked loop will force the rising bottom gate signal of the controller to be synchronized with the rising edge of PLLIN signal. PLLFLTR (Pin B8): The lowpass filter of the phase-locked loop is tied to this pin. This pin can also be used to set the frequency of the internal oscillator with an AC or DC voltage. See the Applications Information section for details. STBYMD (Pin A10): LDO Control Pin. Determines whether the internal LDO remains active when the controller is shut down. See Operations section for details. If the STBYMD pin is pulled to ground, the SS pin is internally pulled to ground to disable start-up and thereby providing a single control pin for turning off the controller. An internal decoupling capacitor is tied to this pin. VFB (Pin B6): 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 an additional resistor between VFB and SGND pins. See the Applications Information section. FCB (Pin A9): Forced Continuous Control Input. The voltage applied to this pin sets the operating mode of the module. When the applied voltage is less than 0.8V, the forced continuous current mode is active in boost operation and the skip cycle mode is active in buck operation. When the pin is tied to INTVCC, the constant frequency discontinuous current mode is active in buck or boost operation. See the Applications Information section. SGND (Pin A7): Signal Ground Pin. This pin connects to PGND at output capacitor point. COMP (Pin B7): 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. PGOOD (Pin B5): Output Voltage Power Good Indicator. Open drain logic output that is pulled to ground when the output voltage is not within ±7.5% of the regulation point. RUN (Pin A8): Run Control Pin. A voltage below 1.6V will turn off the module. There is a 100k resistor between the RUN pin and SGND in the module. Do not apply more than 6V to this pin. See the Applications Information section. SS (Pin A6): Soft-Start Pin. Soft-start reduces the input surge current from the power source by gradually increasing the controller’s current limit. 4609fc 7 LTM4609 Simplified Block Diagram VIN 4.5V TO 36V EXTVCC C1 CIN M1 SW2 INTVCC M2 PGOOD L SW1 RUN ON/OFF VOUT 100k STBYMD 12V 4A CO1 M3 COUT 0.1µF 100k COMP VFB M4 INT COMP CONTROLLER RFB 7.15k RSENSE SENSE+ SS SS 0.1µF PLLIN INT FILTER PLLFLTR RSENSE SENSE– PGND INT FILTER FCB SGND 1000pF TO PGND PLANE AS SHOWN IN FIGURE 15 4609 BD Figure 1. Simplified LTM4609 Block Diagram Decoupling Requirements TA = 25°C. Use Figure 1 configuration. SYMBOL PARAMETER CONDITIONS CIN External Input Capacitor Requirement (VIN = 4.5V to 36V, VOUT = 12V) IOUT = 4A 10 COUT External Output Capacitor Requirement (VIN = 4.5V to 36V, VOUT = 12V) IOUT = 4A 200 MIN TYP MAX UNITS µF 300 µF 4609fc 8 LTM4609 Operation Power Module Description The LTM4609 is a non-isolated buck-boost DC/DC power supply. It can deliver a wide range output voltage from 0.8V to 34V over a wide input range from 4.5V to 36V, by only adding the sensing resistor, inductor and some external input and output capacitors. It provides precisely regulated output voltage programmable via one external resistor. The typical application schematic is shown in Figure 18. The LTM4609 has an integrated current mode buck-boost controller, ultralow RDS(ON) FETs with fast switching speed and integrated Schottky diodes. With current mode control and internal feedback loop compensation, the LTM4609 module has sufficient stability margins and good transient performance under a wide range of operating conditions and with a wide range of output capacitors. The operating frequency of the LTM4609 can be adjusted from 200kHz to 400kHz by setting the voltage on the PLLFLTR pin. Alternatively, its frequency can be synchronized by the input clock signal from the PLLIN pin. The typical switching frequency is 400kHz. The Burst Mode® and skip-cycle mode operations can be enabled at light loads to improve efficiency, while the forced continuous mode and discontinuous mode operations are used for constant frequency applications. Foldback current limiting is activated in an overcurrent condition as VFB drops. Internal overvoltage and undervoltage comparators pull the open-drain PGOOD output low if the output feedback voltage exits the ±7.5% window around the regulation point. Pulling the RUN pin below 1.6V forces the controller into its shutdown state. If an external bias supply is applied on the EXTVCC pin, then an efficiency improvement will occur due to the reduced power loss in the internal linear regulator. This is especially true at the higher end of the input voltage range. Applications Information The typical LTM4609 application circuit is shown in Figure 18. External component selection is primarily determined by the maximum load current and output voltage. Refer to Table 3 for specific external capacitor requirements for a particular application. Output Voltage Programming The PWM controller has an internal 0.8V reference voltage. As shown in the Block Diagram, a 100k internal feedback resistor connects VOUT and VFB pins together. Adding a resistor RFB from the VFB pin to the SGND pin programs the output voltage: VOUT = 0.8V • 100k + RFB RFB Operation Frequency Selection The LTM4609 uses current mode control architecture at constant switching frequency, which is determined by the internal oscillator’s capacitor. This internal capacitor is charged by a fixed current plus an additional current that is proportional to the voltage applied to the PLLFLTR pin. The PLLFLTR pin can be grounded to lower the frequency to 200kHz or tied to 2.4V to yield approximately 400kHz. When PLLFLTR is left open, the PLLFLTR pin goes low, forcing the oscillator to its minimum frequency. A graph for the voltage applied to the PLLFLTR pin vs frequency is given in Figure 2. As the operating frequency increases, the gate charge losses will be higher, thus the efficiency is lower. The maximum switching frequency is approximately 400kHz. Table 1. RFB Resistor (0.5%) vs Output Voltage VOUT 0.8V 1.5V 2.5V 3.3V 5V 6V 8V 9V RFB Open 115k 47.5k 32.4k 19.1k 15.4k 11k 9.76k VOUT 10V 12V 15V 16V 20V 24V 30V 34V 5.23k 4.12k 3.4k 2.74k 2.37k RFB 8.66k 7.15k 5.62k Frequency Synchronization The LTM4609 can also be synchronized to an external source via the PLLIN pin instead of adjusting the voltage on the PLLFLTR pin directly. The power module has a 4609fc 9 LTM4609 Applications Information phase-locked loop comprised of an internal voltage controlled oscillator and a phase detector. This allows turning on the internal top MOSFET for locking to the rising edge of the external clock. A pulse detection circuit is used to detect a clock on the PLLIN pin to turn on the phase-lock loop. The input pulse width of the clock has to be at least 400ns, and 2V in amplitude. The synchronized frequency ranges from 200kHz to 400kHz, corresponding to a DC voltage input from 0V to 2.4V at PLLFLTR. During the start-up of the regulator, the phase-lock loop function is disabled. 450 OPERATING FREQUENCY (kHz) 400 350 300 250 200 150 100 50 0 0 1.0 1.5 2.0 0.5 PLLFLTR PIN VOLTAGE (V) 2.5 4609 F02 Figure 2. Frequency vs PLLFLTR Pin Voltage Low Current Operation To improve efficiency at low output current operation, LTM4609 provides three modes for both buck and boost operations by accepting a logic input on the FCB pin. Table 2 shows the different operation modes. load current is lower than the preset minimum output current level. The MOSFETs will turn on for several cycles, followed by a variable “sleep” interval depending upon the load current. During buck operation, skip-cycle mode sets a minimum positive inductor current level. In this mode, some cycles will be skipped when the output load current drops below 1% of the maximum designed load in order to maintain the output voltage. When the FCB pin voltage is tied to the INTVCC pin, the controller enters constant frequency discontinuous current mode (DCM). For boost operation, if the output voltage is high enough, the controller can enter the continuous current buck mode for one cycle to discharge inductor current. In the following cycle, the controller will resume DCM boost operation. For buck operation, constant frequency discontinuous current mode is turned on if the preset minimum negative inductor current level is reached. At very light loads, this constant frequency operation is not as efficient as Burst Mode operation or skip-cycle, but does provide low noise, constant frequency operation. Input Capacitors In boost mode, since the input current is continuous, only minimum input capacitors are required. However, the input current is discontinuous in buck mode. So the selection of input capacitor CIN is driven by the need of filtering the input square wave current. For a buck converter, the switching duty-cycle can be estimated as: Table 2. Different Operating Modes (VINTVCC = 6V) FCB PIN BUCK BOOST 0V to 0.75V Force Continuous Mode Force Continuous Mode 0.85V to VINTVCC – 1V Skip-Cycle Mode Burst Mode Operation >5.3V DCM with Constant Freq DCM with Constant Freq When the FCB pin voltage is lower than 0.8V, the controller behaves as a continuous, PWM current mode synchronous switching regulator. When the FCB pin voltage is below VINTVCC – 1V, but greater than 0.85V, where VINTVCC is 6V, the controller enters Burst Mode operation in boost operation or enters skip-cycle mode in buck operation. During boost operation, Burst Mode operation is activated if the D= VOUT VIN Without considering the inductor current ripple, the RMS current of the input capacitor can be estimated as: ICIN(RMS) = IOUT(MAX) η • D • (1− D) In the above equation, η is the estimated efficiency of the power module. CIN 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 temperature and hours of life. 4609fc 10 LTM4609 Applications Information 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. Output Capacitors In boost mode, the discontinuous current shifts from the input to the output, so the output capacitor COUT must be capable of reducing the output voltage ripple. For boost and buck modes, the steady ripple due to charging and discharging the bulk capacitance is given by: VRIPPLE,BOOST = VRIPPLE,BUCK = ( IOUT(MAX) • VOUT − VIN(MIN) COUT • VOUT • ƒ ( VOUT • VIN(MAX) − VOUT ) ) 8 • L • COUT • VIN(MAX) • ƒ 2 The steady ripple due to the voltage drop across the ESR (effective series resistance) is given by: VESR,BUCK = ΔIL(MAX) • ESR VESR,BOOST =IL(MAX) • ESR The LTM4609 is designed for low output voltage ripple. The bulk output capacitors defined as COUT are chosen with low enough ESR to meet the output voltage ripple and transient requirements. COUT can be the low ESR tantalum capacitor, the low ESR polymer capacitor or the ceramic capacitor. Multiple capacitors can be placed in parallel to meet the ESR and RMS current handling requirements. The typical capacitance is 300µF. Additional output filtering may be required by the system designer, if further reduction of output ripple or dynamic transient spike is required. Table 3 shows a matrix of different output voltages and output capacitors to minimize the voltage droop and overshoot at a current transient. Inductor Selection The inductor is chiefly decided by the required ripple current and the operating frequency. The inductor current ripple ΔIL is typically set to 20% to 40% of the maximum inductor current. In the inductor design, the worst cases in continuous mode are considered as follows: LBOOST ≥ LBUCK ≥ ( V 2IN • VOUT(MAX) − VIN ) V 2OUT(MAX) • ƒ •IOUT(MAX) • Ripple% ( VOUT • VIN(MAX) − VOUT ) VIN(MAX) • ƒ •IOUT(MAX) • Ripple% where: ƒ is operating frequency, Hz Ripple% is allowable inductor current ripple, % VOUT(MAX) is maximum output voltage, V VIN(MAX) is maximum input voltage, V VOUT is output voltage, V IOUT(MAX) is maximum output load current, A The inductor should have low DC resistance to reduce the I2R losses, and must be able to handle the peak inductor current without saturation. To minimize radiated noise, use a toroid, pot core or shielded bobbin inductor. Please refer to Table 3 for the recommended inductors for different cases. RSENSE Selection and Maximum Output Current RSENSE is chosen based on the required inductor current. Since the maximum inductor valley current at buck mode is much lower than the inductor peak current at boost mode, different sensing resistors are suggested to use in buck and boost modes. The current comparator threshold sets the peak of the inductor current in boost mode and the maximum inductor valley current in buck mode. In boost mode, the allowed maximum average load current is: 160mV ΔI V IOUT(MAX,BOOST) = − L • IN R 2 VOUT SENSE where ΔIL is peak-to-peak inductor ripple current. 4609fc 11 LTM4609 Applications Information In buck mode, the allowed maximum average load current is: IOUT(MAX,BUCK) = 130mV ΔIL + RSENSE 2 The maximum current sensing RSENSE value for the boost mode is: RSENSE(MAX,BOOST) = 2 • 160mV • VIN 2 •IOUT(MAX,BOOST) • VOUT + ΔIL • VIN The maximum current sensing RSENSE value for the buck mode is: RSENSE(MAX,BUCK) = 2 • 130mV 2 •IOUT(MAX,BUCK) – ΔIL A 20% to 30% margin on the calculated sensing resistor is usually recommended. Please refer to Table 3 for the recommended sensing resistors for different applications. Soft-Start The SS pin provides a means to soft-start the regulator. A capacitor on this pin will program the ramp rate of the output voltage. A 1.7µA current source will charge up the external soft-start capacitor. This will control the ramp of the internal reference and the output voltage. The total soft-start time can be calculated as: t SOFTSTART = 2.4V • CSS 1.7µA When the RUN pin falls below 1.6V, then soft-start pin is reset to allow for proper soft-start control when the regulator is enabled again. Current foldback and force continuous mode are disabled during the soft-start process. The soft-start function can also be used to control the output ramp up time, so that another regulator can be easily tracked. Do not apply more than 6V to the SS pin. Run Enable The RUN pin is used to enable the power module. The pin can be driven with a logic input, not to exceed 6V. The RUN pin can also be used as an undervoltage lockout (UVLO) function by connecting a resistor from the input supply to the RUN pin. The equation: V _UVLO = R1+ R2 • 1.6V R2 Power Good The PGOOD pin is an open drain pin that can be used to monitor valid output voltage regulation. This pin monitors a ±7.5% window around the regulation point. COMP Pin This pin is the external compensation pin. The module has already been internally compensated for most output voltages. A spice model is available for other control loop optimization. Fault Conditions: Current Limit and Overcurrent Foldback LTM4609 has a current mode controller, which inherently limits the cycle-by-cycle inductor current not only in steady state operation, but also in transient. Refer to Table 3. To further limit current in the event of an overload condition, the LTM4609 provides foldback current limiting. If the output voltage falls by more than 70%, then the maximum output current is progressively lowered to about 30% of its full current limit value for boost mode and about 40% for buck mode. Standby Mode (STBYMD) The standby mode (STBYMD) pin provides several choices for start-up and standby operational modes. If the pin is pulled to ground, the SS pin is internally pulled to ground, preventing start-up and thereby providing a single control 4609fc 12 LTM4609 Applications Information pin for turning off the controller. If the pin is left open or decoupled with a capacitor to ground, the SS pin is internally provided with a starting current, permitting external control for turning on the controller. If the pin is connected to a voltage greater than 1.25V, the internal regulator (INTVCC) will be on even when the controller is shut down (RUN pin voltage <1.6V). In this mode, the onboard 6V output linear regulator can provide power to keep-alive functions such as a keyboard controller. Thermal Considerations and Output Current Derating INTVCC and EXTVCC The power loss curves in Figures 5 and 6 can be used in coordination with the load current derating curves in Figures 7 to 14 for calculating an approximate θJA for the module. Column designation delineates between no heat sink, and a BGA heat sink. Each of the load current derating curves will lower the maximum load current as a function of the increased ambient temperature to keep the maximum junction temperature of the power module at 115°C allowing a safe margin for the maximum operating temperature below 125°C. Each of the derating curves and the power loss curve that corresponds to the correct output voltage can be used to solve for the approximate θJA of the condition. A complete explanation of the thermal characteristics is provided in the thermal application note for the LTM4609. An internal P-channel low dropout regulator produces 6V at the INTVCC pin from the VIN supply pin. INTVCC powers the control chip and internal circuitry within the module. The LTM4609 also provides the external supply voltage pin EXTVCC. When the voltage applied to EXTVCC rises above 5.7V, the internal regulator is turned off and an internal switch connects the EXTVCC pin to the INTVCC pin thereby supplying internal power. The switch remains closed as long as the voltage applied to EXTVCC remains above 5.5V. This allows the MOSFET driver and control power to be derived from the output when (5.7V < VOUT < 7V) and from the internal regulator when the output is out of regulation (startup, short-circuit). If more current is required through the EXTVCC switch than is specified, an external Schottky diode can be interposed between the EXTVCC and INTVCC pins. Ensure that EXTVCC ≤ VIN. The following list summarizes the three possible connections for EXTVCC: 1.EXTVCC left open (or grounded). This will cause INTVCC to be powered from the internal 6V regulator at the cost of a small efficiency penalty. 2.EXTVCC connected directly to VOUT (5.7V < VOUT < 7V). This is the normal connection for a 6V regulator and provides the highest efficiency. 3.EXTVCC connected to an external supply. If an external supply is available in the 5.5V to 7V range, it may be used to power EXTVCC provided it is compatible with the MOSFET gate drive requirements. In different applications, LTM4609 operates in a variety of thermal environments. The maximum output current is limited by the environmental thermal condition. Sufficient cooling should be provided to ensure reliable operation. When the cooling is limited, proper output current derating is necessary, considering ambient temperature, airflow, input/output condition, and the need for increased reliability. Design Examples Buck Mode Operation As a design example, use input voltage VIN = 12V to 36V, VOUT = 12V and ƒ = 400kHz. Set the PLLFLTR pin at 2.4V or more for 400kHz frequency and connect FCB to ground for continuous current mode operation. If a divider is used to set the frequency as shown in Figure 16, the bottom resistor R3 is recommended not to exceed 1kΩ. To set the output voltage at 12V, the resistor RFB from VFB pin to ground should be chosen as: RFB = 0.8V • 100k ≈ 7.15k VOUT − 0.8V 4609fc 13 LTM4609 Applications Information To choose a proper inductor, we need to know the current ripple at different input voltages. The inductor should be chosen by considering the worst case in the practical operating region. If the maximum output power P is 120W at buck mode, we can get the current ripple ratio of the current ripple ΔIL to the maximum inductor current IL as follows: ΔIL (VIN – VOUT ) • VOUT 2 = IL VIN • L • ƒ • P For the input capacitor, use a low ESR sized capacitor to handle the maximum RMS current. Input capacitors are required to be placed adjacent to the module. In Figure 16, the 10µF ceramic input capacitors are selected for their ability to handle the large RMS current into the converter. The 100µF bulk capacitor is only needed if the input source impedance is compromised by long inductive leads or traces. For the output capacitor, the output voltage ripple and transient requirements require low ESR capacitors. If assuming that the ESR dominates the output ripple, the output ripple is as follows: Figure 3 shows the current ripple ratio at different input voltages based on the inductor values: 2.5µH, 3.3µH, 4.7µH and 6µH. If we need about 40% ripple current ratio at all inputs, the 4.7µH inductor can be selected. At buck mode, sensing resistor selection is based on the maximum output current and the allowed maximum sensing threshold 130mV. If a total low ESR of about 5mΩ is chosen for output capacitors, the maximum output ripple of 21.5mV occurs at the input voltage of 36V with the current ripple at 4.3A. RSENSE = 2 • 130mV 2 • (P / VOUT ) − ΔIL Boost Mode Operation Consider the safety margin about 30%, we can choose the sensing resistor as 9mΩ. CURRENT RIPPLE RATIO 0.8 VOUT = 12V ƒ = 400kHz 0.6 For boost mode operation, use input voltage VIN = 5V to 12V, VOUT = 12V and ƒ = 400kHz. Set the PLLFLTR pin and RFB as in buck mode. If the maximum output power P is 50W at boost mode and the module efficiency η is about 90%, we can get the current ripple ratio of the current ripple ΔIL to the maximum inductor current IL as follows: 2.5µH 3.3µH 4.7µH 0.4 ΔVOUT(P-P) = ESR • ΔIL 6µH ΔIL (VOUT − VIN ) • VIN 2 η = VOUT • L • ƒ • P IL 0.2 0 12 24 30 18 INPUT VOLTAGE VIN (V) 36 4609 F03 Figure 3. Current Ripple Ratio at Different Inputs for Buck Mode 4609fc 14 LTM4609 Applications Information CURRENT RIPPLE RATIO 0.8 VOUT = 12V ƒ = 400kHz If assuming that the ESR dominates the output ripple, the output ripple is as follows: 1.5µH 0.6 If a total low ESR about 5mΩ is chosen for output capacitors, the maximum output ripple of 70mV occurs at the input voltage of 5V with the peak inductor current at 14A. 2.5µH 0.4 3.3µH 4.7µH 0.2 An RC snubber is recommended on SW1 to obtain low switching noise, as shown in Figure 17. 0 5 6 8 9 10 7 INPUT VOLTAGE VIN (V) 11 12 4609 F04 Figure 4. Current Ripple Ratio at Different Inputs for Boost Mode Figure 4 shows the current ripple ratio at different input voltages based on the inductor values: 1.5µH, 2.5µH, 3.3µH and 4.7µH. If we need 30% ripple current ratio at all inputs, the 3.3µH inductor can be selected. At boost mode, sensing resistor selection is based on the maximum input current and the allowed maximum sensing threshold 160mV. RSENSE = ΔVOUT(P-P) = ESR •IL(MAX) 2 • 160mV P 2• + ΔIL η • VIN(MIN) Consider the safety margin about 30%, we can choose the sensing resistor as 8mΩ. For the input capacitor, only minimum capacitors are needed to handle the maximum RMS current, since it is a continuous input current at boost mode. A 100µF capacitor is only needed if the input source impedance is compromised by long inductive leads or traces. Since the output capacitors at boost mode need to filter the square wave current, more capacitors are expected to achieve the same output ripples as the buck mode. Wide Input Mode Operation If a wide input range is required from 5V to 36V, the module will work in different operation modes. If input voltage VIN = 5V to 36V, VOUT = 12V and ƒ = 400kHz, the design needs to consider the worst case in buck or boost mode design. Therefore, the maximum output power is limited to 60W. The sensing resistor is chosen at 8mΩ, the input capacitor is the same as the buck mode design and the output capacitor uses the boost mode design. Since the maximum output ripple normally occurs at boost mode in the wide input mode design, more inductor ripple current, up to 150% of the inductor current, is allowed at buck mode to meet the ripple design requirement. Thus, a 3.3µH inductor is chosen at the wide input mode. The maximum output ripple voltage is still 70mV if the total ESR is about 5mΩ. Additionally, the current limit may become very high when the module runs at buck mode due to the low sensing resistor used in the wide input mode operation. Safety Considerations The LTM4609 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 needs to be provided to protect each unit from catastrophic failure. 4609fc 15 LTM4609 Applications Information Table 3. Typical Components (ƒ = 400kHz) COUT1 VENDORS PART NUMBER COUT2 VENDORS PART NUMBER TDK C4532X7R1E226M (22µF, 25V) Sanyo 16SVP180MX (180µF, 16V), 20SVP150MX (150µF, 20V) INDUCTOR VENDORS PART NUMBER RSENSE VENDORS PART NUMBER Toko FDA1254 Vishay Power Metal Strip Resistors WSL1206-18 Sumida CDEP134, CDEP145, CDEP147 Panasonic Thick Film Chip Resistors ERJ12 VIN (V) VOUT (V) RSENSE (0.5W RATING) Inductor (µH) CIN (CERAMIC) CIN (BULK) COUT1 (CERAMIC) COUT2 (BULK) IOUT(MAX)* (A) 5 10 2 × 16mW 0.5W 2.2 None 150µF 35V 4 × 22µF 25V 2 × 180µF 16V 4 15 10 2 × 18mW 0.5W 2.2 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 11 20 10 2 × 20mW 0.5W 3.3 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 10 24 10 2 × 18mΩ 0.5W 3.3 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 10 32 10 2 × 22mΩ 0.5W 4.7 2 × 10µF 50V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 9 36 10 2 × 22mΩ 0.5W 4.7 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 180µF 16V 9 6 12 2 × 14mΩ 0.5W 2.2 None 150µF 35V 4 × 22µF 25V 2 × 180µF 16V 4 16 12 2 × 16mW 0.5W 2.2 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 11 20 12 2 × 18mW 0.5W 3.3 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 10 24 12 2 × 18mΩ 0.5W 3.3 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 9 32 12 2 × 22mΩ 0.5W 4.7 2 × 10µF 50V 150µF 35V 2 × 22µF 25V 2 × 180µF 16V 9 36 12 2 × 22mΩ 0.5W 4.7 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 180µF 16V 9 5 16 2 × 18mW 0.5W 3.3 None 150µF 35V 4 × 22µF 25V 2 × 150µF 20V 2.5 8 16 2 × 16mW 0.5W 3.3 None 150µF 35V 4 × 22µF 25V 2 × 150µF 20V 4 12 16 2 × 14mW 0.5W 2.2 None 150µF 35V 4 × 22µF 25V 2 × 150µF 20V 8 20 16 2 × 20mW 0.5W 2.2 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 150µF 20V 10 24 16 2 × 20mΩ 0.5W 3.3 2 × 10µF 25V 150µF 35V 2 × 22µF 25V 2 × 150µF 20V 10 32 16 2 × 22mΩ 0.5W 4.7 2 × 10µF 50V 150µF 35V 2 × 22µF 25V 2 × 150µF 20V 9 36 16 2 × 22mΩ 0.5W 6 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 150µF 20V 9 5 20 2 × 18mΩ 0.5W 3.3 NONE 150µF 50V 4 × 22µF 25V 2 × 150µF 50V 2 10 20 2 × 18mΩ 0.5W 3.3 NONE 150µF 50V 4 × 22µF 25V 2 × 150µF 50V 5 32 20 1 × 12mΩ 0.5W 6 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 150µF 50V 9 36 20 1 × 13mΩ 0.5W 8 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 150µF 50V 8 5 24 2 × 16mΩ 0.5W 3.3 NONE 150µF 50V 4 × 22µF 25V 2 × 150µF 50V 1.5 12 24 2 × 18mΩ 0.5W 4.7 NONE 150µF 50V 4 × 22µF 25V 2 × 150µF 50V 5 32 24 1 × 14mΩ 0.5W 4.7 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 150µF 50V 8 36 24 1 × 13mΩ 0.5W 7 2 × 10µF 50V 150µF 50V 2 × 22µF 25V 2 × 150µF 50V 8 4609fc 16 LTM4609 Applications Information Table 3. Typical Components (ƒ = 400kHz) Continued VIN (V) VOUT (V) RSENSE (0.5W RATING) Inductor (µH) CIN (CERAMIC) CIN (BULK) COUT1 (CERAMIC) COUT2 (BULK) IOUT(MAX)* (A) 5 30 2 × 16mΩ 0.5W 3.3 NONE 150µF 50V 4 × 22µF 50V 2 × 150µF 50V 1.3 12 30 2 × 14mΩ 0.5W 4.7 NONE 150µF 50V 4 × 22µF 50V 2 × 150µF 50V 3 32 30 1 × 12mΩ 0.5W 2.5 2 × 10µF 50V 150µF 50V 2 × 22µF 50V 2 × 150µF 50V 8 36 30 1 × 13mΩ 0.5W 4.7 2 × 10µF 50V 150µF 50V 2 × 22µF 50V 2 × 150µF 50V 8 5 34 2 × 18mΩ 0.5W 3.3 NONE 150µF 50V 4 × 22µF 50V 2 × 150µF 50V 1 12 34 2 × 16mΩ 0.5W 4.7 NONE 150µF 50V 4 × 22µF 50V 2 × 150µF 50V 3 24 34 1 × 12mΩ 0.5W 5.6 NONE 150µF 50V 4 × 22µF 50V 2 × 150µF 50V 5 36 34 1 × 12mΩ 0.5W 2.5 2 × 10µF 50V 150µF 50V 2 × 22µF 50V 2 × 150µF 50V 8 INDUCTOR MANUFACTURER WEBSITE PHONE NUMBER Sumida www.sumida.com 408-321-9660 Toko www.toko.com 847-297-0070 SENSING RESISTOR MANUFACTURER WEBSITE PHONE NUMBER Panasonic www.panasonic.com/industrial/components 949-462-1816 KOA www.koaspeer.com 814-362-5536 Vishay www.vishay.com 800-433-5700 *Maximum load current is based on the Linear Technology DC1198A at room temperature with natural convection. Poor board layout design may decrease the maximum load current. Typical Applications (Power Loss includes all external components) 7 7 6 6 5 5 POWER LOSS (W) POWER LOSS (W) 4 3 2 1 0 3 1 2 LOAD CURRENT (A) 4609 F05 Figure 5. Boost Mode Operation 4 3 2 1 5VIN TO 16VOUT 5VIN TO 30VOUT 0 32VIN TO 12VOUT 36VIN TO 20VOUT 0 0 1 2 3 4 5 6 LOAD CURRENT (A) 7 8 9 4609 F06 Figure 6. Buck Mode Operation 4609fc 17 LTM4609 3.0 3.0 2.5 2.5 MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) Typical Applications 2.0 1.5 1.0 0.5 5VIN TO 16VOUT WITH 0LFM 5VIN TO 16VOUT WITH 200LFM 5VIN TO 16VOUT WITH 400LFM 0 25 35 2.0 1.5 1.0 0.5 0 45 55 65 75 85 95 105 115 AMBIENT TEMPERATURE (°C) 45 65 85 105 AMBIENT TEMPERATURE (°C) 25 4609 F07 5VIN TO 16VOUT WITH 0LFM 5VIN TO 16VOUT WITH 200LFM 5VIN TO 16VOUT WITH 400LFM 1.50 1.50 1.25 1.25 1.00 0.75 0.50 5VIN TO 30VOUT WITH 0LFM 5VIN TO 30VOUT WITH 200LFM 5VIN TO 30VOUT WITH 400LFM 0.25 0 25 35 45 55 65 75 85 95 AMBIENT TEMPERATURE (°C) 1.00 0.75 0.50 5VIN TO 30VOUT WITH 0LFM 5VIN TO 30VOUT WITH 200LFM 5VIN TO 30VOUT WITH 400LFM 0.25 0 105 25 35 45 55 65 75 85 95 AMBIENT TEMPERATURE (°C) 10 9 9 8 8 MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) Figure 10. 5VIN to 30VOUT with Heat Sink 10 7 6 5 4 3 2 7 6 5 4 3 2 1 1 0 105 4609 F10 4609 F09 Figure 9. 5VIN to 30VOUT without Heat Sink 4609 F08 Figure 8. 5VIN to 16VOUT with Heat Sink MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) Figure 7. 5VIN to 16VOUT without Heat Sink 125 25 35 45 55 65 75 85 AMBIENT TEMPERATURE (°C) 32VIN TO 12VOUT WITH 0LFM 32VIN TO 12VOUT WITH 200LFM 32VIN TO 12VOUT WITH 400LFM 95 4609 F11 Figure 11. 32VIN to 12VOUT without Heat Sink 0 25 35 45 55 65 75 85 AMBIENT TEMPERATURE (°C) 32VIN TO 12VOUT WITH 0LFM 32VIN TO 12VOUT WITH 200LFM 32VIN TO 12VOUT WITH 400LFM 95 4609 F12 Figure 12. 32VIN to 12VOUT with Heat Sink 4609fc 18 LTM4609 8 8 7 7 MAXIMUM LOAD CURRENT (A) MAXIMUM LOAD CURRENT (A) Typical Applications 6 5 4 3 2 1 0 6 5 4 3 2 1 25 35 45 55 65 75 85 95 AMBIENT TEMPERATURE (°C) 36VIN TO 20VOUT WITH 0LFM 36VIN TO 20VOUT WITH 200LFM 36VIN TO 20VOUT WITH 400LFM 0 105 4609 F13 25 35 45 55 65 75 85 95 AMBIENT TEMPERATURE (°C) 36VIN TO 20VOUT WITH 0LFM 36VIN TO 20VOUT WITH 200LFM 36VIN TO 20VOUT WITH 400LFM Figure 13. 36VIN to 20VOUT without Heat Sink 105 4609 F14 Figure 14. 36VIN to 20VOUT with Heat Sink applications information Table 4. Boost Mode AIR FLOW (LFM) HEAT SINK θJA (°C/W)* Figure 5 0 None 11.4 Figure 5 200 None 8.5 16, 30 Figure 5 400 None 7.5 Figure 8, 10 16, 30 Figure 5 0 BGA Heat Sink 11.0 Figure 8, 10 16, 30 Figure 5 200 BGA Heat Sink 7.9 Figure 8, 10 16, 30 Figure 5 400 BGA Heat Sink 7.1 DERATING CURVE VOUT (V) POWER LOSS CURVE Figure 7, 9 16, 30 Figure 7, 9 16, 30 Figure 7, 9 Table 5. Buck Mode VOUT (V) POWER LOSS CURVE AIR FLOW (LFM) HEAT SINK θJA (°C/W)* Figure 11, 13 12, 20 Figure 6 0 None 8.2 Figure 11, 13 12, 20 Figure 6 200 None 5.9 Figure 11, 13 12, 20 Figure 6 400 None 5.4 Figure 12, 14 12, 20 Figure 6 0 BGA Heat Sink 7.5 Figure 12, 14 12, 20 Figure 6 200 BGA Heat Sink 5.3 Figure 12, 14 12, 20 Figure 6 400 BGA Heat Sink 4.8 DERATING CURVE HEAT SINK MANUFACTURER PART NUMBER WEBSITE Aavid Thermalloy 375424B00034G www.aavidthermalloy.com Cool Innovations 4-050503P to 4-050508P www.coolinnovations.com *The results of thermal resistance from junction to ambient θJA are based on the demo board DC 1198A. Thus, the maximum temperature on board is treated as the junction temperature (which is in the µModule regulator for most cases) and the power losses from all components are counted for calculations. It has to be mentioned that poor board design may increase the θJA. 4609fc 19 LTM4609 Applications Information Layout Checklist/Example The high integration of LTM4609 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, RSENSE, SW1, SW2, PGND and VOUT. It helps to minimize the PCB conduction loss and thermal stress. • Place high frequency input and output ceramic capacitors next to the VIN, PGND and VOUT pins to minimize high frequency noise • Route SENSE– and SENSE+ leads together with minimum PC trace spacing. Avoid sense lines passing through noisy areas, such as switch nodes. SW1 • 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 the top layer and other power layers • Do not put vias directly on pads, unless the vias are capped. • Use a separated SGND ground copper area for components connected to signal pins. Connect the SGND to PGND underneath the unit. Figure 15. gives a good example of the recommended layout. SW2 VIN L1 RSENSE VOUT CIN COUT + – SGND PGND PGND RSENSE 4609 F15 KELVIN CONNECTIONS TO RSENSE Figure 15. Recommended PCB Layout (LGA Shown, for BGA Use Circle Pads) 4609fc 20 LTM4609 Typical Applications VIN 12V TO 36V 10µF 50V ×2 ON/OFF CLOCK SYNC PGOOD VIN PLLIN V OUT RUN COMP SW2 EXTVCC C3 0.1µF RSENSE STBYMD SENSE+ SS SENSE– SGND 100µF 25V SW1 PLLFLTR R3 1k L1 4.7µH LTM4609 INTVCC R1 1.5k + FCB VOUT 12V 10A R2 9mΩ VFB PGND RFB 7.15k 4609 TA02 Figure 16. Buck Mode Operation with 12V to 36V Input VIN 5V TO 12V CLOCK SYNC 4.7µF 35V PGOOD VIN ON/OFF RUN COMP R1 1.5k R3 1k PLLIN V OUT FCB LTM4609 INTVCC SW1 PLLFLTR SW2 EXTVCC C3 0.1µF L1 3.3µH 2200pF + 330µF 25V OPTIONAL FOR LOW SWITCHING NOISE RSENSE SENSE+ STBYMD SS SGND 2Ω 22µF 25V ×2 VOUT 12V 4A SENSE– PGND VFB R2 8mΩ RFB 7.15k 4609 TA03 Figure 17. Boost Mode Operation with 5V to 12V Input with Low Switching Noise (Optional) 4609fc 21 LTM4609 Typical Applications VIN 5V TO 36V 10µF 50V ×2 ON/OFF CLOCK SYNC PGOOD VIN PLLIN V OUT RUN FCB COMP LTM4609 SW1 INTVCC R1 1.5k 22µF 25V ×4 2200pF 330µF 25V VOUT 12V 4A 2Ω L1 3.3µH PLLFLTR + SW2 R3 1k EXTVCC C3 0.1µF RSENSE SENSE+ STBYMD SS R2 8mΩ SENSE– SGND VFB PGND RFB 7.15k 4609 TA04 Figure 18. Wide Input Mode with 5V to 36V Input, 12V at 4A Output VIN 8V TO 36V 10µF 50V ×2 ON/OFF CLOCK SYNC PGOOD VIN RUN COMP R1 1.5k R3 1k PLLIN V OUT FCB LTM4609 INTVCC SW1 PLLFLTR SW2 EXTVCC C3 0.1µF 220µF 50V RSENSE SENSE+ STBYMD SS SGND + L1 4.7µH VOUT 32V 2A SENSE– PGND VFB R2 9mΩ RFB 2.55k 4609 TA05 Figure 19. 32V at 2A Design 4609fc 22 LTM4609 Typical Applications VIN 5V TO 36V CLOCK SYNC 0° PHASE 10µF 50V R5 100k PGOOD VIN PLLIN V OUT RUN FCB LTM4609 200Ω 5.1V ZENER C1 0.1µF R4 324k LTC6908-1 5.1V COMP SW1 INTVCC SW2 PLLFLTR V+ OUT1 EXTVCC GND OUT2 SS SET MOD SGND C2 22µF 25V ×2 VOUT 12V 8A 330µF 25V RSENSE SENSE+ STBYMD C3 0.1µF L1 3.3µH + SENSE– PGND R2 8mΩ VFB RFB* 3.57k 2-PHASE OSCILLATOR CLOCK SYNC 180° PHASE 10µF 50V PGOOD VIN PLLIN V OUT FCB RUN LTM4609 COMP SW1 INTVCC SW2 PLLFLTR RSENSE SENSE+ EXTVCC STBYMD SS SGND L2 3.3µH SENSE– PGND VFB C4 22µF 25V ×2 + 330µF 25V *RFB IS SELECTED USING R3 8mΩ 100k + RFB VOUT = 0.8V N RFB WHERE N IS THE NUMBER OF PARALLELED MODULES. 4609 TA06 Figure 20. Two-Phase Parallel, 12V at 8A Design 4609fc 23 4 E PACKAGE TOP VIEW 3.1750 3.1750 SUGGESTED PCB LAYOUT TOP VIEW 1.9050 PIN “A1” CORNER 0.6350 0.0000 0.6350 Y 6.9850 5.7150 4.4450 3.1750 1.9050 0.6350 0.0000 0.6350 1.9050 3.1750 4.4450 5.7150 6.9850 X D aaa Z 0.27 2.45 MIN 2.72 0.60 NOM 2.82 0.63 15.00 15.00 1.27 13.97 13.97 0.32 2.50 DIMENSIONS 0.37 2.55 0.15 0.10 0.05 MAX 2.92 0.66 NOTES DETAIL B PACKAGE SIDE VIEW A TOTAL NUMBER OF LGA PADS: 141 SYMBOL A b D E e F G H1 H2 aaa bbb eee DETAIL A H1 SUBSTRATE eee S X Y DETAIL B H2 MOLD CAP 0.630 ±0.025 SQ. 143x bbb Z (Reference LTC DWG # 05-08-1840 Rev A) Z 24 1.9050 LGA Package 141-Lead (15mm × 15mm × 2.82mm) e b 11 10 9 7 G 6 e 5 PACKAGE BOTTOM VIEW 8 4 3 1 DETAIL A 2 DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE 4 TRAY PIN 1 BEVEL LGA 141 1111 REV A PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX µModule 5. PRIMARY DATUM -Z- IS SEATING PLANE BALL DESIGNATION PER JESD MS-028 AND JEP95 3 2. ALL DIMENSIONS ARE IN MILLIMETERS NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 COMPONENT PIN “A1” 3 SEE NOTES F b 12 A B C D E F G H J K L M C(0.22 x 45°) PAD 1 LTM4609 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 4609fc 6.9850 5.7150 4.4450 4.4450 5.7150 6.9850 aaa Z aaa Z 0.630 ±0.025 Ø 141x 3.1750 3.1750 SUGGESTED PCB LAYOUT TOP VIEW 1.9050 PACKAGE TOP VIEW E 0.6350 0.0000 0.6350 4 1.9050 PIN “A1” CORNER 6.9850 5.7150 4.4450 4.4450 5.7150 6.9850 Y 6.9850 5.7150 4.4450 3.1750 1.9050 0.6350 0.0000 0.6350 1.9050 3.1750 4.4450 5.7150 6.9850 X D 2.45 – 2.55 aaa Z SYMBOL A A1 A2 b b1 D E e F G aaa bbb ccc ddd eee 0.15 0.10 0.20 0.30 0.15 MAX 3.62 0.70 2.92 0.90 0.66 NOTES DETAIL B PACKAGE SIDE VIEW DIMENSIONS NOM 3.42 0.60 2.82 0.75 0.63 15.0 15.0 1.27 13.97 13.97 A A2 TOTAL NUMBER OF BALLS: 141 MIN 3.22 0.50 2.72 0.60 0.60 DETAIL A b1 0.27 – 0.37 SUBSTRATE A1 ddd M Z X Y eee M Z DETAIL B MOLD CAP ccc Z Øb (141 PLACES) // bbb Z Z (Reference LTC DWG # 05-08-1899 Rev A) (Reference LTC DWG # 05-08-1899 Rev Ø) 141-Lead (15mm × 15mm × 3.42mm) BGA Package 141-Lead (15mmBGA × 15mm × 3.42mm) Package e b 11 10 9 7 G 6 e 5 PACKAGE BOTTOM VIEW 8 4 3 2 1 DETAILS OF PIN #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PIN #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE BALL DESIGNATION PER JESD MS-028 AND JEP95 TRAY PIN 1 BEVEL BGA 141 1011 REV A PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX µModule 6. SOLDER BALL COMPOSITION IS 96.5% Sn/3.0% Ag/0.5% Cu 5. PRIMARY DATUM -Z- IS SEATING PLANE 4 3 2. ALL DIMENSIONS ARE IN MILLIMETERS NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 COMPONENT PIN “A1” 3 SEE NOTES F b 12 DETAIL A A B C D E F G H J K L M PIN 1 LTM4609 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 4609fc 25 LTM4609 Package Description Pin Assignment Table 6 (Arranged by Pin Number) PIN NAME FUNCTION PIN NAME FUNCTION PIN NAME FUNCTION PIN NAME FUNCTION PIN NAME FUNCTION PIN NAME FUNCTION A1 PGND C1 PGND E1 VOUT G1 VOUT J1 SW1 L1 SW1 A2 PGND C2 PGND E2 VOUT G2 VOUT J2 SW1 L2 SW1 A3 PGND C3 PGND E3 PGND G3 VOUT J3 SW1 L3 SW1 A4 SENSE+ C4 PGND E4 PGND G4 VOUT J4 SW1 L4 SW1 A5 SENSE– C5 PGND E5 PGND G5 RSENSE J5 RSENSE L5 RSENSE A6 SS C6 PGND E6 PGND G6 RSENSE J6 RSENSE L6 RSENSE A7 SGND C7 PGND E7 PGND G7 RSENSE J7 RSENSE L7 SW2 A8 RUN C8 PGND E8 PGND G8 RSENSE J8 SW2 L8 SW2 A9 FCB C9 PGND E9 PGND G9 RSENSE J9 SW2 L9 SW2 A10 STBYMD C10 PGND E10 PGND G10 RSENSE J10 VIN L10 VIN A11 PGND C11 PGND E11 PGND G11 RSENSE J11 VIN L11 VIN A12 PGND C12 PGND E12 PGND G12 RSENSE J12 VIN L12 VIN B1 PGND D1 PGND F1 VOUT H1 VOUT K1 SW1 M1 SW1 B2 PGND D2 PGND F2 VOUT H2 VOUT K2 SW1 M2 SW1 B3 PGND D3 PGND F3 VOUT H3 VOUT K3 SW1 M3 SW1 B4 PGND D4 PGND F4 VOUT H4 VOUT K4 SW1 M4 SW1 B5 PGOOD D5 PGND F5 INTVCC H5 RSENSE K5 RSENSE M5 RSENSE B6 VFB D6 PGND F6 EXTVCC H6 RSENSE K6 RSENSE M6 RSENSE B7 COMP D7 PGND F7 – H7 RSENSE K7 SW2 M7 SW2 B8 PLLFLTR D8 PGND F8 – H8 RSENSE K8 SW2 M8 SW2 B9 PLLIN D9 PGND F9 – H9 RSENSE K9 SW2 M9 SW2 B10 PGND D10 PGND F10 RSENSE H10 RSENSE K10 VIN M10 VIN B11 PGND D11 PGND F11 RSENSE H11 RSENSE K11 VIN M11 VIN B12 PGND D12 PGND F12 RSENSE H12 RSENSE K12 VIN M12 VIN 4609fc 26 LTM4609 Revision History (Revision history begins at Rev B) REV DATE DESCRIPTION B 10/10 MP-grade part added. Reflected throughout the data sheet. PAGE NUMBER C 03/12 Added the BGA Package option and updated the Typical Application. 1 Updated the Pin Configuration and Order Information sections. 2 Updated Note 2. 4 Added INTVCC maximum load current. 7 Updated the recommended heat sinks table. 19 Added BGA Package drawing. 25 Updated the Related Parts table. 28 1-26 4609fc 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 its circuits as described herein will not infringe on existing patent rights. 27 LTM4609 Package Photos Related Parts PART NUMBER DESCRIPTION COMMENTS LTC3780 36V Buck-Boost Controller Synchronous Operation; Single Inductor, 4V ≤ VIN ≤ 36V, 0.8V ≤ VOUT ≤ 30V LTC3785 10V Buck-Boost Controller Synchronous, No RSENSE™, 2.7V ≤ VIN ≤ 10V, 2.7V ≤ VOUT ≤ 10V LTM4601/LTM4601A 12A DC/DC µModule Regulator with PLL, Output Tracking/ Margining and Remote Sensing Synchronizable, PolyPhase® Operation to 48A, LTM4601-1 Has No Remote Sensing LTM4603 6A DC/DC µModule with PLL and Output Tracking/Margining and Remote Sensing Synchronizable, PolyPhase Operation, LTM4603-1 Version Has No Remote Sensing, Pin Compatible with the LTM4601 LTM4604A 4A, Low VIN, DC/DC µModule Regulator 2.375V ≤ VIN ≤ 5.5V, 0.8V ≤ VOUT ≤ 5V, 9mm × 15mm × 2.32mm LTM4605/LTM4607 5A High Efficiency Buck-Boost DC/DC µModule Regulators Pin Compatible with LTM4609, Lower Voltage Versions of the LTM4609 LTM4606/LTM4612 Ultralow Noise DC/DC µModule Regulators Low EMI, LTM4606 Verified by Xilinx to Power Rocket IO™, CISPR22 Compliant LTM4608A 8A, Low VIN, DC/DC µModule Regulator 2.7V ≤ VIN ≤ 5.5V, 0.6V ≤ VOUT ≤ 5V, 9mm × 15mm × 2.82mm LTM4627 20V, 15A DC/DC Step-Down µModule Regulator 4.5V ≤ VIN ≤ 20V, 0.6V ≤ VOUT ≤ 5V, PLL Input, VOUT Tracking, Remote Sense Amplifier, 15mm × 15mm × 4.32mm LGA or 15mm × 15mm × 4.92mm BGA 4609fc 28 Linear Technology Corporation LT 0312 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com LINEAR TECHNOLOGY CORPORATION 2009