LTM4615 Triple Output, Low Voltage DC/DC Module Regulator Features Description Dual 4A Output Power Supply with 1.5A VLDOTM n Short-Circuit and Overtemperature Protection n Power Good Indicators Switching Regulators Section--Current Mode Control n Input Voltage Range: 2.375V to 5.5V n 4A DC Typical, 5A Peak Output Current Each n 0.8V Up to 5V Output Each, Parallelable n 2% Total DC Output Error n Output Voltage Tracking n Up to 95% Efficiency n Programmable Soft-Start VLDO Section n VLDO, 1.14V to 3.5V Input Range n VLDO, 0.4V to 2.6V, 1.5A Output n VLDO, 40dB Supply Rejection at f SW n 1% Total DC Output Error n Small and Very Low Profile Package: 15mm x 15mm x 2.82mm The LTM(R)4615 is a complete 4A dual output switching mode DC/DC power supply plus an additional 1.5A VLDO (very low dropout) linear regulator. Included in the package are the switching controllers, power FETs, inductors, a 1.5A regulator and all support components. The dual 4A DC/DC converters operate over an input voltage range of 2.375V to 5.5V, and the VLDO operates from a 1.14V to 3.5V input. The LTM4615 supports output voltages ranging from 0.8V to 5V for the DC/DC converters, and 0.4V to 2.6V for the VLDO. The three regulator output voltages are set by a single resistor for each output. Only bulk input and output capacitors are needed to complete the design. n 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 a current mode architecture enables a very fast transient response to line and load changes without sacrificing stability. The device supports output voltage tracking for supply rail sequencing. Applications n n n n Additional features include overvoltage protection, overcurrent protection, thermal shutdown and programmable soft-start. The power module is offered in a space saving and thermally enhanced 15mm x 15mm x 2.82mm LGA package. The LTM4615 is RoHS compliant with Pb-free finish. Telecom and Networking Equipment Industrial Power Systems Low Noise Applications FPGA, SERDES Power L, LT, LTC, LTM, Linear Technology, the Linear logo, Module and PolyPhase are registered trademarks and VLDO and LTpowerCAD are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131, 6724174. Typical Application Efficiency vs Output Current 1.2V at 4A, 1.5V at 4A and 1V at 1A DC/DC Module(R) Regulator 91 22F 6.3V 10k 100F 6.3V 1.2V 10F VIN VIN1 PGOOD1 VOUT1 FB1 TRACK1 RUN/SS1 LDO_IN EN3 VIN2 PGOOD2 VOUT2 LTM4615 FB2 TRACK2 RUN/SS2 LDO_OUT FB3 PGOOD3 GND1 GND3 GND2 PGOOD2 10F 6.3V 10k VIN 87 VOUT2 1.5V 4A PGOOD3 22F 6.3V 5.76k VOUT3 1V AT 1A 10F 6.3V 100F 6.3V VOUT2 1.5V 85 83 VOUT3 1V (VIN = 1.2V) 81 VOUT1 1.2V 79 77 3.32k 75 10k VOUT3 EFFICIENCY (%) VOUT1 1.2V 4A PGOOD1 10F 6.3V 10k VIN = 3.3V 89 VIN 3V TO 5.5V 4615 TA01a 0 2 1 3 OUTPUT CURRENT (A) 4 4615 TA01b 4615fb For more information www.linear.com/LTM4615 1 LTM4615 Absolute Maximum Ratings (Note 1) Switching Regulators VIN1, VIN2, PGOOD1, PGOOD2....................... -0.3V to 6V COMP1, COMP2, RUN/SS1, RUN/SS2 VFB1, VFB2,TRACK1, TRACK2....................... -0.3V to VIN SW, VOUT....................................... -0.3V to (VIN + 0.3V) Very Low Dropout Regulator LDO_IN, PGOOD3, EN3................................. -0.3V to 6V LDO_OUT.........................................................-0.3 to 4V FB3......................................... -0.3V to (LDO_IN + 0.3V) LDO_OUT Short-Circuit.................................... Indefinite Internal Operating Temperature Range (Notes 2, 5)............................................. -40C to 125C Junction Temperature............................................ 125C Storage Temperature Range................... -55C to 125C Pin Configuration TOP VIEW TRACK1 RUN/SS1 COMP1 PGOOD1 FB1 M VOUT1 L K SW1 GND1 LDO_IN PGOOD3 VIN1 J GND1 H LDO_OUT G FB3 GND3 FB2 BOOST3 EN3 GND3 F GND2 E RUN/SS2 D VIN2 VOUT2 C B GND2 A 1 2 3 4 5 6 7 8 9 10 11 12 TRACK2 COMP2 SW2 PGOOD2 LGA PACKAGE 144-LEAD (15mm x 15mm x 2.82mm) TJMAX = 125C, JCbottom = 2-3C/W, JA = 15C/W, JCtop = 25C/W, VALUES DETERMINED FROM 4 LAYER 76mm x 95mm PCB WEIGHT = 1.6g Order Information LEAD FREE FINISH TRAY PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTM4615EV#PBF LTM4615EV#PBF LTM4615V 144-Lead (15mm x 15mm x 2.82mm) LGA -40C to 125C LTM4615IV#PBF LTM4615IV#PBF LTM4615V 144-Lead (15mm x 15mm x 2.82mm) LGA -40C to 125C 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/ See Note 2. 2 4615fb For more information www.linear.com/LTM4615 LTM4615 Electrical Characteristics The l denotes the specifications which apply over the full internal operating temperature range (Note 2), otherwise specifications are at TA = 25C, VIN = 5V, LDO_IN = 1.2V unless otherwise noted. Per Typical Application Figure 12. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Switching Regulator Section: per Channel VIN(DC) Input DC Voltage Range l 2.375 5.5 V VOUT(DC) Output DC Voltage Range l 0.8 5.0 V VOUT(DC) Output Voltage l 1.460 1.45 1.49 1.49 1.512 1.512 V V 1.6 2 2.3 V 12 mA mA A CIN = 22F, COUT = 100F, RFB = 5.76k, VIN = 2.375V to 5.5V, IOUT = 0A to 4A (Note 6) 0C TJ 125C VIN(UVLO) Undervoltage Lockout Threshold IOUT = 0A IINRUSH(VIN) Input Inrush Current at Start-Up IOUT = 0A, CIN = 22F, COUT = 100F, VOUT = 1.5V, VIN = 5.5V 0.35 IQ(VIN) Input Supply Bias Current VIN = 2.375V, VOUT = 1.5V, Switching Continuous VIN = 5.5V, VOUT = 1.5V, Switching Continuous Shutdown, RUN = 0, VIN = 5V 28 45 7 IS(VIN) Input Supply Current VIN = 2.375V, VOUT = 1.5V, IOUT = 4A VIN = 5.5V, VOUT = 1.5V, IOUT = 4A IOUT(DC) Output Continuous Current Range VIN = 5.5V, VOUT = 1.5V (Note 6) VOUT(LOAD + LINE) Load and Line Regulation Accuracy VOUT = 1.5V, 0A to 4A (Note 6) VIN = 2.375V to 5.5V VOUT Output Ripple Voltage IOUT = 0A, COUT = 100F VIN = 5V, VOUT = 1.5V fs Output Ripple Voltage Frequency IOUT = 4A, VIN = 5V, VOUT = 1.5V VOUT(START) Turn-On Overshoot tSTART 3.2 1.48 0 1.0 1.3 l VOUT(AC) Turn-On Time A A A 4 A 1.30 1.6 % % 12 mVP-P 1.25 MHz COUT = 100F, VOUT = 1.5V, RUN/SS = 10nF, IOUT = 0A VIN = 3.3V VIN = 5V 20 20 mV mV COUT = 100F, VOUT = 1.5V, IOUT = 1A Resistive Load, TRACK = VIN and RUN/SS = Float VIN = 5V 0.5 ms VOUT(LS) Peak Deviation for Dynamic Load Load: 0% to 50% to 0% of Full Load, COUT = 100F, VIN = 5V, VOUT = 1.5V 25 mV tSETTLE Settling Time for Dynamic Load Step Load: 0% to 50% to 0% of Full Load, VIN = 5V, VOUT = 1.5V 10 s IOUT(PK) Output Current Limit COUT = 100F, VIN = 5V, VOUT = 1.5V 8 A VFB Voltage at FB Pin IOUT = 0A, VOUT = 1.5V l 0.790 0.786 0.8 0.8 0.6 0.75 0.807 0.809 0.2 IFB VRUN RUN Pin On/Off Threshold ITRACK TRACK Pin Current A 0.9 0.2 VTRACK(OFFSET) Offset Voltage VTRACK(RANGE) Tracking Input Range TRACK = 0.4V RFBHI Resistor Between VOUT and FB Pins VPGOOD PGOOD Range RPGOOD PGOOD Resistance 4.96 4.99 mV 0.8 V 5.02 k 7.5 Open-Drain Pull-Down 90 V A 30 0 V V % 150 4615fb For more information www.linear.com/LTM4615 3 LTM4615 Electrical Characteristics The l denotes the specifications which apply over the full internal operating temperature range (Note 2), otherwise specifications are at TA = 25C, VIN = 5V, LDO_IN = 1.2V unless otherwise noted. Per Typical Application Figure 12. SYMBOL PARAMETER CONDITIONS MIN VLDO_IN Operating Voltage (Note 3) IIN(LDO_IN) Operating Current IOUT = 0mA, VOUT = 1V, EN3 = 1.2V IIN(SHDN) Shutdown Current EN3 = 0V, LDO_IN = 1.5V VBOOST3 BOOST3 Output Voltage EN3 = 1.2V VBOOST3(UVLO) Undervoltage Lockout VFB3 FB3 Internal Reference Voltage TYP MAX UNITS VLDO Section VLDO_OUT Output Voltage Range VDO Dropout Voltage l 3.5 1 l 0.6 20 A 4.8 5 5.2 V 0.397 0.395 0.4 0.4 0.404 0.405 2.6 V 100 250 mV 4.99 5.02 k 0.4 VLDO_IN = 1.5V, VFB3 = 0.38V, IOUT = 1.5A (Note 4) LDO Top Feedback Resistor IOUT Output Current VEN3 = 1.2V 4.96 ILIM Output Current Limit (Note 5) l en Output Voltage Noise Frequency = 10Hz to 1MHz, ILOAD = 1A VIH_EN3 EN3 Input High Voltage 1.14V VLDO_IN 3.5V VIL_EN3 EN3 Input Low Voltage 1.14V VLDO_IN 3.5V IIN_EN3 EN3 Input Current VOL_PGOOD3 PGOOD Low Voltage IPGOOD3 = 2mA PGOOD Threshold Output Threshold Relative to VFB3 PGOOD3 High to Low PGOOD3 Low to High l V 1.5 2.5 A 300 RMS 1 -14 -4 V V A V -1 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 LTM4615 is tested under pulsed load conditions such that TJ TA. The LTM4615E is guaranteed to meet performance specifications over the 0C to 125C internal operating temperature range. Specifications over the -40C to 125C internal operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM4615I is guaranteed to meet specifications over the full internal operating temperature range. Note that the maximum ambient temperature is determined by specific operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors. V mA 4.3 1mA IOUT 1.5A, 1.14V VLDO_IN 3.5V, BOOST3 = 5V, 1V VOUT 2.59V LDO_RHI 4 1.14 0.4 V 1 A 0.1 0.4 V -12 -3 -10 -2 % % Note 3: Minimum operating voltage required for regulation is: VIN VOUT(MIN) + VDROPOUT Note 4: Dropout voltage is the minimum input to output differential needed to maintain regulation at a specified output current. In dropout the output voltage will be equal to VIN - VDROPOUT . Note 5: The LTM4615 has overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperatures will exceed 125C when overtemperature is activated. Continuous overtemperature activation can impair long-term reliability. Note 6: See output current derating curves for different VIN, VOUT and TA. 4615fb For more information www.linear.com/LTM4615 LTM4615 Typical Performance Characteristics Switching Regulators Efficiency vs Output Current VIN = 3.3V 95 95 95 90 90 90 85 80 65 0 1 85 80 VOUT = 2.5V VOUT = 1.8V VOUT = 1.5V VOUT = 1.2V VOUT = 0.8V 75 VOUT = 1.8V VOUT = 1.5V VOUT = 1.2V VOUT = 0.8V 70 70 2 3 OUTPUT CURRENT (A) 4 EFFICIENCY (%) 100 75 65 0 1 3.0 2.5 80 2 4 3 OUTPUT CURRENT (A) 65 VOUT 20mV/DIV 1.0 20s/DIV VIN = 5V VOUT = 1.2V COUT = 100F, 6.3V CERAMICS 0.5 0 4 ILOAD 2A/DIV VOUT 20mV/DIV 1.5 1 2 3 OUTPUT CURRENT (A) Load Transient Response ILOAD 2A/DIV 2.0 0 4615 G03 Load Transient Response VOUT = 3.3V VOUT = 2.5V VOUT = 1.8V VOUT = 1.5V VOUT = 1.2V VOUT = 0.8V VOUT = 3.3V VOUT = 2.5V VOUT = 1.8V VOUT = 1.5V VOUT = 1.2V VOUT = 0.8V 75 4615 G02 Minimum Input Voltage at 4A Load 3.5 85 70 4615 G01 VOUT (V) Efficiency vs Output Current VIN = 5V 100 EFFICIENCY (%) EFFICIENCY (%) Efficiency vs Output Current VIN = 2.5V 20s/DIV VIN = 5V VOUT = 1.5V COUT = 100F, 6.3V CERAMICS 4615 G05 4615 G06 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 VIN (V) 4615 G04 Load Transient Response Load Transient Response Load Transient Response ILOAD 2A/DIV ILOAD 2A/DIV VOUT 20mV/DIV ILOAD 2A/DIV VOUT 20mV/DIV VOUT 20mV/DIV 20s/DIV VIN = 5V VOUT = 1.8V COUT = 100F, 6.3V CERAMICS 4615 G07 20s/DIV VIN = 5V VOUT = 2.5V COUT = 100F, 6.3V CERAMICS 4615 G08 20s/DIV VIN = 5V VOUT = 3.3V COUT = 100F, 6.3V CERAMICS 4615 G09 4615fb For more information www.linear.com/LTM4615 5 LTM4615 Typical Performance Characteristics Start-Up Start-Up 806 VOUT 1V/DIV VFB vs Temperature 804 VOUT 1V/DIV VFB (mV) 802 IIN 1A/DIV IIN 1A/DIV 800 798 4615 G10 VIN = 5V 200s/DIV VOUT = 2.5V COUT = 100F NO LOAD (0.01F SOFT-START CAPACITOR) VIN = 5V 200s/DIV VOUT = 2.5V COUT = 100F 4A LOAD (0.01F SOFT-START CAPACITOR) 4615 G11 796 794 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125 4615 G12 Short-Circuit Protection 1.5V Short, No Load Current Limit Short-Circuit Protection 1.5V Short, 4A Load 1.6 1.4 1.2 VOUT 0.5V/DIV VOUT 0.5V/DIV IIN 1A/DIV IIN 1A/DIV VOUT (V) 1.0 0.8 0.6 VOUT = 1.5V VIN = 5V 0.2 VIN = 3.3V VIN = 2.5V 0 4 5 3 0.4 4615 G14 20s/DIV 7 6 OUTPUT CURRENT (A) 4615 G15 100s/DIV 8 4615 G13 VLDO VFB3 vs Temperature Dropout Voltage vs Input Voltage 200 404 180 403 10kHz 50 400 1.5A 399 140 120 100 80 60 398 VBOOST3 = 5V VLDO_IN = 1.5V VLDO_OUT =1.2V 397 -25 0 25 50 75 TEMPERATURE (C) 100 125 4615 G16 RIPPLE REJECTION (dB) 1mA DROPOUT (mV) FB3 VOLTAGE (mV) 401 6 VFB3 = 0.38V ILDO_OUT =1.5A 160 402 396 -50 Ripple Rejection 60 -40C 25C 85C 125C 40 20 0 1.2 1.4 1.6 1.8 2.0 VLDO_IN (V) 2.2 2.4 1MHz 40 100kHz 30 20 VBOOST3 = 5V VLDO_OUT =1.2V IOUT = 800mA COUT = 10F 10 2.6 4615 G17 0 1.2 1.4 1.6 1.8 2.0 2.2 VLDO_IN (V) 2.4 2.6 4615 G18 4615fb For more information www.linear.com/LTM4615 LTM4615 Typical Performance Characteristics Delay from Enable to Power Good Output Current Limit 5.0 60 4.5 5.0 VLDO_OUT = 0V TA = 25C 4.0 30 VBOOST3 = 5V VLDO_IN = 1.5V VLDO_OUT =1.2V IOUT = 800mA COUT = 10F 20 10 0 100 1000 10000 100000 1000000 1E+07 FREQUENCY (Hz) 3.5 3.5 DELAY (ms) 40 3.0 2.5 2.0 VLDO_OUT = 0.8V RLDO_OUT = 8 -40C 25C 85C 4.5 4.0 50 ILDO_OUT (A) RIPPLE REJECTION (dB) Ripple Rejection 70 CURRENT LIMIT 4615 G19 2.5 2.0 1.5 1.0 THERMAL LIMIT 1.5 1.0 1.0 3.0 0.5 1.5 2.0 3.0 2.5 VLDO_IN (V) 3.5 0 1.0 1.5 2.5 2.0 VLDO_IN (V) 4615 G20 Output Load Transient Response 3.0 3.5 4615 G21 IN Supply Transient Response 1.5A ILDO_OUT 2mA 2V VLDO_IN 1.5V VLDO_OUT AC 20mV/DIV VLDO_OUT AC 10mV/DIV VLDO_OUT = 1.5V 50s/DIV COUT = 10F VLDO_IN = 1.7V VBOOST3 = 5V VLDO_OUT = 1.2V 10s/DIV ILDO_OUT = 800mA COUT = 10F VBOOST3 = 5V TA = 25C 4615 G22 BOOST3 Ripple and Feedthrough to VLDO_OUT BOOST3/OUT Start-Up EN3 4615 G23 HI LO BOOST3 AC 20mV/DIV 5V BOOST3 1V 1.5V VLDO_OUT AC 5mV/DIV VLDO_OUT 0V TA = 25C RLDO_OUT = 1 VLDO_IN = 1.7V 200s/DIV 4615 G24 VLDO_OUT = 1.2V 20s/DIV VLDO_IN = 1.5V ILDO_OUT = 1A COUT = 10F TA = 25C 4615 G25 4615fb For more information www.linear.com/LTM4615 7 LTM4615 Pin Functions VIN1, VIN2 (J1-J5, K1-K5); (C1-C6, D1-D5): Power Input Pins. Apply input voltage between these pins and GND pins. Recommend placing input decoupling capacitance directly between VIN pins and GND pins. VOUT1, VOUT2 (K9-K12, L9-L12, M9-M12); (C9-C12, D9-D12, E11-E12): Power Output Pins. Apply output load between these pins and GND pins. Recommend placing output decoupling capacitance directly between these pins and GND pins. Review Table 4. GND1, GND2, (H1, H7-H12, J6-J12, K6-K8 L1, L7-L8, M1-M8); (A1-A12, B1, B7-B12, C7-C8, D6-D8, E1, E8-E10): Power Ground Pins for Both Input and Output Returns. TRACK1, TRACK2 (L3, E3): Output Voltage Tracking Pins. When the module is configured as a master output, then a soft-start capacitor is placed on the RUN/SS pin to ground to control the master ramp rate, or an external ramp can be applied to the master regulator's track pin to control it. Slave operation is performed by putting a resistor divider from the master output to ground, and connecting the center point of the divider to this pin on the slave regulator. If tracking is not desired, then connect the TRACK pin to VIN. Load current must be present for tracking. See the Applications Information section. FB1, FB2 (L6, E6): The Negative Input of the Switching Regulators' Error Amplifier. Internally, these pins are connected to VOUT with a 4.99k precision resistor. Different output voltages can be programmed with an additional resistor between the FB and GND pins. Two power modules can current share when this pin is connected in parallel with the adjacent module's FB pin. See the Applications Information section. FB3 (F6): The Negative Input of the LDO Error Amplifier. Internally the pin is connected to LDO_OUT with a 4.99k resistor. Different output voltages can be programmed with an additional resistor between the FB3 and GND pins. See the Applications Information section. 8 COMP1, COMP2 (L5, E5): Current Control Threshold and Error Amplifier Compensation Point. The current comparator threshold increases with this control voltage. Two power modules can current share when this pin is connected in parallel with the adjacent module's COMP pin. Each channel has been internally compensated. See the Applications Information section. PGOOD1, PGOOD2 (L4, E4): 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/SS1, RUN/SS2 (L2, E2): Run Control and Soft-Start Pin. A voltage above 0.8V will turn on the module, and below 0.5V will turn off the module. This pin has a 1M resistor to VIN and a 1000pF capacitor to GND. See the Applications Information section for soft-start information. SW1, SW2 (H2-H6, B2-B6): The switching node of the circuit is used for testing purposes. This can be connected to copper on the board for improved thermal performance. SW1 and SW2 must be floating on separate copper planes. LDO_IN (G1-G4): VLDO Input Power Pins. Place input capacitor close to these pins. LDO_OUT (G9-G12): VLDO Output Power Pins. Place output capacitor close to these pins. Minimum 1mA load is necessary for proper output voltage accuracy. BOOST3 (E7): Boost Supply for Driving the Internal VLDO NMOS Into Full Enhancement. The pin is use for testing the internal boost converter. The output is typically 5V. GND3 (F1-F5, F7, F9-F12, G6-G8): The power ground pins for both input and output returns for the internal VLDO. PGOOD3 (G5): VLDO Power Good Pin. EN3 (F8): VLDO Enable Pin. 4615fb For more information www.linear.com/LTM4615 LTM4615 Simplified Block Diagram Switching Regulator Block Diagram VIN PGOOD RUN/SS RSS 1M CSS 1000pF CSSEXT TRACK SUPPLY 4.99k TRACK 5.76k VIN 22F 2.375V TO 5.5V 6.3V 4.7F 6.3V CONTROL, DRIVE POWER FETS COMP M1 0.47H M2 470pF VOUT 1.5V 4A VOUT 4.7F 6.3V 22F 6.3V x3 RFBHI 4.99k INTERNAL COMP GND FB SW 4615 F01a RFB 5.76k VLDO Block Diagram BOOST3 5V BOOST VIN 1.14V TO 3.5V 4.7F LDO_IN 4.7F 6.3V 0.4V 10F GND3 EN3 + - GND3 GND3 ENABLE VOUT 1V 10F 1.5A LDO_OUT CONTROL LDO_RHI 4.99k 4.7F 6.3V GND3 POWER GOOD FB3 RFBLDO 3.32k PGOOD3 GND3 10k 4615 F01b GND 1V Figure 1. Simplified LTM4615 Block Diagram of Each Switching Regulator Channel and the VLDO Decoupling Requirements TA = 25C. Use Figure 1 configuration for each channel. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS CIN External Input Capacitor Requirement (VIN = 2.375V to 5.5V, VOUT = 1.5V) IOUT = 4A 22 COUT External Output Capacitor Requirement (VIN = 2.375V to 5.5V, VOUT = 1.5V) IOUT = 4A 66 100 F LDO_IN LDO Input Capacitance IOUT = 1A 4.7 10 F LDO_OUT LDO Output Capacitance IOUT = 1A 10 F F 4615fb For more information www.linear.com/LTM4615 9 LTM4615 Operation LTM4615 Power Module Description Dual Switching Regulator Section The LTM4615 is a standalone dual nonisolated switching mode DC/DC power supply with an additional onboard 1.5A VLDO. It can deliver up to 4A of DC output current for each channel with few external input and output capacitors. This module provides two precisely regulated output voltages programmable via one external resistor for each channel from 0.8V DC to 5V DC over a 2.375V to 5.5V input voltage range. The VLDO is an independent 1.5A linear regulator that can be powered from either switching converter. The typical application schematic is shown in Figure 12. The LTM4615 has two integrated constant frequency current mode regulators, with built-in power MOSFETs with fast switching speed. The typical switching frequency is 1.25MHz. With current mode control and internal feedback loop compensation, these switching regulators have 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. Current mode control provides cycle-by-cycle fast current limit. Besides, current limiting is provided in an overcurrent condition with thermal shutdown. In addition, internal overvoltage and undervoltage comparators pull the opendrain PGOOD outputs low if the particular output feedback voltage exits a 7.5% window around the regulation point. Furthermore, in an overvoltage condition, internal top FET, M1, is turned off and bottom FET, M2, is turned on and held on until the overvoltage condition clears, or current limit is exceeded. Pulling each specific RUN/SS pin below 0.8V forces the specific regulator controller into its shutdown state, turning off both M1 and M2 for each power stage. At low load current, each regulator works in continuous current mode by default to achieve minimum output voltage ripple. The LTM4615 is internally compensated to be stable over the operating conditions. Table 4 provides a guideline for input and output capacitance for several operating conditions. The LTpowerCADTM Design Tool is provided for transient and stability analysis. The FB pins are used to program the specific output voltage with a single resistor to ground. VLDO Section The VLDO (very low dropout) linear regulator operates from a 1.14V to 3.5V input. The VLDO uses an internal NMOS transistor as the pass device in a source-follower configuration. The BOOST3 pin is the output of an internal boost converter that supplies the higher supply drive to the pass device for low dropout enhancement. The internal boost converter operates on very low current, thus optimizing high efficiency for the VLDO in close to dropout operation. An undervoltage lockout comparator on the LDO ensures that the boost voltage is greater than 4.2V before enabling the LDO, otherwise the LDO is disabled. The LDO provides a high accuracy output capable of supply 1.5A of output current with a typical drop out of 100mV. A single ceramic 10F capacitor is all that is required for output capacitor bypassing. A low reference voltage allows the VLDO to have lower output voltages than the commonly available LDO. The device also includes current limit and thermal overload protection. The NMOS follower architecture has fast transient response without the traditional high drive currents in dropout. The VLDO includes a soft-start feature to prevent excessive current on the input during start-up. When the VLDO is enabled, the soft-start circuitry gradually increases the reference voltage from 0V to 0.4V over a period of approximately 200s. The TRACK pins are used for power supply tracking for each specific regulator. See the Applications Information section. 10 4615fb For more information www.linear.com/LTM4615 LTM4615 Applications Information Dual Switching Regulator The typical LTM4615 application circuit is shown in Figure 12. External component selection is primarily determined by the maximum load current and output voltage. Refer to Table 4 for specific external capacitor requirements for a particular application. VIN to VOUT Step-Down Ratios There are restrictions in the maximum VIN to VOUT stepdown ratio that can be achieved for a given input voltage on the two switching regulators. The LTM4615 is 100% duty cycle, but the VIN to VOUT minimum dropout will be a function the load current. A typical 0.5V minimum is sufficient. Output Voltage Programming Each regulator channel has an internal 0.8V reference voltage. As shown in the block diagram, a 4.99k internal feedback resistor connects the VOUT and FB pins together. The output voltage will default to 0.8V with no feedback resistor. Adding a resistor RFB from the FB pin to GND programs the output voltage: VOUT = 0.8V * 4.99k +RFB RFB For a buck converter, the switching duty cycle can be estimated as: D= VOUT VIN Without considering the inductor ripple current, the RMS current of the input capacitor can be estimated as: ICIN(RMS) = IOUT(MAX) % * D * (1- D) In the above equation, % is the estimated efficiency of the power module. If a low inductance plane is used to power the device, then no input capacitance is required. The internal 4.7F ceramics on each channel input are typically rated for 1A of RMS ripple current up to 85C operation. The worse-case ripple current for the 4A maximum current is 2A or less. An additional 10F or 22F ceramic capacitor can be used to supplement the internal capacitor with an additional 1A to 2A ripple current rating. Output Capacitors or equivalently, RFB = current requirements. A 47F bulk capacitor can be used for more input capacitance. This 47F capacitor is only needed if the input source impedance is compromised by long inductive leads or traces. The bulk capacitor can be a switcher-rated aluminum electrolytic OS-CON capacitor. 4.99k VOUT -1 0.8V Table 1. FB Resistor Table vs Various Output Voltages VOUT 0.8V 1.2V 1.5V 1.8V 2.5V 3.3V FB Open 10k 5.76k 3.92k 2.37k 1.62k Input Capacitors The LTM4615 module should be connected to a low AC impedance DC source. One 4.7F ceramic capacitor is included inside the module for each regulator channel. Additional input capacitors are needed if a large load step is required, up to the full 4A level, and for RMS ripple The LTM4615 switchers are designed for low output voltage ripple on each channel. The bulk output capacitors are chosen with low enough effective series resistance (ESR) to meet the output voltage ripple and transient requirements. The output capacitors can be a low ESR tantalum capacitor, low ESR polymer capacitor or ceramic capacitor. The typical output capacitance range is 66F to 100F. Additional output filtering may be required by the system designer if further reduction of output ripple or dynamic transient spikes is required. Table 4 shows a matrix of different output voltages and output capacitors to minimize the voltage droop and overshoot during a 2A/ s transient. The table optimizes total equivalent ESR and total bulk capacitance to maximize transient performance. 4615fb For more information www.linear.com/LTM4615 11 LTM4615 Applications Information Fault Conditions: Current Limit and Overtemperature Protection The LTM4615 has current mode control, which inherently limits the cycle-by-cycle inductor current not only in steady-state operation, but also in transient. Along with current limiting in the event of an overload condition, the LTM4615 has overtemperature shutdown protection that inhibits switching operation around 150C for each channel. Run Enable and Soft-Start The RUN/SS pins provide a dual function of enable and soft-start control for each channel. The RUN/SS pins are used to control turn on of the LTM4615. While each enable pin is below 0.5V, the LTM4615 will be in a low quiescent current state. At least a 0.8V level applied to the enable pins will turn on the LTM4615 regulators. This pin can be used to sequence the regulator channels. The soft-start control is provided by a 1M pull-up resistor (RSS) and a 1000pF capacitor (CSS) as drawn in the block diagram for each channel. An external capacitor can be applied to the RUN/SS pin to increase the soft-start time. A typical value is 0.01F. The approximate equation for soft-start: where RSS and CSS are shown in the block diagram of Figure 1, and the 1.8V is soft-start upper range. The softstart function can also be used to control the output ramp-up time, so that another regulator can be easily tracked to it. Output Voltage Tracking Output voltage tracking can be programmed externally using the TRACK pins. Either output can be tracked up or down with another regulator. The master regulator's output is divided down with an external resistor divider that is the same as the slave regulator's feedback divider to implement coincident tracking. The LTM4615 uses a very accurate 4.99k resistor for the internal top feedback resistor. Figure 2 shows an example of coincident tracking. Equations: RFB1 TRACK1= * Master 4.99k +RFB1 4.99k Slave = 1+ * TRACK1 RFB1 VIN tSOFTSTART = In * RSS * CSS VIN - 1.8V VIN 3V TO 5.5V C1 PGOOD1 10F 6.3V R3 10k SLAVE 1.2V 4A C10 22F 6.3V C3 22F 6.3V C9 22F 6.3V 1.5V RTB 4.99k L1 0.2H* 1.2V C4 22F 6.3V RFB1 10k RTA 10k C12 10F *FAIR-RITE 0805 2508056007Y6 OPTIONAL FILTER C2 10F PGOOD2 6.3V VIN2 VIN1 PGOOD1 PGOOD2 VOUT1 VOUT2 FB1 FB2 COMP1 COMP2 TRACK1 TRACK2 LTM4615 RUN/SS2 RUN/SS1 LDO_OUT LDO_IN FB3 EN3 PGOOD3 BOOST3 GND1 GND3 GND2 R4 10k MASTER 1.5V 4A RFB2 5.76k VIN OR A CONTROL RAMP 1V LOW NOISE AT 1A R6 10k PGOOD3 R5 3.32k 1V LOW NOISE C11 10F 6.3V C5 22F 6.3V C6 22F 6.3V C8 22F 6.3V C7 22F 6.3V C13 CSSEXT 4615 F02 Figure 2. Dual Outputs (1.5V and 1.2V) with Tracking 12 4615fb For more information www.linear.com/LTM4615 LTM4615 Applications Information TRACK1 is the track ramp applied to the slave's track pin. TRACK1 applies the track reference for the slave output up to the point of the programmed value at which TRACK1 proceeds beyond the 0.8V reference value. The TRACK1 pin must go beyond the 0.8V to ensure the slave output has reached its final value. Ratiometric tracking can be achieved by a few simple calculations and the slew rate value applied to the master's TRACK pin. As mentioned above, the TRACK pin has a control range from 0V to 0.8V. The control ramp slew rate applied to the master's TRACK pin is directly equal to the master's output slew rate in Volts/Time. The equation: In ratiometric tracking, a different slew rate maybe desired for the slave regulator. RTB can be solved for when SR is slower than MR. Make sure that the slave supply slew rate is chosen to be fast enough so that the slave output voltage will reach it final value before the master output. For example, MR = 2.5V/ms and SR = 1.8V/1ms. Then RTB = 6.98k. Solve for RTA to equal to 3.24k. The master output must be greater than the slave output for the tracking to work. Output load current must be present for tracking to operate properly during power-down. Power Good MR * 4.99k = RTB SR where MR is the master's output slew rate and SR is the slave's output slew rate in Volts/Time. When coincident tracking is desired, then MR and SR are equal, thus RTB is equal to 4.99k. RTA is derived from equation: RTA = Figure 3 shows the output voltage tracking waveform for coincident tracking. 0.8V VFB VTRACK VFB + - 4.99k RFB RTB where VFB is the feedback voltage reference of the regulator, and VTRACK is 0.8V. Since RTB is equal to the 4.99k top feedback resistor of the slave regulator in equal slew rate or coincident tracking, then RTA is equal to RFB with VFB = VTRACK. Therefore RTB = 4.99k and RTA = 10k in Figure 2. OUTPUT VOLTAGE (V) MASTER OUTPUT SLAVE OUTPUT PGOOD1 and PGOOD2 are open-drain pins that can be used to monitor valid output voltage regulation. These pins monitor a 7.5% window around the regulation point. If the output is disabled, the respective pin will go low. COMP Pin This pin is the external compensation pin. The module has already been internally compensated for all output voltages. Table 4 is provided for most application requirements. The LTpowerCAD Design Tool is provided for other control loop optimization. The COMP pins must be tied together in parallel operation. Parallel Switching Regulator Operation The LTM4615 switching regulators are inherently current mode control. Paralleling will have very good current sharing. This will balance the thermals on the design. Figure 13 shows a schematic of a parallel design. The voltage feedback equation changes with the variable N as channels are paralleled. The equation: VOUT TIME 4.99k +RFB N = 0.8V * RFB N is the number of paralleled channels. 4615 F03 Figure 3. Output Voltage Coincident Tracking 4615fb For more information www.linear.com/LTM4615 13 LTM4615 Applications Information pacitance can be used, but a ceramic capacitor must be used in parallel at the output. VLDO Section Adjustable Output Voltage The output voltage is set by the ratio of two resistors. A 4.99k resistor is built onboard the module from LDO_OUT to FB3. An additional resistor (RFBLDO)is required from FB3 to GND3 to set the output voltage over a range of 0.4V to 2.6V. Minimum output current of 1mA is required for full output voltage range. 4.99k +RFBLDO RFBLDO or equivalently, RFBLDO = 4.99k V LDO _ OUT 0.4V Short-Circuit/Thermal Protection The VLDO has built-in short-circuit current limiting of ~3A as well as overtemperature protection. During shortcircuit conditions the device is in control to 3A, and as the internal temperature rises to approximately 150C, then the internal boost and LDO are shut down until the internal temperature drops back to 140C. The device will cycle in and out of this mode with no latchup or damage. Long term over stress in this condition can degrade the device over time. The equation: VLDO _ OUT = 0.4V * Extra consideration should be given to the use of ceramic capacitors related to dielectrics, temperature and DC bias effects on the capacitor. The VLDO requires a minimum 10F value. The X7R and X5R dielectrics are more stable with DC bias and temperature, thus more preferred. -1 Power Good Operation Reverse Current Protection The VLDO includes an open-drain power good (PGOOD3) pin with hysteresis. If the VLDO is in shutdown or under UVLO conditions (BOOST3 < 4.2V), then PGOOD3 is low impedance to ground. PGOOD3 becomes high impedance when the VLDO output voltage rises to 93% of its regulated voltage. PGOOD3 stays high impedance until the output voltage falls to 91% of its regulated voltage. A pull-up resistor can be inserted between the PGOOD3 pin and a positive logic supply such as the VLDO output or VIN. LDO_IN should be at least 1.14V or greater for power good to operate properly. The VLDO features reverse current protection to limit current draw from any supplementary power source at the output. Figure 4 shows the reverse input current limit versus input voltage for a nominal VLDO_OUT setpoint of 1.5V. Note: Positive input current represents current flowing into the LDO_IN pin. With LDO_OUT held at or below the output regulation voltage and LDO_IN varied, input current flow will follow the Figure 4 curve. Input reverse current ramps up to 16A as LDO_IN approaches LDO_OUT. The VLDO is designed to be stable with a wide range of ceramic output capacitors. The ESR of the output capacitors affects stability, especially smaller value capacitors. An output capacitor of 10F or greater with an ESR of 0.05 or less is recommended to ensure stability. Larger value capacitors can be used to reduce the transient deviations under load changes. Bypass capacitors that are used at the load device can also increase the effective output capacitance. High ESR tantalum or electrolytic bulk ca- 14 IN CURRENT LIMIT ABOVE 1.45V 20 LDO_IN CURRENT (A) Output Capacitance and Transient Response 30 10 0 -10 -20 -30 0 0.3 0.9 0.6 1.2 LDO_IN VOLTAGE (V) 1.5 1.8 4615 F04 Figure 4. Reverse Current Limit for VLDO 4615fb For more information www.linear.com/LTM4615 LTM4615 Applications Information Reverse input current will spike up as LDO_IN gets to within about 30mV of LDO_OUT as reverse current protection circuitry is disabled and normal operation resumes. As LDO_IN transitions above LDO_OUT the reverse current transitions into short circuit current as long as LDO_OUT is held below the regulation voltage. Thermal Considerations and Output Current Derating The power loss curves in Figures 5 and 6 can be used in coordination with the load current derating curves in Figures 7 to 10 for calculating an approximate JA thermal resistance for the LTM4615 with various heat sinking and airflow conditions. Both of the LTM4615 outputs are at full 4A load current, and the power loss curves in Figures 5 and 6 are combined power losses plotted for both output voltages up to 4A each. The VLDO regulator is set to have a power dissipation of 0.5W since it is generally used with dropout voltages of 0.5V or less. For example: 1.2V to 1V, 1.5V to 1V, 1.5V to 1.2V and 1.8V to 1.5V. Other dropout voltages can be supported at VLDO maximum load, but further thermal analysis will be required for the VLDO. The 4A output voltages are 1.2V and 3.3V. These voltages are chosen to include the lower and higher output voltage ranges for correlating the thermal resistance. Thermal models are derived from several temperature measurements in a controlled temperature chamber along with thermal modeling analysis. The junction temperatures are monitored while ambient temperature is increased with and without airflow. The junctions are maintained at ~120C 2.5 while lowering output current or power with increasing ambient temperature. The 120C value is chosen to allow for a 5C margin window relative to the maximum 125C limit. The decreased output current will decrease the internal module loss as ambient temperature is increased. The power loss curves in Figures 5 and 6 show this amount of power loss as a function of load current that is specified for both channels. The monitored junction temperature of 120C minus the ambient operating temperature specifies how much module temperature rise can be allowed. As an example, in Figure 7 the load current is derated to 3A for each channel with 0LFM at ~90C and the power loss for both channels at 5V to 1.2V at 3A output is ~1.4W. Add the VDLO power loss of 0.5W to equal 1.9W. If the 90C ambient temperature is subtracted from the 120C maximum junction temperature, then the difference of 30C divided by 1.9W equals a 15.7C/W thermal resistance. Table 2 specifies a 15C/W value which is very close. Table 2 and Table 3 provide equivalent thermal resistances for 1.2V and 3.3V outputs with and without air flow and heat sinking. The combined power loss for the two 4A outputs plus the VLDO power loss can be summed together and multiplied by the thermal resistance values in Tables 2 and 3 for module temperature rise under the specified conditions. The printed circuit board is a 1.6mm thick four layer board with two ounce copper for the two outer layers and 1 ounce copper for the two inner layers. The PCB dimensions are 95mm x 76mm. The BGA heat sinks are listed below Table 3. The data sheet lists the JC (Junction to Case) thermal resistances under the Pin Configuration diagram. 3.0 VIN = 5V POWER LOSS (W) POWER LOSS (W) 2.0 1.5 1.0 0.5 0 VIN = 5V 2.5 2.0 1.5 1.0 0.5 0 1 2 3 4 0 0 LOAD CURRENT (A) 4615 F05 Figure 5. 1.2V Power Loss 1 2 3 LOAD CURRENT (A) 4 4615 F06 Figure 6. 3.3V Power Loss 4615fb For more information www.linear.com/LTM4615 15 LTM4615 Applications Information 4.5 4.5 VIN = 5V 4.0 4.0 3.5 LOAD CURRENT (A) LOAD CURRENT (A) 3.5 3.0 2.5 2.0 1.5 1.0 40 50 3.0 2.5 2.0 1.5 1.0 0LFM NO HEATSINK 200LFM NO HEATSINK 400LFM NO HEATSINK 0.5 0 VIN = 5V 0LFM HEATSINK 200LFM HEATSINK 400LFM HEATSINK 0.5 0 60 70 80 90 100 110 120 AMBIENT TEMPERATURE (C) 40 60 70 80 90 100 110 120 AMBIENT TEMPERATURE (C) 50 4615 F08 4615 F07 Figure 7. 1.2V No Heat Sink 4.5 4.0 Figure 8. 1.2V Heat Sink 4.5 VIN = 5V 4.0 3.5 LOAD CURRENT (A) LOAD CURRENT (A) 3.5 3.0 2.5 2.0 1.5 1.0 40 50 3.0 2.5 2.0 1.5 1.0 0LFM NO HEATSINK 200LFM NO HEATSINK 400LFM NO HEATSINK 0.5 0 VIN = 5V 0LFM HEATSINK 200LFM HEATSINK 400LFM HEATSINK 0.5 60 70 80 90 100 110 120 AMBIENT TEMPERATURE (C) 0 40 50 60 70 80 90 100 110 120 AMBIENT TEMPERATURE (C) 4615 F10 4615 F09 Figure 9. 3.3V No Heat Sink 16 Figure 10. 3.3V Heat Sink 4615fb For more information www.linear.com/LTM4615 LTM4615 Applications Information Table 2. 1.2V Output DERATING CURVE VIN (V) POWER LOSS CURVE AIRFLOW (LFM) HEAT SINK JA (C/W) Figure 7 5 Figure 5 0 None 15 Figure 7 5 Figure 5 200 None 12 Figure 7 5 Figure 5 400 None 10 Figure 8 5 Figure 5 0 BGA Heat Sink 14 Figure 8 5 Figure 5 200 BGA Heat Sink 9 Figure 8 5 Figure 5 400 BGA Heat Sink 8 DERATING CURVE VIN (V) POWER LOSS CURVE AIRFLOW (LFM) HEAT SINK JA (C/W) Figure 9 5 Figure 6 0 None 15 Table 3. 3.3V Output Figure 9 5 Figure 6 200 None 12 Figure 9 5 Figure 6 400 None 10 Figure 10 5 Figure 6 0 BGA Heat Sink 14 Figure 10 5 Figure 6 200 BGA Heat Sink 9 Figure 10 5 Figure 6 400 BGA Heat Sink 8 HEAT SINK MANUFACTURER PART NUMBER WEBSITE Aavid 375424B00034G www.aavid.com Cool Innovations 4-050503P to 4-050508P www.coolinnovations.com 4615fb For more information www.linear.com/LTM4615 17 LTM4615 Applications Information Safety Considerations * Place high frequency ceramic input and output capacitors next to the VIN, GND and VOUT pins to minimize high frequency noise. The LTM4615 modules do not provide galvanic 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. * 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. Layout Checklist/Example The high integration of LTM4615 makes the PCB board layout very simple and easy. However, to optimize its electrical and thermal performance, some layout considerations are still necessary. * Do not put via directly on pads unless the via is capped. Figure 11 gives a good example of the recommended layout. * Use large PCB copper areas for high current path, including VIN, GND and VOUT. It helps to minimize the PCB conduction loss and thermal stress. VOUT1 GND1 CONTROL CIN1 GND1 M COUT1 COUT2 V OUT1 L K VIN1 SW1 J GND1 C LD0_IN IN2 CONTROL GND1 H COUT3 G GND3 F GND2 E GND3 COUT4 COUT5 D VIN2 LDO_OUT VOUT2 C B GND2 GND2 A CIN3 1 2 3 4 GND2 5 6 SW2 7 8 9 10 11 12 GND2 4615 F11 Figure 11. Recommended PCB Layout 18 4615fb For more information www.linear.com/LTM4615 LTM4615 Applications Information VIN 3V TO 5.5V CIN2 10F PGOOD2 6.3V CIN1 PGOOD1 10F 6.3V R3 10k VOUT1 1.2V 4A 100F 6.3V 22F 6.3V VIN L1 0.2H* COUT1 22F 6.3V 1.2V RFB1 10k C12 10F VIN2 VIN1 PGOOD1 PGOOD2 VOUT1 VOUT2 FB1 FB2 COMP1 COMP2 TRACK1 TRACK2 LTM4615 RUN/SS2 RUN/SS1 LDO_OUT LDO_IN FB3 EN3 PGOOD3 BOOST3 GND1 GND3 GND2 R4 10k RFB2 5.76k VIN VOUT3 1V LOW NOISE AT 1A R6 10k *FAIR-RITE 0805 2508056007Y6 IF MORE FILTERING REQUIRED PGOOD3 R5 3.32k C11 10F 6.3V VOUT3 VOUT2 1.5V 4A COUT2 100F 6.3V 22F 6.3V 22F 6.3V 4615 F12 Figure 12. Typical 3V to 5.5VIN, 1.5V and 1.2V at 4A and 1V at 1A Design Table 4. Output Voltage Response vs Component Matrix (Refer to Figure 12) 0A to 2.5A Load Step Typical Measured Values COUT1 AND COUT2 CERAMIC VENDORS VALUE PART NUMBER COUT1 AND COUT2 BULK VENDORS VALUE PART NUMBER TDK 22F 6.3V C3216X7SOJ226M Sanyo POSCAP 150F 10V 10TPD150M Murata 22F 16V GRM31CR61C226KE15L Sanyo POSCAP 220F 4V 4TPE220MF TDK 100F 6.3V C4532X5R0J107MZ CIN BULK VENDORS VALUE PART NUMBER Murata 100F 6.3V GRM32ER60J107M Sanyo POSCAP 100F 10V 10CE100FH VOUT CIN CIN COUT1 AND COUT2 COUT1 AND COUT2 (V) (CERAMIC) (BULK)* (CER) EACH (POSCAP) EACH 1.2 100F None 10F x2 100F, 22F x2 1.2 100F 220F 10F x2 22F x1 1.2 100F None 10F x2 100F, 22F x2 1.2 100F 220F 10F x2 22F x1 1.5 100F None 10F x2 100F, 22F x2 1.5 100F 220F 10F x2 22F x1 1.5 100F None 10F x2 100F, 22F x2 1.5 100F 220F 10F x2 22F x1 1.8 100F None 10F x2 100F, 22F x2 1.8 100F 220F 10F x2 22F x1 1.8 100F 220F 10F x2 22F x1 2.5 None None 10F x2 22F x1 2.5 100F 150F 10F x2 22F x1 2.5 100F 150F 10F x2 22F x1 3.3 100F 150F 10F x2 22F x1 *Bulk capacitance is optional if VIN has very low input impedance. ITH None None None None None None None None None None None None None None None VIN (V) 5 5 3.3 3.3 5 5 3.3 3.3 5 5 3.3 5 5 3.3 5 DROOP PEAK-TO-PEAK RECOVERY LOAD STEP (mV) DEVIATION TIME (s) (A/s) 33 68 11 2.5 25 50 9 2.5 33 68 8 2.5 25 50 10 2.5 30 60 11 2.5 28 60 11 2.5 30 60 10 2.5 27 56 10 2.5 34 68 12 2.5 30 60 12 2.5 30 60 12 2.5 50 90 10 2.5 33 60 10 2.5 50 95 12 2.5 50 90 12 2.5 RFB (k) 10 10 10 10 5.76 5.76 5.76 5.76 3.92 3.92 3.92 2.37 2.37 2.37 1.62 4615fb For more information www.linear.com/LTM4615 19 LTM4615 Applications Information VIN 3V TO 5.5V C2 10F 6.3V C1 10F PGOOD1 6.3V R3 10k 1.2V FB2 L1* 0.2H COMP2 VIN RUN/SS2 1.2V R1 4.99k VIN1 PGOOD1 VOUT1 FB1 COMP1 TRACK1 RUN/SS1 LDO_IN EN3 BOOST3 GND1 C12 10F LTM4615 GND2 *FAIR-RITE 0805 2508056007Y6 IF MORE FILTERING REQUIRED VIN2 PGOOD2 VOUT2 FB2 COMP2 TRACK2 RUN/SS2 LDO_OUT FB3 PGOOD3 GND3 PGOOD1 FB2 COMP2 VIN C5 100F 6.3V C6 100F 6.3V VOUT2 1.2V 8A VOUT3 1V LOW NOISE AT 1A R6 10k PGOOD3 R5 3.32k C11 10F 6.3V C13 0.01F 1V LOW NOISE 4615 F13 Figure 13. LTM4615 Parallel 1.2V at 8A Design, 1V at 1A Design VIN 5V C1 10F PGOOD1 6.3V VOUT1 2.5V 4A R3 10k SLAVE C3 22F 6.3V C9 22F 6.3V 3.3V RTB 4.99k C4 22F 6.3V 2.5V RFB1 2.37k RTA C12 2.37k 10F C1 10F 6.3V PGOOD2 VIN2 VIN1 PGOOD2 PGOOD1 VOUT1 VOUT2 FB2 FB1 COMP2 COMP1 TRACK2 TRACK1 LTM4615 RUN/SS1 RUN/SS2 LDO_IN LDO_OUT EN3 FB3 BOOST3 PGOOD3 GND1 GND3 GND2 R4 10k MASTER VIN OR A CONTROL RAMP VOUT3 1.8V AT 1A R6 10k PGOOD3 R5 1.43k RFB2 1.62k C6 22F 6.3V VOUT2 3.3V 4A C5 C11 22F 10F 6.3V 6.3V 1.8V 4615 F14 Figure 14. 3.3V and 2.5V at 4A with Output Voltage Tracking Design, 1.8V at 1A 20 4615fb For more information www.linear.com/LTM4615 4 For more information www.linear.com/LTM4615 3.1750 1.9050 3.1750 SUGGESTED PCB LAYOUT TOP VIEW 0.6350 0.0000 0.6350 PACKAGE TOP VIEW E 1.9050 PIN "A1" CORNER 6.9850 5.7150 4.4450 4.4450 5.7150 6.9850 aaa Z 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 bbb 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 eee S X Y H1 SUBSTRATE 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: 144 SYMBOL A b D E e F G H1 H2 aaa bbb eee DETAIL A 0.630 0.025 SQ. 143x DETAIL B H2 MOLD CAP Z F e b 12 b 11 10 9 3x, C (0.22 x45) 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 7 TRAY PIN 1 BEVEL ! PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX Module A B C D E F G H J K L M 7 SEE NOTES DIA 0.630 PAD 1 LGA 144 1112 REV C PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG Module PRODUCTS. REVIEW EACH PACKAGE LAYOUT CAREFULLY 6. THE TOTAL NUMBER OF PADS: 144 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 (Reference LTC DWG # 05-08-1816 Rev C) LGA Package 144-Lead (15mm x 15mm x 2.82mm) LTM4615 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 4615fb 21 LTM4615 Package Description LTM4615 Component LGA Pinout PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION A1 GND2 B1 GND2 C1 VIN2 D1 VIN2 E1 GND2 F1 GND3 A2 GND2 B2 SW2 C2 VIN2 D2 VIN2 E2 RUN/SS2 F2 GND3 A3 GND2 B3 SW2 C3 VIN2 D3 VIN2 E3 TRACK2 F3 GND3 A4 GND2 B4 SW2 C4 VIN2 D4 VIN2 E4 PGOOD2 F4 GND3 A5 GND2 B5 SW2 C5 VIN2 D5 VIN2 E5 COMP2 F5 GND3 A6 GND2 B6 SW2 C6 VIN2 D6 GND2 E6 FB2 F6 FB3 A7 GND2 B7 GND2 C7 GND2 D7 GND2 E7 BOOST3 F7 GND3 A8 GND2 B8 GND2 C8 GND2 D8 GND2 E8 GND2 F8 EN3 A9 GND2 B9 GND2 C9 VOUT2 D9 VOUT2 E9 GND2 F9 GND3 A10 GND2 B10 GND2 C10 VOUT2 D10 VOUT2 E10 GND2 F10 GND3 A11 GND2 B11 GND2 C11 VOUT2 D11 VOUT2 E11 VOUT2 F11 GND3 A12 GND2 B12 GND2 C12 VOUT2 D12 VOUT2 E12 VOUT2 F12 GND3 PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION PIN ID FUNCTION G1 LDO_IN H1 GND1 J1 VIN1 K1 VIN1 L1 GND1 M1 GND1 G2 LDO_IN H2 SW1 J2 VIN1 K2 VIN1 L2 RUN/SS1 M2 GND1 G3 LDO_IN H3 SW1 J3 VIN1 K3 VIN1 L3 TRACK1 M3 GND1 G4 LDO_IN H4 SW1 J4 VIN1 K4 VIN1 L4 PGOOD1 M4 GND1 G5 PGOOD3 H5 SW1 J5 VIN1 K5 VIN1 L5 COMP1 M5 GND1 G6 GND3 H6 SW1 J6 GND1 K6 GND1 L6 FB1 M6 GND1 G7 GND3 H7 GND1 J7 GND1 K7 GND1 L7 GND1 M7 GND1 G8 GND3 H8 GND1 J8 GND1 K8 GND1 L8 GND1 M8 GND1 G9 LDO_OUT H9 GND1 J9 GND1 K9 VOUT1 L9 VOUT1 M9 VOUT1 G10 LDO_OUT H10 GND1 J10 GND1 K10 VOUT1 L10 VOUT1 M10 VOUT1 G11 LDO_OUT H11 GND1 J11 GND1 K11 VOUT1 L11 VOUT1 M11 VOUT1 G12 LDO_OUT H12 GND1 J12 GND1 K12 VOUT1 L12 VOUT1 M12 VOUT1 22 4615fb For more information www.linear.com/LTM4615 LTM4615 Revision History REV DATE DESCRIPTION A 01/12 Added pin functions to the Pin Configuration diagram. Updated EN3 in the Absolute Maximum Ratings section. Corrected the VOUT accuracy limit. 2 Clarified the SW1 and SW2 electrical connections. 8 B 07/13 PAGE NUMBER Added the internal power inductor value to the Block Diagram. 9 Clarified the PGOOD behavior. 13 Clarified the reverse current protection behavior. 14 Added the suggested heat sink. 17 Changed "Overcurrent Foldback" to "Overtemperature" 12 4615fb 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. For more information www.linear.com/LTM4615 23 LTM4615 Package Photograph Related Parts PART NUMBER DESCRIPTION COMMENTS LTM4628 26V, Dual 8A, DC/DC Step-Down Module Regulator 4.5V VIN 26.5V, 0.6V VOUT 5V, Remote Sense Amplifier, Internal Temperature Sensing Output, 15mm x 15mm x 4.32mm LGA LTM4627 20V, 15A DC/DC Step-Down Module Regulator 4.5V VIN 20V, 0.6V VOUT 5V, PLL Input, VOUT Tracking, Remote Sense Amplifier, 15mm x 15mm x 4.32mm LGA LTM4611 1.5VIN(MIN), 15A DC/DC Step-Down Module Regulator 1.5V VIN 5.5V, 0.8V VOUT 5V, PLL Input, Remote Sense Amplifier, VOUT Tracking, 15mm x 15mm x 4.32mm LGA LTM4618 6A DC/DC Step-Down Module Regulator 4.5V VIN 26.5V, 0.8V VOUT 5V, PLL Input, VOUT Tracking, 9mm x 15mm x 4.32mm LGA LTM4613 8A EN55022 Class B DC/DC Step-Down Module Regulator 5V VIN 36V, 3.3V VOUT 15V, PLL Input, VOUT Tracking and Margining, 15mm x 15mm x 4.32mm LGA LTM4601AHV 28V, 12A DC/DC Step-Down Module Regulator 4.5V VIN 28V, 0.6V VOUT 5V, PLL Input, Remote Sense Amplifier, VOUT Tracking and Margining, 15mm x 15mm x 2.8mm LGA or 15mm x 15mm x 3.42mm BGA LTM4601A 20V, 12A DC/DC Step-Down Module Regulator 4.5V VIN 20V, 0.6V VOUT 5V, PLL Input, Remote Sense Amplifier, VOUT Tracking and Margining, 15mm x 15mm x 2.8mm LGA or 15mm x 15mm x 3.42mm BGA LTM8027 60V, 4A DC/DC Step-Down Module Regulator 4.5V VIN 60V, 2.5V VOUT 24V, CLK Input, 15mm x 15mm x 4.32mm LGA LTM8033 36V, 3A EN55022 Class B DC/DC Step-Down Module Regulator 3.6V VIN 36V, 0.8V VOUT 24V, Synchronizable, 11.25mm x 15mm x 4.32mm LGA LTM8061 32V, 2A Step-Down Module Battery Charger with Programmable Input Current Limit Compatible with Single Cell or Dual Cell Li-Ion or Li-Poly Battery Stacks (4.1V, 4.2V, 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 24 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTM4615 (408) 432-1900 FAX: (408) 434-0507 www.linear.com 4615fb LT 0713 REV B * PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2009