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LTM4619 Dual, 26VIN, 4A DC/DC Module Regulator FEATURES
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DESCRIPTION
The LTM(R)4619 is a complete dual 4A step-down switching mode DC/DC power supply. Included in the package are the switching controller, power FETs, inductor, and all support components. Operating over input voltage ranges of 4.5V to 26.5V, the LTM4619 supports two outputs with voltage ranges of 0.8V to 5V, each set by a single external resistor. Its high efficiency design delivers 4A continuous current (5A peak) for each output. High switching frequency and a current mode architecture enable a very fast transient response to line and load changes without sacrificing stability. The two outputs are interleaved with 180 phase to minimize the ripple noise and reduce the I/O capacitors. The device supports frequency synchronization and output voltage tracking for supply rail sequencing. Burst Mode operation or pulse-skipping mode can be selected for light load operations. Fault protection features include overvoltage protection, overcurrent protection and foldback current limit for short-circuit protection. The low profile package (2.8mm) enables utilization of unused space on the bottom of PC boards for high density point of load regulation. The power module is offered in a space saving and thermally enhanced 15mm x 15mm x 2.8mm LGA package. The LTM4619 is Pb-free and RoHS compliant.
Complete Standalone Power Supply Wide Input Voltage Range: 4.5V to 26.5V (EXTVCC Available for VIN 5.5V) Dual 180 Out-of-Phase Outputs with 4A DC Typical, 5A Peak Output Current for Each Dual Outputs with 0.8V to 5V VOUT Range Output Voltage Tracking 1.5% Total DC Output Error Current Mode Control/Fast Transient Response Power Good Phase-Lockable Fixed Frequency 250kHz to 780kHz On Board Frequency Synchronization Parallel Current Sharing Selectable Burst Mode(R) Operation Output Overvoltage Protection Small Surface Mount Footprint, Low Profile (15mm x 15mm x 2.8mm) LGA Package
APPLICATIONS
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Telecom and Networking Equipment Servers Storage Cards ATCA Cards Industrial Equipment Point of Load Regulation
L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode and Module are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Dual 4A 3.3V/2.5V DC/DC Module(R) Regulator
MODE/PLLIN INTVCC FREQ/PLLFLTR 19.1k EFFICIENCY (%) VFB2 COMP2 LTM4619 VOUT2 TK/SS2 RUN2 EXTVCC PGND
4619 TA01a
Efficiency and Power Loss at 12V input
95 90 85 80 75 70 POWER LOSS 65 60 55 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 2.5VOUT 3.3VOUT 3.5 4 0.5 1.0 EFFICIENCY 1.5 POWER LOSS (W) 2.0
5.5V TO 26.5V
10F 2
28k 22pF
VIN
VFB1 COMP1 VOUT1
22pF VOUT2 3.3V/4A
VOUT1 2.5V/4A
100F 0.1F
TK/SS1 RUN1 PGOOD SGND
100F 0.1F
0
4619 TA01b
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LTM4619 ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
M L K J H G F E D C B A 1 2 3 4 5 6 7 8 9 10 11 12
VIN ............................................................. -0.3V to 28V INTVCC, PGOOD, RUN1, RUN2, EXTVCC ....... -0.3V to 6V COMP1, COMP2, VFB1, VFB2, .................... -0.3V to 2.7V MODE/PLLIN, TK/SS1, TK/SS2, FREQ/PLLFLTR ...................................... -0.3V to INTVCC VOUT1, VOUT2 .................................................. 0.8V to 5V Internal Operating Temperature Range (Note 2) .......................................................... -40C to 125C Junction Temperature ........................................... 125C Maximum Reflow Body Temperature .................... 245C Storage Temperature Range................... -55C to 125C
LGA PACKAGE 144-LEAD (15mm x 15mm x 2.8mm) TJMAX = 125C, JA = 13C/W, JP = 6C/W JA DERIVED FROM 95mm x 76mm PCB WITH 4 LAYERS WEIGHT = 1.7g
ORDER INFORMATION
LEAD FREE FINISH LTM4619EV#PBF LTM4619IV#PBF TRAY LTM4619EV#PBF LTM4619IV#PBF PART MARKING* LTM4619V LTM4619V PACKAGE DESCRIPTION 144-Lead (15mm x 15mm x 2.8mm) LGA 144-Lead (15mm x 15mm x 2.8mm) LGA TEMPERATURE RANGE -40C to 125C -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/
The l denotes the specifications which apply over the full internal operating temperature range, otherwise specifications are at TA = 25C, VIN = 12V. Per typical application in Figure 18. Specified as each channel. (Note 3)
SYMBOL VIN(DC) VOUT1, 2(RANGE) VOUT1, 2(DC) PARAMETER Input DC Voltage Output Voltage Range Output Voltage CONDITIONS VIN 5.5V, Connect VIN and INTVCC Together VIN = 5.5V to 26.5V CIN = 10F x1, COUT = 100F Ceramic, 100F POSCAP , RSET = 28.0k VIN = 12V, VOUT = 2.5V, IOUT = 0A VIN = 12V, VOUT = 2.5V, IOUT = 4A
l l
ELECTRICAL CHARACTERISTICS
MIN 4.5 0.8
TYP
MAX 26.5 5.0
UNITS V V
l
2.483 2.470 2.00 1.85
2.52 2.52 2.2 2.0
2.557 2.570 2.35 2.15
V V V V
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Input Specifications VIN(UVLO) Undervoltage Lockout Thresholds VINTVCC Rising VINTVCC Falling
2
LTM4619 ELECTRICAL CHARACTERISTICS
SYMBOL IINRUSH(VIN) IQ(VIN) PARAMETER Input Inrush Current at Start-Up Input Supply Bias Current
The l denotes the specifications which apply over the full internal operating temperature range, otherwise specifications are at TA = 25C, VIN = 12V. Per typical application in Figure 18. Specified as each channel (Note 3).
CONDITIONS IOUT = 0A, CIN = 10F COUT = 100F VOUT = 2.5V , , VIN = 12V VIN = 12V, VOUT1 = 2.5V, Switching Continuous VIN = 12V, VOUT2 = 2.5V, Switching Continuous VIN = 26.5V, VOUT1 = 2.5V, Switching Continuous VIN = 26.5V, VOUT2 = 2.5V, Switching Continuous Shutdown, RUN = 0, VIN = 20V VIN = 12V, VOUT = 2.5V, IOUT = 4A VIN = 26.5V, VOUT = 2.5V, IOUT = 4A VIN = 12V, VRUN > 2V, No Load EXTVCC Ramping Positive
l
MIN
TYP 0.25 30 30 40 40 40 0.97 0.480
MAX
UNITS A mA mA mA mA A A A
IS(VIN) INTVCC EXTVCC Output Specifications IOUT1, 2(DC) VOUT1(LINE) VOUT(NOM) VOUT2(LINE) VOUT(NOM) VOUT1(LOAD) VOUT1(NOM) VOUT2(LOAD) VOUT2(NOM) VOUT1, 2(AC)
Input Supply Current Internal VCC Voltage EXTVCC Switchover Voltage
4.8 4.5 0
l l l l
5 4.7
5.2
V V
Output Continuous Current Range VIN = 12V, VOUT = 2.5V (Note 5) Line Regulation Accuracy Line Regulation Accuracy Load Regulation Accuracy Load Regulation Accuracy Output Ripple Voltage VOUT = 2.5V, VIN from 6V to 26.5V IOUT = 0A For Each Output VOUT = 2.5V, VIN from 6V to 26.5V IOUT = 0A For Each Output For Each Output, VOUT = 2.5V, 0A to 4A (Note 5) VIN = 12V For Each Output, VOUT = 2.5V, 0A to 4A (Note 5) VIN = 12V IOUT = 0A, COUT = 100F X5R Ceramic VIN = 12V, VOUT = 2.5V VIN = 26.5V, VOUT = 2.5V IOUT = 2A, VIN = 12V, VOUT = 2.5V FREQ/PLLFLTR = INTVCC COUT = 100F X5R Ceramic, VOUT = 2.5V, IOUT = 0A VIN = 12V VIN = 26.5V COUT = 100F X5R Ceramic, VOUT = 2.5V, IOUT = 0A Resistive Load, VIN = 12V VIN = 26.5V Load: 0% to 50% to 0% of Full Load COUT = 100F X5R Ceramic,VOUT = 2.5V, VIN = 12V Load: 0% to 50% to 0% of Full Load COUT = 100F X5R Ceramic,VOUT = 2.5V, VIN = 12V COUT = 100F X5R Ceramic, VIN = 6V, VOUT = 2.5V VIN = 26.5V, VOUT = 2.5V IOUT = 0A, VOUT = 2.5V VTK/SS = 0V, VOUT = 2.5V In Dropout (Note 4) (Note 4)
4 0.15 0.25 0.15 0.25 0.6 0.6 0.3 0.5 0.3 0.5 0.8 0.8
A % % % % % %
20 25 780
mV mV kHz
fS VOUTSTART
Output Ripple Voltage Frequency Turn-On Overshoot
10 10
mV mV
tSTART
Turn-On Time
0.250 0.130 15 10 12 11 0.792 0.788 0.9 0.8 0.8 1.3 97 90 0.808 0.810 1.7
ms ms mV s A A V A % ns
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VOUTLS tSETTLE IOUTPK
Peak Deviation for Dynamic Load Settling Time for Dynamic Load Step Output Current Limit
Control Section VFB1, VFB2 ITK/SS1, 2 DFMAX tON(MIN) Voltage at VFB Pin Soft-Start Charge Current Maximum Duty Factor Minimum On-Time
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LTM4619 ELECTRICAL CHARACTERISTICS
SYMBOL fNOM fLOW fHIGH RMODE/PLLIN IFREQ PARAMETER Nominal Frequency Lowest Frequency Highest Frequency MODE/PLLIN Input Resistance Frequency Setting Sinking Current Sourcing Current RUN Pin ON/OFF Threshold Resistor Between VOUT and VFB Pins for Each Channel PGOOD Voltage Low PGOOD Leakage Current PGOOD Range IPGOOD = 2mA VPGOOD = 5V VFB Ramping Negative VFB Ramping Positive -5 5 -7.5 7.5 fMODE > fOSC fMODE < fOSC RUN Rising RUN Falling 1.1 1.02 60.1
The l denotes the specifications which apply over the full internal operating temperature range, otherwise specifications are at TA = 25C, VIN = 12V. Per typical application in Figure 18. Specified as each channel. (Note 3)
CONDITIONS VFREQ = 1.2V VFREQ = 0V VFREQ 2.4V MIN 450 210 700 TYP 500 250 780 250 -13 13 1.22 1.14 60.4 0.1 1.35 1.27 60.7 0.3 2 -10 10 MAX 550 290 860 UNITS kHz kHz kHz k A A V V k V A % %
VRUN1, 2 RFB1, RFB2 VPGL IPGOOD VPGOOD
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 LTM4619E is guaranteed to meet performance specifications over the 0C to 125C internal operating temperature range. Specifications over the full -40C to 125C internal operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM4619I 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. Note 3: The two outputs are tested separately and the same testing condition is applied to each output. Note 4: 100% tested at wafer level only. Note 5: See Output Current Derating curves for different VIN, VOUT and TA.
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Load Current with 5VIN (f = 500kHz for 0.8VOUT, 1.2VOUT and 1.5VOUT)
95 90 85 EFFICIENCY (%) 80 75 70 65 60 55 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 3.5 4 0.8VOUT 2.5VOUT 3.3VOUT 1.2VOUT EFFICIENCY (%) 1.5VOUT 95 90 85 80 1.5VOUT 75 70 65 60 55 0 0.5 1 1.5 2 2.5 3 LOAD CURRENT (A) 2.5VOUT
(Refer to Figures 18 and 19)
Efficiency vs Load Current with 12VIN (f = 500kHz for 1.2VOUT and 1.5VOUT)
3.3VOUT 5VOUT 95 90 85 EFFICIENCY (%) 80 75 70 65 60 55 50 45 3.5 4
Efficiency vs Load Current with 24VIN (f = 500kHz for 1.5VOUT)
3.3VOUT 5VOUT
1.5VOUT 2.5VOUT
1.2VOUT
0
0.5
1
1.5 2 2.5 3 LOAD CURRENT (A)
3.5
4
4619 G01
4619 G02
4619 G03
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LTM4619 TYPICAL PERFORMANCE CHARACTERISTICS
1.2V Output Transient Response (Refer to Figures 18 and 19)
1.5V Output Transient Response
2.5V Output Transient Response
IOUT 1A/DIV VOUT 50mV/DIV 100s/DIV 6VIN 1.2VOUT AT 2A/s LOAD STEP f = 780kHz COUT 2 22F, 6.3V X5R CERAMIC COUT 1 330F, 6.3V SANYO POSCAP
4619 G04
IOUT 1A/DIV VOUT 50mV/DIV 100s/DIV 6VIN 1.5VOUT AT 2A/s LOAD STEP f = 780kHz COUT 2 22F, 6.3V X5R CERAMIC COUT 1 330F, 6.3V SANYO POSCAP
4619 G05
IOUT 1A/DIV VOUT 50mV/DIV 100s/DIV 6VIN 2.5VOUT AT 2A/s LOAD STEP f = 780kHz COUT 2 22F, 6.3V X5R CERAMIC COUT 1 330F, 6.3V SANYO POSCAP
4619 G06
3.3V Output Transient Response
Start-Up, IOUT = 0A
Start-Up, IOUT = 4A
IOUT 1A/DIV VOUT 50mV/DIV 100s/DIV 6VIN 3.3VOUT AT 2A/s LOAD STEP f = 780kHz COUT 2 22F, 6.3V X5R CERAMIC COUT 1 330F, 6.3V SANYO POSCAP
4619 G07
VIN 1V/DIV
VIN 1V/DIV
IIN 0.5A/DIV 20ms/DIV VIN = 12V, VOUT = 2.5V, IOUT = 0A COUT = 2 22F 10V AND 1 100F 6.3V CERAMIC CAPs CSOFTSTART = 0.1F USE RUN PIN TO CONTROL START-UP
4619 G08
IIN 0.5A/DIV 20ms/DIV VIN = 12V, VOUT = 2.5V, IOUT = 4A RESISTIVE LOAD COUT = 2 22F 10V, AND 1 100F 6.3V CERAMIC CAPs CSOFTSTART = 0.1F USE RUN PIN TO CONTROL START-UP
4619 G09
Short Circuit, IOUT = 0A
VOUT 1V/DIV VOUT 1V/DIV
Short Circuit, IOUT = 4A
IIN 0.5A/DIV IIN 0.5A/DIV 50s/DIV VIN = 12V, VOUT = 2.5V, IOUT = 0A COUT = 2 22F 10V, AND 1 100F 6.3V CERAMIC CAPs
4619 G10
50s/DIV VIN = 12V, VOUT = 2.5V, IOUT = 4A COUT = 2 22F 10V, AND 1 100F 6.3V CERAMIC CAPs
4619 G11
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LTM4619 PIN FUNCTIONS
VIN (J1 to J3, J10 to J12, K1 to K4, K9 to K12, L1 to L5, L8 to L12, M1 to M12): Power Input Pins. Apply input voltage between these pins and PGND pins. Recommend placing input decoupling capacitance directly between VIN pins and PGND pins. For VIN < 5.5, tie VIN and INTVCC together. VOUT1, VOUT2 (A10 to D10, A11 to D11, A12 to D12, A1 to D1, A2 to D2, A3 to D3): 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 (H1, H2, H4, H9, H11, H12, G1 to G12, F1 to F5, F7 to F12, E1 to E12, D4 to D9, C4 to C9, B4 to B9, A4 to A9): Power ground pins for both input and output returns. INTVCC (F6): Internal 5V Regulator Output. This pin is for additional decoupling of the 5V internal regulator. EXTVCC (J4): External Power Input to Controller. When EXTVCC is higher than 4.7V, the internal 5V regulator is disabled and external power supplies current to reduce the power dissipation in the module. This will improve the efficiency more at high input voltages. SGND (J6, J7, H6, H7): Signal Ground Pin. Return ground path for all analog and low power circuitry. Tie a single connection to PGND in the application. MODE/PLLIN (H8): Mode selection or external synchronization pin. Tying this pin high enables pulse-skipping mode. Tying this pin low enables force continuous operation. Floating this pin enables Burst Mode operation. A clock on the pin will force the controller into continuous mode of operation and synchronize the internal oscillator. The external clock input high threshold is 1.6V, while the input low threshold is 1V. FREQ/PLLFLTR (J8): Frequency Selection Pin. An internal lowpass filter is tied to this pin. The frequency can be selected from 250kHz to 780kHz by varying the DC voltage on this pin from 0V to 2.4V. Leave this pin floating when external synchronization is used. TK/SS1, TK/SS2 (K8, K5): Output Voltage Tracking and Soft-Start Pins. Internal soft-start currents of 1.3A charge the soft-start capacitors. See the Applications Information section to use the tracking function. VFB1, VFB2 (K7, K6): The negative input of the error amplifier. Internally, this pin is connected to VOUT with a 60.4k precision resistor. Different output voltages can be programmed with an additional resistor between VFB and SGND pins. See the Applications Information section for details. COMP1, COMP2 (L7, L6): Current Control Threshold and Error Amplifier Compensation Point. The module has been internally compensated for most I/O ranges. PGOOD (H5): 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. RUN1, RUN2 (J9, J5): Run Control Pins. 0.5A pull-up currents on these pins turn on the module if these pins are floating. Forcing either of these pins below 1.2V will shut down the corresponding outputs. An additional 4.5A pull-up current is added to this pin, once the RUN pin rises above 1.2V. Also, active control or pull-up resistors can be used to enable the RUN pin. The maximum voltage is 6V on these pins. SW1, SW2 (H10, H3): Switching Test Pins. These pins are provided externally to check the operation frequency.
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LTM4619 SIMPLIFIED BLOCK DIAGRAM
INTERNAL FILTER 1.5F INTVCC PGOOD MODE/PLLIN EXTVCC VIN R1 TK/SS1 CSS1 RUN1 COMP1 R2 R2 * VIN R1 R2 = UVLO THRESHOLD = 1.22V TK/SS2 CSS2 RUN2 COMP2 INTERNAL COMP 60.4k FREQ INTERNAL FILTER VFB2 RSET2 19.1k M4 L2 10F INTERNAL COMP POWER CONTROL M3 1.5F 60.4k VFB1 RSET1 28k M2 L1 M1
+
CIN
VIN 4.5V TO 26.5V*
10F
+
PGND SW1 VOUT1 2.5V/4A COUT1 PGND
PGND SW2
+
VOUT2 3.3V/4A COUT2 PGND
SGND
4619 BD
*USE EXTVCC FOR VIN 5.5V, OR TIE VIN AND EXTVCC TOGETHER FOR VIN 5.5V
Figure 1. Simplified LTM4619 Block Diagram
DECOUPLING REQUIREMENTS
SYMBOL CIN COUT1 COUT2 PARAMETER External Input Capacitor Requirement (VIN = 4.5V to 26.5V, VOUT1 = 2.5V, VOUT2 = 3.3V) External Output Capacitor Requirement (VIN = 4.5V to 26.5V, VOUT1 = 2.5V, VOUT2 = 3.3V)
TA = 25C. Use Figure 1 configuration.
CONDITIONS IOUT1 = 4A, IOUT2 = 4A IOUT1 = 4A IOUT2 = 4A MIN 10 200 200 TYP MAX UNITS F F F
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LTM4619 OPERATION
The LTM4619 is a dual-output standalone non-isolated switching mode DC/DC power supply. It can deliver up to 4A (DC current) for each output with few external input and output capacitors. This module provides precisely regulated output voltages programmable via external resistors from 0.8VDC to 5.0VDC over 4.5V to 26.5V input voltages. The typical application schematic is shown in Figure 18. The LTM4619 has integrated constant frequency current mode regulators and built-in power MOSFET devices with fast switching speed. The typical switching frequency is 780kHz. To reduce switching noise, the two outputs are interleaved with 180 phase internally and it can be synchronized externally using the PLLIN pin. With current mode control and internal feedback loop compensation, the LTM4619 module has sufficient stability margins and good transient performance with a wide range of output capacitors, even with all ceramic output capacitors. Current mode control provides cycle-by-cycle fast current limit and current foldback in a short-circuit condition. Internal overvoltage and undervoltage comparators pull the open-drain PGOOD output low if the output feedback voltage exits a 7.5% window around the regulation point. The power good pin is disabled during start-up. Pulling the RUN pin below 1.2V forces the controller into its shutdown state, by turning off both MOSFETs. The TK/SS pin is used for programming the output voltage ramp and voltage tracking during start-up. See the Applications Information section. The LTM4619 is internally compensated to be stable over all operating conditions. The Linear Technology Module Power Design Tool will be provided for transient and stability analysis. The VFB pin is used to program the output voltage with a single external resistor to ground. Multiphase operation can be easily employed with the synchronization. High efficiency at light loads can be accomplished with selectable Burst Mode operation or pulse-skipping mode using the MODE pin. Efficiency graphs are provided for light load operations in the Typical Performance Characteristics section.
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LTM4619 APPLICATIONS INFORMATION
The typical LTM4619 application circuit is shown in Figure 18. External component selection is primarily determined by the maximum load current and output voltage. Output Voltage Programming The PWM controller has an internal 0.8V reference voltage. As shown in the block diagram, a 60.4k internal feedback resistor RFB connects VOUT to VFB pin. The output voltage will default to 0.8V with no feedback resistor. Adding a resistor RSET from VFB pin to SGND programs the output voltage: VOUT = 0.8V * 60.4k + RSET RSET
1.2 121 1.5 68.1 1.8 48.7 2.5 28.0 3.3 19.1 5 11.5
Without considering the inductor current ripple, for each output, the RMS current of the input capacitor can be estimated as: ICIN(RMS) = IOUT(MAX) * D * (1- D)
Table 1. VFB Resistor Table vs Various Output Voltages
VOUT (V) RSET (k) 0.8 Open
In the above equation, is the estimated efficiency of the power module. The bulk capacitor can be a switcher-rated electrolytic aluminum capacitor, polymer capacitor for bulk input capacitance due to high inductance traces or leads. One 10F ceramic input capacitor is typically rated for 2A of RMS ripple current, so the RMS input current at the worst case for each output at 4A maximum current is about 2A. If a low inductance plane is used to power the device, then two 10F ceramic capacitors are enough for both outputs at 4A load and no external input bulk capacitor is required. Output Capacitors The LTM4619 is designed for low output voltage ripple noise. The bulk output capacitors defined as COUT are chosen with low enough effective series resistance (ESR) to meet the output voltage ripple and transient requirements. COUT can be the low ESR tantalum capacitor, the low ESR polymer capacitor or ceramic capacitor. The typical output capacitance range for each output is from 47F to 220F Additional output filtering may be required by the . system designer, if further reduction of output ripples or dynamic transient spikes is required. The Linear Technology Module Power Design Tool will be provided for stability analysis. Multiphase operation will reduce effective output ripple as a function of the number of phases. Application Note 77 discusses this noise reduction versus output ripple current cancellation, but the output capacitance should be considered carefully as a function of stability and transient response. The Linear Technology Module Power Design Tool can calculate the output ripple reduction as the number of implemented phases increased by N times.
Input Capacitors The LTM4619 module should be connected to a low ACimpedance DC source. Two 1.5F input ceramic capacitors are included inside the module. Additional input capacitors are needed if a large load is required up to the 4A level. A 47F to 100F surface mount aluminum electrolytic bulk capacitor can be used for more input bulk capacitance. This bulk capacitor is only needed if the input source impedance is compromised by long inductive leads, traces or not enough source capacitance. For a buck converter, the switching duty-cycle can be estimated as: D= VOUT VIN
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LTM4619 APPLICATIONS INFORMATION
Mode Selections and Phase-Locked Loop The LTM4619 can be enabled to enter high efficiency Burst Mode operation, constant-frequency pulse-skipping mode, or forced continuous conduction mode. To select the forced continuous operation, tie the MODE/PLLIN pin to a DC voltage below 0.8V. To select pulse-skipping mode of operation, tie the MODE/PLLIN pin to INTVCC. To select Burst Mode operation, float the MODE/PLLIN pin. Frequency Synchronization A phase-lock loop is available on the LTM4619 to synchronize the internal clock to an external clock source connected on the MODE/PLLIN pin. The clock high level needs to be higher than 1.6V and the clock low level needs to be lower than 1V. The frequency programming voltage and or the programming voltage divider must be removed from the FREQ/PLLFLTR pin when synchronizing to an external clock. The FREQ/PLLFLTR pin has the required onboard PLL filter components for clock synchronization. The LTM will default to forced continuous mode while being clock synchronized. Channel 1 is synchronized to the rising edge on the external clock, and channel 2 is 180 degrees out-of-phase with the external clock. Frequency Selection The switching frequency of the LTM4619's controllers can be selected using the FREQ/PLLFLTR pin. If the MODE/ PLLIN pin is not being driven by an external clock source, the FREQ/PLLFLTR pin can be set from 0V to 2.4V to program the controller's operating frequency from 250kHz to 780kHz using a voltage divider to INTVCC (see Figure 19). The typical frequency is 780kHz. If the output is too low or the minimum on-time is reached, the frequency needs to decrease to enlarge the turn-on time. Otherwise, a significant amount of cycle skipping can occur with correspondingly larger current and voltage ripple. Refer to the figure of Output Voltage vs Minimum On-Time to choose a proper frequency.
900 800 700 FREQUENCY (kHz) 600 500 400 300 200 100 0 0 0.5 1 1.5 FREQ PIN VOLTAGE (V) 2 2.5
4619 F02
Figure 2. Switching Frequency vs FREQ/PLLFLTR Pin Voltage
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LTM4619 APPLICATIONS INFORMATION
Soft-Start and Tracking The LTM4619 has the ability to either soft-start by itself with a capacitor or track the output of another channel or external supply. When one particular channel is configured to soft-start by itself, a capacitor should be connected to its TK/SS pin. This channel is in the shutdown state if its RUN pin voltage is below 1.2V. Its TK/SS pin is actively pulled to ground in this shutdown state. Once the RUN pin voltage is above 1.2V, the channel powers up. A soft-start current of 1.3A then starts to charge its soft-start capacitor. Note that soft-start or tracking is achieved not by limiting the maximum output current of the controller but by controlling the output ramp voltage according to the ramp rate on the TK/SS pin. Current foldback is disabled during this phase to ensure smooth soft-start or tracking. The soft-start or tracking range is defined to be the voltage range from 0V to 0.8V on the TK/SS pin. The total soft-start time can be calculated as: 0.8V * CSS t SOFT-START = 1.3A Output voltage tracking can be programmed externally using the TK/SS pin. The master channel is divided down with an external resistor divider that is the same as the slave channel's feedback divider to implement coincident tracking. The LTM4619 uses an accurate 60.4k resistor internally for the top feedback resistor. Figure 3 shows an example of coincident tracking. Figure 4 shows the output voltages with coincident tracking. R1 VSLAVE = 1+ * VTRACK R2 VTRACK is the track ramp applied to the slave's TK/SS2 pin. VTRACK has a control range of 0V to 0.8V. When the master's output is divided down with the same resistor values used to set the slave's output, then the slave will coincident track with the master until it reaches its final value. The master will continue to its final value from the slave's regulation point. Ratiometric modes of tracking can be achieved by selecting different divider resistors values to change the output tracking ratio. The master output must be greater than the slave output for the tracking to work. Master and slave data inputs can be used to implement the correct resistors values for coincident or ratio tracking.
VIN 5.5V TO 28V
MODE/PLLIN INTVCC VIN FREQ/PLLFLTR CIN R3 19.1k C2 22pF VFB1 COMP1 VOUT1 COUT1 C1 0.1F TK/SS1 RUN1 PGOOD SGND VFB2 COMP2 LTM4619 V OUT2 TK/SS2 RUN2 EXTVCC PGND
4619 F03
VOUT1 3.3V
C3 22pF
R4 28k VOUT2 2.5V COUT2 OUTPUT VOLTAGE
MASTER OUTPUT
SLAVE OUTPUT
VOUT1 R1 60.4k R2 28k
TIME
4619 F04
Figure 3. Example of Coincident Tracking
Figure 4. Coincident Tracking
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LTM4619 APPLICATIONS INFORMATION
0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 1-PHASE 2-PHASE 3-PHASE 4-PHASE 6-PHASE
RMS INPUT RIPPLE CURRENT DC LOAD CURRENT
0.1 0.15
0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 DUTY FACTOR (VOUT/VIN) 4619 F05
Figure 5. Normalized Input RMS Ripple Current vs Duty Factor for One to Six Phases
1.00 0.95 0.90 0.85 0.80 0.75 PEAK-TO-PEAK OUTPUT RIPPLE CURRENT DIr 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 DUTY CYCLE (VOUT/VIN) 4619 F06 1-PHASE 2-PHASE 3-PHASE 4-PHASE 6-PHASE
RATIO =
Figure 6. Normalized Output Ripple Current vs Duty Cycle, Dlr = VOUT T/L
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LTM4619 APPLICATIONS INFORMATION
Multiphase Operation Multiphase operation with multiple LTM4619 devices in parallel will lower the effective input RMS ripple current as well as the output ripple current due to the interleaving operation of the regulators. Figure 5 provides a ratio of input RMS ripple current to DC load current as a function of duty cycle and the number of paralleled phases. Choose the corresponding duty factor and the number of phases to get the correct ripple current value. For example, the 2-phase parallel for one LTM4619 design provides 8A at 2.5V output from a 12V input. The duty cycle is DC = 2.5V/12V = 0.21. The 2-phase curve has a ratio of ~0.25 for a duty cycle of 0.21. This 0.25 ratio of RMS ripple current to a DC load current of 8A equals ~2A of input RMS ripple current for the external input capacitors. The effective output ripple current is lowered with multiphase operations as well. Figure 6 provides a ratio of peak-to-peak output ripple current to the normalized output ripple current as a function of duty factor and the number of paralleled phases. Choose the corresponding duty factor and the number of phases to get the correct output ripple current ratio value. If a 2-phase operation is chosen at 12VIN to 2.5VOUT with a duty factor of 21%, then 0.6 is the ratio of the normalized output ripple current to inductor ripple DIr at the zero duty factor. This leads to ~1.3A of the effective output ripple current IL if the DIr is at 2.2A. Refer to Application Note 77 for a detailed explanation of the output ripple current reduction as a function of paralleled phases. The output voltage ripple has two components that are related to the amount of bulk capacitance and effective series resistance (ESR) of the output bulk capacitance. Therefore, the output voltage ripple can be calculated with the known effective output ripple current. The equation: VOUT(P-P) IL/(8 * f * N * COUT) + ESR * IL where f is frequency and N is the number of parallel phases. RUN Pin The RUN pins can be used to enable or sequence the particular regulator channel. The RUN pins have their own internal 0.5A current source to pull up the pin to 1.2V, and then the current increases to 4.5A above 1.2V. Careful consideration is needed to assure that board contamination or residue does not load down the 0.5A pull-up current. Otherwise active control to these pins can be used to activate the regulators. A voltage divider can be used from VIN to set an enable point that can be used as a UVLO feature for the regulator. The resistor divider needs to be low enough resistance to swamp out the pullup current sources and not enable the device when not attended. See the Simplified Block Diagram. Power Good The PGOOD pin is connected to an open drain of an internal N-channel MOSFET. The MOSFET turns on and pulls the PGOOD pin low when either VFB pin voltage is not within 7.5% of the 0.8V reference voltage. The PGOOD pin is also pulled low when either RUN pin is below 1.2V or when the LTM4619 is in the soft-start or tracking phase. When the VFB pin voltage is within the 7.5% requirement, the MOSFET is turned off and the pin is allowed to be pulled up by an external resistor to a source of up to 6V. The PGOOD pin will flag power good immediately when both VFB pins are within the 7.5% window. However, there is an internal 17s power bad mask when either VFB goes out of the 7.5% window.
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LTM4619 APPLICATIONS INFORMATION
INTVCC and EXTVCC The INTVCC is the internal 5V regulator that powers the LTM4619 internal circuitry and drives the power MOSFETs. The input voltage of the LTM4619 must be 6V or above for the INTVCC to regulate to the proper 5V level due to the internal LDO dropout from the input voltage. For applications that need to operate below 6V input, then the input voltage can be connected directly to the EXTVCC pin to bypass the LDO dropout concern, or an external 5V supply can be used to power the EXTVCC pin when the input voltage is at high end of the supply range to reduce power dissipation in the module. For example the dropout voltage for 24V input would be 24V - 5V = 19V. This 19V headroom then multiplied by the power MOSFET drive current of ~15mA would equal ~0.3W additional power dissipation. So utilizing an external 5V supply on the EXTVCC would improve design efficiency and reduce device temperature rise. Slope Compensation The module has already been internally compensated for all output voltages. The Linear Technology Module Power Design Tool will be provided for control loop optimization. Burst Mode Operation and Pulse-Skipping Mode The LTM4619 regulator can be placed into high efficiency power saving modes at light load condition to conserve power. The Burst Mode operation can be selected by floating the MODE/PLLIN pin, and pulse-skipping mode can be selected by pulling the MODE/PLLIN pin to INTVCC. Burst Mode operation offers the best efficiency at light load, but output ripple will be higher and lower frequency ranges are capable which can interfere with some systems. Pulse-skipping mode efficiency is not as good as Burst Mode operation, but this mode only skips pulses to save efficiency and maintains a lower output ripple and a higher switching frequency. Burst Mode operation and pulse-skipping mode efficiencies can be reviewed in graph supplied in the Typical Performance Characteristics section. Fault Conditions: Current Limit and Overcurrent Foldback The LTM4619 has a current mode controller, which inherently limits the cycle-by-cycle inductor current not only in steady-state operation, but also in transient. To further limit current in the event of an overload condition, the LTM4619 provides foldback current limiting. If the output voltage falls by more than 50%, then the maximum output current is progressively lowered to one-third of its full current limit value. Foldback current limiting is disabled during the soft-start and tracking up. Thermal Considerations and Output Current Derating In different applications, the LTM4619 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 the ambient temperature, airflow, input/output conditions, and the need for increased reliability. Two outputs of LTM4619 are paralleled to get high output current for derating curve tests. The power loss curves in Figures 7 and 8 can be used in coordination with the load current derating curves in Figures 9 to 16 for calculating an approximate JA for the module with various cooling methods. Application Note 103 provides a detailed explanation of the analysis for the thermal models and the derating curves. Tables 2 and 3 provide a summary of the equivalent JA for the noted conditions. These equivalent JA parameters are correlated to the measured values, and are improved with airflow. The junction temperature is maintained at 125C or below for the derating curves. Safety Considerations The LTM4619 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.
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14
LTM4619 APPLICATIONS INFORMATION
Table 2. 1.5V Output
DERATING CURVE Figures 9, 11 Figures 9, 11 Figures 9, 11 Figures 10, 12 Figures 10, 12 Figures 10, 12 VIN (V) 6, 12 6, 12 6, 12 6, 12 6, 12 6, 12 POWER LOSS CURVE Figure 7 Figure 7 Figure 7 Figure 7 Figure 7 Figure 7 AIRFLOW (LFM) 0 200 400 0 200 400 HEATSINK none none none BGA Heatsink BGA Heatsink BGA Heatsink JA (C/W) 12.8 9.0 8.0 11.9 8.4 7.4
Table 3. 3.3V Output
DERATING CURVE Figures 13, 15 Figures 13, 15 Figures 13, 15 Figures 14, 16 Figures 14, 16 Figures 14, 16 HEATSINK MANUFACTURER Aavid Thermalloy VIN (V) 12, 24 12, 24 12, 24 12, 24 12, 24 12, 24 POWER LOSS CURVE Figure 8 Figure 8 Figure 8 Figure 8 Figure 8 Figure 8 PART NUMBER 375424B00034G AIRFLOW (LFM) 0 200 400 0 200 400 WEBSITE www.aavid.com HEATSINK none none none BGA Heatsink BGA Heatsink BGA Heatsink JA (C/W) 13.4 9.6 8.5 12.5 8.9 7.9
3.0 2.5 POWER LOSS (W) POWER LOSS (W) 2.0 1.5 1.0 0.5 0 6V LOSS 12V LOSS 0 2 4 6 LOAD CURRENT (A) 8
4619 F07
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 0 2 4 6 LOAD CURRENT (A) 12V LOSS 24V LOSS 8
4619 F08
Figure 7. Power Loss at 1.5V Output
Figure 8. Power Loss at 3.3V Output
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15
LTM4619 APPLICATIONS INFORMATION
8 7 6 LOAD CURRENT (A) 5 4 3 2 1 0 70 75 6VIN TO 1.5VOUT 0LFM 6VIN TO 1.5VOUT 200LFM 6VIN TO 1.5VOUT 400LFM 80 85 90 95 100 105 110 115 AMBIENT TEMPERATURE (C)
4619 F09
8 7 6 LOAD CURRENT (A) 5 4 3 2 1 0 70 75 6VIN TO 1.5VOUT 0LFM 6VIN TO 1.5VOUT 200LFM 6VIN TO 1.5VOUT 400LFM 80 85 90 95 100 105 110 115 AMBIENT TEMPERATURE (C)
4619 F10
Figure 9. 6VIN to 1.5VOUT without Heat Sink
8 7 6 LOAD CURRENT (A) LOAD CURRENT (A) 5 4 3 2 1 0 70 75 12VIN TO 1.5VOUT 0LFM 12VIN TO 1.5VOUT 200LFM 12VIN TO 1.5VOUT 400LFM 80 85 90 95 100 105 110 115 AMBIENT TEMPERATURE (C)
4619 F11
Figure 10. 6VIN to 1.5VOUT with Heat Sink
8 7 6 LOAD CURRENT (A) 5 4 3 2 12VIN TO 1.5VOUT 0LFM 12VIN TO 1.5VOUT 200LFM 12VIN TO 1.5VOUT 400LFM 1 0 12VIN TO 3.3VOUT 0LFM 12VIN TO 3.3VOUT 200LFM 12VIN TO 3.3VOUT 400LFM 60 65 70 75 80 85 90 95 100 105 110 AMBIENT TEMPERATURE (C)
4619 F13
8 7 6 5 4 3 2 1 0 70 75
80 85 90 95 100 105 110 115 AMBIENT TEMPERATURE (C)
4619 F12
Figure 11. 12VIN to 1.5VOUT without Heat Sink
8 7 6 LOAD CURRENT (A) LOAD CURRENT (A) 5 4 3 2 1 0 12VIN TO 3.3VOUT 0LFM 12VIN TO 3.3VOUT 200LFM 12VIN TO 3.3VOUT 400LFM 60 65 70 75 80 85 90 95 100 105 110 AMBIENT TEMPERATURE (C)
4619 F14
Figure 12. 12VIN to 1.5VOUT with Heat Sink
8 7 6 5 4 3 2 1 0 40 24VIN TO 3.3VOUT 0LFM 24VIN TO 3.3VOUT 200LFM 24VIN TO 3.3VOUT 400LFM 50 60 70 80 90 AMBIENT TEMPERATURE (C) 100
4619 F15
Figure 13. 12VIN to 3.3VOUT without Heat Sink
8 7 6 LOAD CURRENT (A) 5 4 3 2 1 0 40 24VIN TO 3.3VOUT 0LFM 24VIN TO 3.3VOUT 200LFM 24VIN TO 3.3VOUT 400LFM 50 60 70 80 90 AMBIENT TEMPERATURE (C) 100
4619 F16
Figure 14. 12VIN to 3.3VOUT with Heat Sink
Figure 15. 24VIN to 3.3VOUT without Heat Sink
Figure 16. 24VIN to 3.3VOUT with Heat Sink
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LTM4619 APPLICATIONS INFORMATION
Layout Checklist/Example The high integration of LTM4619 makes the PCB board layout very simple and easy. However, to optimize its electrical and thermal performance, some layout considerations are still necessary. * Use large PCB copper areas for high current path, including VIN, PGND, VOUT1 and VOUT2. It helps to minimize the PCB conduction loss and thermal stress. * Place high frequency ceramic input and output capacitors next to the VIN, PGND and VOUT pins to minimize high frequency noise. * Place a dedicated power ground layer underneath the unit. * To minimize the via conduction loss and reduce module thermal stress, use multiple vias for interconnections between top layer and other power layers. * Do not put vias directly on the pad. * Use a separated SGND ground copper area for components connected to signal pins. Connect the SGND to PGND underneath the unit. * Decouple the input and output grounds to lower the output ripple noise. Refer to Figure 17. Figure 17 gives a good example of the recommended layout.
TOP VIEW PGND
M L
VIN
PGND
CIN2
K J H G F E D C B A 1 2 3 4 5 6 7 8 9 10 11 12
CIN1
COUT2 VOUT2 PGND
COUT1 VOUT1
Figure 17. Recommended PCB Layout
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17
LTM4619 TYPICAL APPLICATIONS
VIN 4.5V TO 26.5V
CIN 10F 2
11.5k C1 22pF
VIN
MODE/PLLIN INTVCC FREQ/PLLFLTR 19.1k VFB2 COMP2 LTM4619 VOUT2 TK/SS2 RUN2 0.1F R1 (OPT*) COUT2 100F C2 22pF VOUT2 3.3V/4A
VFB1 COMP1 VOUT1
VOUT1 5V/4A
COUT1 100F 0.1F 100k INTVCC PGOOD
TK/SS1 RUN1
PGOOD SGND
PGND
EXTVCC
4619 F18
VIN
*R1 IS NEEDED FOR 4.5V < VIN < 5.5V
Figure 18. Typical 4.5V to 26.5V Input, 5V and 3.3V Outputs at 4A Design
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18
LTM4619 TYPICAL APPLICATIONS
EXTERNAL 5V SUPPLY FOR INPUT VOLTAGE BELOW 5.5V MODE/PLLIN CIN 10F 2 121k C1 22pF VIN VFB1 COMP1 VOUT1 COUT1 100F 2 TK/SS1 0.1F 100k PGOOD SGND PGOOD PGND
4619 F19
VIN 4.5V TO 26.5V
INTVCC EXTVCC FREQ/PLLFLTR VFB2 COMP2
R1 3.83k
R2 1.21k
68.1k C2 22pF COUT2 100F 2
VOUT1 1.2V/4A
LTM4619
VOUT2 TK/SS2 RUN2 0.1F
VOUT2 1.5V/4A
RUN1
INTVCC
Figure 19. Typical 4.5V to 26.5V Input, 1.2V and 1.5V Outputs at 4A Design with Adjusted Frequency at 500kHz
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LTM4619 TYPICAL APPLICATIONS
VIN 6V TO 26.5V
CIN 10F
MODE/PLLIN EXTVCC INTVCC VIN FREQ/PLLFLTR COMP1 COMP2 TK/SS1 TK/SS2 LTM4619 VFB1 VFB2 VOUT1 VOUT2 RUN2 RUN1 SGND PGND
4619 F20
C1 51pF
R1 5.76k
C3 0.1F
PGOOD
C4 100F
+
VOUT2 5V/8A C5 330F
Figure 20. Output Paralleled LTM4619 Module for 5V Output at 8A Design
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20
LTM4619 TYPICAL APPLICATIONS
CLOCK SYNC, 0 PHASE VIN 6V TO 26.5V MODE/PLLIN INTVCC FREQ/PLLFLTR VFB2 COMP2 LTM4619 VOUT2 TK/SS2 RUN2 EXTVCC PGND R2 19.1k C11 22pF VOUT1 R1 60.4k R4 19.1k C4 22F
+
CIN1 330F VOUT1 5V/4A
CIN2 10F 2x
VIN R3 11.5k C3 22F C10 22pF
VFB1 COMP1 VOUT1
+
C2 220F
+
TK/SS1 C1 0.1F RUN1 PGOOD
VOUT2 3.3V/4A C5 220F
2 PHASE OSCILLATOR V+ R9 143k C3 0.1F SET OUT1 MOD ON/OFF
SGND
GND LTC6908-2 OUT2
CLOCK SYNC, 90 PHASE MODE/PLLIN INTVCC FREQ/PLLFLTR VFB2 COMP2 LTM4619 VOUT2 TK/SS2 RUN2 EXTVCC PGND
4619 F21
VIN R7 28k VOUT3 2.5V/4A C12 22pF
VFB1 COMP1 VOUT1 TK/SS1 RUN1 PGOOD R11 28k SGND
C13 22pF VOUT1 R5 60.4k R6 48.7k
R8 48.7k C6 22F
+
C9 220F
C8 22F
VOUT1 R10 60.4k
+
VOUT4 1.8V/4A C7 220F
Figure 21. 4-Phase, Four Outputs (5V, 3.3V, 2.5V and 1.8V) with Tracking
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21
LTM4619 PACKAGE DESCRIPTION
Pin Assignment Table 4 (Arranged by Pin Function)
PIN NAME A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 VOUT2 VOUT2 VOUT2 GND GND GND GND GND GND VOUT1 VOUT1 VOUT1 VOUT2 VOUT2 VOUT2 GND GND GND GND GND GND VOUT1 VOUT1 VOUT1 VOUT2 VOUT2 VOUT2 GND GND GND GND GND GND VOUT1 VOUT1 VOUT1 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 E12 F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 PIN NAME VOUT2 VOUT2 VOUT2 GND GND GND GND GND GND VOUT1 VOUT1 VOUT1 GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND GND INTVCC GND GND GND GND GND GND G1 G2 G3 G4 G5 G6 G7 G8 G9 G10 G11 G12 H1 H2 H3 H4 H5 H6 H7 H8 H9 H10 H11 H12 J1 J2 J3 J4 J5 J6 J7 J8 J9 J10 J11 J12 PIN NAME GND GND GND GND GND GND GND GND GND GND GND GND GND GND SW2 GND PGOOD SGND SGND MODE/PLLIN GND SW1 GND GND VIN VIN VIN EXTVCC RUN2 SGND SGND FREQ/PLLFLTR RUN1 VIN VIN VIN K1 K2 K3 K4 K5 K6 K7 K8 K9 K10 K11 K12 L1 L2 L3 L4 L5 L6 L7 L8 L9 L10 L11 L12 M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 PIN NAME VIN VIN VIN VIN TK2 VFB2 VFB1 TK1 VIN VIN VIN VIN VIN VIN VIN VIN VIN COMP2 COMP1 VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN VIN
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22
DETAIL A X Y M L K J H 15 BSC MOLD CAP SUBSTRATE 13.97 BSC G F E D C B A PADS SEE NOTES 12 11 10 9 8 3 DETAIL B 1.9050 3.1750 4.4450 5.7150 6.9850 0.630 0.025 SQ. 143x eee S X Y 7 6 5 4 3 2 1 DIA 0.630 PAD 1 2.72 - 2.92 0.12 - 0.28 13.97 BSC 3x, C (0.22 x45)
PACKAGE DESCRIPTION
aaa Z
15 BSC
0.27 - 0.37 2.45 - 2.55 DETAIL B bbb Z Z
PAD 1 CORNER
1.27 BSC
4
aaa Z
PACKAGE TOP VIEW
PACKAGE BOTTOM VIEW
6.9850
5.7150
4.4450
3.1750
1.9050
6.9850
5.7150
(Reference LTC DWG # 05-08-1816)
4.4450 DETAIL A
LGA Package 144-Lead (15mm x 15mm x 2.82mm)
3.1750
1.9050
0.6350 0.0000 0.6350
NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS 3 4 LAND DESIGNATION PER JESD MO-222, SPP-010
LTMXXXXXX mModule
COMPONENT PIN "A1"
0.6350 0.0000 0.6350
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.
DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. THE TOTAL NUMBER OF PADS: 144 SYMBOL TOLERANCE 0.10 aaa bbb 0.10 0.05 eee
TRAY PIN 1 BEVEL PACKAGE IN TRAY LOADING ORIENTATION
1.9050
3.1750
4.4450
5.7150
6.9850
SUGGESTED PCB LAYOUT TOP VIEW
LGA 144 0308 REV A
LTM4619
23
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LTM4619 PACKAGE PHOTOGRAPH
RELATED PARTS
PART NUMBER LTM4614 LTM4615 LTM4616 DESCRIPTION Dual 4A Low VIN DC/DC Module Triple Low VIN DC/DC Module Dual 8A Low VIN DC/DC Module COMMENTS 2.375V VIN 5.5V; 0.8V VOUT 5V; 15mm x 15mm x 2.8mm LGA Two 4A Outputs and One 1.5A; 15mm x 15mm x 2.8mm LGA 2.7V VIN 5.5V; 0.6V VOUT 5V; 15mm x 15mm x 2.8mm LGA
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24 Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
LT 0709 * PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2009

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