LTM4602 LINER | Alldatasheet
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Technical content
6A High Effi ciency DC/DC µModule The L TM®4602 is a complete 6A DC/DC step down power supply. Included in the package are the switching control- ler , power FETs, inductor , and all support components. Operating over an input voltage range of 4.5V to 20V , the L TM4602 supports an output voltage range of 0.6V to 5V , set by a single resistor . This high effi ciency design delivers 6A continuous current (8A peak), needing no heat sinks or airfl ow to meet power specifi cations. Only bulk input and output capacitors are needed to fi nish the design. The low profi le package (2.8mm) enables utilization of unused space on the bottom of PC boards for high density point of load regulation. High switching frequency and an adaptive on-time current mode architecture enables a very fast transient response to line and load changes without sacrifi cing stability. Fault protection features include integrated overvoltage and short circuit protection with a defeatable shutdown timer . A built-in soft-start timer is adjustable with a small capacitor . The L TM4602 is packaged in a thermally enhanced, compact (15mm × 15mm) and low profi le (2.8mm) over-molded Land Grid Array (LGA) package suitable for automated as- sembly by standard surface mount equipment. For the 4.5V to 28V input range version, refer to the L TM4602HV . n Telecom and Networking Equipment n Servers n Industrial Equipment n Point of Load Regulation n Complete Switch Mode Power Supply n Wide Input Voltage Range: 4.5V to 20V n 6A DC, 8A Peak Output Current n 0.6V to 5V Output Voltage n 1.5% Output Voltage Regulation n Ultrafast T ransient Response n Current Mode Control n Pb-Free (e4) RoHS Compliant Package with Gold- Pad Finish n Pin Compatible with the L TM4600 n Up to 92% Effi ciency n Programmable Soft-Start n Output Overvoltage Protection n Optional Short-Circuit Shutdown Timer n See the L TM4602HV for Operation Up to 28VIN n Small Footprint, Low Profi le (15mm × 15mm × 2.8mm) Surface Mount LGA Package 6A μModuleTM Power Supply with 4.5V to 20V Input Effi ciency vs Load Current with 12VIN (FCB = 0) VIN CIN
4602 TA01a
4.5V TO 20V VOUT 1.5V 6ACOUT RSET 66.5k LOAD CURRENT (A) EFFICIENCY (%) 100 2 4
4602 TA01b
0.8VOUT 1.2VOUT 1.5VOUT 1.8VOUT 2.5VOUT 3.3VOUT 3.3VOUT (950kHz)* *950kHz INSTEAD OF 1.3MHz INCREASES 3.3V EFFICIENCY 2% L, L T , L TC and L TM are registered trademarks of Linear Technology Corporation. μModule is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6100678, 6580258, 5847554, 6304066. TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Operating Temperature Range (Note 2).... –40°C to 85°C (Note 1) The l denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V . External CIN = 120μF , COUT = 200μF/Ceramic per typical application (front page) confi guration. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VIN(DC) Input DC Voltage l 4.5 20 V VOUT(DC) Output Voltage FCB = 0V V IN = 5V or 12V , VOUT = 1.5V , IOUT = 0A l 1.478 1.470 1.50 1.50 1.522 1.530 V Input Specifi cations V IN(UVLO) Under Voltage Lockout Threshold I OUT = 0A 3.4 4 V IINRUSH(VIN) Input Inrush Current at Startup I OUT = 0A. VOUT = 1.5V , FCB = 0 V IN = 5V V IN = 12V 0.6 0.7 A A I Q(VIN) Input Supply Bias Current IOUT = 0A, EXTVCC Open V IN = 12V , VOUT = 1.5V , FCB = 5V V IN = 12V , VOUT = 1.5V , FCB = 0V V IN = 5V , VOUT = 1.5V , FCB = 5V V IN = 5V , VOUT = 1.5V , FCB = 0V Shutdown, RUN = 0.8V , V IN = 12V 1.2 1.0 50 100 mA mA mA mA μA RUN/SS FCB PGOOD VIN PGND VOUT COMP SGND EXTVCC VOSET fADJ SVIN LGA PACKAGE 104-LEAD (15mm × 15mm × 2.8mm) TOP VIEW TJMAX = 125°C, θJA = 15°C/W , θJC = 6°C/W , θJA DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS WEIGHT = 1.7g PIN CONFIGURATION ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
LEAD FREE FINISH PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE L TM4602EV#PBF L TM4602V 104-Lead (15mm × 15mm × 2.8mm) LGA –40°C to 85°C L TM4602IV#PBF L TM4602V 104-Lead (15mm × 15mm × 2.8mm) LGA –40°C to 85°C Consult L TC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container . Consult L TC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: http://www.linear .com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear .com/packaging/ ORDER INFORMATION
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 L TM4602E is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The L TM4602I is guaranteed over the –40°C to 85°C temperature range. Note 3: Test assumes current derating versus temperature. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS I S(VIN) Input Supply Current V IN = 12V , VOUT = 1.5V , IOUT = 6A VIN = 12V , VOUT = 3.3V , IOUT = 6A VIN = 5V , VOUT = 1.5V , IOUT = 6 A 0.88 1.80 2.08 A A A Output Specifi cations I OUTDC Output Continuous Current Range (See Output Current Derating Curves for Different V IN, VOUT and TA) VIN = 12V , VOUT = 1.5V 0 6 A ΔVOUT(LINE) VOUT Line Regulation Accuracy V OUT = 1.5V , IOUT = 0A, FCB = 0V , VIN = 4.5V to 20V l 0.15 0.3 % ΔVOUT(LOAD) VOUT Load Regulation Accuracy V OUT = 1.5V , IOUT = 0A to 6A, FCB = 0V , VIN = 5V , VIN = 12V (Note 3) l ±0.25 ±0.15 ±0.5 ±1.0 V OUT(AC) Output Ripple Voltage V IN = 12V , VOUT = 1.5V , IOUT = 0A, FCB = 0V 10 15 mV P-P fs Output Ripple Voltage Frequency V OUT = 1.5V , IOUT = 6A, FCB = 0V 850 kHz tSTART Turn-On Time V OUT = 1.5V , IOUT = 1A V IN = 12V V IN = 5V 0.5 0.7 ms ms ΔVOUTLS Voltage Drop for Dynamic Load Step V OUT = 1.5V , Load Step: 0A/μs to 3A/μs COUT = 22μF 6.3V , 330μF 4V POSCAP, See Table 2 30 mV tSETTLE Settling Time for Dynamic Load Step Load: 10% to 50% to 10% of Full Load 25 μs IOUTPK Output Current Limit Output Voltage in Foldback V IN = 12V , VOUT = 1.5V V IN = 5V , VOUT = 1.5V A A Control Stage VOSET Voltage at VOSET Pin I OUT = 0A, VOUT = 1.5V l 0.591 0.6 0.609 V VRUN/SS RUN ON/OFF Threshold 0.8 1.5 2 V IRUN(C)/SS Soft-Start Charging Current V RUN/SS = 0V –0.5 –1.2 –3 μA IRUN(D)/SS Soft-Start Discharging Current V RUN/SS = 4V 0.8 1.8 3 μA VIN – SVIN EXTVCC = 0V , FCB = 0V 100 mV IEXTVCC Current into EXTVCC Pin EXTV CC = 5V , FCB = 0V , VOUT = 1.5V , IOUT = 0A 16 mA RFBHI Resistor Between VOUT and VOSET Pins 100 k Ω VFCB Forced Continuous Threshold 0.57 0.6 0.63 V IFCB Forced Continuous Pin Current V FCB = 0.6V –1 –2 μA PGOOD Output ΔV OSETH PGOOD Upper Threshold V OSET Rising 7.5 10 12.5 % ΔVOSETL PGOOD Lower Threshold V OSET Falling –7.5 –10 –12.5 % ΔVOSET(HYS) PGOOD Hysteresis V OSET Returning 2 % VPGL PGOOD Low Voltage I PGOOD = 5mA 0.15 0.4 V The l denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at TA = 25°C, VIN = 12V . Per typical application (front page) confi guration.
Effi ciency vs Load Current with 5VIN (FCB = 0) Effi ciency vs Load Current with 12VIN (FCB = 0) Effi ciency vs Load Current with 20V IN (FCB = 0) 1.2V T ransient Response 1.5V T ransient Response 1.8V T ransient Response 2.5V T ransient Res ponse 3.3V T ransient Res ponse (See Figure 21 for all curves) VOUT 50mV/DIV 1.2V AT 3A/μs LOAD STEP COUT = 1 × 22μF, 6.3V CERAMICS 330μF, 4V SANYO POSCAP IOUT 2A/DIV 20μs/DIV 4602 G05 1.5V AT 3A/μs LOAD STEP COUT = 1 × 22μF, 6.3V CERAMICS 330μF, 4V SANYO POSCAP 20μs/DIV 4602 G06 VOUT 50mV/DIV IOUT 2A/DIV 1.8V AT 3A/μs LOAD STEP COUT = 1 × 22μF, 6.3V CERAMICS 330μF, 4V SANYO POSCAP 20μs/DIV 4602 G07 VOUT 50mV/DIV IOUT 2A/DIV 2.5V AT 3A/μs LOAD STEP COUT = 1 × 22μF, 6.3V CERAMICS 330μF, 4V SANYO POSCAP 20μs/DIV 4602 G08 VOUT 50mV/DIV IOUT 2A/DIV 3.3V AT 3A/μs LOAD STEP COUT = 1 × 22μF, 6.3V CERAMICS 330μF, 4V SANYO POSCAP 20μs/DIV 4602 G09 VOUT 50mV/DIV IOUT 2A/DIV LOAD CURRENT (A) EFFICIENCY (%) 100 2 4
4602 G01
0.8VOUT 1.2VOUT 1.5VOUT 1.8VOUT 2.5VOUT 3.3VOUT* *FOR 5V TO 3.3V CONVERSION, SEE FREQUENCY ADJUSTMENT IN APPLICATIONS INFORMATION LOAD CURRENT (A) EFFICIENCY (%) 100 2 4
4602 G02
0.8VOUT 1.2VOUT 1.5VOUT 1.8VOUT 2.5VOUT 3.3VOUT 3.3VOUT (950kHz)* *950kHz INSTEAD OF 1.3MHz INCREASES 3.3V EFFICIENCY 2% LOAD CURRENT (A) EFFICIENCY (%)
4602 G03
1.2VOUT 1.5VOUT 1.8VOUT 2.5VOUT 3.3VOUT Light Load Effi ciency vs Load Current with 12VIN (FCB > 0.7V , <5V) LOAD CURRENT (A) EFFICIENCY (%) 100 0.8
4602 G04
1.2VOUT 1.5VOUT 1.8VOUT 2.5VOUT 3.3VOUT TYPICAL PERFORMANCE CHARACTERISTICS
Start-Up, No Load, IOUT = 0A Start-Up, IOUT = 6A (Resistive Load) Short-Circuit Protection, IOUT = 0A Short-Circuit Protection, IOUT = 6A VIN to VOUT Step-Down Ratio (See Figure 21 for all curves) VIN (V) 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 51 5
4602 G14
VOUT (V) 3.3V 2.5V 1.8V 1.5V 1.2V fADJ = OPEN SEE FREQUENCY ADJUSTMENT DISCUSSION FOR 12VIN TO 5VOUT AND 5VIN TO 3.3VOUT CONVERSION 0.6V VIN = 12V VOUT = 1.5V COUT = 1 × 22μF, 6.3V X5R 330μF, 4V SANYO POSCAP NO EXTERNAL SOFT-START CAPACITOR 200μs/DIV 4602 G10 VOUT 0.5V/DIV IIN 0.5A/DIV VIN = 12V VOUT = 1.5V COUT = 1 × 22μF, 6.3V X5R 330μF, 4V SANYO POSCAP NO EXTERNAL SOFT-START CAPACITOR 500μs/DIV 4602 G11 VOUT 0.5V/DIV IIN 0.5A/DIV VIN = 12V VOUT = 1.5V COUT = 1 × 22μF, 6.3V X5R 330μF, 4V SANYO POSCAP NO EXTERNAL SOFT-START CAPACITOR 20μs/DIV 4602 G12 VOUT 0.5V/DIV IIN 0.5A/DIV VIN = 12V VOUT = 1.5V COUT = 1 × 22μF, 6.3V X5R 330μF, 4V SANYO POSCAP NO EXTERNAL SOFT-START CAPACITOR 20μs/DIV 4602 G13 VOUT 0.5V/DIV IIN 0.5A/DIV TYPICAL PERFORMANCE CHARACTERISTICS
VIN (Bank 1): Power Input Pins. Apply input voltage be- tween these pins and PGND pins. Recommend placing input decoupling capacitance directly between V IN pins and PGND pins. fADJ (Pin A15): A 110k resistor from VIN to this pin sets the one-shot timer current, thereby setting the switching frequency. The L TM4602 switching frequency is typically 850kHz. An external resistor to ground can be selected to reduce the one-shot timer current, thus lower the switching frequency to accommodate a higher duty cycle step down requirement. See the applications section. SV IN (Pin A17): Supply Pin for Internal PWM Controller . Leave this pin open or add additional decoupling capacitance. EXTVCC (Pin A19): External 5V supply pin for controller . If left open or grounded, the internal 5V linear regulator will power the controller and MOSFET drivers. For high input voltage applications, connecting this pin to an external 5V will reduce the power loss in the power module. The EXTV CC voltage should never be higher than VIN. VOSET (Pin A21): The Negative Input of The Error Amplifi er . Internally, this pin is connected to VOUT with a 100k precision resistor . Different output voltages can be programmed with additional resistors between the V OSET and SGND pins. COMP (Pin B23): Current Control Threshold and Error Amplifi er Compensation Point. The current comparator threshold increases with this control voltage. The voltage ranges from 0V to 2.4V with 0.8V corresponding to zero sense voltage (zero current). SGND (Pin D23): Signal Ground Pin. All small-signal components should connect to this ground, which in turn connects to PGND at one point. RUN/SS (Pin F23): Run and Soft-Start Control. Forcing this pin below 0.8V will shut down the power supply. Inside the power module, there is a 1000pF capacitor which provides approximately 0.7ms soft-start time with 200μF output capacitance. Additional soft-start time can be achieved by adding additional capacitance between the RUN/SS and SGND pins. The internal short-circuit latchoff can be disabled by adding a resistor between this pin and the V IN pin. This pullup resistor must supply a minimum 5μA pull up current. FCB (Pin G23): Forced Continuous Input. Grounding this pin enables forced continuous mode operation regardless of load conditions. Tying this pin above 0.63V enables discontinuous conduction mode to achieve high effi ciency operation at light loads. There is an internal 4.75k resistor between the FCB and SGND pins. PGOOD (Pin J23): Output Voltage Power Good Indicator . When the output voltage is within 10% of the nominal voltage, the PGOOD is open drain output. Otherwise, this pin is pulled to ground. PGND (Bank 2): Power ground pins for both input and output returns. V OUT (Bank 3): Power Output Pins. Apply output load between these pins and PGND pins. Recommend placing High Frequency output decoupling capacitance directly between these pins and PGND pins. (See Package Description for Pin Assignment) E C A RUN/SS FCB PGOOD V IN BANK 1 PGND BANK 2 VOUT BANK 3 COMP SGND EXTVCC VOSET fADJ SVIN TOP VIEW 11 13 10 12 15 17 14 16 19 21 18 20 22 94 95 96 97 98 99 100 101 102 103 104 19181716765432 84 85 86 87 88 89 90 91 74 75 76 77 78 79 80 63 64 65 66 67 68 69 52 53 54 55 56 57 58 42 43 44 45 46 47 11109 13 14 15 26 27 28 29 30 31 33 34 35 36 37 38 1 23 B D F G H J L M N P R T K
4602 PN01
T A = 25°C, VIN = 12V . Use Figure 1 confi guration. Figure 1. Simplifi ed L TM4602 Block Diagram
4602 F01
μModule Description The L TM4602 is a standalone nonisolated synchronous switching DC/DC power supply. It can deliver up to 6A of DC output current with only bulk external input and output capacitors. This module provides a precisely regulated output voltage programmable via one external resistor from 0.6V DC to 5.0VDC, not to exceed 80% of the input voltage. The input voltage range is 4.5V to 20V . A simplifi ed block diagram is shown in Figure 1 and the typical application schematic is shown in Figure 21. The L TM4602 contains an integrated L TC constant on-time current-mode regulator , ultralow R DS(ON) FETs with fast switching speed and integrated Schottky diode. The typical switching frequency is 850kHz at full load. With current mode control and internal feedback loop compensation, the L TM4602 module has suffi cient stability margins and good transient performance under a wide range of operat- ing conditions and with a wide range of output capacitors, even all ceramic output capacitors (X5R or X7R). Current mode control provides cycle-by-cycle fast current limit. In addition, foldback current limiting is provided in an overcurrent condition while V OSET drops. Also, the L TM4602 has defeatable short-circuit latch off. Internal overvoltage and undervoltage comparators pull the open- drain PGOOD output low if the output feedback voltage exits a ±10% window around the regulation point. Furthermore, in an overvoltage condition, internal top FET Q1 is turned off and bottom FET Q2 is turned on and held on until the overvoltage condition clears. Pulling the RUN/SS pin low forces the controller into its shutdown state, turning off both Q1 and Q2. Releasing the pin allows an internal 1.2μA current source to charge up the soft-start capacitor . When this voltage reaches 1.5V , the controller turns on and begins switching. At low load current the module works in continuous cur- rent mode by default to achieve minimum output voltage ripple. It can be programmed to operate in discontinuous current mode for improved light load effi ciency when the FCB pin is pulled up above 0.8V and no higher than 6V . The FCB pin has a 4.75k resistor to ground, so a resistor to V IN can set the voltage on the FCB pin. When EXTVCC pin is grounded or open, an integrated 5V linear regulator powers the controller and MOSFET gate drivers. If a minimum 4.7V external bias supply is ap- plied on the EXTV CC pin, the internal regulator is turned off, and an internal switch connects EXTV CC to the gate driver voltage. This eliminates the linear regulator power loss with high input voltage, reducing the thermal stress on the controller . The maximum voltage on EXTV CC pin is 6V . The EXTVCC voltage should never be higher than the VIN voltage. Also EXTVCC must be sequenced after VIN. OPERATION
mined by the maximum load current and output voltage. SET, several external components are added. Figure 2. L TM4602 Margining Implementation
4602 F02
The L TM4602 is designed for low output voltage ripple. The bulk output capacitors C OUT is chosen with low enough effective series resistance (ESR) to meet the output voltage ripple and transient requirements. C OUT can be low ESR tantalum capacitor , low ESR polymer capacitor or ceramic capacitor (X5R or X7R). The typical capacitance is 200μF if all ceramic output capacitors are used. The internally optimized loop compensation provides suffi cient stability margin for all ceramic capacitors applications. Additional output fi ltering may be required by the system designer , if further reduction of output ripple or dynamic transient spike is required. Refer to Table 2 for an output capaci- tance matrix for each output voltage droop, peak to peak deviation and recovery time during a 3A/μs transient with a specifi c output capacitance. Fault Conditions: Current Limit and Overcurrent Foldback The L TM4602 has a current mode controller , which inher- ently limits the cycle-by-cycle inductor current not only in steady-state operation, but also in transient. To further limit current in the event of an over load condi- tion, the L TM4602 provides foldback current limiting. If the output voltage falls by more than 50%, then the maximum output current is progressively lowered to about one sixth of its full current limit value. Soft-Start and Latchoff with the RUN/SS pin The RUN/SS pin provides a means to shut down the L TM4602 as well as a timer for soft-start and overcurrent latchoff. Pulling the RUN/SS pin below 0.8V puts the L TM4602 into a low quiescent current shutdown (I Q ≤ 100μA). Releasing the pin allows an internal 1.2μA cur- rent source to charge up the timing capacitor C SS. Inside L TM4602, there is an internal 1000pF capacitor from RUN/ SS pin to ground. If RUN/SS pin has an external capacitor C SS_EXT to ground, the delay before starting is about: tDELAY = 1.5V 1.2μA •( CSS _ EXT+ 1000pF) When the voltage on RUN/SS pin reaches 1.5V , the L TM4602 internal switches are operating with a clamping of the maximum output inductor current limited by the RUN/SS pin total soft-start capacitance. As the RUN/SS pin voltage rises to 3V , the soft-start clamping of the inductor current is released. V IN to VOUT Step-Down Ratios There are restrictions in the maximum V IN to VOUT step down ratio that can be achieved for a given input voltage. These constraints are shown in the Typical Performance Characteristics curves labeled “V IN to V OUT Step-Down Ratio”. Note that additional thermal derating may apply. See the Thermal Considerations and Output Current Derating sections of this data sheet. APPLICATIONS INFORMATION
Table 2. Output Voltage Response Versus Component Matrix (Refer to Figure 21), 0A to 3A Step (Typical Values)
down to ground in order to restart operation. Generally 0.1μF is more than suffi cient. Figure 3. RUN/SS Pin Voltage During Startup and RUN during start-up and short circuit.
4602 F03
4602 F04
Figure 5. This function allows the L TM4602 to be turned sequence of the output voltage. Figure 5. Enable Circuit with External Logic Figure 6. Output Voltage T racking with the L TC2923 Controller power supply tracking controller such as the L TC2923. values. See the L TC2923 data sheet for more details. supply that powers the control circuitry and FET drivers.
- EXTVCC grounded. Internal 5V LDO is always powered
from the internal 5V regulator .
- EXTVCC connected to an external supply. Internal LDO
MOSFET remains on when the inductor current reverses. provides minimum output voltage ripple.
4602 F05
4602 F06
curves for other output voltages. provided to protect each unit from catastrophic failure. tion loss is minimized and light load effi ciency is improved. output voltage ripple increases at light load. sharing among modules to balance the thermal stress. where N is the number of L TM4602s in parallel. Figure 7. Parallel T wo μModules with Load Sharing OPTI-LOOP is a registered trademark of Linear Technology Corporation.
4602 F07
Figure 14. 5V to 3.3V , No Heat Sink Figure 15. 5V to 3.3V , BGA Heat Sink
4602 F08
4602 F09
4602 F10
4602 F11
4601 F13
4602 F14
4602 F15
Table 4. 3.3V Output Table 3. 1.5V Output
200 None 14
400 None 12
- Use large PCB copper areas for high current path, including V IN, PGND and VOUT. It helps to minimize the PCB conduction loss and thermal stress.
- Place high frequency ceramic input and output capaci- tors next to the VIN, PGND and VOUT pins to minimize high frequency noise.
- Place a dedicated power ground layer underneath the unit.
- To minimize the via conduction loss and reduce module thermal stress, use multiple vias for interconnection between top layer and other power layers.
- Do not put vias directly on pads unless they are capped.
- Use a separated SGND ground copper area for com- ponents connected to signal pins. Connect the SGND to PGND underneath the unit. Figure 18 gives a good example of the recommended layout. L TM4602 Frequency Adjustment The L TM4602 is designed to typically operate at 850kHz across most input and output conditions. The control ar- chitecture is constant on time valley mode current control. The f ADJ pin is typically left open or decoupled with an optional 1000pF capacitor . The switching frequency has been optimized to maintain constant output ripple over the operating conditions. The equations for setting the operat- ing frequency are set around a programmable constant on time. This on time is developed by a programmable current into an on board 10pF capacitor that establishes a ramp that is compared to a voltage threshold equal to the output voltage up to a 2.4V clamp. This I ON current is equal to: ION = (VIN – 0.7V)/110k, with the 110k onboard resistor
Figure 16. 12V to 3.3V , No Heat Sink Figure 17. 12V to 3.3V , BGA Heat Sink
4602 F16
Figure 18. Recommended PCB Layout
- 10pF and tOFF = ts – tON. The frequency is equal to: Freq. = DC/tON. The ION current is proportional to VIN, and the regulator duty cycle is inversely proportional to VIN, there- fore the step-down regulator will remain relatively constant frequency as the duty cycle adjustment takes place with lowering V IN. The on time is proportional to VOUT up to a 2.4V clamp. This will hold frequency relatively constant with different output voltages up to 2.4V . The regulator switching period is comprised of the on time and off time as depicted in Figure 19. VIN PGND TOP LAYER VOUT
4600 F16
tOFF must be greater than 400ns, or tS – tON > 400ns. 1MHz frequency or 1μs period is chosen for 12V to 5V . 400ns minimum off-time is limited below 9V .
4602 F19
Figure 19. L TM4602 Switching Period onds and a minimum (tOFF) off time of 400 nanoseconds.
Equations for setting frequency for 5V to 3.3V: I ON = (VIN – 0.7V)/110k; ION = 39μA frequency = (I ON/[2.4V • 10pF]) • DC = 1.07MHz; DC = duty cycle, duty cycle is (VOUT/VIN) t S = t ON + t OFF, tON = on-time, t OFF = off-time of the switching period; tS = 1/frequency tOFF must be greater than 400ns, or tS – tON > 400ns. t ON = DC • tS ~450kHz frequency or 2.22μs period is chosen for 5V to 3.3V . Frequency range is about 450kHz to 650kHz from 4.5V to 7V input. t ON = 0.66 • 2.22μs ≅ 1.46μs t OFF = 2.22μs – 1.46μs ≅ 760ns tON and tOFF are above the minimums with adequate guard band. Using the frequency = (ION/[2.4V • 10pF]) • DC, solve for ION = (450kHz • 2.4V • 10pF) • (1/0.66) ≅ 16μA. ION current calculated from 5V input was 39μA, so a resistor from fADJ to ground = (0.7V/30.1k) = 23μA. 39μA – 23μA = 16μA, sets the adequate I ON current for proper frequency range for the higher duty cycle conversion of 5V to 3.3V . Input voltage range is limited to 4.5V to 7V . Higher input voltages can be used without the 30.1k on f ADJ. The inductor ripple current gets too high above 7V , and the 400ns minimum off-time is limited below 4.5V . In 12V to 3.3V applications, if a 35k resistor is added from the f ADJ pin to ground, then a 2% effi ciency gain will be achieved as shown in the 12V effi ciency graph in the Typi- cal Performance Characteristics. This is due to the lower transition losses in the power MOSFETs after lowering the switching frequency down from 1.3MHz to 950kHz. APPLICATIONS INFORMATION
Figure 21. Typical Application, 5V to 20V Input, 0.6V to 5V Output, 6A Max Figure 20. VIN to VOUT Step-Down Ratio for 12VIN to 5VOUT and 5VIN to 3.3VOUT
4602 F20a
4602 F20b
4602 F21
4602 TA02
15.8k EXTVCC RUN COMP FCB VOUT VOUT = 0.6V • ([100k/N] + RSET)/RSET WHERE N = 2 C1, C7: TDK C3216X5R1E106MT C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501 C5, C10: SANYO POSCAP, 4TPE330MI PGOOD VOSET SVIN PGNDSGND VOUT 2.5V 12A VIN 4.5V TO 20V 10μF 25V 10μF 25V C10 330μF 22μF VIN LTM4602 fADJ 100k EXTVCC RUN COMP FCB VOUT PGOOD VOSET SVIN PGNDSGND RUN/SOFT-START 220pF 330μF 22μF VIN LTM4602 fADJ Current Sharing Between T wo L TM4602 Modules Parallel Operation and Load Sharing TOTAL LOAD INDIVIDUAL SHARE
4602 TA03
2.5VOUT 12AMAX TYPICAL APPLICATION
104-Lead (15mm × 15mm) (Reference LTM DWG # 05-05-1800) NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 2. ALL DIMENSIONS ARE IN MILLIMETERS LAND DESIGNATION PER JESD MO-222, SPP-010 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. THE TOTAL NUMBER OF PADS: 104 DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER IS A MARKED FEATURE OR A NOTCHED BEVELED PAD SYMBOL aaa bbb eee TOLERANCE 0.15 0.10 0.15 2.72 – 2.92 DETAIL B DETAIL B SUBSTRATE MOLD CAP 0.27 – 0.37 2.45 – 2.55 bbb Z Z BSC TOP VIEW BSC
4 PAD 1
X Y aaa Z aaa Z 13.97 BSC 12.70 BSC 0.11 – 0.27 13.93 BSC 11 13 10 12 15 17 14 16 19 21 18 20 22 LGA104 0206 BOTTOM VIEW C(0.30) PAD 1 PADS SEE NOTES 94 95 96 97 98 99 100 101 102 103 104 19181716765432 84 85 86 87 88 89 90 91 74 75 76 77 78 79 80 63 64 65 66 67 68 69 52 53 54 55 56 57 58 42 43 44 45 46 47 11109 13 14 15 26 27 28 29 30 31 33 34 35 36 37 38 M YXeee1 SUGGESTED SOLDER PAD LAYOUT TOP VIEW 94 95 96 97 98 99 100 101 102 103 104 19181716765432 84 85 86 87 88 89 90 91 74 75 76 77 78 79 80 63 64 65 66 67 68 69 52 53 54 55 56 57 58 42 43 44 45 46 47 11109 13 14 15 26 27 28 29 30 31 33 34 35 36 37 38 0.0000 1.2700 2.5400 0.3175 0.3175 4.4450 5.7150 6.9850 1.4675 5.7158 6.9421 4.4458 6.3500 6.3500 3.8100 3.8100 1.2700 0.3175 0.3175 0.0000 1.2700 3.1758 1.9058 0.6358 0.0000 0.6342 1.9042 3.1742 4.4442 5.7142 6.9865 2.7375 4.0075 5.2775 6.5475 6.9888 1.0900 2.3600 4.4950 5.7650 5.0800 5.0800 2.5400 2.5400 A B C D E F G H J L M N P R T K PACKAGE DESCRIPTION
PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME A1 - B1 V IN C1 - D1 V IN E1 - F1 V IN G1 PGND H1 - A2 - B2 - C2 - D2 - E2 - F2 - G2 - H2 - A3 V IN B3 - C3 - D3 - E3 - F3 - G3 - H3 - A4 - B4 - C4 - D4 - E4 - F4 - G4 - H4 - A5 V IN B5 - C5 - D5 - E5 - F5 - G5 - H5 - A6 - B6 - C6 - D6 - E6 - F6 - G6 - H6 - A7 V IN B7 - C7 - D7 - E7 - F7 - G7 - H7 PGND A8 - B8 - C8 - D8 - E8 - F8 - G8 - H8 - A9 V IN B9 - C9 - D9 - E9 - F9 - G9 - H9 PGND A10 - B10 - C10 V IN D10 - E10 V IN F10 - G10 - H10 - A11 V IN B11 - C11 - D11 - E11 - F11 - G11 - H11 PGND A12 - B12 - C12 V IN D12 - E12 V IN F12 - G12 - H12 - A13 V IN B13 - C13 - D13 - E13 - F13 - G13 - H13 PGND A14 - B14 - C14 V IN D14 - E14 V IN F14 - G14 - H14 - A15 f ADJ B15 - C15 - D15 - E15 - F15 - G15 - H15 PGND A16 - B16 - C16 - D16 - E16 - F16 - G16 - H16 - A17 SV IN B17 - C17 - D17 - E17 - F17 - G17 - H17 PGND A18 - B18 - C18 - D18 - E18 - F18 - G18 - H18 - A19 EXTV CC B19 - C19 - D19 - E19 - F19 - G19 - H19 - A20 - B20 - C20 - D20 - E20 - F20 - G20 - H20 - A21 V OSET B21 - C21 - D21 - E21 - F21 - G21 - H21 - A22 - B22 - C22 - D22 - E22 - F22 - G22 - H22 - A23 - B23 COMP C23 - D23 SGND E23 - F23 RUN/SS G23 FCB H23 - PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME J1 PGND K1 - L1 - M1 - N1 - P1 - R1 - T1 - J2 - K2 - L2 PGND M2 PGND N2 PGND P2 V OUT R2 V OUT T2 V OUT J3 - K3 - L3 - M3 - N3 - P3 - R3 - T3 - J4 - K4 - L4 PGND M4 PGND N4 PGND P4 V OUT R4 V OUT T4 V OUT J5 - K5 - L5 - M5 - N5 - P5 - R5 - T5 - J6 - K6 - L6 PGND M6 PGND N6 PGND P6 V OUT R6 V OUT T6 V OUT J7 - K7 PGND L7 - M7 - N7 - P7 - R7 - T7 - J8 - K8 L8 PGND M8 PGND N8 PGND P8 V OUT R8 V OUT T8 V OUT J9 - K9 PGND L9 - M9 - N9 - P9 - R9 - T9 - J10 - K10 L10 PGND M10 PGND N10 PGND P10 V OUT R10 V OUT T10 V OUT J11 - K11 PGND L11 - M11 - N11 - P11 - R11 - T11 - J12 - K12 - L12 PGND M12 PGND N12 PGND P12 V OUT R12 V OUT T12 V OUT J13 - K13 PGND L13 - M13 - N13 - P13 - R13 - T13 - J14 - K14 - L14 PGND M14 PGND N14 PGND P14 V OUT R14 V OUT T14 V OUT J15 - K15 PGND L15 - M15 - N15 - P15 - R15 - T15 - J16 - K16 - L16 PGND M16 PGND N16 PGND P16 V OUT R16 V OUT T16 V OUT J17 - K17 PGND L17 - M17 - N17 - P17 - R17 - T17 - J18 - K18 - L18 PGND M18 PGND N18 PGND P18 V OUT R18 V OUT T18 V OUT J19 - K19 - L19 - M19 - N19 - P19 - R19 - T19 - J20 - K20 - L20 PGND M20 PGND N20 PGND P20 V OUT R20 V OUT T20 V OUT J21 - K21 - L21 - M21 - N21 - P21 - R21 - T21 - J22 - K22 - L22 PGND M22 PGND N22 PGND P22 V OUT R22 V OUT T22 V OUT J23 PGOOD K23 - L23 - M23 - N23 - P23 - R23 - T23 - Pin Assignment Tables (Arranged by Pin Number) PACKAGE DESCRIPTION
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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. PIN NAME G1 PGND H11 H13 H15 H17 PGND PGND PGND PGND PGND PGND J1 PGND K11 K13 K15 K17 PGND PGND PGND PGND PGND PGND L10 L12 L14 L16 L18 L20 L22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND M10 M12 M14 M16 M18 M20 M22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND N10 N12 N14 N16 N18 N20 N22 PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PGND PIN NAME P10 P12 P14 P16 P18 P20 P22 V OUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT R10 R12 R14 R16 R18 R20 R22 V OUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT T10 T12 T14 T16 T18 T20 T22 V OUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT PIN NAME A11 A13 V IN VIN VIN VIN VIN VIN B1 V IN C10 C12 C14 V IN VIN VIN D1 V IN E10 E12 E14 V IN VIN VIN F1 V IN PIN NAME A15 f ADJ A17 SV IN A19 EXTV CC A21 V OSET B23 COMP D23 SGND F23 RUN/SS G23 FCB J23 PGOOD Pin Assignment Tables (Arranged by Pin Number) PACKAGE DESCRIPTION
© LINEAR TECHNOLOGY CORPORATION 2007 LT 0807 REV A • PRINTED IN USA Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com 1.8V, 6A Regulator
4602 TA04
C1, C2: TDK C3216X5R1E106MT C3: TAIYO YUDEN, JMK316BJ226ML-T501 C4: SANYO POSCAP, 4TPE330MI V OUT 1.8V AT 6A VIN 4.5V TO 20V 100k EXTVCC RUN COMP FCB VOUT PGOOD VOSET SVIN PGNDSGND 10μF 25V 100pF 330μF PGOOD 22μF VIN LTM4602 fADJ RSET 49.9k 10μF 25V This product contains technology licensed from Silicon Semiconductor Corporation. PART NUMBER DESCRIPTION COMMENTS L TC2900 Quad Supply Monitor with Adjustable Reset Timer Monitors Four Supplies; Adjustable Reset Timer L TC2923 Power Supply T racking Controller T racks Both Up and Down; Power Supply Sequencing L T3825/L T3837 Synchronous Isolated Flyback Controllers No Optocoupler Required; 3.3V , 12A Output; Simple Design L TM4600 10A DC/DC μModule 10A Basic DC/DC Module L TM4601 12A DC/DC μModule with PLL, Output T racking/ Margining and Remote Sensing Synchronizable, PolyPhase ® Operation, L TM4601-1 Version has no Remote Sensing, Fast T ransient Response L TM4603 6A DC/DC μModule with PLL and Output T racking/ Margining and Remote Sensing Synchronizable, PolyPhase Operation, L TM4603-1 Version has no Remote Sensing, Fast T ransient Response PolyPhase is a registered trademark of Linear Technology Corporation. TYPICAL APPLICATION RELATED PARTS