LSM16A-W3 MURATA | Alldatasheet
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Ḥ +INPUT (2) COMMON (3) PWM CONTROLLER CURRENT SENSE REFERENCE & ERROR AMP VCC ON/OFF CONTROL (1) VOUT TRIM (5) +OUTPUT (4) +SENSE (6) COMMON (3) Figure 1. Simplified Schematic 3.3 Volt output fully rated at 16 Amps.
16 Amps at ambient temperatures to +65°C
FEATURES
/square6 Step-down, wide input buck regulators for distributed 3-5V power architectures /square6 3V to 5V wide-input range /square6 Non-isolated, fixed-frequency, synchronous-rectifier topology /square6 Tape and reel SMT package /square6 ±1% setpoint accuracy /square6 Efficiencies to 95% @ 16 Amps /square6 Noise as low as 30mVp-p /square6 Stable no-load operation /square6 Remote on/off control /square6 Sense pin and output voltage trim /square6 No derating to +65°C with no fan /square6 Designed to meet UL/IEC/EN60950-1 safety /square6 EMC compliant Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC’s in SMT Packages Typical unit Typical topology is shown. LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 1 of 12 For full details go to www.murata-ps.com/rohs www.murata-ps.com Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000
1 On/Off Control
3 Common
~ Typical at TA = +25°C under nominal line voltage and full-load conditions, unless noted. All models are tested/specified with external 22μF tantalum input and output capacitors. These capacitors are necessary to accommodate our test equipment and may not be required to achieve specified performance in your applications. See I/O Filtering and Noise Reduction. Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth and may be reduced with external filtering. See I/O Filtering and Noise Reduction for details. These devices have no minimum-load requirements and will regulate under no-load conditions. Regulation specifications describe the output-voltage deviation as the line voltage or load is varied from its nominal/midpoint value to either extreme. Nominal line voltage, no-load/full-load conditions. V IN = 4.5 Volts minimum for VOUT = 3.3 Volts. LSM-T/16-W3 specs are given with VOUT = 3.3 Volts, unless noted. MECHANICAL SPECIFICATIONSPART NUMBER STRUCTURE Performance Specifications and Ordering Guide~ Case C45 3-4#/00%2,%!$3 #/0,!.!2 "/44/-6)%7 490 490 %130 2ECOMMENDED0AD3IZEXX %130 Maximum Rated Output Current in Amps Non-Isolated SMT Output Configuration: L = Unipolar Low Voltage Nominal Output Voltage: or 0.75-3.3 (T) Volts Input Voltage Range: W3 = 3 to 5.5 Volts (5V nominal) L SM 16- / W3-1.8 BOTTOM VIEW 1.36 (34.54) 0.375 (9.53) 0.112 TYP . (2.84) 0.052 (1.32) LSM WITH REMOVEABLE HEAT SHIELD FOR HIGH TEMPERATURE SOLDER CAUTION PRESS TO REMOVE THE HEAT SHIELD AFTER THE SOLDER PROCESS 0.60 (15.24) 0.049 (1.24) 0.310 (7.87) 0.010 (0.254) 0.55 (13.97) 0.052 (1.32) 0.062 (1.57) 0.047 (1.19) 0.570 (14.48) 3E Q .S P .@ 0.190 (4.83) 3456 NOTCH IN SHELL INDICATES PIN ONE Refer to the last page for Tape and Reel information. Model V OUT (Volts) IOUT (Amps) R/N (mVp-p) Typ. Max. Regulation (Max.) Line Load VIN Nom (Volts) Range (Volts) IIN (mA/A) Efficiency (Full Load) VIN = nom. VIN = min. Min. Typ. Typ. Package (Case Pinout) Output Input DIMENSIONS IN INCHES (mm) RoHS-6 hazardous substance compliant* * Contact Murata-PS for availability. Third Angle Projection Dimensions are in inches (mm shown for ref. only). Components are shown for reference only. Tolerances (unless otherwise specified): .XX ± 0.02 (0.5) Angles ± 2˚ LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 2 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
Input Voltage Range 3-5.5 Volts (5V nominal) Input Current: Normal Operating Conditions See Ordering Guide Inrush Transient 0.02A 2 sec Standby/Off Mode 8mA Output Short-Circuit Condition 60-110mA average (model dependent) Input Reflected Ripple Current 10-70mAp-p, model dependent Input Filter Type Capacitive Overvoltage Protection None Reverse-Polarity Protection None Undervoltage Shutdown None On/Off Control On = open to +V IN (internal pull-up to +VIN) Off = 0 to +0.4V (1mA) Output VOUT Accuracy (50% load) ±1.5% Temperature Coefficient ±0.02%/°C Minimum Loading ~ No load Maximum Capacitive Load 5000μF (electrolytic), 2000μF (0.02 Ω ESR, OSCON) VOUT Trim Range ±10% Ripple/Noise (20MHz BW) ~ See Ordering Guide Total Accuracy 3% over line/load/temperature Efficiency See Ordering Guide Overcurrent Detection and Short-Circuit Protection: Current-Limiting Detection Point 19-30 Amps (model dependent) Short-Circuit Detection Point 98% of V OUT set SC Protection Technique Hiccup with auto recovery Short-Circuit Current 600mA average Dynamic Characteristics Transient Response (50% load step) 30-70μsec to ±2% of final value (model dependent) Start-Up Time: V IN to VOUT and On/Off to VOUT 7msec Switching Frequency 300 ±50kHz Environmental Calculated MTBF TBD Operating Temperature: (Ambient) –40 to +85°C (with derating) See Derating Curves Maximum PC Board Temperature +100°C Thermal Shutdown +115°C (110 to 125°C) EMI Conducted or radiated, Class B FCC Part 15, EN55022 Safety Designed to meet UL/IEC/EN60950-1, CSA-C22.2 No. 234 Physical Pin Dimensions/Material 0.112" x 0.062" (2.84 x 1.57mm) rectangular copper with gold plate over nickel underplate Weight 0.28 ounces (7.8g) Flamability Rating UL94V-0 Performance/Functional Specifications Typical @ TA = +25°C under nominal line voltage, 200 lfm air flow, and full-load conditions unless noted. ~ ~ All models are tested/specified with external 22μF tantalum input and output capacitors.These capacitors are necessary to accommodate our test equipment and may not be required to achieve specified performance in your applications. All models are stable and regulate within spec under no-load conditions. See Technical Notes and Performance Curves for details. The On/Off Control (pin 1) is designed to be driven with open-collector logic or the application of appropriate voltages (referenced to Common, pin 3). Applying a voltage to On/Off Control when no input voltage is applied to the converter may cause permanent damage. Output noise may be further reduced with the installation of additional external output filtering. See I/O Filtering and Noise Reduction. MTBF’s are calculated using Telcordia SR-332(Bellcore), ground fixed, T A = +25°C, full power, natural convection, +67°C pcb temperature. Input Ripple Current is tested/specified over a 5-20MHz bandwidth with an external 2 x 100μF input capacitor and a simulated source impedance of 1000μF and 1μH. See I/O Filtering, Input Ripple Current, and Output Noise for details. LSM-0.75/16-W3 can not be trimmed down. Input voltage must be 4.5V minimum for 3.3V output. TECHNICAL NOTES Input Voltage: 7 Volts (3.3V OUT and "T" models) On/Off Control (Pin 1) +VIN Input Reverse-Polarity Protection None Output Overvoltage Protection None Output Current Current limited. Devices can withstand sustained output short circuits without damage. Storage Temperature –40 to +125°C Lead Temperature See Reflow Solder Profile These are stress ratings. Exposure of devices to any of these conditions may adversely affect long-term reliability. Proper operation under conditions other than those listed in the Performance/Functional Specifications Table is not implied. Absolute Maximum Ratings I/O Filtering and Noise Reduction All models in the LSM W3 Series are tested and specified with external 22μF tantalum input and output capacitors. These capacitors are necessary to accommodate our test equipment and may not be required to achieve desired performance in your application. The LSM’s are designed with high-quality, high-performance internal I/O caps, and will operate within spec in most appli- cations with no additional external components. In particular, the LSM’s input capacitors are specified for low ESR and are fully rated to handle the units’ input ripple currents. Similarly, the internal output capacitors are specified for low ESR and full-range frequency response. In critical applications, input/output ripple/noise may be further reduced using filtering techniques, the simplest being the installation of external I/O caps. External input capacitors serve primarily as energy-storage devices. They minimize high-frequency variations in input voltage (usually caused by IR drops in conductors leading to the DC/DC) as the switching converter draws pulses of current. Input capacitors should be selected for bulk capacitance (at appropri- ate frequencies), low ESR, and high rms-ripple-current ratings. The switching nature of modern DC/DC’s requires that the dc input voltage source have low ac impedance at the frequencies of interest. Highly inductive source imped- ances can greatly affect system stability. Your specific system configuration may necessitate additional considerations. LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 3 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
Many DC/DC’s using synchronous rectification suffer from Output Reverse Conduction. If those devices have a voltage applied across their output before a voltage is applied to their input (this typically occurs when another power supply starts before them in a power-sequenced application), they will either fail to start or self destruct. In both cases, the cause is the “freewheeling” or “catch” FET biasing itself on and effectively becoming a short circuit. LSM W3 SMT DC/DC converters do not suffer from Output Reverse Conduc- tion. They employ proprietary gate drive circuitry that makes them immune to moderate applied output overvoltages. Thermal Considerations and Thermal Protection The typical output-current thermal-derating curves shown below enable designers to determine how much current they can reliably derive from each model of the LSM W3 SMT’s under known ambient-temperature and air-flow conditions. Similarly, the curves indicate how much air flow is required to reli- ably deliver a specific output current at known temperatures. The highest temperatures in LSM W3 SMT’s occur at their output inductor, whose heat is generated primarily by I 2R losses. The derating curves were developed using thermocouples to monitor the inductor temperature and vary- ing the load to keep that temperature below +110°C under the assorted condi- tions of air flow and air temperature. Once the temperature exceeds +115°C (approx.), the thermal protection will disable the converter. Automatic restart occurs after the temperature has dropped below +110°C. As you may deduce from the derating curves and observe in the efficiency curves on the following pages, LSM W3 SMT’s maintain virtually constant efficiency from half to full load, and consequently deliver very impressive temperature performance even if operating at full load. Lastly, when LSM W3 SMT’s are installed in system boards, they are obviously subject to numerous factors and tolerances not taken into account here. If you are attempting to extract the most current out of these units under demanding temperature conditions, we advise you to monitor the output-inductor tempera- ture to ensure it remains below +110°C at all times. Start Up Considerations When power is first applied to the DC/DC converter, operation is different than when the converter is running and stabilized. There is some risk of start up difficulties if you do not observe several application features. Lower input volt- age converters may have more problems here since they tend to have higher input currents. Operation is most critical with any combination of the following external factors: 1 – Low initial input line voltage and/or poor regulation of the input source. 2 – Full output load current on lower output voltage converters. 3 – Slow slew rate of input voltage. 4 – Longer distance to input voltage source and/or higher external input source impedance. 5 – Limited or insufficient ground plane. External wiring that is too small. 6 – Too small external input capacitance. Too high ESR. 7 – High output capacitance causing a start up charge overcurrent surge. 8 – Output loads with excessive inductive reactance or constant current characteristics. If the input voltage is already at the low limit before power is applied, the start up surge current may instantaneously reduce the voltage at the input terminals to below the specified minimum voltage. Even if this voltage depression is very brief, this may interfere with the on-board controller and possibly cause a failed start. Or the converter may start but the input current load will now drive the input voltage below its running low limit and the converter will shut down. If you measure the input voltage before start up with a Digital Voltmeter (DVM), the voltage may appear to be adequate. Limited external capacitance and/or too high a source impedance may cause a short downward spike at power up, causing an instantaneous voltage drop. Use an oscilloscope not a DVM to observe this spike. The converter’s soft-start controller is sensitive to input voltage. What matters here is the actual voltage at the input terminals at all times. Symptoms of start-up difficulties may include failed started, output oscillation or brief start up then overcurrent shutdown. Since the input voltage is never abso- lutely constant, the converter may start up at some times and not at others. Solutions To improve start up, review the conditions above. One of the better solutions is to place a moderate size capacitor very close to the input terminals. You may need two parallel capacitors. A larger electrolytic or tantalum cap supplies the surge current and a smaller parallel low-ESR ceramic cap gives low AC imped- ance. Too large an electrolytic capacitor may have higher internal impedance (ESR) and/or lower the start up slew rate enough to upset the DC/DC’s control- ler. Make sure the capacitors can tolerate reflected switching current pulses from the converter. The capacitors will not help if the input source has poor regulation. A converter which starts successfully at 3.3 Volts will turn off if the input voltage decays to below the input voltage theshold, regardless of external capacitance. Increase the input start up voltage if possible to raise the downward voltage spike. Also, make sure that the input voltage ramps up in a reasonably short time (less than a few milliseconds). If possible, move the input source closer to the converter to reduce ohmic losses in the input wiring. Remember that the input current is carried both by the wiring and the ground plane return. Make sure the ground plane uses adequate thickness copper. Run additional bus wire if necessary. Any added output capacitor should use just enough capacitance (and no more) to reduce output noise at the load and to avoid marginal threshold noise problems with external logic. An output cap will also “decouple” inductive reac- tance in the load. Certain kinds of electronic loads include “constant current” characteristics which destabilize the output with insufficient capacitance. If the wiring to the eventual load is long, consider placing this decoupling cap at the load. Use the Remote Sense input to avoid ohmic voltage drop errors. An elegant solution to start up problems is to apply the input voltage with the Remote On/Off control first in the off setting (for those converters with an On/Off Control). After the specified start-up delay (usually under 20 mSec), turn on the converter. The controller will have already been stabilized. The short delay will not be noticed in most applications. Be aware of applications which need “power management” (phased start up). Finally, it is challenging to model some application circuits with absolute fidelity. How low is the resistance of your ground plane? What is the inductance (and distributed capacitance) of external wiring? Even a detailed mathematical model may not get all aspects of your circuit. Therefore it is difficult to give cap values which serve all applications. Some experimentation may be required. LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 7 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
Typical Performance Curves for the LSM W3 SMT Series ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 8 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
Typical Performance Curves for the LSM W3 SMT Series ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 9 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT # ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). ,3- 0OWER$ISSIPATIONVS,OAD#URRENT # ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS ,3- 7AND,3- 0OWER$ISSIPATIONVS,OAD#URRENT # 6). ,OAD#URRENT!MPS 0OWER$ISSIPATION7ATTS n ,3- 7-AXIMUM/UTPUT#URRENTVS!MBIENT4EMPERATURE 6). /UTPUT#URRENT!MPS !MBIENT4EMPERATUREo# LFM .ATURAL#ONVECTION LFM LFM ,3- %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT c#6/54 ,OAD#URRENT!MPS %FFICIENCY 6). 6). 6). Typical Performance Curves for the LSM W3 SMT Series LSM-16A W3 Models Non-Isolated, Wide Input SMT DC/DC Converters MDC_LSM-16A_W3.A04 Page 10 of 12 Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000www.murata-ps.com
quently reflowed using high-temperature, lead-free solder. low-temperature solder (usually Sn63/Pb37 with a melting point of +183°C). “cool down” the Sn63 profile you are likely using today. Figure 6. Reflow Solder Profile