Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters For full details go to www.murata-ps.com/rohs Typical unit FEATURES PRODUCT OVERVIEW Step-down, wide input buck regulators for distributed 3-5V power architectures 3V to 5.5V wide-input range LSN Series W3 are ideal building blocks for emerging, on-board power-distribution schemes in which isolated 3 to 5.5V buses deliver power to any number of non-isolated, step-down buck regulators. LSN W3 DC/DC’s accept 3 to 5.5 Volts and convert it, with the highest efficiency in the smallest space, to a 0.75, 1, 1.2, 1.5, 1.8, 2, 2.5, or 3.3 Volt output fully rated at 16 Amps. LSN W3’s are ideal point-of-use/load power processors. They typically require no external components. Their surface-mount packages occupy a mere 1.3" x 0.53" (33.0 x 13.5mm), and are only 0.34 inches (8.6mm) high. The LSN’s best-in-class power density is achieved with a fully synchronous, fixedfrequency, buck topology that also delivers: high efficiency (97%, 3.3Vout, 8A), low noise 0.75/1/1.2/1.5/1.8/2/2.5/3.3VOUT @16A Non-isolated, fixed-frequency, synchronous-rectifier topology ±1% setpoint accuracy Efficiencies to 95% @ 16 Amps Noise as low as 30mVp-p Stable no-load operation Remote on/off control Sense pin and output voltage trim No derating to +65°C with no fan UL/IEC/EN60950-1 certification pending (30mVp-p typ.), tight line/load regulation (±0.1%/±0.25% max.), quick step response (30μsec), stable no-load operation, and no output reverse conduction. The fully functional LSN’s feature output overcurrent detection, continuous short-circuit protection, over-temperature protection, a remote on/off control pin (pull low to disable), an output-voltage trim function, and a sense pin. High efficiency enables the LSN W3’s to deliver rated output currents of 16 Amps at ambient temperatures to +65°C with natural convection. If your new system boards call for multiple supply voltages, check out the economics of on-board 3-5.5V distributed power. If you don’t need to pay for multiple isolation barriers, DATEL’s non-isolated LSN W3 SMT’s will save you money. EMC compliant /54054 ).054 3%.3% #/--/. #/--/. #522%.4 3%.3% 6## /./&& #/.42/, 07#/.42/,,%2 Typical topology is shown. 2%&%2%.#% %22/2!-0 6/54 42) Figure 1. Simplified Schematic www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 1 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters Performance Specifications and Ordering Guide ~ ORDERING GUIDE Preliminary Output Models VOUT (Volts) IOUT (Amps) LSN-0.75/16-W3 LSN-1/16-W3 LSN-1.2/16-W3 LSN-1.5/16-W3 LSN-1.8/16-W3 LSN-2/16-W3 LSN-2.5/16-W3 LSN-3.3/16-W3 LSN-T/16-W3 0.75 1 1.2 1.5 1.8 2 2.5 3.3 0.75-3.3 16 16 16 16 16 16 16 16 16 Input R/N (mVp-p) Regulation (Max.) Typ. Max. Line Load VIN Nom. (Volts) 30 30 30 30 30 30 30 30 30 50 50 50 50 50 50 50 50 50 ±0.1% ±0.1% ±0.1% ±0.1% ±0.1% ±0.1% ±0.1% ±0.1% ±0.05% ±0.25% ±0.25% ±0.25% ±0.25% ±0.25% ±0.25% ±0.25% ±0.25% ±0.15% 5 5 5 5 5 5 5 5 5 ~ 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. PART NUMBER STRUCTURE P A R T N U M B E R Range (Volts) IIN (mA/A) Min. Typ. Typ. Package (Case, Pinout) 3-5.5 3-5.5 3-5.5 3-5.5 3-5.5 3-5.5 3-5.5 3-5.5 3-5.5 70/2.79 70/3.72 70/4.36 70/5.33 70/6.30 70/6.92 70/8.56 50/11.12 50/11.12 84% 84% 86% 88% 89.5% 90.5% 91.5% 93% 93% 86% 86% 88% 90% 91.5% 92.5% 93.5% 95% 95% 86.5% 86.5% 88.5% 90.5% 92% 92.5% 94% 95% 95% B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 B8/B8x, P59 MECHANICAL SPECIFICATIONS Output Configuration: L = Unipolar Low Voltage RoHS-6 compliant* Blank = Vertical Mount H = Horizontal Mount J = Reversed Pin Vertical Mount Non-Isolated SIP Nominal Output Voltage: 0.75, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3 or 0.75-3.3 Volts %130 Note: Not all model number combinations are available. Contact MPS. * Contact MPS for availability. Ò$)! Ò -). Ò$)! Ò Dimensions in inches (mm) %130 Pin 1 2 3 4 Function P59 +Output +Output +Sense +Output www.murata-ps.com ,!9/540!44%2. 4/06)%7 Case B8 Vertical Mounting (Standard) Case B8A Horizontal Mounting 2%#/--%.$%$ #/00%20!$ /.0#"31). -!8 )3/,!4).' 0!$ %130 %130 ,!9/540!44%2. 4/06)%7 -!8 -!8 Ò$)! Ò Input Voltage Range: W3 = 3-5.5 Volts (5V nominal) Maximum Rated Output Current in Amps -!8 S T R U C T U R E VIN = min 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. VIN = 4.5 Volts minimum for VOUT = 3.3 Volts. Unless noted, LSN-T/16-W3 specifications are at 3.3VOUT. L SN - 1.8 / 16 - W3 H - C %130 Efficiency (Full Load) VIN = nom. I/O Connections Pin Function P59 5 Common 6 Common 7 +Input 8 +Input Pin 9 10 11 %130 ,!9/540!44%2. 4/06)%7 Function P59 No Pin VOUT Trim On/Off Control Case B8B Reverse Pin Vertical Mounting (Tyco-compatible) Component locations are typical and may vary. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 2 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters Performance/Functional Specifications Typical @ TA = +25°C under nominal line voltage and full-load conditions unless noted. ~ Input 3-5.5 Volts (5V nominal) Input Voltage Range Input Current: Normal Operating Conditions Inrush Transient Standby/Off Mode Output Short-Circuit Condition Input Reflected Ripple Current Input Filter Type Overvoltage Protection Reverse-Polarity Protection Undervoltage Shutdown On/Off Control See Ordering Guide 0.02A2 sec 8mA 60-110mA average (model dependent) 10-20mAp-p, model dependent Capacitive None None None On = open or low (<0.4V max.) Off = high (>2.5V to VIN max.), 1mA Absolute Maximum Ratings Input Voltage: Continuous or transient Output ±1.5% VOUT Accuracy (50% load) See Technical Notes and Performance Curves for details. The On/Off Control 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, TA = +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. Setting accuracy for LSN-T/16-W3 is ±2%. Input voltage must be 4.5V minimum for 3.3V output. Temperature Coefficient Minimum Loading ~ Maximum Capacitive Load ±0.02%/°C No load 5000μF (electrolytic), 2000μF (0.027 ESR, OSCON) ±10% VOUT Trim Range See Ordering Guide Ripple/Noise (20MHz BW) ~ Total Accuracy 3% over line/load/temperature Efficiency See Ordering Guide Overcurrent Detection and Short-Circuit Protection: Current-Limiting Detection Point 20-36 Amps (model dependent) Short-Circuit Detection Point 98% of VOUT set SC Protection Technique Hiccup with auto recovery Short-Circuit Current 600mA average 6 Volts (0.75, 1, 1.2, 1.5, 1.8, 2, 2.5 VOUT) 7 Volts (3.3VOUT 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. Dynamic Characteristics Transient Response (50% load step) Start-Up Time: VIN to VOUT and On/Off to VOUT Switching Frequency 30-70μsec to ±2% of final value (model dependent) 7msec 300 ±50kHz Environmental Calculated MTBF TBD Operating Temperature: (Ambient) Without Derating (Natural convection) –40 to +63/71°C (model dependent, see Derating Curves) With Derating See Derating Curves PC-Board Temperature Thermal Shutdown +100°C maximum +115°C (110 to 125°C) Physical Dimensions Pin Dimensions/Material Weight See Mechanical Specifications 0.112" x 0.062" (2.84 x 1.57mm) rectangular tellurium copper alloy with 100-300 microinches of tin electroplate over 100 microinches of nickel underplate 0.28 ounces (7.8g) Flamability Rating UL94V-0 EMI Conducted and Radiated FCC Part 15, EN55022 Class B may require external filter Safety UL/cUL/IEC/EN 60950-1, CSA-C22.2 No.234 ~ 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. www.murata-ps.com TECHNICAL NOTES I/O Filtering and Noise Reduction All models in the LSN 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 LSN’s are designed with high-quality, high-performance internal I/O caps, and will operate within spec in most applications with no additional external components. In particular, the LSN’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 appropriate 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 impedances can greatly affect system stability. Your specific system configuration may necessitate additional considerations. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 3 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters TO OSCILLOSCOPE Input Fusing Most applications and or safety agencies require the installation of fuses at the inputs of power conversion components. The LSN W3 Series are not internally fused. Therefore, if input fusing is mandatory, either a normal-blow or a fast-blow fuse with a value no greater than twice the maximum input current should be installed within the ungrounded input path to the converter. CURRENT PROBE +INPUT LBUS + VIN CBUS CIN – As a rule of thumb however, we recommend to use a normal-blow or slow-blow fuse with a typical value of about twice the maximum input current, calculated at low line with the converter’s minimum efficiency. COMMON CIN = 2 x 100μF, ESR < 700m7 @ 100kHz CBUS = 1000μF, ESR < 100m7 @ 100kHz LBUS = 1μH Figure 2. Measuring Input Ripple Current Output ripple/noise (also referred to as periodic and random deviations or PARD) may be reduced below specified limits with the installation of additional external output capacitors. Output capacitors function as true filter elements and should be selected for bulk capacitance, low ESR, and appropriate frequency response. Any scope measurements of PARD should be made directly at the DC/DC output pins with scope probe ground less than 0.5" in length +SENSE In particular, for a non-isolated converter’s output voltage to meet SELV (safety extra low voltage) requirements, its input must be SELV compliant. If the output needs to be ELV (extra low voltage), the input must be ELV. Input Overvoltage and Reverse-Polarity Protection LSN W3 SMT Series DC/DC’s do not incorporate either input overvoltage or input reverse-polarity protection. Input voltages in excess of the specified absolute maximum ratings and input polarity reversals of longer than “instantaneous” duration can cause permanent damage to these devices. COPPER STRIP +OUTPUT C1 Safety Considerations LSN W3 SMT’s are non-isolated DC/DC converters. In general, all DC/DC’s must be installed, including considerations for I/O voltages and spacing/separation requirements, in compliance with relevant safety-agency specifications (usually UL/IEC/EN60950-1). C2 SCOPE RLOAD COMMON COPPER STRIP C1 = NA C2 = 22μF TANTALUM LOAD 2-3 INCHES (51-76mm) FROM MODULE Figure 3. Measuring Output Ripple/Noise (PARD) All external capacitors should have appropriate voltage ratings and be located as close to the converters as possible. Temperature variations for all relevant parameters should be taken into consideration. You should add only enough output capacitance to attenuate the noise to your desired level. Large amounts of output capacitance cause poor dynamic response (step load changes, etc.). Too great an output capacitor can make the converter oscillate (actually increasing the noise!) while substantial capacitance which is less than the oscillation threshold can still cause ringing and overshoot. Finally, you must use less output capacitance if the cap is a low ESR type (OSCON, etc.). The most effective combination of external I/O capacitors will be a function of your line voltage and source impedance, as well as your particular load and layout conditions. Our Applications Engineers can recommend potential solutions and discuss the possibility of our modifying a given device’s internal filtering to meet your specific requirements. Contact our Applications Engineering Group for additional details. www.murata-ps.com Start-Up Time The VIN to VOUT Start-Up Time is the interval between the time at which a ramping input voltage crosses the lower limit of the specified input voltage range and the fully loaded output voltage enters and remains within its specified accuracy band. Actual measured times will vary with input source impedance, external input capacitance, and the slew rate and final value of the input voltage as it appears to the converter. The On/Off to VOUT Start-Up Time assumes the converter is turned off via the On/Off Control with the nominal input voltage already applied to the converter. The specification defines the interval between the time at which the converter is turned on and the fully loaded output voltage enters and remains within its specified accuracy band. See Typical Performance Curves. Remote Sense LSN W3 SMT Series DC/DC converters offer an output sense function on pin 3. The sense function enables point-of-use regulation for overcoming moderate IR drops in conductors and/or cabling. Since these are non-isolated devices whose inputs and outputs usually share the same ground plane, sense is provided only for the +Output. The remote sense line is part of the feedback control loop regulating the DC/DC converter’s output. The sense line carries very little current and consequently requires a minimal cross-sectional-area conductor. As such, it is not a low-impedance point and must be treated with care in layout and cabling. Sense lines should be run adjacent to signals (preferably ground), and in cable and/or discrete-wiring applications, twisted-pair or similar techniques should be used. To prevent high frequency voltage differences between VOUT and Sense, we recommend installation of a 1000pF capacitor close to the converter. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 4 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters The sense function is capable of compensating for voltage drops between the +Output and +Sense pins that do not exceed 10% of VOUT. [VOUT(+) – Common] – [Sense(+) – Common] b 10%VOUT Power derating (output current limiting) is based upon maximum output current and voltage at the converter’s output pins. Use of trim and sense functions can cause the output voltage to increase, thereby increasing output power beyond the LSN’s specified rating. Therefore: (VOUT at pins) x (IOUT) b rated output power The internal 10.57resistor between +Sense and +Output (see Figure 1) serves to protect the sense function by limiting the output current flowing through the sense line if the main output is disconnected. It also prevents output voltage runaway if the sense connection is disconnected. Note: If the sense function is not used for remote regulation, +Sense (pin 3) must be tied to +Output (pin 4) at the DC/DC converter pins. On/Off Control and Power-up Sequencing The On/Off Control pin may be used for remote on/off operation. LSN W3 SIP Series DC/DC’s are designed so they are enabled when the control pin is left open (internal pull-down to Common) and disabled when the control pin is pulled high (+2.5V to +VIN), as shown in Figures 4 and 5. Dynamic control of the on/off function is best accomplished with a mechanical relay or open-collector/open-drain drive circuit. The drive circuit should be able to sink appropriate current when activated and withstand appropriate voltage when deactivated. For a controlled start-up of one or more LSN-W3’s, or if several output voltages need to be powered-up in a given sequence, the On/Off Control pin can be pulled high (external pull-up resistor, converter disabled) and then driven low with an external open collector device to enable the converter. Output Overvoltage Protection LSN W3 Series DC/DC converters do not incorporate output overvoltage protection. In the extremely rare situation in which the device’s feedback loop is broken, the output voltage may run to excessively high levels (VOUT = VIN). If it is absolutely imperative that you protect your load against any and all possible overvoltage situations, voltage limiting circuitry must be provided external to the power converter. Output Overcurrent Detection Overloading the power converter’s output for an extended time will invariably cause internal component temperatures to exceed their maximum ratings and eventually lead to component failure. High-current-carrying components such as inductors, FET’s and diodes are at the highest risk. LSN W3 Series DC/DC converters incorporate an output overcurrent detection and shutdown function that serves to protect both the power converter and its load. If the output current exceeds it maximum rating by typically 50% (24 Amps) or if the output voltage drops to less than 98% of it original value, the LSN W3’s internal overcurrent-detection circuitry immediately turns off the converter, which then goes into a "hiccup" mode. While hiccupping, the converter will continuously attempt to restart itself, go into overcurrent, and then shut down. Under these conditions, the average output current will be approximately 400mA, and the average input current will be approximately 40mA. Once the output short is removed, the converter will automatically restart itself. ).054 3(54$/7. K7 /./&& #/.42/, 3)'.!, '2/5.$ Output Voltage Trimming Allowable trim ranges for each model in the LSN W3 Series are ±10%. Trimming is accomplished with either a trimpot or a single fixed resistor. The trimpot should be connected between +Output and Common with its wiper connected to the Trim pin as shown in Figure 6 below. K7 #/.42/,,%2 0/7%2 #/--/. /54054 ).054 Figure 4. Driving the On/Off Control Pin with an Open-Collector Drive Circuit The on/off control function, however, can be externally inverted so that the converter will be disabled while the input voltage is ramping up and then “released” once the input has stabilized. ).054 3(54$/7. K7 05,,50 490)#!, /./&& #/.42/, K7 42)- K7 4URNS ,/!$ #/--/. #/--/. Figure 6. Trim Connections Using a Trimpot 3)'.!, '2/5.$ K7 #/.42/,,%2 0/7%2 #/--/. Figure 5. Inverting On/Off Control Pin Signal and Power-Up Sequencing www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 5 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters +OUTPUT Adjustment beyond the specified ±10% adjustment range is not recommended. When using trim in combination with Remote Sense, the maximum rated power must not be exceeded (see Remote Sense). Trim Down +INPUT TRIM LOAD Note: Install either a fixed trim-up resistor or a fixed trim-down resistor depending on desired output voltage. Trim Up COMMON COMMON Figure 7. Trim Connections Using Fixed Resistors A trimpot can be used to determine the value of a single fixed resistor which can then be connected, as shown in Figure 7, between the Trim pin and +Output to trim down the output voltage, or between the Trim pin and Common to trim up the output voltage. Fixed resistors should have absolute TCR’s less than 100ppm/oC to ensure stability. The equations below can be starting points for selecting specific trim-resistor values. Recall, untrimmed devices are guaranteed to be ±1% accurate. Trim Equations 4RIM$OWN ,3.7 4"$ n6/ RTRIM (kΩ) 2450K7 6/n 24$/7.K7 n6/ n 6/n n6/ n 6/n n6/ n 6/n n 2450K7 6/n n 6/n n6/ n 2450K7 6/n 24$/7.K7 n6/ n 6/n n6/ n 3.3V 6.947 3.16 VTRIM (in Volts) = 0.7 –(0.1698 x (VO – 0.7525)) The LSN-T/16-W3 fixed trim voltages to set the output voltage are: 2450K7 6/n n VOUT (Typ.) 0.75V VTRIM 2450K7 6/n 2450K7 6/n Open 1.0V 1.2V 1.5V 1.8V 2.5V 3.3V 0.6928V 0.624V 0.5731V 0.5221V 0.4033V 0.267V n ,3.7 24$/7.K7 80.021 41.973 23.077 15.004 2.5V The LSN-T/16-W3 may also be trimmed using an external voltage applied between the Trim input and Output Common. Be aware that the internal “load” impedance looking into the Trim pin is approximately 5k7. Therefore, you may have to compensate for this in the source resistance of your external voltage reference. n ,3.7 6/n 1.8V The equation for this voltage adjustment is: ,3.7 24$/7.K7 1.5V Voltage Trim 2450K7 ,3.7 24$/7.K7 1.2V CAUTION: To retain proper regulation, do not exceed the 3.3V output ,3.7 24$/7.K7 Open 1.0V n ,3.7 6/n The trim equation is as follows for the LSN-T/16-W3: VOUT (Typ.) 0.75V ,3.7 24$/7.K7 As with other trim adjustments, be sure to use a precision low-tempco resistor (±100 ppm/°C) mounted close to the converter with short leads. Also be aware that the output voltage accuracy is ±2% (typical) therefore you may need to vary this resistance slightly to achieve your desired output setting. LSN-T/16-W3 fixed resistance values to set the output voltages are: .O4RIM$OWN n IMPORTANT: For outputs greater than 3 Volts up to 3.3 Volts maximum, the input supply must be 4.5 Volts minimum. 21070 RTRIM (7) = _____________ –5110 VO – 0.7525 4RIM5P 6/n “T” Model (LSN-T/16-W3) This version of the the LSN-W3 series offers a special output voltage trimming feature which is fully compatible with competitive units. The output voltage may be varied using a single trim resistor from the Trim Input to Power Common. The output voltage range is 0.75 Volts to 3.3 Volts. n Note: Resistor values are in k7. Accuracy of adjustment is subject to tolerances of resistors and factory-adjusted, initial output accuracy. VO = desired output voltage. VONOM = nominal output voltage. www.murata-ps.com Output Reverse Conduction 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. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 6 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters LSN W3 DC/DC converters do not suffer from Output Reverse Conduction. They employ proprietary gate drive circuitry that makes them immune to moderate applied output overvoltages. 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. 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 LSN W3 Series under known ambient-temperature and air-flow conditions. Similarly, the curves indicate how much air flow is required to reliably deliver a specific output current at known temperatures. As you may deduce from the derating curves and observe in the efficiency curves on the following pages, LSN W3’s maintain virtually constant efficiency from half to full load, and consequently deliver very impressive temperature performance even if operating at full load. 20 Amps Extended Operation Under restricted conditions, the LSN W3 models with low output voltages may produce up to 20 Amps of output current up to approximately +45°C ambient temperature. There is no model number change. The Derating curve illustrates typical performance. For this test, the converter was mounted on a 12cm x12cm double-sided pc board with 2 ounce copper. This 20 Amp operation is available with the following restrictions: • Only 1.2 Volt and 1.5 Volt output models are verified for operation at this time. • The user must assure that there is adequate airflow at all times with no airflow blockage by other large components. Make sure no adjacent components have high temperatures. Be aware of systems using a CPU temperature monitor to control the fan. • Use only low to moderate ambient temperature. • The user must assure that the total output power is not exceeded. • This operation applies only to nominal input line voltage. Since efficiency degrades at low line voltage, internal heat dissipation increases, thereby exceeding the maximum output power. The Derating curve is drawn where the hot spot on the converter (usually a power FET) reaches approximately +115°C. Although operation is possible slightly beyond this point, DATEL strongly advises using this as the maximum temperature for greatest reliability. www.murata-ps.com ,3.7-AXIMUM/UTPUT#URRENTVS!MBIENT4EMPERATURE 6).6 /UTPUT#URRENT!MPS The highest temperatures in LSN W3’s occur at their output inductor, whose heat is generated primarily by I 2 R losses. The derating curves were developed using thermocouples to monitor the inductor temperature and varying the load to keep that temperature below +110°C under the assorted conditions of air Lastly, when LSN W3’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 temperature to ensure it remains below +110°C at all times. LFM LFM n !MBIENT4EMPERATUREo# Do not forget that a small overcurrent glitch while running 20 Amps output could instantly shut down the converter using the Over Current sensor. This margin of safety is considerably wider at 16 Amps maximum current. Make sure your output current usage is smooth!! If you are in doubt, contact DATEL to discuss your application. Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 7 of 8 Single Output LSN-W3 Models Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT 16 Amp DC/DC Converters Typical Performance Curves ,3.47 %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT c#6/546 ,3.47 %FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT c#6/546 6).6 %FFICIENCY %FFICIENCY 6).6 6).6 6).6 6).6 6).6 ,OAD#URRENT!MPS ,OAD#URRENT!MPS ,3.47-AXIMUM/UTPUT#URRENTVS!MBIENT4EMPERATURE 6/5466).6 /UTPUT#URRENT!MPS .ATURAL#ONVECTION LFM LFM LFM n !MBIENT4EMPERATUREo# USA: Tucson (AZ), Tel: (800) 547 2537, email: [email protected] Canada: Toronto, Tel: (866) 740 1232, email: [email protected] UK: Milton Keynes, Tel: +44 (0)1908 615232, email: [email protected] France: Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: [email protected] Germany: München, Tel: +49 (0)89-544334-0, email: [email protected] Murato Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 www.murata-ps.com ISO 9001 REGISTERED email: [email protected] DS-0548 11/20/07 Japan: Tokyo, Tel: 3-3779-1031, email: [email protected] Osaka, Tel: 6-6354-2025, email: [email protected] Website: www.murata-ps.jp China: Shanghai, Tel: +86 215 027 3678, email: [email protected] Guangzhou, Tel: +86 208 221 8066, email: [email protected] © 2007 Murata Power Solutions, Inc. Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MDC_LSN W3 Models.A01 Page 8 of 8