Apsm10

Transcript

Lambda’s new SM Series of Power Modules are ideally designed for Telecommunications and Network applications. APPLICATION NOTES SM10 Series of Power Modules Lambda Electronics, Inc. 515 Broad Hollow Road Melville, New York 11747 Tel: (516) 694-4200 or Toll Free: (800) LAMBDA-4/5 Fax: (516) 293-0519 REVISION HISTORY Program Manager Description Quality Manager Marketing Manager Revision Date A 4/30/98 Initial Relaese Peter Brune David Wandrey Mike Wagner B 8/11/99 Drawings Update Peter Brune David Wandrey Mike Wagner -a- LAMBDA ELECTRONICS INC. λ Table of Contents Page I. PREFACE ......................................................................................................................................... 1 A. B. Introduction .................................................................................................................................. 1 External Components.................................................................................................................... 1 II. MOUNTING PIN/DEFINITION ....................................................................................................... 1 III. BLOCK DIAGRAM.......................................................................................................................... 2 IV. FUNCTIONAL DESCRIPTION........................................................................................................ 2 A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T. U. V. W. X. V. Operational................................................................................................................................... 2 Output Voltage Adjustment........................................................................................................... 3 Output Voltage and Noise Measurement Method .......................................................................... 4 Input EMI Filter ........................................................................................................................... 4 Maximum Line Regulation ........................................................................................................... 4 Maximum Load Regulation........................................................................................................... 4 Over Voltage Protection (OVP)..................................................................................................... 4 Remote On/Off ............................................................................................................................. 5 Parallel Operation......................................................................................................................... 5 Series Operation ........................................................................................................................... 5 In Rush Current ............................................................................................................................ 6 Operating Humidity ...................................................................................................................... 6 Storage ......................................................................................................................................... 7 Altitude ........................................................................................................................................ 7 Cooling Method............................................................................................................................ 7 Short Circuit................................................................................................................................. 7 High Voltage Potential Testing (Hi-Pot)........................................................................................ 7 Isolation Resistance ...................................................................................................................... 7 Vibration Specification ................................................................................................................. 7 Shock Specification....................................................................................................................... 7 Efficiency ..................................................................................................................................... 8 Cross Regulation........................................................................................................................... 8 Drop Test...................................................................................................................................... 8 ESD.............................................................................................................................................. 8 LAYOUT INSTRUCTIONS.............................................................................................................. 8 A. B. Patterns for PCB ........................................................................................................................... 8 Recommended Reflow Solder Profiles........................................................................................... 8 Exhibit A........................................................................................................................................... 9 Exhibit B......................................................................................................................................... 10 Exhibit C......................................................................................................................................... 10 C. Recommended Soldering To Different Metal Finishes................................................................. 10 D. Recommended De-Soldering Tool............................................................................................... 11 VI. OUTPUT DERATING .................................................................................................................... 12 -i- LAMBDA ELECTRONICS INC. λ Table of Contents Page VII. A. B. C. D. E. TROUBLESHOOTING .............................................................................................................. 12 No Output................................................................................................................................... 12 High Output Voltage................................................................................................................... 12 Low Output Voltage.................................................................................................................... 12 Excessive Output Ripple ............................................................................................................. 12 Excessive Load/Line Regulation ................................................................................................. 12 - ii - LAMBDA ELECTRONICS INC. I. λ PREFACE A. Introduction The Lambda SM10 series are 10 watt surface mount DC-DC power converters. This new product line includes 12 DC-DC converters. OEM designers have access to a wide range of converters for on board power applications. In order to get the most benefit out of the SM series for your specific application, please look over this entire set of notes before proceeding. B. II. External Components 1. Input Fuse: An internal input fuse is not provided with the SM Series. To ensure safe operation, please attach an external fuse (Fast Blow type or Normal Type) to the ungrounded input line for each module. Recommended Fuse Standard Current Rating SM10 24V models 1.0 A SM10 48V models 0.5 A 2. Input Reversal: Accidentally reversing the input connections could damage the module. This should be a voided by using a protective diode and input fuse as shown below. MOUNTING PIN/DEFINITION SM_Applic_Notes Page 1 of 12 Rev. B LAMBDA ELECTRONICS INC. Pin 1 2 3 4 5 6 7 8 9 10 11 12 SM10 SINGLE OUTPUT Function Pin Thermal 13 Thermal 14 Vin 15 Vin 16 Thermal 17 Thermal 18 Thermal 19 Vin + 20 Vin + 21 Thermal 22 No Conn 23 Rem ON/OFF 24 III. BLOCK DIAGRAM Function Rem Prg Thermal Thermal Vout + Vout + Vout + Thermal Vout Vout Vout Thermal Thermal λ Pin 1 2 3 4 5 6 7 8 9 10 11 12 SM10 DUAL OUTPUT Function Pin Thermal 13 Thermal 14 Vin 15 Vin 16 Thermal 17 Thermal 18 Thermal 19 Vin + 20 Vin + 21 Thermal 22 No Conn 23 Rem ON/OFF 24 Function Rem Prg Thermal Vout + Vout + Thermal Common Common Common Thermal Vout Vout Thermal Switching Frequency: 330kHz (fixed) IV. FUNCTIONAL DESCRIPTION A. Operational 1. Input Voltage Range: The input voltage range of the SM Series is 18-36 VDC for 24V input models and 36-75 VDC for 48V input modules. 2. Input Voltage Ripple Specification: Peak to peak ripple should be minimized to under 1Vp-p. In addition, peak input should not exceed the maximum input voltage range, as stated above. Vp-p less than 1V Input Vltg Time SM_Applic_Notes Page 2 of 12 Rev. B LAMBDA ELECTRONICS INC. B. λ 3. Input Fuse (F1): An external input fuse is not provided in the power module. To ensure safe operation and protection to the module, an external fuse is recommended. The fuse should be installed in line with the ungrounded input. 4. Startup Voltage and Dropout Voltage: The SM series of module can sense the input voltage. Startup voltage on 24V models ranges from 16.5V to 18V; dropout voltage is from 15V to 17V. The startup voltage on the 48V models ranges from 34.5V to 36V; dropout voltage is from 30V to 33.5V. Output Voltage Adjustment The SM series outputs are adjustable to ±10% of Vout nominal. Output voltage adjustment is obtained via the combination of the internal programming string circuit and an external resistance (Rt.). The formulas below were derived from the two circuits below. Please refer to them or the graphs for output adjustment. A resistor is placed from the remote voltage program pin to -Vo for increasing output voltage, and to +Vo for decreasing output voltage. Adjustment for Decreasing Output Voltage Voltage Adjustment for Increasing Output Voltage RT= R3 Vref Vout-Vref R1 RT= Vout - Vref Vref R2 Vref R2 Output Voltage 3.3V 5V 12V 15 R3 Vout-Vref R1 R1 787 2.46K Single Dual 9.42K 21.3K 12.4K 27.4K R3 1K 9.42K Single Dual 17.8K 20K 17.8K 21.3K NOTE: For all SM Modules, the value for R2 is 2.49k, and the reference voltage (Vref) is 2.5V. Vout = output voltage ( for single output models). Vout = 2x output voltage ( for dual output models). SM_Applic_Notes Page 3 of 12 Rev. B LAMBDA ELECTRONICS INC. C. λ Output Voltage and Noise Measurement Method The measurement method for output voltage and ripple is base on EIAJ RC-90023A. When measuring the ripple voltage, make sure that the oscilloscope probe leads are not too long. If there is influence from other machinery, a precise measurement cannot be made. Also, depending on the frequency area of the oscilloscope, there can be considerable change in the measurements. Install a film capacitor (1µF) at a distance of 5cm from the output terminals of the power module. Place the EIAJ attachment with a coaxial cable across the film capacitor, and measure the output peak to peak ripple voltage. Use a 100MHz oscilloscope. D. Input EMI Filter An external input filter is required to meet class “B” conducted EMI limits. For a recommended filter circuit and PCB layout see the instruction manual. E. Maximum Line Regulation This is the maximum value that the output voltage will change when the input voltage is varied slowly within the input voltage range. F. Maximum Load Regulation This is the maximum value that the output voltage will change when the output current is varied slowly within the input voltage range. Dynamic Load: After the application of 25% step load change in output current, output voltage will stay within 2% of preset value recovering to within 1% in less than millisecond after the application of transient. G. Over Voltage Protection (OVP) The SM Series is equipped with an OVP circuit which prevents damage to the load caused by excessive power supply output voltage. If the output voltage rises above the OVP detection voltage, the output will clamp to specified OVP value. When confirming the OVP function, be sure to use the output variation function (TRM) to raise the output voltage. If an output external voltage is applied to the output terminals as a configuration method, the converter could be damaged. We highly recommend that you do not use this method. SM_Applic_Notes Page 4 of 12 Rev. B LAMBDA ELECTRONICS INC. H. λ Remote On/Off A standard remote ON/OFF control circuit is provided in the primary circuit. For secondary control, isolation can be achieved through the use of an optocoupler or relay. +Vin -Vin Relay or Transistor ON/OFF Remote ON/OFF Level for INPUT -SG Open Short I. ON/OFF Output On Off Parallel Operation Multiple SM modules can be connected in parallel only with resistors or diodes as shown on the picture. 1) Select R1,R2 . 2) Install a variable resistor from Remote Programming pin to Vo- to adjust output voltage. 3) Adjust output voltage to make V1=V2 in order to make both converters share the output current. J. Series Operation All SM modules allow for series operation with any combination of output voltages. Example: Vout desired = 30V Iout desired = 2A SM_Applic_Notes Page 5 of 12 Rev. B LAMBDA ELECTRONICS INC. λ The maximum output voltage available with a standard SM module is 15V. Therefore, two modules can be connected in series to provide 30V. +/- Output Series Operation When the load on the positive side is isolated from the load on the negative side, the following connection hookup is recommended. Note that bypassing diodes are not needed when operating in this mode. +V + - -V Load +V + -V - Series Operation for High Output Voltage Applications When using SM modules in a high voltage configuration, external bypassing diodes need to be connected to prevent a reverse voltage from being applied to either module. Note that high voltage series operation can be used up to a maximum of 500 Vdc. K. • Peak Reverse Voltage VRRM>2x the power module output voltage • Average Output Current Io>twice the power module output current • Forward Voltage VF=minimum (schottky barrier type recommended) + -V D1 + - D2 + - In Rush Current All modules meet the requirements for inrush current as specified by ETSI-300-132. Max surge current as defined by ETSI-300-132 is 48 Amps. L. Operating Humidity Avoid the buildup of condensation on or in the power module. This could lead to malfunction or damaged of the module. SM_Applic_Notes Page 6 of 12 Rev. B LAMBDA ELECTRONICS INC. M. N. λ Storage 1. Temperature: Please note that sudden temperature changes can cause condensation buildup, or other harmful conditions to terminal solder. 2. Humidity: High temperature and humidity can cause the terminals on the module to oxidize. The quality of the solder can decrease. Please take care with the method of storage you use. Altitude 10,000 feet maximum operating 45,000 feet maximum storage O. Cooling Method Insert the DC-DC converter into the P.C. Board and mount vertically. The converter will operate under specified conditions using natural convection with no additional airflow required. P. Short Circuit Units will withstand short circuit conditions for a maximum of 30 seconds (@ nominal input, 25°C). Q. High Voltage Potential Testing (Hi-Pot) Input to output (48 volt input) ....... 900 VAC 1500 VDC Input to output (24 volt input) ....... 500 VAC 700 VDC R. Isolation Resistance Input to output (48 volt input)..................... 106 Ohms, minimum S. Vibration Specification 2.5 G-rms, 10 Hz-500Hz sweep vibration, for a period of 1 hour per axis. T. Shock Specification IEC68-27 SM_Applic_Notes Page 7 of 12 Rev. B LAMBDA ELECTRONICS INC. U. Efficiency SM10-24V Models SM10-48V Models V. λ Output 3.3V Single 5V Single 12V/15V Single All Duals Output 3.3V Single 5V Single 12V/15V Single All Duals Efficiency 76% 78% 80% 80% Efficiency 76% 80% 80% 80% Cross Regulation Current change from 10%-100% of full load on positive output will result in less than 3.0% (Max.) change in the negative output voltage. W. Drop Test GR63-Core X. ESD All SM modules, when installed per recommended methods are not ESD sensitive devices and meet the requirements of ENC61000-4-2 severity level 3 and 4. V. LAYOUT INSTRUCTIONS A. Patterns for PCB B. Recommended Reflow Solder Profiles Today most reflow solder furnaces use forced convection as the heat transfer technique but passive infrared and straight infrared (IR) systems are still encountered. Vapor phase reflow systems are seldom encountered in today’s surface mount assembly lines. It does not matter what type of reflow system is used; the heat transfer technique to reflow solder on the printed wiring board (PWB) is still basically the same. Heat is transferred from the heat source to the PWB surface, to the pads melting the solder paste, which forms the required solder joint. Source temperature or furnace set points are higher than the resulting PWB surface with the exception of vapor phase soldering where the temperatures are the same. It is not uncommon to see 30oC or more temperature differences between furnace set points and actual SM_Applic_Notes Page 8 of 12 Rev. B LAMBDA ELECTRONICS INC. λ PWB surface temperatures. Reliable solder joints require accurate profiles to be run to insure that the solder pads reach required temperatures for adequate periods of time. Proper profiles require several thermocouples be attached to points on the PWB to insure that each portion of the PWB is reaching proper temperatures for the right amount of time. Thermocouples need to be 36 gage or approximately .004” or .1mm in diameter. This insures that the thermocouple mass does not interfere with accurate readings. Thermocouples need to be embedded into high temperature solder on a lead or component pad, typically 10/88/2 or 10% Sn, 88% Pb, and 2% Ag is ideal to attach thermocouples. Loose thermocouple wire can be taped to the PWB surface with high temperature tape. Leads of SM power supplies cannot exceed 220oC so its components do not undergo secondary reflow, which would damage the supply. Profiling a PWB should include a thermocouple attached to a SM lead, a component pad near a corner of the PWB and at a minimum of one more attached to a component pad near the center of the PWB. These points need to be monitored to insure that the hottest portion of the PWB or corner does not get to potentially harmful temperatures while the coolest portion of the PWB or board center or SM lead is hot enough to insure proper reflow of the solder paste. Typically 63/37 solder needs to be above 205oC to insure low viscosity and good intermetallic compound (IMC) layer formation. Temperatures above 230oC can be harmful to plastic molded integrated circuits (plastic package cracking) and lead to excessive IMC formation. Most solder paste manufacturers recommend dwell times above the solder liquidus temperature or 186oC for 63/37 solder of approximately 45 to 60 seconds with peak temperatures of 210 to 220oC. These are measured temperatures on the PWB surface and not furnace set points. SM Unit’s electronics can withstand all standard cleaning method available for Electronic Manufacturing Processes. Exhibit A (Before Reflow) CORNER CENTER PIN SM_Applic_Notes Page 9 of 12 Rev. B LAMBDA ELECTRONICS INC. λ Exhibit B REFLOW PROFILE 220 Thermocouples Locations 200 180 Degrees°C 160 140 Pin 120 Corner 100 Center 80 60 40 20 9:23 9:23 9:22 9:22 9:22 9:21 9:21 9:21 9:20 9:20 9:20 9:19 9:19 9:19 9:18 9:18 0 Tim e Exhibit C (After Reflow) C. Recommended Soldering To Different Metal Finishes Electronic components and printed wiring boards (PWB) are available with a variety of lead finishes including solder, typically 60/40, pure tin, gold flash over nickel, silver over nickel and palladium over nickel. Solder finish and pure tin are the most common followed by gold flash. Silver and palladium finished PWB and components are less common but are also encountered. SM_Applic_Notes Page 10 of 12 Rev. B LAMBDA ELECTRONICS INC. λ Soldering and solder wetting to a surface finish are two different phenomena and must be considered separately. Solder wetting to a finish like gold, silver or palladium involves the molten solder in a solder process alloying with those materials. For soldering to take place, tin which is the active metal in the solder, needs to alloy with the base metal of copper or nickel and not the precious metal layer. This resulting alloy is an intermetallic compound (IMC) that is the result of solid state diffusion of tin into that base metal. Once the solder has wet to a finish, the precious metal finish needs to be dissolved into the solder to then allow tin to diffuse into the base metal of copper or nickel. So gold, silver and palladium over nickel components and boards need to be soldered at slightly higher temperatures and for slightly longer periods of time. This insures dissolution of the precious metal finish into the solder and to allow tin diffusion into the base metal to form the required IMC layer in a solder joint. Solder and tin plated surfaces do not pose problems because IMC layers form even at room temperature and is accelerated at soldering temperatures. During the soldering process solder plated surfaces wet to the solder and an IMC has already been formed. Tin plated surfaces also have the required IMC. Reflow temperatures do not need to reach the melting temperature of tin because it rapidly dissolves into the solder. Also the solder does not need to completely dissolve the tin layer but just wet to it because an IMC layer has already formed. Tin rapidly dissolves into the solder forming a very slightly tin rich solder as a result of it alloying with the base solder. Typical tin plate thickness ranges 80–120 micro inch or 2-3 microns. Solder mass on a pad from solder paste screened on prior to reflow has typically 30 to 40 times more solder. The resulting solder alloy from dissolving thin tin plating into the solder joint is still nearly that of the starting solder. Nickel-plated copper leads are used on the SM series of power supplies to eliminate excessive tin copper intermetallic layers from forming. Tin-nickel IMC layers form at much lower rates at commonly encountered soldering and use temperatures than do tin-copper layers. Intermetallic compound layers are very brittle and can fracture if they are too thick. Nickel is commonly used as a diffusion barrier to protect the copper lead frame. Nickel plated copper leads are used to minimize IMC formation during all solder and repair temperature cycles and still provide a solderable surface. The SM power supply has copper lead frames, which is soldered to the customer’s Printed Circuit Board, to provide a more compliant mechanical interface. D. Recommended De-Soldering Tool For all SM soldering and de-soldering rework requirements, custom nozzles designed for the Air-Vac DRS24 series automated rework system can be ordered directly from Air-Vac as follows: Model Air-Vac Part Number SM10 SM20 SM30 N2510B2510BA N1810B1810BA N1410B1410BA Address: Air-Vac Engineering Company Inc. 30 Progress Avenue Seymour, CT 06493 Telephone: (203) 888-9900 SM_Applic_Notes Page 11 of 12 Rev. B LAMBDA ELECTRONICS INC. VI. OUTPUT DERATING O ut p ut 100% P o w er 0% -20° -10° 0° 10° 20° 30° 40° 50° Temperature (°°C) 5V, 12V, 15V Outputs VII. λ 60° 70° 80° 90° 100° 3.3V Outputs TROUBLESHOOTING A. No Output • • • • B. Is the standard input voltage being applied? Is the ON/OFF control properly connected? If the remote programming function is being used, is the connection, setup, resistance and variable resistance correct? Are there any abnormalities with the connected load? High Output Voltage If the remote programming function is being used, is the connection, setup, resistance, and variable resistance correct? C. Low Output Voltage • • • • D. Excessive Output Ripple • • E. Is the measurement method the same or similar to the one specified in this manual? Is the input ripple within the input ripple specified value? Excessive Load/Line Regulation • • SM_Applic_Notes Is the standard input voltage being applied? Is the output voltage being measured at the output terminal? If the remote programming function is being used, is the connection, setup, resistance and variable resistor correct? Are there any abnormalities with the connected load? Is the measurement method the same or similar to the one specified in this manual? Is the input ripple within the input ripple specified value? Page 12 of 12 Rev. B