(R) (R) INNOVATION and EXCELLENCE Single Output ULE 20A Models Isolated, High-Density, Eighth-Brick 5-20 Amp, DC/DC Converters Features New 1/8-brick package, 1/4-brick pinout in through-hole or SMT version 0.89 x 2.22 x 0.36 in. (22.6 x 56.4 x 9.1mm) Output current: 5-20 Amps Output voltages: 1.2/1.5/1.8/2.5/3.3/5/12V Input voltage: 24V and 48V nominal Interleaved, synchronous-rectifier topology delivers: * Outstanding efficiency (to 92%) * Low noise (50-70mVp-p) * Stable no-load operation * No output reverse conduction Excellent thermal performance On/off control, trim and sense pins Fully isolated (2250Vdc BASIC) Fully I/O protected; Thermal shutdown UL/EN/IEC60950 certification requested DATEL's new ULE Series "Eighth-Brick" DC/DC Converters are high-current isolated power converters designed for use in high-density system boards. Measuring just 0.89 x 2.22 x 0.36 inches ( 22.6 x 56.4 x 9.1mm), these open-frame, low-profile E-bricks fit the industry-standard quarter-brick footprint. Now you can "cut-and-paste" the layout from your last Q-brick design to save time and save 44% board space (1.86 square inches versus 3.3) in the process. From an 18-36V or 36-75V input, ULE's deliver 1.2, 1.5, 1.8, 2.5, or 3.3 Volt outputs fully rated at 20 Amps (5V @ 12A and 12V @ 5A). They employ an interleaved, synchronous-rectifier topology that exploits 100% of their duty cycle. They simultaneously achieve high efficiency (to 92%), low noise (50-70mVp-p), tight line/load regulation (0.25%), and quick step response (150sec). An open-frame design, high efficiency, low-on-resistance FET's, and planar magnetics embedded in heavy-copper pc boards all contribute to impressive thermal derating. All ULE's deliver full power to +70C with a mere 100lfm (0.5m/s) air flow. The ULE's feature set includes high isolation (2250Vdc, 48V models), input pi filters, input undervoltage shutdown, output overvoltage protection, current limiting, short-circuit protection, and thermal shutdown. The standard footprint carries VOUT trim, on/off control, and sense pins. All ULE E-Bricks are designed to meet the BASIC-insulation requirements of UL/EN/IEC60950, and all "D48" models (36-75V input ranges) will carry the CE mark. Safety certifications, EMC compliance testing and qualification testing (including HALT) are currently in progress. Contact DATEL for latest updates. +SENSE (7) +VOUT (8) +VIN (3) SWITCH CONTROL -VOUT (4) -VIN (1) -SENSE (5) PWM CONTROLLER REMOTE ON/OFF CONTROL* (2) INPUT UNDERVOLTAGE, INPUT OVERVOLTAGE, AND OUTPUT OVERVOLTAGE COMPARATORS OPTO ISOLATION REFERENCE & ERROR AMP VOUT TRIM (6) * Can be ordered with positive ("P" suffix) or negative ("N" suffix) polarity. Figure 1. Simplified Schematic DATEL, Inc., Mansfield, MA 02048 (USA) * Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 * Email: sales@datel.com * Internet: www.datel.com ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Performance Specifications and Ordering Guide Input Output R/N (mVp-p) Load VIN Nom. (Volts) Range (Volts) IIN (mA/A) Min. Typ. Package (Case, Pinout) 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.1% 0.25% 48 48 48 48 24 48 12 24 48 12 24 48 24 48 36-75 36-75 36-75 36-75 18-36 36-75 10-18 18-36 36-75 10-18 18-36 36-75 18-36 36-75 50/0.6 50/0.7 40/0.9 50/1 55/2.5 50/1.2 TBD 50/3.1 50/1.6 TBD 50/2.3 50/1.4 55/2.81 60/1.4 84% 85% 84.5% 85% TBD 86.5% TBD 87% 87% TBD 87.5% 88.5% 86.5% 90% 86% 87% 86% 87% 87% 88% 88% 89% 89% 89% 90% 90.5% 89% 92% C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52,P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 C56, C52, P32 Regulation (Max.) Model VOUT (Volts) IOUT (Amps) Typ. Max. Line ULE-1.2/20-D48 ULE-1.5/20-D48 ULE-1.8/20-D48 ULE-2/20-D48 ULE-2.5/20-D24 ULE-2.5/20-D48 ULE-3.3/20-D12 ULE-3.3/20-D24 ULE-3.3/20-D48 ULE-5/10-D12 ULE-5/12-D24 ULE-5/12-D48 ULE-12/4.2-D24 ULE-12/5-D48 1.2 1.5 1.8 2 2.5 2.5 3.3 3.3 3.3 5 5 5 12 12 20 20 20 20 20 20 20 20 20 10 10 12 4.2 5 50 50 40 50 50 50 50 50 50 50 50 50 50 70 100 100 80 100 100 100 100 100 100 100 100 100 100 140 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.25% 0.1% 0.25% Typical at TA = +25C under nominal line voltage and full-load conditions, unless otherwise noted. All models are tested and specified with external output capacitors (1F multi-layer ceramic in parallel with 10F tantalum). Add "N" or "P" to the part number for Remote Control Polarity. See Part Number Structure. Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth. Efficiency 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. (Load step = 50%.) Nominal line voltage, no load/full load conditions. Contact DATEL for availability. Half load output is 18VIN minimum. Full load output is 20VIN minimum. M E C H A N I C A L S P E C I F I C AT I O N S TOLERANCES: 3 decimal places = 0.005 inches 2 decimal places = 0.01 inches Unless otherwise stated. Case C56 Through-Hole Package I/O Connections Pin Function P32 1 -Input 2 On/Off Control * 3 +Input 4 -Output 5 -Sense 6 Output Trim 7 +Sense 8 +Output * The Remote On/Off can be provided with either positive (P suffix) or negative (N suffix) polarity. Case C52 Surface-Mount Package PA R T N U M B E R S T R U C T U R E U LE - 1.8 / 20 - D48 N M Lx Output Configuration: U = Unipolar/Single Pin Length Option: Through-hole packages only (100 pcs. minimum quantity) L1 Pin length 0.110 0.010 inches (2.79 0.25mm) L2 Pin length 0.145 0.010 inches (3.68 0.25mm) Eighth-Brick Package Nominal Output Voltage: 1.2/1.5/1.8/2.5/3.3/5/12 Volts Surface-Mount Package Contact DATEL for availability Maximum Rated Output Current in Amps Input Voltage Range: D12 = 10-18 Volts (12V nominal) D24 = 18-36 Volts (24V nominal) D48 = 36-75 Volts (48V nominal) 2 Remote On/Off Control Polarity: Add "P" for positive polarity (pin 2 open = converter on) Add "N" for negative polarity (pin 2 open = converter off) Note: Not all model number combinations are available. Contact DATEL. ULE Models 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Performance/Functional Specifications Short Circuit Detection Typical @ TA = +25C under nominal line voltage and full-load conditions, unless noted. Short Circuit Protection Method Hiccup with autorecovery, See Tech Notes Short Circuit Current 2-5 Amps (model dependent) Short Circuit Duration Continuous, output shorted to ground Overvoltage Protection: ULE-1.8/20-D48 ULE-2.5/20-D48 ULE-3.3/20-D48 ULE-5/12-D24 ULE-5/12-D48 Method: magnetic feedback 3Vdc 3Vdc 3.96Vdc 6Vdc 6.4Vdc Capacitive Load (ESR = 0.02 maximum) 10,000F typical 15,000F maximum Input Input Voltage Range: D12 Models D24 Models D48 Models 10-18 Volts (12V nominal) 18-36 Volts (24V nominal) 36-75 Volts (48V nominal) Start-Up Threshold: D12 Models D24 Models D48 Models 9-10 Volts (9.6V typical) 18-20 Volts (19V typical) 31-36 Volts (35V typical) Undervoltage Shutdown: D12 Models D24 Models D48 Models 8.5-9.5 Volts (9V typical) 16.5-18.5 Volts (17.5V typical) 32.5-34.5 Volts (33.5V typical) Input Current: Normal Operating Conditions Standby Mode (Off, Under Voltage) Output Short-Circuit Condition Low Line Voltage (VIN = VMIN): ULE-1.8/20-D48 ULE-2.5/20-D48 ULE-3.3/20-D48 ULE-5/12-D24 ULE-5/12-D48 See Note 6 Dynamic Characteristics See Ordering Guide 1-8mA (model dependent) 40-250mA (model dependent) 1.08 Amps 1.50 Amps 2.05 Amps 3.31 Amps 1.82 Amps Dynamic Load Response: (50-75-50% load step to 2% of VOUT) 200-250Sec, model dependent. Start-Up Time: On/Off or VIN on to VOUT 90mSec for VOUT = nominal Switching Frequency: ULE-1.8/20-D48 ULE-2.5/20-D48 ULE-3.3/20-D48 ULE-5/12-D24 ULE-5/12-D48 340kHz 10% 400kHz 10% 365kHz 10% 485kHz 10% 450kHz 10% Environmental Input Reflected Ripple Current 15-25mAp-p (model dependent) Calculated MTBF Input Filter Type LC type Overvoltage Protection None Operating Temperature Range (Ambient) No derating, natural convection (50-100 lfm self-cooling) +60 to +75C, model dependent, see derating curves With derating See derating curves Storage Temperature Range -40 to +125C Reverse-Polarity Protection 5A max., 10sec max. via external fuse No-load Input Current 16-90mA (model dependent) Remote On/Off Control: Positive Logic ("P" suffix models) OFF = ground pin or +0.8 V max. ON = open pin or +VIN max. ON = ground pin or +0.8 V max. OFF = open pin or +VIN max. Negative Logic ("N" suffix models) Remote Control On/Off Current 1mA pulldown Sense Input Range +10% of VOUT Total Output Power (VOUT x IOUT must not exceed maximum power): ULE-1.8/20-D48 36.36 Watts ULE-2.5/12-D48 50.50 Watts ULE-3.3/20-D48 66.83 Watts ULE-5/12-D24 60.60 Watts ULE-5/12-D48 60.75 Watts 1.25% (except 1.5% 1.8V) 0.02% of VOUT per C Minimum Loading No minimum load Ripple/Noise (20MHz bandwidth) See Ordering Guide Line/Load Regulation See Ordering Guide Efficiency See Ordering Guide VOUT Trim Range -15% to +10% Isolation Voltage, input/ouput: D12 and D24 models D48 models 1500 Vdc min. 2250 Vdc min. Isolation Safety Rating Basic Isolation Resistance 100M Isolation Capacitance 470-1750pF (model dependent) Current Limit Inception (98% of VOUT): ULE-5/12-D24 ULE-5/12-D48 20 Amp models 16A (cold start), 15A (warmed up) 18A (cold start), 16A (warmed up) 26A (cold start), 24A (warmed up) Thermal Protection/Shutdown 120C Altitude 0 to 10,000 feet Relative Humidity 10% to 90%, non-condensing Physical Output Voltage Output Accuracy (50% load): Initial Temperature Coefficient TBD Hours Outline Dimensions See Mechanical Specifications Pin Material (Through-hole model) Round copper with tin-lead plate over nickel underplate Weight TBD ounces Flammability Rating UL94V-0 Electromagnetic Interference FCC Part 15, EN55022, (conducted or radiated) Class B Safety UL/cUL 60950 CSA-C22.2 No.234 IEC/EN 60950 All models are tested and specified with external 22F tantalum input capacitor and 10F/ 1F tantalum/ceramic 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. Standard airflow is 300 lfm for extended operation. Input Ripple Current is tested and specified over a 5-20MHz bandwidth. Input filtering is CIN = 33F, CBUS = 220F, LBUS = 12H. Current limit inception is given at either cold start-up or after warm-up. Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3, ground fixed conditions, TCASE = +25C, full load, natural air convection. The On/Off Control may be driven with open-collector logic or by applying appropriate external voltages referenced to Common. The On/Off Control Input should use either an open collector/open drain transistor or logic gate which does not exceed +VIN. Short circuit shutdown begins when the output voltage degrades approximately 2% from the selected setting. Note that Maximum Power Derating curves indicate an average current at nominal input voltage. At higher temperatures and/or lower airflow, the DC/DC converter will tolerate shorter full current outputs if the total RMS current over time does not exceed the Derating curve. The user must install an external fuse in series with the input to protect against reverse polarity. See Input Fusing. 3 ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S All D12 models will start-up at 9.6V typically and will then work within specifications from 10-18V. Absolute Maximum Ratings Input Voltage: Continuous: 12 Volt input models 24 Volt input models 48 Volt input models Transient (100 mSec. Max.) 12 Volt input models 24 Volt input models 48 Volt input models Start-Up Time 18 Volts 36 Volts 75 Volts The VIN to VOUT Start-Up Time is the interval of time between the point at which the ramping input voltage crosses the Start-Up Threshold 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/output capacitance, and load. The ULE Series implements a soft start circuit that limits the duty cycle of its PWM controller at power up, thereby limiting the input inrush current. 25 Volts 50 Volts 100 Volts On/Off Control (pin 2) +VIN Input Reverse Polarity Protection 5 Amps, 10 sec. max. Output Overvoltage Protection Magnetic feedback. See note (7). Output Current * Current-limited. Devices can withstand sustained short circuit without damage. Storage Temperature -40 to +125C. Lead Temperature +300C, 10 seconds max. Refer to solder profile. The On/Off Control to VOUT start-up time assumes the converter has its nominal input voltage applied but is turned off via the On/Off Control pin. The specification defines the interval between the point at which the converter is turned on and the fully loaded output voltage enters and remains within its specified accuracy band. Similar to the VIN to VOUT start-up, the On/Off Control to VOUT start-up time is also governed by the internal soft start circuitry and external load capacitance. 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. The difference in start up time from VIN to VOUT and from On/Off Control to VOUT is therefore insignificant. Input Source Impedance * The outputs are not intended to sink appreciable current. If the outputs are forced to sink excessive current, damage may result. T E C H N I C A L ULE converters must be driven from a low ac-impedance input source. The DC/DC's performance and stability can be compromised by the use of highly inductive source impedances. The input circuit shown in Figure 2 is a practical solution that can be used to minimize the effects of inductance in the input traces. For optimum performance, components should be mounted close to the DC/DC converter. If the application has a high source impedance, low VIN models can benefit of increased external input capacitance. N O T E S Input Fusing Certain applications and/or safety agencies may require the installation of fuses at the inputs of power conversion components. Fuses should also be used if the possibility of sustained, non-current-limited, input-voltage polarity reversals exist. For DATEL ULE 24-60 Watt DC/DC Converters, you should use slow-blow type fuses, installed in the ungrounded input supply line, with values no greater than the following. Model 12 Volt Input 24 Volt input 48 Volt Input I/O Filtering, Input Ripple Current, and Output Noise All models in the ULE 24-60 Watt DC/DC Converters are tested/specified for input reflected ripple current and output noise using the specified external input/output components/circuits and layout as shown in the following two figures. Fuse Values 10 Amps 5 Amps 4 Amps External input capacitors (CIN in Figure 2) serve primarily as energy-storage elements, minimizing line voltage variations caused by transient IR drops in conductors from backplane to the DC/DC. Input caps should be selected for bulk capacitance (at appropriate frequencies), low ESR, and high rms-ripplecurrent ratings. The switching nature of DC/DC converters requires that dc voltage sources have low ac impedance as highly inductive source impedance can affect system stability. In Figure 2, CBUS and LBUS simulate a typical dc voltage bus. Your specific system configuration may necessitate additional considerations. All relevant national and international safety standards and regulations must be observed by the installer. For system safety agency approvals, the converters must be installed in compliance with the requirements of the end-use safety standard, e.g. IEC/EN/UL60950. Input Undervoltage Shutdown and Start-Up Threshold Under normal start-up conditions, devices will not begin to regulate until the ramping-up input voltage exceeds the Start-Up Threshold Voltage. Once operating, devices will not turn off until the input voltage drops below the Undervoltage Shutdown limit. Subsequent re-start will not occur until the input is brought back up to the Start-Up Threshold. This built in hysteresis prevents any unstable on/off situations from occurring at a single input voltage. 4 ULE Models 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S TO OSCILLOSCOPE CURRENT PROBE +SENSE +INPUT +OUTPUT LBUS + VIN CBUS COPPER STRIP CIN C1 - -INPUT C2 SCOPE RLOAD -OUTPUT CIN = 33F, ESR < 700m @ 100kHz CBUS = 220F, ESR < 100m @ 100kHz LBUS = 12H -SENSE COPPER STRIP C1 = 0.47F CERAMIC C2 = NA LOAD 2-3 INCHES (51-76mm) FROM MODULE Figure 2. Measuring Input Ripple Current Figure 3. Measuring Output Ripple/Noise (PARD) In critical applications, output ripple/noise (also referred to as periodic and random deviations or PARD) may be reduced below specified limits using filtering techniques, the simplest of which is the installation of additional external output capacitors. These output caps function as true filter elements and should be selected for bulk capacitance, low ESR and appropriate frequency response. All external capacitors should have appropriate voltage ratings and be located as close to the converter as possible. Temperature variations for all relevant parameters should also be taken carefully into consideration. Minimum Output Loading Requirements ULE converters employ a synchronous-rectifier design topology and all models regulate within spec and are stable under no-load to full load conditions. Operation under no-load conditions however might slightly increase the output ripple and noise. Thermal Shutdown The most effective combination of external I/O capacitors will be a function of line voltage and source impedance, as well as 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. These ULE converters are equipped with thermal-shutdown circuitry. If environmental conditions cause the internal temperature of the DC/DC converter to rise above the designed operating temperature, a precision temperature sensor will power down the unit. When the internal temperature decreases below the threshold of the temperature sensor, the unit will self start. See Performance/Functional Specifications. In Figure 3, the two copper strips simulate real-world pcb impedances between the power supply and its load. In order to minimize measurement errors, scope measurements should be made using BNC connectors, or the probe ground should be less than 1/2 inch and soldered directly to the fixture. Output Overvoltage Protection ULE output voltages are monitored for an overvoltage condition via magnetic feedback. The signal is coupled to the primary side and if the output voltage rises to a level which could be damaging to the load, the sensing circuitry will power down the PWM controller causing the output voltages to decrease. Following a time-out period the PWM will restart, causing the output voltages to ramp to their appropriate values. If the fault condition persists, and the output voltages again climb to excessive levels, the overvoltage circuitry will initiate another shutdown cycle. This on/off cycling is referred to as "hiccup" mode. Floating Outputs Since these are isolated DC/DC converters, their outputs are "floating" with respect to their input. Designers will normally use the -Output (pin 4) as the ground/return of the load circuit. You can, however, use the +Output (pin 8) as ground/return to effectively reverse the output polarity. Contact DATEL for an optional output overvoltage monitor circuit using a comparator which is optically coupled to the primary side thus allowing tighter and more precise control. Current Limiting As soon as the output current increases to 10% to 50% above its rated value, the DC/DC converter will go into a current-limiting mode. In this condition, the output voltage will decrease proportionately with increases in output current, thereby maintaining somewhat constant power dissipation. This is commonly referred to as power limiting. Current limit inception is defined as the point at which the full-power output voltage falls below the specified tolerance. See Performance/Functional Specifications. If the load current, being drawn from the converter, is significant enough, the unit will go into a short circuit condition as specified under "Performance." 5 ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Short Circuit Condition Trimming Output Voltage When a converter is in current-limit mode, the output voltage will drop as the output current demand increases. If the output voltage drops too low, the magnetically coupled voltage used to develop primary side voltages will also drop, thereby shutting down the PWM controller. Following a time-out period, the PWM will restart causing the output voltages to begin ramping to their appropriate values. If the short-circuit condition persists, another shutdown cycle will be initiated. This on/off cycling is referred to as "hiccup" mode. The hiccup cycling reduces the average output current, thereby preventing internal temperatures from rising to excessive levels. The ULE is capable of enduring an indefinite short circuit output condition. ULE converters have a trim capability that allows users to adjust the output voltages 5% of VOUT. Adjustments to the output voltages can be accomplished via a trim pot (Figure 6) or a single fixed resistor as shown in Figures 7 and 8. A single fixed resistor can increase or decrease the output voltage depending on its connection. The resistor should be located close to the converter and have a TCR less than 100ppm/C to minimize sensitivity to changes in temperature. If the trim function is not used, leave the trim pin floating. A single resistor connected from the Trim to the +Output, or +Sense where applicable, will increase the output voltage in this configuration. A resistor connected from the Trim to the -Output, or -Sense where applicable, will decrease the output voltage in this configuration. FEATURES AND OPTIONS On/Off Control Trim adjustments greater than the specified 5% can have an adverse affect on the converter's performance and are not recommended. Excessive voltage differences between VOUT and Sense, in conjunction with trim adjustment of the output voltage, can cause the overvoltage protection circuitry to activate (see Performance Specifications for overvoltage limits). Power derating is based on maximum output current and voltage at the converter's output pins. Use of trim and sense functions can cause output voltages to increase, thereby increasing output power beyond the converter's specified rating or cause output voltages to climb into the output overvoltage region. Therefore: The input-side, remote On/Off Control function can be ordered to operate with either polarity: Standard models are equipped with Positive-polarity ("P" part-number suffix) and these devices are enabled when the On/Off Control is left open (or is pulled high, applying +13V to +VIN with respect to -Input) as per Figure 4. Positive-polarity devices are disabled when the On/Off Control is pulled low (0 to 0.8V with respect to -Input). Optional Negative-polarity devices ("N" suffix) are off when the On/Off Control is open (or pulled high, applying +3.5V to +VIN), and on when the On/Off Control is pulled low (0 to 0.8V) with respect to -VIN as shown in Figure 5. (VOUT at pins) x (IOUT) <= rated output power Figure 4. Driving the Positive Polarity On/Off Control Pin Figure 6. Trim Connections Using A Trimpot Figure 5. Driving the Negative Polarity On/Off Control Pin Figure 7. Trim Connections To Increase Output Voltages Using a Fixed Resistor Dynamic control of the remote on/off function is facilitated with a mechanical relay or an open-collector/open-drain drive circuit (optically isolated if appropriate). The drive circuit should be able to sink appropriate current (see Performance Specs) when activated and withstand appropriate voltage when deactivated. Applying an external voltage to the On/Off Control when no input power is applied to the converter can cause permanent damage to the converter. 6 ULE Models 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Remote Sense Note: The Sense and VOUT lines are internally connected through low value resistors. Nevertheless, if the sense function is not used for remote regulation the user should connect the +Sense to +VOUT and -Sense to -VOUT at the DC/DC converter pins. ULE series converters have a sense feature to provide point of use regulation, thereby overcoming moderate IR drops in pcb conductors or cabling. The remote sense lines carry very little current and therefore require minimal cross-sectional-area conductors. The sense lines are used by the feedback control-loop to regulate the output. As such, they are not low impedance points and must be treated with care in layouts and cabling. Sense lines on a pcb should be run adjacent to dc signals, preferably ground. In cables and discrete wiring applications, twisted pair or other techniques should be implemented. Figure 8. Trim Connections To Decrease Output Voltages ULE series converters will compensate for drops between the output voltage at the DC/DC and the sense voltage at the DC/DC provided that: Trim Equations Trim Up Trim Down [VOUT(+) -VOUT(-)] -[Sense(+) -Sense (-)] 5% VOUT Output overvoltage protection is monitored at the output voltage pin, not the Sense pin. Therefore, excessive voltage differences between VOUT and Sense in conjunction with trim adjustment of the output voltage can cause the overvoltage protection circuitry to activate (see Performance Specifica- Figure 9. Remote Sense Circuit Configuration tions for overvoltage limits). Power derating is based on maximum output current and voltage at the converter's output pins. Use of trim and sense functions can cause output voltages to increase thereby increasing output power beyond the ULE's specified rating or cause output voltages to climb into the output overvoltage region. Also, the use of Trim Up and Sense combined may not exceed +10% of VOUT. Therefore, the designer must ensure: (VOUT at pins) x (IOUT) rated output power Note: Resistor values are in k. Adjustment accuracy is subject to resistor tolerances and factory-adjusted output accuracy. VO = desired output voltage. 7 ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Typical Performance Curves ULE-1.8/20-D48 Efficiency vs. Line Voltage and Load Current @ +25C 95 90 85 Efficiency (%) 80 75 VIN = 36V 70 VIN = 48V 65 60 55 VIN = 75V 50 1 3 5 7 9 11 13 15 Load Current (Amps) ULE-3.3/20-D48 Efficiency vs. Line Voltage and Load Current @ +25C ULE-3.3/20-D48 Maximum Current Temperature Derating (VIN = 48V, air flow direction is transverse) 25 92.5 90 20 Output Current (Amps) 87.5 Efficiency (%) 85 82.5 VIN = 36V 80 VIN = 48V 77.5 75 100 lfm 15 200 lfm 300 lfm 10 400 lfm 5 72.5 VIN = 75V 70 2 4 6 8 10 12 14 16 18 0 -40 20 0 25 30 35 40 45 50 55 60 65 Ambient Temperature (C) Load Current (Amps) 8 70 75 80 85 ULE Models 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Typical Performance Curves ULE-5/12-D24 Efficiency vs. Line Voltage and Load Current @ +25C ULE-5/12-D24 Maximum Current Temperature Derating (VIN = 24V, air flow direction from input to output) 12.5 92 12 90 Output Current (Amps) 11.5 Efficiency (%) 88 VIN = 18V 86 84 VIN = 24V 100 lfm 11 10.5 200 lfm 10 9.5 300 lfm 9 82 8.5 VIN = 36V 80 2 3 4 5 6 7 8 9 10 11 8 -40 12 0 25 30 35 40 45 50 55 60 65 70 75 80 85 80 85 90 Ambient Temperature (C) Load Current (Amps) ULE-5/12-D48 Efficiency vs. Line Voltage and Load Current @ +25C ULE-5/12-D48 Maximum Current Temperature Derating (VIN = 48V, air flow direction from input to output) 12.5 92 12 90 VIN = 36V 88 Efficiency (%) Output Current (Amps) 11.5 VIN = 48V 86 84 VIN = 75V 11 10.5 100 lfm 10 200 lfm 9.5 9 300 lfm 82 8.5 80 2 3 4 5 6 7 8 9 10 11 8 -40 12 0 30 35 40 45 50 55 60 65 70 Ambient Temperature (C) Load Current (Amps) 9 75 ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Surface-Mount Package ("M" suffix) DATEL's ULE series SMT DC/DC converters are the only higher-power DC/DC's that can be automatically "pick-and-placed" using standard vacuumpickup equipment and subsequently reflowed using high-temperature, lead-free solder. DATEL is not exempted from the Laws of Physics. And we do not have magic solders no one else has. Nevertheless, we have a simple and practical, straightforward approach that works. We assemble our SMT DC/DC's on a hightemperature, plastic lead-frame (nylon 46, UL94V-0 rated) using a high-temperature (+216C), lead-free alloy (Sn96.2%, Ag2.5%, Cu0.8%, Sb0.5%). The lead-frame ensures coplanarity (to within 0.004 in.) of the unit's tin-plated (150 microinches) copper leads and also supports a removable heat shield. Virtually all SMT DC/DC's today are unprotected "open-frame" devices assembled by their vendors with high-temperature solder (usually Sn96.5/ Ag3.5 with a melting point +221C) so that you may attach them to your board using low-temperature solder (usually Sn63/Pb37 with a melting point of +183C). Conceptually straightforward, this "stepped" solder approach has its limitations . . . and is clearly out of step with an industry trending toward the broad use of lead-free solders. No need to experiment and develop reflow profiles that ensure the components on their DC/DC never exceed 215216C. If those components get too hot, "double-reflow" could compromise the reliability of their solder joints. Virtually all these devices demand you "cool down" the Sn63 profile you are likely using today. The disposable heat shield, which has a cutaway exposing the package leads, provides thermal insulation to internal components during reflow and also doubles as the vacuum pick-up location. The insulation properties of the heat shield are so effective that temperature differentials as high as 50C develop inside-to-outside the shield. Oven temperature profiles with peaks of 250-260C and dwell times exceeding 2 minutes above 221C (the melting point of Sn96.5/Ag3.5) are easily achieved. DATEL's new-generation SMT units are shipped in stackable, JEDEC-style plastic. 250 Degrees Celsius 200 Heat Shield Test Board Air Under Shield 150 100 50 Z1 Z2 100 Z3 Z4 200 Z5 Z6 300 Z7 Seconds 400 500 600 Figure 11. Recommended Solder Profile (When The Heat-shield Temperature Exceeds +250C, The Air Within Is 50C Cooler) Figure 10. ULE SMT DC/DC With Disposable Heat Shield 10 ULE Models 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S Automated Assembly Production Notes Heatsinks DATEL's new high-efficiency DC/DC converters are designed for modern surface-mount technology (SMT) automated assembly using screened solder paste, "pick and place" component positioning and forced hot air reflow oven soldering. If you are new to SMT techniques and have a volume application, these features save time, cost and improve manufacturing efficiency. DATEL's DC/DC assembly operations themselves make extensive use of such techniques. If you are using the preinstalled heatsink from DATEL, proceed normally with surface mounting per the information in this section (the heat shield fits completely over the heatsink). However, if you wish to add the heatsink after receiving the converters and heatsink separately, you must install the heatsink before solder reflow. Essentially, install the heatsink then place the assembled converters back in the tray for surface mount positioning. Please observe the torquing and assembly procedure discussed earlier for the heatsink. Even if you have previous SMT experience, you should read the sections below on solder reflow profiles and heat shields. This information is not intended to replace the documentation for your SMT system. We assume that you are already experienced with all the components of your SMT system. Pick and Place pcb Mounting The main issues here are pad area, orientation, positioning accuracy, vacuum pickup and coplanarity. DATEL recommends that pcb pads to interface with the DC/DC converter should be sized as shown in the diagram below. The pads footprint accommodates the positioning accuracy of your SMT equipment and manufactured tolerances of the DC/DC mounting leads. This section will discuss several SMT issues, including: I/O Mechanical Configuration Part Handling and Supply Printed Circuit Board (pcb) Mounting Soldering using Reflow Technology Temperature Profiling Heat Shields and Removal Mechanical Configuration of Input/Output Connections These new converters are supplied either using traditional through-hole pins or SMT leads. (Note that some models are offered only with lead mounting). The pin options insert into plated-through holes in the host pcb. Be aware that some heat dissipation is carried off by either the pins or leads. The Derating Curves assume that some additional pad area is available on your host pcb to absorb the heat. The lead option uses either short tabs in "gullwing" style or standoff leads under the converter. The gullwing leads typically are copper alloy with 150 microinches of tin plating. Solder paste (typically 0.008" to 0.009" thick) is applied to the host pcb using a solder mask pressure screening technique and the board is heated and cooled long enough for the solder to reflow and adhere to both the host pads and the converter's mounting leads. Figure 12. Recommended SMT Mounting Pad Dimensions Orientation: When loaded into JEDEC trays, these converters are all oriented in the same direction. See the diagram below. For the ULE series, a notch is placed on the top of the case (on the removal tabs) to indicate the pin 1 position. You should visually inspect the tray to be sure of this orientation. After such mounting, the entire mechanical mounting load is carried by the solder. Obviously the converters must be accurately positioned all during the solder reflow period. Where solder surface tension is sufficient to force tiny components into position, these larger converters may not move and must be accurately positioned by your SMT system. On the bottom of the converter, the ULE series include optical fiducial marks viewable by your SMT imaging system. See the attached diagram. Observing from the bottom, your SMT imaging camera should find these marks to identify the converter and verify pin 1. On most pick-and-place systems, during head transit, the imaging system will automatically fine tune the end mounting position of the converter using image comparisons from these fiducials or other reference marks you have chosen. Part Handling and Supply SMT eighth- and quarter-brick DC/DC converters (plus installed heat shields if used) are supplied in JEDEC-standard 5.35" by 12.4" waffle trays which are compatible with the feeders on industry-standard pick-and-place machines. Since the converters are larger and heavier than many other components, make sure your system can reliably remove the units from their trays, move them to the host pcb and accurately position them. The plastic heat shield (see below) doubles as a vacuum pickup area. The fiducial marks are placed fairly close together because most imaging systems have a one inch or less observing area since most SMT parts are considerably smaller than these converters. You may prefer to train your imaging system to use a corner of the converter or an I/O lead. In the drawing below, these dimensions are intended for initial search for these marks by your camera. There will be tiny variations in absolute position from unit to unit. 11 ULE Series 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S TO For these reasons, DATEL developed disposable heat shields using high temperature plastic. The DC/DC is installed and reflowed with the shield in place. After successful reflow and cooling, and before washing, the heat shield should be removed. E M CO Temperature Profiling We wish to ramp the temperature up and down to successfully reflow the solder without heat damage. Each reflow oven, humidity conditions, solder paste type, oven feed rate, and the number of heat zones all require a different profile. Therefore you may have to experiment. Since these converters are constructed using high temperature solders, there will be no heat problems on your host pcb using traditional solder with 63% lead and 37% tin with a melting point of +183C. Device lead temperature must remain below 230C for less than 75 seconds, assuming that the heat shield is in place. DATEL uses a 216C melt lead-free tin/silver/copper alloy to assemble these converters. Figure 13. Fiducial Mark Location There are several lead-free solders suitable for your host pcb depending on your SMT system and whatever local certification and environmental regulations you must observe. Contact DATEL if you need specific advice. If you use a camera above the pcb after placement on the solder paste, do not rely on the inkjet marking on the heat shield to verify proper orientation. Use the pin 1 notch instead. Heat Shield Careful thermocouple testing has shown that the interior of the DC/DC under the heat shield is tens of degrees cooler than the outside ambient temperature for typical reflow profiles. This protects internal components and limits the amount of reflow where it is not desired. The heat shield also includes marking for product identification and a date/lot code. Coplanarity: DATEL manufactures these converters with very flat mounting leads (see coplanarity specs) however your host pcb must also be flat for a successful mounting. Be aware of possible warping of the pcb under heat gradients and/or humidity conditions. The solder paste will tolerate a small amount of mismatch and will tend to "wet" the entire pad area by capillary action if the temperatures are correct. On ULE models, the heat shield is attached to the converter using molded plastic pins on the heat shield interior which insert into recessed dimples in the pinframe. An extra molded pin on the heat shield at the pin 1 location (and corresponding notch on the pcb) can only be installed one way properly on the pinframe. If the shield accidentally comes loose, it may be reinstalled by aligning the pins and dimples. Vacuum Pickup: Select the vacuum collet on your SMT placement system for the weight and size of the DC/DC converter. Note that units with heatsinks are slightly heavier. Tests at DATEL have shown that excellent acceleration and transit head speed are available for these converters if the collet size is proper and the vacuum is sufficient. When positioning the vacuum collet, use the geometric center of the heat shield as the pickup area since the center of gravity is very close. To remove the shield from the converter, after successful mounting and cooling, squeeze the heat shield ears inward toward the converter body and pull the shield upwards. Discard or recycle the shield. If you are using a flux wash cycle, remove the heat shield before washing to avoid coming loose inside the washer. Soldering Reflow technology works well for small parts. However, larger components such as these DC/DC's with higher thermal mass may require additional reflow time (but not enough to disturb smaller parts also being reflowed concurrently with the DC/DC). When this is combined with higher temperature lead-free solders (or solders with reduced heavy metals), there is increased risk of reheating components inside the DC/DC enough so that they either change positions (and possibly stop functioning) or the components are damaged by the heat. 12 2 4 - 6 0 W, S I N G L E O U T P U T D C / D C C O N V E RT E R S ULE Models Figure 14. Shipping Tray DATEL (UK) LTD. Tadley, England Tel: (01256)-880444 Internet: www.datel-europe.com E-mail: datel.ltd@datel.com (R) (R) DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01 Internet: www.datel-europe.com E-mail: datel.sarl@datel.com INNOVATION and EXCELLENCE DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 Internet: www.datel.com Email: sales@datel.com DATEL GmbH Munchen, Germany Tel: 89-544334-0 Internet: www.datel-europe.com E-mail: datel.gmbh@datel.com ISO 9001 REGISTERED DATEL China Shanghai, China Tel: 011-86-51317131 E-mail: davidx@datel.com DS-0515 4/04 DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025 Internet: www.datel.co.jp Email: salestko@datel.co.jp, salesosa@datel.co.jp DATEL 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. The DATEL logo is a registered DATEL, Inc. trademark. 13