HPQ-12/25-D48 Series www.murata-ps.com Isolated 300-Watt Quarter Brick DC/DC Converters PRODUCT OVERVIEW Typical unit FEATURES 12 Volts DC fixed output up to 25 Amps Industry standard quarter brick 2.3” x 1.45” x 0.44” open frame package Wide range 36 to 75 Vdc input voltages with 2250 Volt Basic isolation Double lead-free assembly and attachment for RoHS standards Up to 300 Watts total output power High efficiency (94.5%) synchronous rectifier topology Stable no-load operation with no required external components Operating temperature range -40 to +85° C. with no heat sink required Meets UL/EN 60950-1, CSA-C22.2 No. 60950-1, 2nd edition safety approvals Extensive self-protection, current limiting and shut down features “X” optional version omits trim and sense pins F1 The HPQ-12/25-D48 series offers high output current (up to 25 Amps) in an industry standard “quarter brick” package requiring no heat sink for most applications. The HPQ-12/25-D48 series delivers fixed 12 Vdc output at 300 Watts for printed circuit board mounting. Wide range inputs on the 2.3” x 1.45” x 0.44” converter are 36 to 75 Volts DC (48 Volts nominal), ideal for datacom and telecom systems. The fixed output voltage is regulated to within ±2%. Advanced automated surface mount assembly and planar magnetics deliver galvanic isolation rated at 2250 Vdc for basic insulation. To power digital systems, the outputs offer fast settling to current steps and tolerance of higher capacitive loads. Excellent ripple and noise specifications assure compatibility to CPU’s, ASIC’s, programmable logic and FPGA’s. No minimum load is required. For systems needing controlled startup/shutdown, an external remote On/Off control may use either positive or negative polarity. Remote Sense inputs compensate for resistive line drops at high currents. A wealth of self-protection features avoid problems with both the converter and external circuits. These include input undervoltage lockout and overtemperature shutdown using an on-board temperature sensor. Overcurrent protection using the “hiccup” autorestart technique provides indefinite short-circuit protection. Additional safety features include output overvoltage protection and reverse conduction elimination. The synchronous rectifier topology offers high efficiency for minimal heat buildup and “no heat sink” operation. The HPQ-12/25-D48 series meets full safety standards to UL/EN/IEC/CSA 60950-1, 2nd edition and RFI/EMI conducted/radiated emission compliance to EN55022, CISPR22 with external filter. APPLICATIONS Embedded systems, datacom and telecom installations Disk farms, data centers and cellular repeater sites Remote sensor systems, dedicated controllers Instrumentation systems, R&D platforms, automated test fixtures Data concentrators, voice forwarding and speech processing systems *TPMBUJPO Barrier +Vin (3) +Vout (8) t4XJUDIJOH External DC Power Source On/Off Control (2) Open = On $MPTFE0GG 1PTJUJWF polarity) 4FOTF t'JMUFST Controller and Power 5SBOTGFS t$VSSFOU4FOTF 4FOTF Reference and Error Amplifier Trim (6) -Vin (1) -Vout (4) Figure 1. Connection Diagram Typical topology is shown. Murata Power Solutions recommends an external fuse. For full details go to www.murata-ps.com/rohs * “X” option omits trim and sense pins. www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 1 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters ORDERING GUIDE ➀ Output Input R/N (mV pk-pk) Regulation (Max.) ➁ IOUT IIN full VOUT (Amps, Power VIN Nom. Range IIN no load Line Load (Volts) (Volts) load (mA) (Amps) Root Model ➀ (Volts) max.) (Watts) Typ. Max. HPQ-12/25-D48 12 25 300 120 150 ±0.125% ±0.25% 48 36-75 150 6.61 Efficiency Min. Typ. Package (C59) Dimensions (inches) Dimensions (mm) 93.5% 94.5% 1.45x2.3x0.440 max. 36.8x58.4x11.2 ➀ Please refer to the part number structure for additional ordering information and options. ➁ All specifications are at nominal line voltage and full load, +25 deg.C. unless otherwise noted. See detailed specifications. Output capacitors are 1 μF ceramic || 10 μF electrolytic with no input caps.These caps are necessary for our test equipment and may not be needed for your application. PART NUMBER STRUCTURE HPQ - 12 / 25 - D48 N B Family Series: High Power Quarter Brick Nominal Output Voltage Maximum Rated Output : Current in Amps Input Voltage Range: D48 = 36-75 Volts (48V nominal) On/Off Control Polarity N = Negative polarity, standard P = Positive polarity, optional H X Lx - C RoHS Hazardous Materials compliance C = RoHS-6 (does not claim EU RoHS exemption 7b–lead in solder), standard Y = RoHS-5 (with lead), optional, special quantity order Pin length option Blank = standard pin length 0.180 in. (4.6 mm) L1 = 0.110 in. (2.79 mm)* L2 = 0.145 in. (3.68 mm)* *Special quantity order required Trim & Sense Pins Option Blank = Trim and Sense installed, standard X = Trim and Sense removed Conformal coating (optional) Blank = no coating, standard H = Coating added, optional Baseplate (optional) Blank = No baseplate, standard B = Baseplate installed, optional Note: Some model combinations may not be available. Contact Murata Power Solutions for availability. Complete Model Number Example: HPQ-12/25-D48NBHXL1-C Negative On/Off logic, baseplate installed, conformally coated, trim and sense pins removed, 0.110˝ pin length, RoHS-6 compliance www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 2 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters MECHANICAL SPECIFICATIONS (THROUGH-HOLE MOUNT) TOP VIEW 4 7 .2 4 ± 0 .2 0 1 .8 6 0 ± 0 .0 0 8 4 .2 0 0 .1 6 5 Case C59 1 2 .7 0 .5 0 SIDE VIEW 3 .6 9 0 .1 4 5 0.015 minimum clearance between standoffs and highest component PIN S 1-3, 5-7: 0.040±0. 001(1.016±0. 025) PIN S 4, 8: 0.062±0. 001(1.575±0. 025) 3 4 5 6 7 8 LABEL 3 6 .8 1 .4 5 1 5 .2 4 0 .6 0 0 1 1 5 .2 4 0 .6 0 0 1 5 .2 4 0 .6 0 0 2 7 .6 2 0 .3 0 0 4 5 6 7 8 1 2 3 1 5 .2 4 0 .6 0 0 5 0 .8 0 2 .0 0 0 5 0 .8 0 2 .0 0 0 7 .6 2 0 .3 0 0 11.2 0.440 Max PIN S 1-3,5-7: 0. 040±0. 001(1.016±0.025) PIN S 4,8: 0. 062±0. 001(1.575±0. 025) M3 THREADED INSERT 4 PLACES SEE NOTE 1&2 5 8 .4 2 .3 0 5 6 .1 3 2 .2 1 0 0.015 minimum clearance between standoffs and highest component 2 6 .1 6 ± 0 .2 0 1 .0 3 0 ± 0 .0 0 8 3 6 .8 1 .4 5 3 4 .5 4 1 .3 6 0 LABEL TOP VIEW 5 8 .4 2 .3 0 OPEN FRAME PIN SIDE VIEW (NO BASEPLATE) WITH BASEPLATE OPTION, PIN SIDE VIEW ➀ M3 bolts must not exceed 0.138˝ (3.5mm) depth below the baseplate surface. ➁ Applied screw torque must not exceed 5.3 in-lb. (0.6 N-m). These converters are plug-compatible to competitive units. Other units may use different pin numbering or alternate outline views. When laying out your PC board, follow the pin FUNCTION. The 0.145˝ (L2) pin length is shown. Please refer to the part number structure for alternate pin lengths. Dimensions are in inches (mm) shown for ref. only. Third Angle Projection I/O Connections (pin side view) Tolerances (unless otherwise specified): .XX ± 0.02 (0.5) .XXX ± 0.010 (0.25) Angles ± 2˚ Components are shown for reference only. Pin 1 2 3 4 Function P32 Neg. Vin Remote On/Off Control Pos. Vin Neg. Output Pin 5 6 7 8 Function P32 Neg. Sense* Trim* Pos. Sense* Pos. Output * The Sense and Trim pins are removed for the “X” model option. www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 3 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters FUNCTIONAL SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS Input Voltage, Continuous Input Voltage, Transient Isolation Voltage Input Reverse Polarity On/Off Remote Control Output Power Conditions ➀ Full power operation Operating or non-operating, 100 mS max. duration Input to output tested 100 mS IEC/EN/UL 60950-1, 2nd edition None, install external fuse Power on or off, referred to -Vin Minimum Typical/Nominal 36 Maximum Vdc 100 Vdc 2250 Vdc 15 300 Vdc Vdc W None 0 0 Units 75 Current-limited, no damage, 0 25 A short-circuit protected Storage Temperature Range Vin = Zero (no power) -55 125 °C Absolute maximums are stress ratings. Exposure of devices to greater than 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 or recommended. Output Current INPUT Operating voltage range Recommended External Fuse Start-up threshold Undervoltage shutdown Overvoltage protection Reverse Polarity Protection Internal Filter Type Input current Full Load Conditions Low Line Inrush Transient Output in Short Circuit No Load Standby Mode (Off, UV, OT) Reflected (back) ripple current ➁ Pre-biased startup Conditions ➀ ➂ 36 Fast blow Rising input voltage Falling input voltage Rising input voltage None, install external fuse 33 31 Vin = nominal Vin = minimum Vin = 48V. Iout = minimum, unit=ON Measured at input with specified filter External output voltage < Vset 48 20 34 32 None None Pi-type 75 6.61 8.82 0.3 50 150 5 50 Monotonic 6.82 9.09 35 34 100 250 10 70 Vdc A Vdc Vdc Vdc Vdc A A A2-Sec. mA mA mA mA, RMS GENERAL and SAFETY Efficiency Isolation Isolation Voltage, input to output Isolation Voltage, input to output Isolation Voltage, input to baseplate Isolation Voltage, output to baseplate Insulation Safety Rating Isolation Resistance Isolation Capacitance Safety (meets the following requirements) Calculated MTBF Calculated MTBF Vin=48V, full load Vin=45.6V, full load 93.5 93.5 No baseplate With baseplate With baseplate With baseplate 2250 1500 1500 1500 94.5 94.5 % % Vdc Vdc Vdc Vdc basic 10 MΩ pF 1000 UL-60950-1, CSA-C22.2 No.60950-1, IEC/EN60950-1, 2nd edition Per MIL-HDBK-217F, ground benign, Tambient=+TBD°C Per Telcordia SR-332, issue 1, class 3, ground fixed, Tambient=+25°C Yes TBD Hours x 103 1500 Hours x 103 260 KHz DYNAMIC CHARACTERISTICS Fixed Switching Frequency Startup Time Startup Time Dynamic Load Response Dynamic Load di/dt Dynamic Load Peak Deviation Power On, to Vout regulation band, 100% resistive load Remote ON to Vout Regulated 50-75-50% load step to 1% error band 550 same as above 15 mS ±500 15 825 0.1 ±750 mS μSec A / μSec mV 1 0.8 13.5 2 Vdc Vdc mA FEATURES and OPTIONS Remote On/Off Control ➃ “N” suffix: Negative Logic, ON state Negative Logic, OFF state Control Current ON = pin grounded or external voltage OFF = pin open or external voltage open collector/drain 0 3.5 www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 4 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters FUNCTIONAL SPECIFICATIONS (CONT.) FEATURES and OPTIONS (cont.) Remote On/Off Control (cont.) ➃ “P” suffix: Positive Logic, ON state Positive Logic, OFF state Control Current Remote Sense Compliance ➆ Base Plate Conditions ➀ ON = pin open or external voltage OFF = ground pin or external voltage open collector/drain (Vout - Vsense) Sense pins connected externally to respective Vout’s "B" suffix Minimum Typical/Nominal 3.5 0 1 Maximum Units 13.5 0.8 2 V V mA 0.5 V optional OUTPUT Total Output Power Voltage Setting Accuracy Output Voltage Range ➆ Overvoltage Protection Current Output Current Range Minimum Load Current Limit Inception Short Circuit Short Circuit Current Short Circuit Duration (remove short for recovery) Short circuit protection method Hiccup autorestart duty cycle Regulation ➄ Line Regulation Load Regulation Ripple and Noise ➅ Temperature Coefficient Maximum Capacitive Loading At 50% load, no trim User-adjustable Via magnetic feedback 0.0 300 306 W 11.76 -10 12 12.24 +10 18.0 Vdc % of Vnom. Vdc 14.4 0.0 25.0 A No minimum load 32 39 A Hiccup technique, autorecovery within 1.25% of Vout 0.8 1.0 A Output shorted to ground, no damage Continuous Hiccup current limiting Output shorted to ground Non-latching 0.25 98% of Vnom., after warmup Vin=min. to max., Vout=nom., full load Iout=min. to max., Vin=nom. 5 Hz- 20 MHz BW, Cout=1μF MLCC paralleled with 10μF tantalum At all outputs Full resistive load, low ESR 27 % ±0.125 ±0.25 120 150 mV pk-pk 4,700 % of Vout./°C μF 0.02 0 % of Vout % of Vout MECHANICAL (Through Hole Models) Outline Dimensions (no baseplate) (Please refer to outline drawing) Outline Dimensions (with baseplate) Weight C59 case WxLxH 1.45x2.3x0.440 max. 36.8x58.4x11.2 1.45x2.3x0.5 36.8x58.4x12.7 1.51 47 2.4 68 0.04 & 0.062 1.016 & 1.575 Copper alloy 100-299 3.9-19.6 Aluminum No baseplate No baseplate With baseplate With baseplate Through Hole Pin Diameter Through Hole Pin Material TH Pin Plating Metal and Thickness Nickel subplate Gold overplate Baseplate Material Inches mm Inches mm Ounces Grams Ounces Grams Inches mm μ-inches μ-inches ENVIRONMENTAL Operating Ambient Temperature Range Storage Temperature Thermal Protection/Shutdown Electromagnetic Interference Conducted, EN55022/CISPR22 Radiated, EN55022/CISPR22 Relative humidity, non-condensing Altitude Acceleration Shock Sinusoidal Vibration RoHS rating No derating, full power, 200 LFM, no condensation Vin = Zero (no power) Measured at hotspot External filter is required -40 -55 105 110 85 125 125 °C °C ˚C 90 10,000 3048 Class Class %RH feet meters g g B B To +85°C must derate -1%/1000 feet Halfsine wave, 3 axes GR-63-Core, Section 5.4.2 10 -500 -152 50 1 RoHS-6 www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 5 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters Notes ➀ Unless otherwise noted, all specifications apply over the input voltage range, full temperature range, nominal output voltage and full output load. General conditions are near sea level altitude, no base plate installed and natural convection airflow unless otherwise specified. All models are tested and specified with external parallel 1 μF and 10 μF multi-layer ceramic output capacitors. No external input capacitor is used (see Application Notes). All capacitors are low-ESR types wired close to the converter. These capacitors are necessary for our test equipment and may not be needed in the user’s application. ➁ Input (back) ripple current is tested and specified over 5 Hz to 20 MHz bandwidth. Input filtering is Cin = 33 μF, Cbus = 220μF and Lbus = 4.7 μH. ➂ All models are stable and regulate to specification under no load. ➃ The Remote On/Off Control is referred to -Vin. ➄ Regulation specifications describe the output voltage changes as the line voltage or load current is varied from its nominal or midpoint value to either extreme. The load step is ±25% of full load current. ➅ Output Ripple and Noise is measured with Cout = 1μF MLCC paralleled with 10μF tantalum, 20 MHz oscilloscope bandwidth and full resistive load. ➆ The Sense and Trim pins are removed for the “X” model option. ➇ NOTICE—Please use only this customer data sheet as product documentation when laying out your printed circuit boards and applying this product into your application. Do NOT use other materials as official documentation such as advertisements, product announcements, or website graphics. We strive to have all technical data in this customer data sheet highly accurate and complete. This customer data sheet is revision-controlled and dated. The latest customer data sheet revision is normally on our website (www.murata-ps.com) for products which are fully released to Manufacturing. Please be especially careful using any data sheets labeled “Preliminary” since data may change without notice. The pinout (Pxx) and case (Cxx) designations (typically P65 or C59) refer to a generic family of closely related information. It may not be a single pinout or unique case outline. Please be aware of small details (such as Sense pins, Power Good pins, etc.) or slightly different dimensions (baseplates, heat sinks, etc.) which may affect your application and PC board layouts. Study the Mechanical Outline drawings, Input/Output Connection table and all footnotes very carefully. Please contact Murata Power Solutions if you have any questions. TYPICAL PERFORMANCE DATA Maximum Current Temperature Derating vs. Airflow (Vin=Vnom., airflow direction is from -Vin to +Vin, with baseplate, at sea level) 40 30 95 35 25 90 30 VIN = 75 V VIN = 48 V VIN = 36 V 85 25 80 20 75 15 Power Dissipation VIN = 48 V 70 65 3 5 7 9 11 Output Current (Amps) 100 Loss (Watts) Efficiency (%) Efficiency and Power Dissipation @ +25°C 13 15 17 19 21 23 20 15 10 10 5 5 0 25 100 LFM 200 LFM 300 LFM 400 LFM 30 35 Iout (Amps) Maximum Current Temperature Derating vs. Airflow (Vin=Vnom., airflow direction is from Vin to Vout, no baseplate, at sea level) 40 45 50 55 60 65 Ambient Temperature (°C) 70 75 80 85 Power On Startup Delay Output (Vin = 0 to 48V, Iout = 25A, Cload = 0, Ta = +25°C) 30 Output Current (Amps) 25 20 100 LFM 200 LFM 300 LFM 400 LFM 15 10 5 0 30 35 40 45 50 55 60 65 70 75 80 85 Ambient Temperature (°C) www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 6 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters TYPICAL PERFORMANCE DATA Power On Startup Delay Output (Vin = 0 to 48V, Iout = 0A, Cload = 0, Ta = +25°C) Output Short Circuit Hiccup (Vin = Nom., Iout = Imax, Cload = 0, Ta = +25°C) Max = 81A, Period = 1.180s, Pulse width = 6.4ms Step Load Transient Response (Vin = 48V, Cload = 1μF ceramic and 10μF tantalum, Iout = 50-75-50% lmax, Slew = 0.1 mA/μSec., Ta = +25°C) Output Ripple and Noise (Vin=36V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) Output Ripple and Noise (Vin=36V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 7 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters TYPICAL PERFORMANCE DATA Output Ripple and Noise (Vin=48V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) Output Ripple and Noise (Vin=48V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) Output Ripple and Noise (Vin=75V, Iout=0A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) Output Ripple and Noise (Vin=75V, Iout=25A, Cload=0, Ta=+25˚C., ScopeBW=20MHz) www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 8 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters APPLICATION NOTES Input Fusing Certain applications and/or safety agencies may require fuses at the inputs of power conversion components. Fuses should also be used when there is the possibility of sustained input voltage reversal which is not current-limited. For greatest safety, we recommend a fast blow fuse installed in the ungrounded input supply line. The installer must observe all relevant safety standards and regulations. For safety agency approvals, install the converter in compliance with the end-user safety standard. Input Reverse-Polarity Protection If the input voltage polarity is reversed, an internal diode will become forward biased and likely draw excessive current from the power source. If this source is not current-limited or the circuit appropriately fused, it could cause permanent damage to the converter. Input Under-Voltage Shutdown and Start-Up Threshold Under normal start-up conditions, converters will not begin to regulate properly until the rising input voltage exceeds and remains at the Start-Up Threshold Voltage (see Specifications). Once operating, converters will not turn off until the input voltage drops below the Under-Voltage Shutdown Limit. Subsequent restart will not occur until the input voltage rises again above the Start-Up Threshold. This built-in hysteresis prevents any unstable on/off operation at a single input voltage. Users should be aware however of input sources near the Under-Voltage Shutdown whose voltage decays as input current is consumed (such as capacitor inputs), the converter shuts off and then restarts as the external capacitor recharges. Such situations could oscillate. To prevent this, make sure the operating input voltage is well above the UV Shutdown voltage AT ALL TIMES. Start-Up Delay Assuming that the output current is set at the rated maximum, the Vin to Vout StartUp Delay (see Specifications) is the time interval between the point when the rising input voltage crosses the Start-Up Threshold and the fully loaded regulated output voltage enters and remains within its specified regulation band. Actual measured times will vary with input source impedance, external input capacitance, input voltage slew rate and final value of the input voltage as it appears at the converter. These converters include a soft start circuit to moderate the duty cycle of the PWM controller at power up, thereby limiting the input inrush current. The On/Off Remote Control interval from inception to VOUT regulated assumes that the converter already has its input voltage stabilized above the Start-Up Threshold before the On command. The interval is measured from the On command until the output enters and remains within its specified regulation band. The specification assumes that the output is fully loaded at maximum rated current. Input Source Impedance These converters will operate to specifications without external components, assuming that the source voltage has very low impedance and reasonable input voltage regulation. Since real-world voltage sources have finite impedance, performance is improved by adding external filter components. Sometimes only a small ceramic capacitor is sufficient. Since it is difficult to totally characterize all applications, some experimentation may be needed. Note that external input capacitors must accept high speed switching currents. Because of the switching nature of DC/DC converters, the input of these converters must be driven from a source with both low AC impedance and adequate DC input regulation. Performance will degrade with increasing input inductance. Excessive input inductance may inhibit operation. The DC input regulation specifies that the input voltage, once operating, must never degrade below the Shut-Down Threshold under all load conditions. Be sure to use adequate trace sizes and mount components close to the converter. I/O Filtering, Input Ripple Current and Output Noise All models in this converter series are tested and specified for input reflected ripple current and output noise using designated external input/output components, circuits and layout as shown in the figures below. External input capacitors (CIN in the figure) serve primarily as energy storage elements, minimizing line voltage variations caused by transient IR drops in the input conductors. Users should select input capacitors for bulk capacitance (at appropriate frequencies), low ESR and high RMS ripple current ratings. In the figure below, the CBUS and LBUS components simulate a typical DC voltage bus. Your specific TO OSCILLOSCOPE VIN + – + – CURRENT PROBE 1 +INPUT LBUS CBUS CIN 2 −INPUT CIN = 33μF, ESR < 200mΩ @ 100kHz CBUS = 220μF, 100V LBUS = 4.7μH Figure 2. Measuring Input Ripple Current system configuration may require additional considerations. Please note that the values of CIN, LBUS and CBUS may vary according to the specific converter model. In critical applications, output ripple and noise (also referred to as periodic and random deviations or PARD) may be reduced by adding filter elements such as multiple external capacitors. Be sure to calculate component temperature rise from reflected AC current dissipated inside capacitor ESR. In figure 3, the two copper strips simulate real-world printed circuit impedances between the power supply and its load. In order to minimize circuit errors and standardize tests between units, scope measurements should be made using BNC connectors or the probe ground should not exceed one half inch and soldered directly to the fixture. Floating Outputs Since these are isolated DC/DC converters, their outputs are “floating” with respect to their input. The essential feature of such isolation is ideal ZERO CURRENT FLOW between input and output. Real-world converters however do exhibit tiny leakage currents between input and output (see Specifications). These leakages consist of both an AC stray capacitance coupling component www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 9 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters it is quite difficult to insert an anemometer to precisely measure airflow in most applications. Sometimes it is possible to estimate the effective airflow if you thoroughly understand the enclosure geometry, entry/exit orifice areas and the fan flowrate specifications. COPPER STRIP +OUTPUT C1 C2 SCOPE RLOAD −OUTPUT CAUTION: If you exceed these Derating guidelines, the converter may have an unplanned Over Temperature shut down. Also, these graphs are all collected near Sea Level altitude. Be sure to reduce the derating for higher altitude. Output Overvoltage Protection (OVP) This converter monitors its output voltage for an over-voltage condition using an on-board electronic comparator. The signal is optically coupled to the primary side PWM controller. If the output exceeds OVP limits, the sensing circuit will power down the unit, and the output voltage will decrease. After a time-out period, the PWM will automatically attempt to restart, causing the output voltage to ramp up to its rated value. It is not necessary to power down and reset the converter for this automatic OVP-recovery restart. COPPER STRIP C1 = 0.1μF CERAMIC C2 = 10μF LOW ES LOAD 2-3 INCHES (51-76mm) FROM MODULE Figure 3. Measuring Output Ripple and Noise (PARD) and a DC leakage resistance. When using the isolation feature, do not allow the isolation voltage to exceed specifications. Otherwise the converter may be damaged. Designers will normally use the negative output (-Output) as the ground return of the load circuit. You can however use the positive output (+Output) as the ground return to effectively reverse the output polarity. Minimum Output Loading Requirements These converters employ a synchronous rectifier design topology. All models regulate within specification and are stable under no load to full load conditions. Operation under no load might however slightly increase output ripple and noise. If the fault condition persists and the output voltage climbs to excessive levels, the OVP circuitry will initiate another shutdown cycle. This on/off cycling is referred to as “hiccup” mode. Output Fusing The converter is extensively protected against current, voltage and temperature extremes. However, your application circuit may need additional protection. In the extremely unlikely event of output circuit failure, excessive voltage could be applied to your circuit. Consider using an appropriate external protection. Thermal Shutdown To protect against thermal over-stress, these converters include thermal shutdown circuitry. If environmental conditions cause the temperature of the DC/ DC’s to rise above the Operating Temperature Range up to the shutdown temperature, an on-board electronic temperature sensor will power down the unit. When the temperature decreases below the turn-on threshold, the converter will automatically restart. There is a small amount of hysteresis to prevent rapid on/off cycling. CAUTION: If you operate too close to the thermal limits, the converter may shut down suddenly without warning. Be sure to thoroughly test your application to avoid unplanned thermal shutdown. Output Current Limiting As soon as the output current increases to approximately its overcurrent limit, the DC/DC converter will enter a current-limiting mode. The output voltage will decrease proportionally with increases in output current, thereby maintaining a somewhat constant power output. This is commonly referred to as power limiting. Temperature Derating Curves The graphs in the next section illustrate typical operation under a variety of conditions. The Derating curves show the maximum continuous ambient air temperature and decreasing maximum output current which is acceptable under increasing forced airflow measured in Linear Feet per Minute (“LFM”). Note that these are AVERAGE measurements. The converter will accept brief increases in temperature and/or current or reduced airflow as long as the average is not exceeded. Output Short Circuit Condition 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 PWM bias voltage will also drop, thereby shutting down the PWM controller. Following a time-out period, the PWM will restart, causing the output voltage to begin rising to its appropriate value. If the short-circuit condition persists, another shutdown cycle will initiate. This on/off cycling is called “hiccup mode.” The hiccup cycling reduces the average output current, thereby preventing excessive internal temperatures. Note that the temperatures are of the ambient airflow, not the converter itself which is obviously running at higher temperature than the outside air. Also note that “natural convection” is defined as very low flow rates which are not using fan-forced airflow. Depending on the application, “natural convection” is usually about 30-65 LFM but is not equal to still air (0 LFM). Murata Power Solutions makes Characterization measurements in a closed cycle wind tunnel with calibrated airflow. We use both thermocouples and an infrared camera system to observe thermal performance. As a practical matter, Current limiting inception is defined as the point at which full power falls below the rated tolerance. See the Performance/Functional Specifications. Note particularly that the output current may briefly rise above its rated value. This enhances reliability and continued operation of your application. If the output current is too high, the converter will enter the short circuit condition. Trimming the Output Voltage (See Specification Note 7) The Trim input to the converter allows the user to adjust the output voltage over the rated trim range (please refer to the Specifications). In the trim equations and circuit diagrams that follow, trim adjustments use a single fixed resistor connected between the Trim input and either Vout pin. Trimming resistors should have a low temperature coefficient (±100 ppm/deg.C or less) and be mounted www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 10 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters close to the converter. Keep leads short. If the trim function is not used, leave the trim unconnected. With no trim, the converter will exhibit its specified output voltage accuracy. +OUTPUT -INPUT +SENSE There are two CAUTIONs to observe for the Trim input: CAUTION: To avoid unplanned power down cycles, do not exceed EITHER the maximum output voltage OR the maximum output power when setting the trim. If the output voltage is excessive, the OVP circuit may inadvertantly shut down the converter. If the maximum power is exceeded, the converter may enter current limiting. If the power is exceeded for an extended period, the converter may overheat and encounter overtemperature shut down. ON/OFF CONTROL Trim Equations Vout -Vnominal Vnominal Figure 5. Trim adjustments to Decrease Output Voltage using a Fixed Resistor Positive: Models equipped with Positive Logic are enabled when the On/Off pin is left open or is pulled high to +15VDC with respect to –VIN. An internal bias current causes the open pin to rise to +VIN. Positive-polarity devices are disabled when the On/Off is grounded or brought to within a low voltage (see Specifications) with respect to –VIN. 1 -2 Δ Vnominal -Vout Vnominal Radj_down (in kΩ) = where Δ = -OUTPUT Remote On/Off Control On the input side, a remote On/Off Control can be specified with either positive or negative logic as follows: Radj_up (in kΩ) = Vnominal x (1+Δ) - 1 - 2 1.225 x Δ Δ where Δ = LOAD R TRIM DOWN -SENSE +INPUT CAUTION: Be careful of external electrical noise. The Trim input is a senstive input to the converter’s feedback control loop. Excessive electrical noise may cause instability or oscillation. Keep external connections short to the Trim input. Use shielding if needed. TRIM Where Vo = Desired output voltage. Adjustment accuracy is subject to resistor tolerances and factory-adjusted output accuracy. Mount trim resistor close to converter. Use short leads. Note that “Δ” is given as a small fraction, not a percentage. +OUTPUT -INPUT +SENSE Negative: Models with negative polarity are on (enabled) when the On/Off is grounded or brought to within a low voltage (see Specifications) with respect to –VIN. The device is off (disabled) when the On/Off is left open or is pulled high to +15VDC Max. with respect to –VIN. Dynamic control of the On/Off function should be able to sink the specified signal current when brought low and withstand specified voltage when brought high. Be aware too that there is a finite time in milliseconds (see Specifications) between the time of On/Off Control activation and stable, regulated output. This time will vary slightly with output load type and current and input conditions. There are two CAUTIONs for the On/Off Control: ON/OFF CONTROL TRIM LOAD R TRIM UP -SENSE +INPUT -OUTPUT CAUTION: While it is possible to control the On/Off with external logic if you carefully observe the voltage levels, the preferred circuit is either an open drain/open collector transistor or a relay (which can thereupon be controlled by logic). The On/Off prefers to be set at approx. +15V (open pin) for the ON state, assuming positive logic. CAUTION: Do not apply voltages to the On/Off pin when there is no input power voltage. Otherwise the converter may be permanently damaged. Figure 4. Trim adjustments to Increase Output Voltage using a Fixed Resistor www.murata-ps.com email: [email protected] 26 Jul 2010 MDC_HPQ-12/25-D48 Series.A02 Page 11 of 12 HPQ-12/25-D48 Series Isolated 300-Watt Quarter Brick DC/DC Converters Remote Sense Input (See Specification Note 7) Sense inputs compensate for output voltage inaccuracy delivered at the load. This is done by correcting voltage drops along the output wiring such as moderate IR drops and the current carrying capacity of PC board etch. Sense inputs also improve the stability of the converter and load system by optimizing the control loop phase margin. Note: The Sense input and power Vout lines are internally connected through low value resistors to their respective polarities so that the converter can operate without external connection to the Sense. Nevertheless, if the Sense function is not used for remote regulation, the user should connect +Sense to +Vout and –Sense to –Vout at the converter pins. On/Off Enable Control Ground Bounce Protection To improve reliability, if you use a small signal transistor or other external circuit to select the Remote On/Off control, make sure to return the LO side directly to the –Vin power input on the DC/DC converter. To avoid ground bounce errors, do not connect the On/Off return to a distant ground plane or current-carrying bus. If necessary, run a separate small return wire directly to the –Vin terminal. There is very little current (typically 1-5 mA) on the On/Off control however, large current changes on a return ground plane or ground bus can accidentally trigger the converter on or off. If possible, mount the On/Off transistor or other control circuit adjacent to the converter. The remote Sense lines carry very little current. They are also capacitively coupled to the output lines and therefore are in the feedback control loop to regulate and stabilize the output. As such, they are not low impedance inputs and must be treated with care in PC board layouts. Sense lines on the PCB should run adjacent to DC signals, preferably Ground. In cables and discrete wiring, use twisted pair, shielded tubing or similar techniques +VCC Please observe Sense inputs tolerance to avoid improper operation: ON/OFF CONTROL [Vout(+) –Vout(-)] – [ Sense(+) – Sense(-)] ≤ 10% of Vout -INPUT Contact and PCB resistance losses due to IR drops -INPUT +OUTPUT I OUT +SENSE Figure 7. Driving the On/Off Control Pin (suggested circuit) Sense Current ON/OFF CONTROL TRIM LOAD Sense Return -SENSE DC/DC Converter I OUT Return +INPUT -OUTPUT + Vin Preferred location of On/Off control adjacent to -Vin terminal Contact and PCB resistance losses due to IR drops On/Off Enable Figure 6. Remote Sense Circuit Configuration Output overvoltage protection is monitored at the output voltage pin, not the Sense pin. Therefore excessive voltage differences between Vout and Sense together with trim adjustment of the output can cause the overvoltage protection circuit to activate and shut down the output. Power derating of the converter is based on the combination of maximum output current and the highest output voltage. Therefore the designer must insure: (Vout at pins) x (Iout) ≤ (Max. rated output power) Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. ISO 9001 and 14001 REGISTERED On/Off Control Transistor -Vin return Ground plane or power return bus Do not connect control transistor through remote power bus Install separate return wire for On/Off control with remote transistor Figure 8. On/Off Enable Control Ground Bounce Protection 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. © 2010 Murata Power Solutions, Inc. www.murata-ps.com/locations 26 Jul 2010 email: [email protected] MDC_HPQ-12/25-D48 Series.A02 Page 12 of 12