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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 de- livers ? xed 12 vdc output at 300 watts for printed circuit board mounting. wide range inputs on the 2.3 x 1.45 x 0.49 converter are 36 to 75 volts dc (48 volts nominal), ideal for datacom and telecom systems. the ? xed output voltage is regulated to within 0.25%. 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 speci? cations as- sure compatibility to cpus, asics, programmable logic and fpgas. no minimum load is required. for systems needing controlled startup/shutdown, an external remote on/off control may use either posi- tive or negative polarity. remote sense inputs com- pensate for resistive line drops at high currents. a wealth of self-protection features avoid prob- lems with both the converter and external circuits. these include input undervoltage lockout and overtemperature shutdown using an on-board tem- perature sensor. overcurrent protection using the hiccup autorestart technique provides inde? nite short-circuit protection. additional safety features include output overvoltage protection and reverse conduction elimination. the synchronous recti? er to- pology offers high ef? ciency for minimal heat buildup and no heat sink operation. the hpq-12/25-d48 series is certi? ed to full safety standards ul/en/iec/ csa 60950-1, 2nd edition and rfi/emi conducted/ radiated emission compliance to en55022, cispr22 with external ? lter. product overview embedded systems, datacom and telecom installations disk farms, data centers and cellular repeater sites remote sensor systems, dedicated controllers instrumentation systems, r&d platforms, auto- mated test ? xtures data concentrators, voice forwarding and speech processing systems applications features 12 volts dc ? xed output up to 25 amps industry standard quarter brick 2.3 x 1.45 x 0.49 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 ef? ciency (94.5%) synchronous recti? er topology stable no-load operation with no required external components operating temperature range -40 to +85 c. with no heat sink required certi? ed to 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 $ feat ur es f1 external dc power source reference and error ampli?er t4xjudijoh t'jmufst t$vssfou4fotf -vout (4) +vout (8) 4fotf
4fotf
5sjn
on/off control (2) -vin (1) open = on $mptfe0gg +vin (3) 1ptjujwf polarity) controller and power 5sbotgfs *tpmbujpo barrier figure 1. connection diagram typical unit typical topology is shown. murata power solutions recommends an external fuse. * x option omits trim and sense pins. hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters for full details go to www.murata-ps.com/rohs www.murata-ps.com www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 1 of 13
? please refer to the part number structure for additional ordering information and options. ? all speci? cations are at nominal line voltage and full load, +25 deg.c. unless otherwise noted. see detailed speci? cations. output capacitors are 1 f ceramic in parallel with 10 f electrolytic with no input caps.these caps are necessary for our test equipment and may not be needed for your application. ? minimum ef? ciency applies over all input voltages, the full operating temperature range and full load. ordering guide ? root model ? output input ef? ciency package (c59) v out (volts) i out (amps, max.) power (watts) r/n (mv pk-pk) regulation (max.) ? v in nom. (volts) range (volts) i in no load (ma) i in full load (amps) typ. max. line load min. ? typ. dimensions (inches) dimensions (mm) hpq-12/25-d48 hpq-12/25-d48 12 25 300 80 150 0.125% 0.25% 48 36-75 150 6.61 91% 94.5% 1.45x2.3x0.49 max. 1.45x2.3x0.49 max. 36.8x58.4x12.45 36.8x58.4x12.45 part number structure 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 lx d48 input voltage range: d48 = 36-75 volts (48v nominal) / nominal output voltage 12 note: some model combinations may not be available. contact murata power solutions for availability. 25 maximum rated output : current in amps - n on/off control polarity n = negative polarity, standard p = positive polarity, optional - hpq family series: high power quarter brick baseplate (optional) blank = no baseplate, standard b = baseplate installed, optional b rohs hazardous materials compliance c = rohs-6 ( does not claim eu rohs exemption 7bClead in solder ), standard y = rohs-5 (with lead), optional, special quantity order - c conformal coating (optional) blank = no coating, standard h = coating added, optional h trim & sense pins option blank = trim and sense installed, standard x = trim and sense removed x complete model number example: negative on/off logic, baseplate installed, conformally coated, trim and sense pins removed, 0.110? pin length, rohs-6 complian ce hpq-12/25-d48nbhxl1-c hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 2 of 13
third angle projection dimensions are in inches (mm) shown for ref. only. components are shown for reference only. tolerances (unless otherwise speci?ed): .xx 0.02 (0.5) .xxx 0.010 (0.25) angles 2? ? m3 bolts must not exceed 0.118? (3mm) depth below the baseplate surface. ? applied screw torque must not exceed 5.3 in-lb. (0.6 n-m). the standard 0.180? pin length is shown. please refer to the part number structure for alternate pin lengths. 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. label 0.600 15.24 0.300 7.62 0.600 15.24 2.30 58.4 1.45 36.8 1 2 3 8 7 6 5 4 8 7 6 5 4 0.600 15.24 0.300 7.62 0.600 15.24 1 2 3 2.000 50.80 l 0.49 max 12.4 0.165 4.20 0.005 minimum clearance between standoffs and highest component pins 1-3,5-7: 0.0400.001(1.0160.025) pins 4,8: 0.0620.001(1.5750.025) 2.000 50.80 0.50 12.7 pins 1-3,5-7: 0.0400.001(1.0160.025) pins 4,8: 0.0620.001(1.5750.025) 0.005 minimum clearance between standoffs and highest component 2.210 56.13 1.360 34.54 label 1.860 0.008 47.24 0.20 1.030 0.008 26.16 0.20 1.45 36.8 2.30 58.4 0.180 4.6 m3 threaded insert 4 places see note 1&2 bottom pin side view bottom pin side view side view case c59 top view no baseplate top view with baseplate i/o connections (pin side view) pin function p32 pin function p32 1 neg. vin 5 neg. sense* 2 remote on/off control 6 trim* 3 pos. vin 7 pos. sense* 4 neg. output 8 pos. output * the sense and trim pins are removed for the x model option. mechanical specifications (through-hole mount) hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 3 of 13
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 4 of 13 functional specifications absolute maximum ratings conditions ? minimum typical/nominal maximum units input voltage, continuous full power operation 36 75 vdc input voltage, transient operating or non-operating, 100 ms max. duration 100 vdc isolation voltage input to output tested 100 ms 2250 vdc input reverse polarity none, install external fuse none vdc on/off remote control power on or off, referred to -vin 0 15 vdc output power 0 300 w output current current-limited, no damage, short-circuit protected 025a 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-ter m reliability. proper operation under conditions other than those listed in the performance/functional speci? cations table is not implied or recommended. input conditions ? ? operating voltage range 36 48 75 vdc recommended external fuse fast blow 20 a start-up threshold rising input voltage 33 34 35 vdc undervoltage shutdown falling input voltage 31 32 34 vdc overvoltage protection rising input voltage none vdc reverse polarity protection none, install external fuse none vdc internal filter type pi-type input current full load conditions vin = nominal 6.61 6.82 a low line vin = minimum 9.1 a inrush transient vin = 48v. 0.3 a2-sec. output in short circuit 50 100 ma no load iout = minimum, unit=on 150 250 ma standby mode (off, uv, ot) 510ma re? ected (back) ripple current ? measured at input with speci? ed ? lter 50 70 ma, rms pre-biased startup external output voltage < vset monotonic general and safety ef? ciency vin=48v, full load 91 ? 94.5 % vin=36v, full load 91 ? 94.5 % isolation isolation voltage, input to output no baseplate 2250 vdc isolation voltage, input to output with baseplate 2250 vdc isolation voltage, input to baseplate with baseplate 1500 vdc isolation voltage, output to baseplate with baseplate 1500 vdc insulation safety rating basic isolation resistance 10 m isolation capacitance 1000 pf safety certi? ed to ul-60950-1, csa-c22.2 no.60950-1, iec/en60950-1, 2nd edition yes calculated mtbf per mil-hdbk-217f, ground benign, tambient=+tbdc tbd hours x 10 3 calculated mtbf per telcordia sr-332, issue 1, class 3, ground ? xed, tcase=+25c 1500 hours x 10 3 dynamic characteristics fixed switching frequency 260 khz startup time power on, to vout regulation band, 100% resistive load 25 ms startup time remote on to vout regulated 25 ms dynamic load response 50-75-50% load step to 1% error band 550 825 sec dynamic load di/dt 0.1 a / sec dynamic load peak deviation same as above 400 750 mv features and options remote on/off control ? n suf? x: negative logic, on state on = pin grounded or external voltage 0 0.8 vdc negative logic, off state off = pin open or external voltage 3.5 13.5 vdc control current open collector/drain 5 ma
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 5 of 13 features and options (cont.) conditions ? minimum typical/nominal maximum units remote on/off control (cont.) ? p suf? x: positive logic, on state on = pin open or external voltage 3.5 13.5 v positive logic, off state off = ground pin or external voltage 0 0.8 v control current open collector/drain 5 ma remote sense compliance ? vsense=vout - vload, sense pins connected externally to respective vouts 0.5 v base plate "b" suf? x optional output total output power 0.0 300 306 w voltage setting accuracy at 50% load, no trim 11.76 12 12.24 vdc output voltage range ? user-adjustable -10 +10 % of vnom. overvoltage protection via magnetic feedback 110 150 %vout current output current range 0.0 25.0 a minimum load no minimum load current limit inception 97% of vnom., after warmup 110 150 % of iout max. short circuit short circuit current hiccup technique, autorecovery within 1.25% of vout 0.8 1.0 a short circuit duration (remove short for recovery) output shorted to ground, no damage continuous short circuit protection method hiccup current limiting non-latching regulation ? line regulation vin=min. to max., vout=nom., full load 0.125 % of vout load regulation iout=min. to max., vin=nom. 0.25 % of vout ripple and noise ? 5 hz- 20 mhz bw, cout=1f mlcc paralleled with 10f tantalum 80 150 mv pk-pk temperature coef? cient at all outputs 0.02 % of vout./c maximum capacitive loading full resistive load, low esr 0 4,700 f mechanical (through hole models) outline dimensions (no baseplate) c59 case 1.45x2.3x0.49 max. inches (please refer to outline drawing) wxlxh 36.8x58.4x12.45 mm outline dimensions (with baseplate) 1.45x2.3x0.5 inches 36.8x58.4x12.7 mm weight no baseplate 1.51 ounces no baseplate 47 grams with baseplate 2.4 ounces with baseplate 68 grams through hole pin diameter 0.04 & 0.062 inches 1.016 & 1.575 mm through hole pin material copper alloy th pin plating metal and thickness nickel subplate 100-299 -inches gold overplate 3.9-19.6 -inches baseplate material aluminum environmental operating ambient temperature range no derating, full power, 200 lfm, no condensation -40 85 c storage temperature vin = zero (no power) -55 125 c thermal protection/shutdown measured at hotspot 105 110 125 ?c electromagnetic interference external ? lter is required conducted, en55022/cispr22 b class radiated, en55022/cispr22 b class relative humidity, non-condensing to +85c 10 90 %rh altitude must derate -1%/1000 feet -500 10,000 feet -152 3048 meters acceleration 50 g shock halfsine wave, 3 axes 1 g sinusoidal vibration gr-63-core, section 5.4.2 rohs rating rohs-6 functional specifications (cont.)
typical performance data ef? ciency and power dissipation @ +25 c maximum current temperature derating vs. air? ow (vin=vnom., air? ow direction is from -vin to +vin, with baseplate, at sea level) 0 5 10 15 20 25 30 30 35 40 45 50 55 60 65 70 75 80 85 100 lfm 200 lfm 300 lfm 400 lfm output current (amps) ambient temperature (c) maximum current temperature derating vs. air? ow (vin=vnom., air? ow direction is from vin to vout, no baseplate, at sea level) 0 5 10 15 20 25 30 30 35 40 45 50 55 60 65 70 75 80 85 100 lfm 200 lfm 300 lfm 400 lfm output current (amps) ambient temperature (c) power on startup delay output (vin = 0 to 48v, iout = 25a, cload = 0, ta = +25 c) 3 5 7 9 11 13 15 17 19 21 23 25 75 80 85 90 95 100 v in = 36 v v in = 48 v v in = 75 v ef?ciency (%) iout (amps) hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 6 of 13 notes ? unless otherwise noted, all speci? cations 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 air? ow unless otherwise speci? ed. all models are tested and speci? ed with external parallel 1 f and 10 f 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 users application. ? input (back) ripple current is tested and speci? ed over 5 hz to 20 mhz bandwidth. input ? ltering is cin = 33 f, cbus = 220f and lbus = 4.7 h. ? all models are stable and regulate to speci? cation under no load. ? the remote on/off control is referred to -vin. ? regulation speci? cations 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. ? output ripple and noise is measured with cout = 1f mlcc paralleled with 10f tantalum, 20 mhz oscilloscope bandwidth and full resistive load. ? the sense and trim pins are removed for the x model option. ? noticeplease 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 of? cial 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 cus- tomer 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. ? minimum ef? ciency applies over all input voltages, the full operating temperature range and full load.
typical performance data max = 81a, period = 1.180s, pulse width = 6.4ms step load transient response (vin = 48v, cload = 1 f ceramic and 10 f tantalum, iout = 50-75-50% lmax, slew = 0.1a/ sec., ta = +25 c) output ripple and noise (vin=36v, iout=25a, cload=0, ta=+25?c., scopebw=20mhz) output ripple and noise (vin=36v, iout=0a, cload=0, ta=+25?c., scopebw=20mhz) 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) hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 7 of 13
typical performance data output ripple and noise (vin=48v, iout=0a, 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=48v, iout=25a, cload=0, ta=+25?c., scopebw=20mhz) output ripple and noise (vin=75v, iout=25a, cload=0, ta=+25?c., scopebw=20mhz) hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 8 of 13
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 9 of 13 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 perma- nent 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 speci? cations). 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 shut- down whose voltage decays as input current is consumed (such as capacitor inputs), the converter shuts off and then restarts as the external capacitor re- charges. 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 start- up delay (see speci? cations) 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 speci? ed regulation band. actual measured times will vary with input source impedance, external input capacitance, input volt- age slew rate and ? nal 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 v out 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 speci? ed regulation band. the speci? cation assumes that the output is fully loaded at maximum rated current. input source impedance these converters will operate to speci? cations without external components, assuming that the source voltage has very low impedance and reasonable in- put voltage regulation. since real-world voltage sources have ? nite impedance, performance is improved by adding external ? lter components. sometimes only a small ceramic capacitor is suf? cient. since it is dif? cult to totally characterize all applications, some experimentation may be needed. note that external input capacitors must accept high speed switching currents. application notes 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 speci? es 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 speci? ed for input re? ected ripple current and output noise using designated external input/output compo- nents, circuits and layout as shown in the ? gures below. external input capaci- tors (c in in the ? gure) 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 ? gure below, the c bus and l bus components simulate a typical dc voltage bus. your speci? c system con? guration may require additional considerations. please note that the values of c in , l bus and c bus may vary according to the speci? c converter model. in critical applications, output ripple and noise (also referred to as periodic and random deviations or pard) may be reduced by adding ? lter elements such as multiple external capacitors. be sure to calculate component temperature rise from re? ected ac current dissipated inside capacitor esr. in ? gure 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 connec- tors or the probe ground should not exceed one half inch and soldered directly to the ? xture. floating outputs since these are isolated dc/dc converters, their outputs are ? oating 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 speci? cations). these leakages consist of both an ac stray capacitance coupling component and a dc leakage resistance. when using the isolation feature, do not allow the isolation voltage to exceed speci? cations. 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. c in v in c bus l bus c in = 33f, esr < 200m @ 100khz c bus = 220f, 100v l bus = 4.7h +input ?input current probe to oscilloscope + C + C figure 2. measuring input ripple current
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 10 of 13 minimum output loading requirements these converters employ a synchronous recti? er design topology. all models regulate within speci? cation and are stable under no load to full load conditions. operation under no load might however slightly increase output ripple and noise. thermal shutdown to protect against thermal over-stress, these converters include thermal shut- down circuitry. if environmental conditions cause the temperature of the dc/ dcs to rise above the operating temperature range up to the shutdown tem- perature, 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. temperature derating curves the graphs in the next section illustrate typical operation under a variety of condi- tions. the derating curves show the maximum continuous ambient air temperature and decreasing maximum output current which is acceptable under increasing forced air? ow 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 air? ow as long as the average is not exceeded. note that the temperatures are of the ambient air? ow, not the converter itself which is obviously running at higher temperature than the outside air. also note that natural convection is de? ned as very low ? ow rates which are not using fan-forced air? ow. depending on the application, natural convection is usu- ally 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 air? ow. we use both thermocouples and an infrared camera system to observe thermal performance. as a practical matter, it is quite dif? cult to insert an anemometer to precisely measure air? ow in most applications. sometimes it is possible to estimate the effective air? ow if you thoroughly understand the enclosure geometry, entry/exit ori? ce areas and the fan ? owrate speci? cations. 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 pri- mary 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 volt- age to ramp up to its rated value. it is not necessary to power down and reset the converter for this automatic ovp-recovery restart. 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. 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. current limiting inception is de? ned as the point at which full power falls below the rated tolerance. see the performance/functional speci? cations. note particularly that the output current may brie? y 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. 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 initi- ate. this on/off cycling is called hiccup mode. the hiccup cycling reduces the average output current, thereby preventing excessive internal temperatures. trimming the output voltage (see speci? cation 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 speci? cations). in the trim equations and circuit diagrams that follow, trim adjustments use a single ? xed resistor connected between the trim input and either vout pin. trimming resistors should have a low temperature coef? cient (100 ppm/deg.c or less) and be mounted 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 speci? ed output voltage accuracy. 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. figure 3. measuring output ripple and noise (pard) c1 c1 = 0.1f ceramic c2 = 10f low es load 2-3 inches (51-76mm) from module c2 r load copper strip copper strip scope +output ?output
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 11 of 13 caution: be careful of external electrical noise. the trim input is a senstive input to the converters feedback control loop. excessive electrical noise may cause instability or oscillation. keep external connections short to the trim input. use shielding if needed. trim equations 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 ? is given as a small fraction, not a percentage. remote on/off control on the input side, a remote on/off control can be speci? ed with either positive or negative logic as follows: positive: models equipped with positive logic are enabled when the on/off pin is left open or is pulled high to +13.5v dc with respect to Cv in . an internal bias current causes the open pin to rise to +v in . positive-polarity devices are disabled when the on/off is grounded or brought to within a low voltage (see speci? cations) with respect to Cv in . on positive-polarity models, to reduce noise coupling on the external on/off control, use the circuit shown in ? gure 6. negative: models with negative polarity are on (enabled) when the on/off is grounded or brought to within a low voltage (see speci? cations) with respect to Cv in . the device is off (disabled) when the on/off is left open or is pulled high to +13.5v dc max. with respect to Cv in . dynamic control of the on/off function should be able to sink the speci? ed signal current when brought low and withstand speci? ed voltage when brought high. be aware too that there is a ? nite time in milliseconds (see speci? cations) 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: 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. +13.5v (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. r adj_up ( in k ) = - - 2 v nominal x (1+) 1 1.225 x where = v nominal - v out v nominal r adj_down ( in k ) = - 2 1 where = v out - v nominal v nominal figure 4. trim adjustments to increase output voltage using a fixed resistor load r trim up +output +sense trim -sense -output -input on/off control +input figure 5. trim adjustments to decrease output voltage using a fixed resistor +output +sense trim -sense -output -input on/off control +input load r trim down figure 7. driving the on/off control pin (suggested circuit) on/off control -input +vcc figure 6. on/off control filter on/off -input 316 k 47 k 0.1 f 2.5v circuit +input
hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters www.murata-ps.com email: sales@murata-ps.com 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 12 of 13 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 Cvin 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 Cvin 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. figure 9. on/off enable control ground bounce protection preferred location of on/off control adjacent to -vin terminal dc/dc converter install separate return wire for on/off control with remote transistor on/off control transistor do not connect control transistor through remote power bus ground plane or power return bus + vin on/off enable -vin return remote sense input (see speci? cation 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 mod- erate 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 Csense to Cvout at the converter pins. 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 please observe sense inputs tolerance to avoid improper operation: [vout(+) Cvout(-)] C [ sense(+) C sense(-)] 10% of vout 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 protec- tion 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 ensure: (vout at pins) x (iout) (max. rated output power) figure 8. remote sense circuit con? guration load contact and pcb resistance losses due to ir drops contact and pcb resistance losses due to ir drops +output +sense trim -sense -output -input on/off control +input sense current i out sense return i out return
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>?i> ,/>???>i? ???v>???`? 6>?>l?i ??ii`v>? i>??} i?i?i? ?l?i? i??i>?i ?i??? ?v?? v?????>? *iv????? ???>i >?i???ii ??li??11/ 1????`i i?-11/? vertical wind tunnel murata power solutions employs a custom-designed enclosed vertical wind tunnel, infrared video camera system and test instrumentation for accurate air? ow and heat dissipation analysis of power products. the system includes a precision low ? ow-rate anemometer, variable speed fan, power supply input and load controls, temperature gauges and adjustable heating element. the ir camera can watch thermal characteristics of the unit under test (uut) with both dynamic loads and static steady- state conditions. a special optical port is used which is transpar- ent to infrared wavelengths. the computer ? les from the ir camera can be studied for later analysis. both through-hole and surface mount converters are soldered down to a host carrier board for realistic heat absorption and spreading. both longitudinal and transverse air? ow studies are possible by rotation of this carrier board since there are often signi? cant differences in the heat dissipation in the two air? ow directions. the combination of both adjustable air? ow, adjustable ambient heat and adjustable input/output currents and voltages mean that a very wide range of measurement conditions can be studied. the air? ow collimator mixes the heat from the heating element to make uniform temperature distribution. the collimator also reduces the amount of turbulence adjacent to the uut by restor- ing laminar air? ow. such turbulence can change the effective heat transfer characteristics and give false readings. excess turbulence removes more heat from some surfaces and less heat from others, possibly causing uneven overheating. both sides of the uut are studied since there are different thermal gradients on each side. the adjustable heating element and fan, built-in temperature gauges and no-contact ir camera mean that power supplies are tested in real- world conditions. figure 10. vertical wind tunnel hpq-12/25-d48 series isolated 300-watt quarter brick dc/dc converters 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 her ein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. speci? cations are subject to cha nge without notice. ? 2010 murata power solutions, inc. www.murata-ps.com/locations email: sales@murata-ps.com murata power solutions, inc. 11 cabot boulevard, mans? eld, ma 02048-1151 u.s.a. iso 9001 and 14001 registered 16 dec 2010 mdc_h pq-12/25-d48 series.a05 page 13 of 13

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