b4-3 mfw series 70 watts models vdc o utput single 5 12 15 dual ? 2 ? 5 triple +5 & 12 +5 & 15 dc/dc c onverters 28 v olt i nput size (max.): 3.20 x 2.46 x 0.595 inches (81.3 x 62.5 x 15.11 mm) see section b8, case l, for dimensions. weight: 140 grams typical screening: standard or es.see section c2 for screening options, see section a5 for ordering information. description the mfw series of dc/dc converters offers up to 70 watts of power from single, dual, or triple outputs in one package. using hybrid thick film technology a power density of over 20 watts per cubic inch is achieved. these devices are packaged in hermetically sealed cold rolled steel enclosures with a tin plate finish making them ideal for use in military, aerospace, or other high reliability applications. unscreened models are guaranteed to pass a gross leak test (maximum leak rate of 0.001 atm-cc/sec). environmentally screened units (designated by the /es suffix) are hermetically solder sealed. see section c2 for screening specifications. d esign m ethodology the mfw series converters utilize a quasi-square wave forward converter design with a nominal switching frequency of 245 khz. isolation between input and output is provided with a transformer in the forward power loop and a wideband, temperature insensitive optical link in the feedback control loop. output regulation is accom- plished with constant frequency pulse width modulation. in addition, the load regulation of the single output models is further enhanced through the use of remote output voltage sense pins to overcome the adverse effects of line resistance voltage drops. short circuit protection is provided by detecting peak primary switching current on a cycle by cycle basis and limiting it to approximately 130% of the full load input current. this method results in quick and positive current limiting under short circuit conditions. l ow n oise the mfw series converters offer low noise on both the input and output lines. a two section, four pole lc input filter is included to provide very low reflected line ripple current. adherence to mil- std-461c (ce03) is possible with the addition of the fmb-461 filter. output ripple is maintained at less than 50 mv p-p for single and dual output models and 85 mv for triple output models. w ide v oltage r ange all models of the mfw series are designed to provide full power operation over an input voltage range of 19 to 40 vdc. operation below an input of 19 volts, including operation in mil-std-704e emergency power conditions, is possible with derated output power. please refer to the derating information and the low voltage drop-out graphs (figures 10 and 11) on the following pages. w ide t emperature r ange full load operation of any of the mfw series converters is available at case temperatures of ?5? to + 85?. operation up to +125? is possible with derated output power. the mfw series converters are provided in a flange mount case designed to facilitate the removal of internally generated heat. because of this, heat sinking requirements are minimal. sustained full power operation does however require that an efficient heat sink be attached to the base- plate. please refer to the heat sink requirements section for more information. i nhibit /s ync f eature standard on all models of the mfw series is a dual mode inhibit/sync pin. this pin serves as both an output inhibit and as a synchronization input. in the inhibit mode an open collector ttl compatible low (<0.8 v) will disable internal switching thereby inhibiting the unit's output. inhibiting in this manner results in an extremely low quiescent current. since a pull-up resistor is included internally, this pin may be left open should the inhibit function not be desired. in a digital system it is often desirable to synchronize the input or output ripple with the system clock. for this reason each model of the mfw series was designed to synchronize with a system clock applied to the inhibit/sync pin. please refer to the technical data section for timing details for the external sync feature. f eatures ?5? to + 85? operation 19 to 40 vdc input fully isolated optocoupler feedback fixed frequency, 245 khz typical topology ?push-pull forward 50 v for up to 50 ms transient protection inhibit/sync function indefinite short circuit protection remote sense on single models up to 84% efficiency
recommended operating conditions absolute maximum ratings typical characteristics b4-4 mfw series 70 watt dc/dc c onverters single outputs mfw2805s mfw2812s mfw2815s parameter condition min typ max min typ max min. typ max units output full load 4.95 5.00 5.05 11.88 12.00 12.12 14.85 15.00 15.15 vdc voltage output v in = 19 to 40 12.00 5.83 4.67 a current output tc = ?5? to +85? 60 70 70 w power output full load bw 2 mhz 30 50 30 50 30 50 mv p-p ripple line v in = 19 to 40 10 20 10 20 10 20 mv regulation load no load to full 10 20 10 25 10 25 mv regulation input voltage 19 28 40 19 28 40 19 28 40 vdc input no load 75 90 70 90 70 90 ma current inhibited 30 35 30 35 30 35 input refl. full load 10 25 10 25 10 25 ma p-p ripple bw 10 mhz efficiency 78 80 81 83 81 83 % startup with low 5 10 8 10 8 10 ms delay impedance source output power 60 to 70 watts depending on model lead soldering temperature (10 sec per lead) 300? storage temperature range (case) ?5? to +125? output voltage temperature coefficient 150 ppm/?, typical input to output capacitance 160 pf, typical isolation 100 megohm minimum at 500 v conversion frequency free run mode 245 khz, typical inhibit pin voltage (unit enabled) 4.5 to 5.5 v electrical characteristics: 25? tc, 28 vdc vin, 100% load, free run, unless otherwise specified. input voltage range 19 to 40 vdc continuous (see derating) case operating temperature (tc) ?5? to +85? full power sync and inhibit derating output power/current and input voltage sync in (245 to 370 khz.) duty cycle 70% min, 98% max logic low 0.8 v max logic high 4.5 v min referenced to input common if sync is not used, leave unconnected inhibit ttl open collector logic low (output disabled) inhibit pin current 1 ma max referenced to input common logic high (output enabled) v = 3 4.5 v temperatures are referenced to the temperature at the converter s baseplate linearly derate output power/current from 100% at 85? to 0% at 125?. above 105? linearly derate steady state input voltage to 33 volts at 125?. indefinite short circuit protection is not guaranteed above 85? case. operation below an input voltage of 19 volts, including operation in mil- std-704e emergency power conditions, is possible with derated output power. see figures 10 and 11.
b4-5 mfw series 70 watt dc/dc c onverters dual and triple outputs mfw2812d mfw2815d mfw28512t mfw28515t parameter condition min typ max min typ max min typ max min typ max units output full main 4.95 5.05 5.10 4.90 4.95 5.05 voltage load dual 11.88 12.00 12.12 14.85 15.00 15.15 11.65 11.80 12.05 15.05 15.30 15.55 vdc output v in = main 4.0 10.0 4.0 10.0 a current 1, 2 19 to 40 dual 2.92 5.5 2.33 4.4 1.67 4.2 1.33 3.33 output main 20 50 20 50 power 1, 2 dual 35 66.5 35 66.5 20 50 20 50 w total 70 ?0 ?0 ?0 output full load main 5085 5085 mv p-p ripple bw 2 mhz dual 30 50 30 50 50 85 50 85 line v in = main 2 20 2 20 mv regulation 19 to 40 dual 10 25 10 25 100 200 100 200 load 3 no load main 5 20 5 20 mv regulation to full dual 25 50 25 50 480 600 300 450 cross 4 dual regulation +po = 3 w to 35 w ?o = 35 w 1.5 3.0 1.5 3.0 +po = 20 w to 50 w % ?o = 50 w to 20 w 2.0 4.0 2.0 3.5 cross 5 main +po = 33 w regulation dual +po = 3 w to 27 w 2.3 6.0 2.3 5.0 ?o = 27 w to 3 w main % +po = 3 w to 30 w dual po = 15 w 5.4 9.0 5.0 7.0 input voltage 19 28 40 19 28 40 19 28 40 19 28 40 vdc input no load 75 90 75 90 60 110 60 110 ma current inhibited 30 35 30 35 30 35 30 35 input refl. full load 15 40 15 40 15 40 15 40 ma p-p ripple bw 10 mhz efficiency 80 83 80 83 80 84 80 84 % startup 15 25 15 25 6 10 6 10 ms delay electrical characteristics: 25? tc, 28 vdc vin, 100% load, free run, unless otherwise specified. notes 1. on dual output models the maximum combined output power is 70 watts. a maximum of 95% (66.5 w) is available from any single output. 2. on triple output models the maximum combined output power is 60 watts. a maximum of 50 watts is available from a single output. 3. balanced loads. 4. regulation effect on the negative dual output during the defined conditions. 5. regulation effect on both dual outputs during the defined conditions.
b4-6 mfw series 70 watt dc/dc c onverters c alculating m aximum a mbient t emperature the mfw series of dc/dc converters has an upper operating temperature of + 85? at the baseplate of the case. the degree of heat sinking required to remain within this limit may be determined from figure 1 which shows the maximum allowed internal power dissipation (p diss vs. ambient temperature for various heat sink thermal resistances. p diss may be calculated as: p diss = p out / efficiency ?p out the efficiency for all combinations of p out and v in for the various models may be obtained from the graphs on the preceding pages. example: converter = mfw2815d, t amb = 70?, v in = 28 vdc, p out = 45 watts efficiency = 85% (from figure 7) p diss = (45 / 85) ?45 = 7.95 watts from figure 1 we can see that this situation will require thermal resistance of approximately 4.5? / watt. conversely we may also find the maximum ambient temperature which can be tolerated if we know the heat sink thermal resistance. example: converter = mfw2805s, v in = 28 vdc, p out = 45 w. thermal resistance = 3? / watt. efficiency = 83.5% (from figure 3) p diss = (45 / 0.835) ?45 = 8.89 watts. from figure 1 we can see that the maximum allowed ambient temperature is approximately 75?. h eat s ink r ecommendations an mfw series converter in still air (other than convective currents) and with no conductive cooling paths other than through electrical connections at the pins will exhibit a thermal resistance of approxi- mately 4? / watt. in cases where this value proves to be too high it is recommended that additional heat sinking be supplied. the simplest method of accomplishing this is to firmly attach the converter to a pcb thereby providing a conductive thermal path. secondly it is recommended that airflow be provided over the converter. although each situation requires a thorough thermal analysis these two measures can reduce the thermal resistance to as low as 2? / watt. if calculations indicate further heat sinking is required it is recommended that additional thermal mass be provided either under the base plate or on top of the converter's mounting flanges or both. thermal management degrees centigrade watts 20 40 60 80 100 120 140 20 15 10 5 u=4 c/w u=3 c/w u=2 c/w u=0 c/w internal power dissipation (max) vs. ambient temperature f igure 1
pin out b4-7 mfw series 70 watt dc/dc c onverters squared corner indicates pin one. bottom view mfw 12 3 4 5 6 7 8 9 10 f igure 2: p in o ut model numbering key mfw 28 512 t / es base model input voltage output voltage screening number of outputs (s = single, d = dual, t = triple) (main and aux. vout for triple models) (standard screening has no designator in this position.) pin single output dual output triple output 1 positive input positive input positive input 2 case ground case ground case ground 3 input common input common input common 4 inhibit/sync in inhibit/sync in inhibit/sync in 5 negative sense negative output negative aux. output 6 positive sense positive output positive aux. output 7, 8 output common output common output common 9, 10 positive output no connection main (+5) output see section b8, case l, for dimensions.
b4-8 mfw series 70 watt dc/dc c onverters typical performance curves: 25? tc , 28 vdc vin, 100% load, free run, unless otherwise specified. f igure 6 f igure 8 10 20 30 40 50 60 70 87 85 83 81 79 77 75 73 71 40 v 28 v 19 v efficiency (%) output power (watts) mfw2812d efficiency vs line & load 10 20 30 40 50 60 70 87 85 83 81 79 77 75 73 71 40 v 28 v 19 v efficiency (%) output power (watts) mfw28512t efficiency vs line & load efficiency (%) 10 20 30 40 50 60 70 86 85 84 83 82 81 80 79 78 40 v 28 v 20 v output power (watts) mfw2805s efficiency vs line & load f igure 3 10 20 30 40 50 60 70 89 88 87 86 85 84 83 82 81 40 v 28 v 19 v efficiency (%) output power (watts) mfw2812s efficiency vs line & load f igure 4 10 20 30 40 50 60 70 87 85 83 81 79 77 75 73 71 40 v 28 v 19 v efficiency (%) output power (watts) mfw2815d efficiency vs line & load f igure 7 f igure 5 10 20 30 40 50 60 70 89 88 87 86 85 84 83 82 81 40 v 28 v 19 v efficiency (%) output power (watts) mfw2815s efficiency vs line & load 10 20 30 40 50 60 70 87 85 83 81 79 77 75 73 71 40 v 28 v 19 v efficiency (%) output power (watts) mfw28515t efficiency vs line & load f igure 9 input voltage (volts) 15 10 20 30 40 50 60 70 16 17 18 283r5s 2815s 2812s 2805s output power (watts) low line dropout vs. load (50 mv drop) mfw single output models f igure 10 f igure 11 15 10 20 30 40 50 60 70 16 17 18 19 mfw2815d mfw2812d mfw28512t mfw28515t input voltage (volts) output power (watts) low line dropout vs. load (50 mv drop) mfw dual and triple output models 20621-001-dts rev a dq# 1016 all technical information is believed to be accurate, but no responsibility is assumed for errors or omissions. interpoint reserves the right to make changes in products or specifications without notice. mfw series is a trademark of interpoint. copyright 1991- 1999 interpoint. all rights reserved.
b8-31 case l c ases 0.060 min (1.52) 0.060 min (1.52) 0.337 min (8.56) 0.337 min (8.56) 3.20 max (81.3) 2.46 max (62.5) materials header cold rolled steel/nickel/tin cover cold rolled steel/nickel/tin pins #52 alloy pins 1-4, and 9-10 #52 alloy with copper core pins 5-8 ceramic seal case dimensions in inches (mm) tolerance 0.005 (0.13) for three decimal places 0.01 (0.2) for two decimal places unless otherwise specified caution heat from reflow or wave soldering may damage the device. solder pins individually with heat application not exceeding 300 c for 10 seconds per pin. squared corner indicates pin one case l top view cover placement and min/max dimensions see figure 50 for pin configuration f igure 49: c ase l m aximum d imensions
b8-32 case l c ases solder seal solder tip-off 2.850 (72.39) 0.550 (13.97) 1.600 (40.64) 0.350 (8.89) 0.000 0.00 0.000 0.180 (4.57) 0.040 +0.007/-0.000 (1.02 +0.18/-0.00) 0.595 max (15.11) 0.250 +0.05/-0.00 (6.35 +1.3/-0.0) 0.625 (15.88) 0.825 (20.96) 1.025 (26.04) 1.325 (33.66) 1.425 (36.20) 1.625 (41.28) 2.280 (57.91) .0.040 +0.005/-0.002 (1.02 +0.13/-0.05) bottom view 12 3 4 5 6 7 8 9 10 squared corner indicates pin one mfw series: screening ?standard or es hr700 series: no screening options case l 0.141 x 6 (3.58) f igure 50: c ase l d imensions
c2-12 qa screening 85? products test (85? products excluding hr products) standard /es pre-cap inspection method 2017 yes yes temperature cycle (10 times) method 1010, cond. b, -55? to 125? no yes constant acceleration method 2001, 500 g no yes burn-in 96 hours at 70? ambient (typical) no yes final electrical test mil-prf-38534, group a subgroups 1 and 4: +25? case yes yes hermeticity testing fine leak, method 1014, cond. a no yes gross leak, method 1014, cond. c no yes gross leak, dip (1 x 10 -3 ) yes no final visual inspection method 2009 yes yes test methods are referenced to mil-std-883 as determined by mil-prf-38534. mfw series mtw series mhe/mlp series mhl series mrh series mto series msr series dch series fm/fma/fmb emi filters msf emi filter 85? p roducts applies to the following products:
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