DC/DC Converters 28 Volt Input mfw Series 70 Watt NOT RECOMMENDED FOR NEW DESIGNS Features • –55°C to + 85°C operation • 19 to 40 VDC input models VDC Output • 50 V for 50 ms transient protection dual • Fully isolated ±12 ±15 • Fixed frequency switching • Remote sense on single models TRIPLE +5 & ±12 +5 & ±15 • Inhibit/sync function • Indefinite short circuit protection • Up to 84% efficiency Size (max.): Weight: Screening: 3.20 x 2.46 x 0.595 inches (81.3 x 62.5 x 15.11 mm) See case L for dimensions. 140 grams typical Standard or ES. See screening table for more information. description The MFW Series™ of DC/DC converters offers up to 70 watts of power from 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. Design Methodology 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 accomplished 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. Low Noise 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-STD461C (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. Crane Aerospace & Electronics Electronics Group (Interpoint Brand) PO Box 97005 • Redmond WA 98073-9705 425.882.3100 • [email protected] www.interpoint.com Wide Voltage Range 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. Wide Temperature Range Full load operation of any of the MFW Series converters is available at case temperatures of –55°C to + 85°C. Operation up to +125°C 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 baseplate. Please refer to the heat sink requirements section for more information. Inhibit/Sync Feature 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. Page 1 of 7 MFW Rev F 20100212 DC/DC Converters absolute maximum ratings sync and inhibit Output Power •60 to 70 watts depending on model Lead Soldering Temperature (10 sec per lead) •300°C Storage Temperature Range (Case) •–55°C to +125°C Sync In (245 to 370 kHz.) •Duty cycle 70% min, 98% max. •Logic low 0.8V 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 = ≥ 4.5V recommended operating conditions Input Voltage Range •19 to 40 VDC continuous (see Derating) Case Operating Temperature (Tc) •–40°C to +85°C full power derating Output Power/Current and input voltage Temperatures are referenced to the temperature at the converter’s baseplate • Linearly derate output power/current from 100% at 85°C to 0% at 125°C. • Above 105°C linearly derate steady state input voltage to 33 volts at 125°C. • Indefinite short circuit protection is not guaranteed above 85°C 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. www.interpoint.com mfw series 70 Watt Page 2 of 7 MFW Rev F 20100212 typical characteristics Output Voltage Temperature Coefficient •150 ppm/°C, 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 DC/DC Converters mfw series 70 Watt Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified. dual and triple output models PARAMETER CONDITIONS output voltage output current1,2 line regulation cross regulation4 TYP MAX — 4.95 5.05 5.10 4.95 5.05 main — — — — — — — 4.0 10.0 — 4.0 10.0 dual — 2.92 5.5 — 2.33 4.4 — 1.67 4.2 — 1.33 3.33 main — — — — — — — 20 50 — 20 50 ±dual — 66.5 — 66.5 — 20 50 — 20 50 total — 70 — 70 — — 60 — — 60 — — 35 — 4.90 main — — — — — — — 50 85 — 50 85 dual — 30 50 — 30 50 — 50 85 — 50 85 2 20 — 2 20 100 200 — 100 200 5 20 — 5 20 600 — 300 450 main — — — — — — dual — 10 25 — 10 25 — main — — — — — — dual — 25 50 — 25 50 — 480 — 1.5 3.0 — 1.5 3.0 — — — — — — — 2.0 4.0 — 2.0 3.5 — — — — — — — — — — — — — 2.3 6.0 — 2.3 5.0 — — — — — — — 5.4 9.0 — 5.0 7.0 19 28 40 19 28 40 19 28 40 19 28 40 dual main +po = 33 w dual +po = 3 w to 27 w -po = 27 w to 3 w main +po = 3 w to 30 w dual ±po = 15 w input voltage input ripple current MAX MIN ±15.05 ±15.30 ±15.55 +po = 3 w to 35 w -po = 35 w input current mfw2815t TYP ±11.65 ±11.80 ±12.05 +po = 20 w to 50 w -po = 50 w to 20 w cross regulation5 mfw2812t MIN MAX ±14.85 ±15 ±15.15 35 — — TYP ±11.88 ±12 ±12.12 vin = 19 to 40 no load to full MIN — full load bw ≤ 2 MHz — mfw2815d MAX main vin = 19 to 40 load regulation3 TYP dual full load output power1,2 output ripple mfw2812d MIN — — no load — 75 90 — 75 90 — inhibited — 30 35 — 30 35 — full load bw ≤ 10 MHz — 15 40 — 15 40 60 110 — 60 110 30 35 — 30 35 — 15 40 — 15 40 UNITS VDC A W mV p-p mV mV % % VDC mA mA p-p efficiency 80 83 — 80 83 — 80 84 — 80 84 — % startup delay — 15 25 15 25 6 10 — 6 10 ms — 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 www.interpoint.com — 4.Regulation effect on the negative dual output during the defined conditions. 5.Regulation effect on both dual outputs during the defined conditions. Page 3 of 7 MFW Rev F 20100212 DC/DC Converters Thermal Management Calculating Maximum Ambient Temperature The MFW Series of DC/DC converters has an upper operating temperature of + 85°C 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 (PDISS vs. ambient temperature for various heat sink thermal resistances. PDISS may be calculated as: PDISS = POUT / efficiency – POUT The efficiency for all combinations of POUT and VIN for the various models may be obtained from the graphs on the preceding pages. Example:Converter = MFW2815D, TAMB = 70°C, VIN = 28 VDC, POUT = 45 watts Efficiency = 85% (From Figure 7) PDISS = (45 / 85) – 45 = 7.95 watts From Figure 1 we can see that this situation will require thermal resistance of approximately 4.5°C / 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, VIN = 28 VDC, POUT = 45 W. Thermal Resistance = 3°C / watt. Efficiency = 83.5% (From Figure 3) PDISS = (45 / 0.835) – 45 = 8.89 watts. mfw series 70 Watt From Figure 1 we can see that the maximum allowed ambient temperature is approximately 75°C. Heat Sink Recommendations 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 approximately 4°C / 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°C / 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. PIN OUT 20 W /W C/W °C/W °C/ 4°CU=3° U=2 U=0 U= Watts 15 10 5 PinDual OutputTriple Output 1Positive Input Positive Input 2Case Ground Case Ground 3Input Common Input Common 4Inhibit/Sync In Inhibit/Sync In 5Negative Output Neg. Aux. Output 6Positive Output Positive Aux. Output 7, 8Output CommonOutput Common 9, 10No ConnectionMain (+5) Output Squared corner indicates pin one. 20° 40° 60° 80° 100° 120° 140° Degrees Centigrade Internal Power Dissipation (max) vs. Ambient Temperature 1 2 3 4 Figure 1 BOTTOM VIEW MFW See case L for dimensions. 9 7 5 10 8 6 Figure 2: Pin Out www.interpoint.com Page 4 of 7 MFW Rev F 20100212 DC/DC Converters mfw series 70 Watt Typical Performance Curves: 25°C Tc , 28 VDC Vin, 100% load, free run, unless otherwise specified. 87 19 V 19 V 85 83 83 83 81 79 28 V 77 Efficiency (%) 85 75 81 79 28 V 77 40 V 73 71 20 30 40 50 60 Output Power (Watts) 70 20 30 40 50 60 40 V Output Power (Watts) 10 70 MFW2815D Efficiency vs Line & Load Figure 3 28 V 77 71 10 MFW2812D Efficiency vs Line & Load 79 73 71 10 81 75 75 40 V 73 Figure 4 20 18 Input Voltage (Volts) 81 28 V 79 77 75 40 V 73 50 60 70 Figure 5 2815S 85 83 40 Output Power (Watts) 283R5S 17 2812S 16 2805S Input Voltage (Volts) 19 V 30 MFW28512T Efficiency vs Line & Load 19 87 Efficiency (%) 87 19 V 85 Efficiency (%) Efficiency (%) 87 18 MFW2815D MFW2812D 17 MFW28512T MFW28515T 16 15 15 71 10 20 30 40 50 60 Output Power (Watts) 70 MFW28515T Efficiency vs Line & Load 10 20 30 40 50 60 70 Output Power (Watts) Low Line Dropout vs. Load (50 mV drop) MFW Single Output Models Figure 7 Figure 6 model numbering key MFW Base Model Input Voltage 28 512 T / ES Output Voltage (Main and Aux. Vout for triple models) Number of Outputs (D = dual, T = triple) Screening (Standard screening has no designator in this position.) www.interpoint.com Page 5 of 7 MFW Rev F 20100212 10 20 30 40 50 60 Output Power (Watts) 70 Low Line Dropout vs. Load (50 mV drop) MFW Dual and Triple Output Models Figure 8 DC/DC Converters mfw series 70 Watt CASE L Squared corner indicates pin one Solder Seal 3.20 max (81.3) 0.141 dia. x 6 (3.58) 2.850 (72.39) 1 .0.040 +0.005/-0.002 (1.02 +0.13/-0.05) 2 3 4 BOTTOM VIEW 1.600 (40.64) Solder Tip-off 9 7 5 10 8 6 0.550 (13.97) 0.350 (8.89) Case dimensions in inches (mm) Tolerance ±0.005 (0.13) for three decimal places ±0.01 (0.3) 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 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 L, Rev C, 20060803 Please refer to the numerical dimensions for accuracy. All 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. Copyright © 1999-2006 Interpoint Corp. All rights reserved. Figure 9: Case l www.interpoint.com Page 6 of 7 MFW Rev F 20100212 2.280 (57.91) 2.460 max (62.50) 1.625 (41.28) 1.325 (33.66) 1.425 (36.20) 1.025 (26.04) 0.825 (20.96) 0.625 (15.88) 0.00 0.180 (4.57) 0.250 +0.05/-0.00 (6.35 +1.3/-0.0) 0.000 0.040 +0.007/-0.000 (1.02 +0.18/-0.00) 0.595 max (15.11) 0.000 DC/DC Converters mfw series 70 Watt STANDARD AND /ES (NON-QML) PRODUCTS ENVIRONMENTAL SCREENING 1 standard nOn-Qml2 /es nOn-Qml2 Pre-cap Inspection Method 2017, 2032 yes yes Temperature Cycle (10 times) Method 1010, Cond. B, -55°C to +125°C, ambient no yes Constant Acceleration Method 2001, 500 g no yes Burn-in Method 1015 3 96 hours no yes Final Electrical Test MIL-PRF-38534, Group A Subgroups 1 and 4: +25°C case yes yes Hermeticity Test Fine Leak, Method 1014, Cond. A Gross Leak, Method 1014, Cond. C Gross Leak, Dip (1 x 10-3) no no yes yes yes no Final visual inspection Method 2009 yes yes test perFOrmed testmethodsarereferencedtomIL-StD-883asdeterminedbymIL-PRF-38534. Test methods are referenced to MIL-STD-883 as determined by MIL-PRF-38534. Notes: 1. refers to products that do not offer QmL screening. Notes: 1.2.Standardand/eS,non-QmLproducts,donotmeetalloftherequirementsofmIL-PRF-38534. Refers to products that do not offer QML screening. 3.Burn-indesignedtobringthecasetemperaturetothemaximumcasetemperatureoftheproduct.Refertothespecificproductinformation 2. Standard and /ES, products, do not meet all of the requirements of MIL-PRF-38534. for the maximum casenon-QML temperature. 3. Burn-in designed to bring the case temperature to the maximum case temperature of 85°C. MFW Series DC/DC Converters, MFW Rev F 20100212. This revision supersedes all previous releases. 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 © 1999 - 2010 Interpoint Corporation. All rights reserved. www.interpoint.com Page 7 of 7