FEATURES DC/DC CONVERTERS 28 VOLT INPUT • –55°C to +85°C operation • 18 to 40 VDC input (19 to 40 VDC MTW2805S) • Fully Isolated • Optocoupler feedback • Fixed frequency • Topology – Push-Pull Forward • 50 V for up to 50 ms transient protection • Inhibit function • Indefinite short circuit protection • Remote sense on MTW2805S model • Up to 86% efficiency MTW SERIES 30 WATT MODELS VDC OUTPUT SINGLE 5 12 15 DUAL ±12 ±15 Size (max.): 2.720 x 1.350 x 0.505 inches (69.09 x 34.29 x 12.83 mm) See Section B8, case J5, for dimensions. Weight: 60 grams max. Screening: Standard or ES. See Section C2 for screening options, see Section A5 for ordering information. DESCRIPTION The MTW Series™ of DC/DC converters offer the high efficiency and wide input voltage range of switching regulators with the isolation, excellent output regulation, and low output noise typical of linear regulators without requiring the use of external components. MTW converters are built using thick-film hybrid technology and are sealed in metal packages for military, aerospace and other high-reliability applications. Unscreened models are sealed with solder and are guaranteed to pass a gross leak test (maximum leak rate of 1 x 10-3 atm.-cc/sec). Environmentally screened models (/ES) are hermetically sealed with solder and will pass a fine leak and gross leak test as described in Section C2. MTW converters use a constant frequency pulse-width modulated switching regulator design operating in the forward mode with a clock switching frequency of 240 to 300 kHz. Isolation is achieved through the use of a transformer in the forward power circuit and an optocoupler in the feedback control loop. The full load output power of 30 watts is available over the entire 18 to 40 VDC (19 to 40 VDC for MTW2805S) input range. On dual output models, up to 90% of full power is available from either output up to a combined total of 30 watts. Input transients of 50 V to up to 50 ms. duration will not impair normal operation. Efficiency is high over the entire input voltage range and from approximately 25% of full load to full load (see typical efficiency curves). MTW converters are provided with indefinite short circuit protection through the use of current limiting techniques. When the output current reaches approximately 125% of the full rated load, the output voltage begins to reduce to protect the converter. The converter can sustain a true short circuit condition indefinitely. An inhibit is provided to allow power shut-down and start-up from a logic input. An open circuit on the inhibit pin allows normal operation, while a connection between the inhibit pin and input common disables the internal oscillator and shuts down the output. In the inhibit mode, approximately 1 mA must be sunk from pin the inhibit pin. An open collector, active low, is required to activate the inhibit function. All MTW converters are characterized by close output regulation over the entire operating range with no minimum power requirement. On 12 and 15 VDC output models, typical line regulation is 10 to 20 mv. The MTW2805S model uses external remote sense pins which monitor the voltage at the load to provide typical regulation in the 5 to 7 mV range. The voltage sensing circuitry operates in a true four terminal voltage mode, eliminating the adverse effects of line resistance voltage drops. The remote sense pins may be left unconnected, but see cautions in on the following pages. For normal operation, remote sense pins should be connected to their respective output pins. The MTW Series offers low noise on both the input and output line. in the single output converters, two-section L-C filters at both the input and output limit output ripple voltage and minimize reflected ripple on the input line. A small value (1000 pF, 500 V) ceramic capacitor connected between the case and input common pin of the single volt output models will reduce EMI on the input lines to levels near those required by MIL-STD-461C’s CE03 standard. In the dual output converters, single-section L-C filters are used at the input and outputs. If compliance with MIL-STD-461 is necessary, use of Interpoint’s FMA-416 EMI filter or FM-704A transient suppressor is recommended. With temperatures measured at the baseplate, the MTW Series is rated for full power operation from –55°C to +85°C with the power derated linearly to 0 at 115°C. The MTW’s flanged case facilitates removal of heat and provides for mechanically secure mounting.In applications requiring full power operation, an efficient heat sink attached to the baseplate is required. B4-9 MTW SERIES 30 WATT DC/DC CONVERTERS TYPICAL CHARACTERISTICS INHIBIT ABSOLUTE MAXIMUM RATINGS Input Voltage • 18 to 40 VDC (19 to 40 VDC MTW2805S) Output Power • 30 watts Lead Soldering Temperature (10 sec per lead) • 300°C Storage Temperature Range (Case) • –55°C to +125°C Inhibit TTL Open Collector • Logic low (output disabled) Inhibit pin current 1 mA typical • Referenced to input common • Logic high (output enabled) Open collector Output Voltage Temperature Coefficient • 100 ppm/°C, typical Input to Output Capacitance • 80 pF typical single output models • 70 pF typical MTW2812D • 60 pF typical MTW2815D Current Limit • 125% of full load typical Isolation • 100 megohm minimum at 500 V Conversion Frequency • 240 to 300 kHz Inhibit Pin Voltage (unit enabled) • 11 to 15 V single output models • 8 to 12 V MTW2812D • 10 to 14 V MTW2815D RECOMMENDED OPERATING CONDITIONS Input Voltage Range • 18 to 40 VDC continuous (19 to 40 MTW2805S) • 50 V for 50 msec transient Case Operating Temperature (Tc) • –55°C to +85°C full power • –55°C to +115°C absolute Derating Output Power/Current • Linearly from 100% at 85°C to 0% at 115° C Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified. MTW2805S PARAMETER MTW2812S MTW2815S MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS OUTPUT VOLTAGE 4.95 5.0 5.05 11.88 12.0 12.12 14.85 15.0 15.15 VDC OUTPUT CURRENT — — 6.0 — — 2.5 — — 2.0 A — — 30.0 — — 30.0 — — 30.0 W OUTPUT POWER CONDITIONS –55°C TO +85°C BW ≤ 2 MHz — 30 50 — 30 65 — 30 65 mV p-p LINE REGULATION1 MIN. TO MAX. VIN — 7 20 — 10 25 — 10 25 mV LOAD REGULATION1 NO LOAD TO FULL — 5 20 — 10 20 — 10 20 INPUT VOLTAGE NO LOAD TO FULL 19 28 40 18 28 40 18 28 40 –55°C TO +85°C TRANSIENT 50 ms — — 50 — — 50 — — 50 NO LOAD — 15 20 — 20 35 — 20 35 FULL LOAD — — 1370 — — 1400 — — 1400 INHIBITED — — 15 — — 22 — — 22 OUTPUT RIPPLE INPUT CURRENT mV VDC mA INPUT RIPPLE CURRENT BW ≤ 2 MHz — 5 10 — 10 20 — 10 20 80 82 — 82 84 — 84 86 — % DELAY2 — 15 — — 30 — — 40 — ms OVERSHOOT — 300 — — 400 — — 400 — mV EFFICIENCY START-UP mA p-p Notes 1. For MTW2805S, with the remote sense pins connected to the load and no resistance between the output pins and load. 2. A low output impedance power source is required on the input to realize this start-up time. If less than full surge current is available, start-up time will be longer CAUTION Permanent damage to the MTW2805S will result if pin 6 is shorted to ground. Damage may also result if pin 4 or pin 5 is disconnected from the load during operation with the remote sense leads connected to the load. If remote sense pins are not connected to the load, the output voltage of the MTW2805S will rise to approximately 6.2 VDC measured across pins 4 and 5. B4-10 MTW SERIES 30 WATT DC/DC CONVERTERS Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified. PARAMETER OUTPUT VOLTAGE MTW2812D TYP MAX MIN +VOUT 11.88 12.0 12.12 14.85 15.0 15.15 – VOUT 11.88 12.0 12.12 14.85 15.0 15.15 OUTPUT CURRENT MIN MTW2815D TYP MAX CONDITION UNITS VDC — — 2.5 — — 2.0 A OUTPUT POWER1 OUTPUT RIPPLE VOLTAGE –55°C to +85°C — — 30.0 — — 30.0 W BW ≤ 2 MHz — 50 85 — 50 85 mV p-p LINE REGULATION VIN = 18 TO 40 — 10 25 — 10 25 mV LOAD REGULATION NO LOAD TO FULL — 20 50 — 20 50 mV +VOUT — 2.5 3.5 — 2.2 3.2 – VOUT — 2.5 3.5 — 2.2 3.2 CROSS REGULATION2 INPUT VOLTAGE –55°C to +85°C INPUT CURRENT % CONTINUOUS 18 28 40 18 28 40 TRANSIENT 50 ms — — 50 — — 50 NO LOAD FULL LOAD INHIBITED — — — 35 — — 50 1350 24 — — — 45 — — 60 1400 24 mA mA p-p VDC INPUT RIPPLE CURRENT BW ≤ 2 MHz — 15 50 — 15 50 81 84 — 82 85 — % DELAY3 — 30 — — 30 — ms OVERSHOOT — 500 — — 500 — mV EFFICIENCY START-UP Notes 1. Up to 90% of full power is available from either output providing the total power does not exceed 30 watts. 2. The effect on the output voltage of either output (held at 3 watts) when the other output is varied from 3 to 27 watts. 3. A low output impedance power source is required on the input to realize this start-up time. If less than full surge current is available, start-up time will be longer PIN OUT Pin 1 2 3 4 5 6 7 8 9 10 MTW2805S Positive Input Inhibit Sense Return Output Common Positive Output Positive Sense Case Ground No connection No connection Input Common Single Output Positive Input Inhibit No connection Output Common Positive Output No connection Case Ground No connection No connection Input Common Dual Output Positive Input No connection Positive Output Output Common Negative Output No connection Case Ground Inhibit Input Common Input Common Squared corner and dot on top of cover indicate pin one. 1 2 3 4 5 BOTTOM VIEW MTW See section B8, case J5, for dimensions. 10 9 8 7 6 FIGURE 1: PIN OUT B4-11 DC/DC CONVERTERS MTW SERIES 30 WATT MODEL NUMBERING KEY MTW 28 12 D / ES Base Model Voltage In Output Voltage Number of Outputs (S = single, D = dual) Screening (Standard screening has no designator in this position.) Typical Performance Curves: 25°C Tc 88 86 19 V 86 82 80 78 40 V 84 82 28 V 80 78 40 V 76 76 72 72 70 70 70 74 68 15 20 25 30 40 V 78 74 10 28 V 80 72 5 18 V 82 74 68 5 10 15 20 25 68 30 5 10 15 20 25 30 Output Power (Watts) Output Power (Watts) Output Power (Watts) MTW2805S Efficiency MTW2812S Efficiency MTW2812D Efficiency FIGURE 4 FIGURE 2 FIGURE 3 88 18 18 84 Input Voltage (Volts) 28 V 82 80 78 76 74 40 V 17 MTW2812S 16 MTW2815S 15 72 Inupt Voltage (Volts) 18 V 86 Efficiency (%) Efficiency (%) 28 V 76 88 86 18 V 84 Efficiency (%) Efficiency (%) 84 88 17 MTW2815D 16 MTW2812D 15 70 68 5 10 15 20 30 14 5 10 15 20 25 30 14 5 10 15 20 25 30 Output Power (Watts) Output Power (Watts) MTW2815D Efficiency MTW2812S and MTW2815S Low Line Dropout MTW2812D and MTW2815D Low Line Dropout FIGURE 5 B4-12 25 Output Power (Watts) FIGURE 6 24421-001-DTS Rev A DQ# 1017 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. MTW Series is a trademark of Interpoint. Copyright © 1994 - 1999 Interpoint. All rights reserved. FIGURE 7 CASES CASE J Dot on top of case indicates pin one CASE J BOTTOM VIEW See Figures 36 - 40 for pin configuration 1.350 max (34.29) 2.720 max (69.09) Flange Thickness: Cases J1 and J5 Case J2 Cases J3 and J4 0.060 (1.52) 0.073 (1.85) max 0.067 +0.005/-0.007 (1.70 +0.13/-0.8) Materials Header Case J1 Cold Rolled Steel/Nickel/Gold Cases J2 - J5 Cold Rolled Steel/Nickel/Tin Cover Case J1 Kovar/Nickel Case J2 - J5 Cold Rolled Steel/Nickel/Tin Pins #52 alloy (all cases) Case J1 MHV Series Triple – compression glass seal MTR Series Triple – ceramic seal Cases J2 - J5 compression glass 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. FIGURE 35: CASE J MAXIMUM DIMENSIONS Note: Although every effort has been made to render the case drawings at actual size, variations in the printing process may cause some distortion. Please refer to the numerical dimensions for accuracy. B8-22 CASES CASE J BOTTOM VIEW CASE J4 Flanged cases: Designator required in Case Option position of model number. FMD28-461 EMI Filter (down-leaded): Screening – Standard or ES Squared corner and dot on top of case indicate pin one. Solder Seal 1.173 (29.79 1 0.040 dia. (1.02) 2 0.162 dia (4.11) 0.673 (17.09) 4 3 1.770 (44.96) 5 0.173 (4.39) 1.370 (34.80) Solder Tip-off 1.980 (50.29) 0.170 (4.32) 0.000 0.210 (5.33) 0.25 (6.4) 0.000 0.505 max (12.83) 0.000 FIGURE 39: CASE J4 BOTTOM VIEW CASE J5 Flanged cases: Designator required in Case Option position of model number for MHL Series and MTO Series only. MHL Series, MTO Series, MTW Series: Screening – Standard or ES HR300 Series: no screening options Squared corner and dot on top of case indicate pin one. Solder Seal 1.173 (29.79 1 0.040 dia. (1.02) 2 3 4 5 0.162 dia (4.11) 0.673 (17.09) 9 8 7 6 1.770 (44.96) 10 0.173 (4.39) 1.370 (34.80) Solder Tip-off 1.980 (50.29) 0.970 (24.64) 0.570 (14.48) 0.170 (4.32) 0.000 0.210 (5.33) 0.25 (6.4) 0.000 0.505 max (12.83) 0.000 FIGURE 40: CASE J5 B8-25 QA SCREENING 85°C PRODUCTS 85°C PRODUCTS TEST (85°C Products excluding HR products) STANDARD /ES yes yes no yes no yes no yes yes yes 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 yes yes PRE-CAP INSPECTION Method 2017 TEMPERATURE CYCLE (10 times) Method 1010, Cond. B, -55°C to 125°C CONSTANT ACCELERATION Method 2001, 500 g BURN-IN 96 hours at 70°C ambient (typical) FINAL ELECTRICAL TEST MIL-PRF-38534, Group A Subgroups 1 and 4: +25°C case HERMETICITY TESTING FINAL VISUAL INSPECTION Method 2009 Test methods are referenced to MIL-STD-883 as determined by MIL-PRF-38534. Applies to the following products: 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 C2-12