MCOTS-C-28-3R3S-DM Single Output Demi-brick 16-40V Military COTS DC‑DC Converter Continuous Input 16-50V 3.3V 15A 87% @ 7.5A / 87% @ 15A Transient Input Output Output Efficiency The Mil-COTS DC-DC Converters bring SynQor’s field proven high-efficiency synchronous rectification technology to the Military/Aerospace industry. SynQor’s ruggedized encased packaging approach ensures survivability in demanding environments. These converters operate at a fixed frequency and follow conservative component derating guidelines. They are designed and manufactured to comply with a wide range of military standards. -S R3S-DM-N -3 8 -2 -C MCOTS CONVERTER DC-DC .3Vout @ 15A 28Vin 3 Safety Features Made in USA • 1000V, 100MΩ input-to-output isolation • Certified 60950-1 requirement for basic insulation (see Standards and Qualifications page) Operational Features • • • • • Mechanical Features • • • • Demi-brick Pin-out configuration Size: 1.55” x 1.52” x 0.50” (39.4 x 38.6 x12.7 mm) Total weight: 1.97 oz. (56 g) Flanged baseplate version available High efficiency, 86% at full rated load current Operating input voltage range: 16-40V Fixed frequency switching to provide predictable EMI Clock synchronization No minimum load requirement Protection Features Control Features • • • • • On/Off control referenced to input return • Remote sense for the output voltage • Output voltage trim range of +10%, -10% Input under-voltage lockout Output current limit and short circuit protection Active back bias limit Output over-voltage protection Screening/Qualification Compliance Features MilCOTS series converters (With an MCOTS filter) are designed to meet: • MIL-HDBK-704-8 (A-F) • RTCA/DO-160 Section 16 • MIL-STD-1275 (B, D) • MIL-STD-461 (C, D, E, F) • DEF-STAN 61-5 (Part 6)/(5 or 6) for VIN > 16V (with MCOTS-F-28-T-HT) Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 • • • • AS9100 & ISO 9001 certified facility Qualified to MIL-STD-810 Available with S-Grade or M-Grade screening Temperature cycling per MIL-STD-883, Method 1010, Condition B, 10 cycles • Burn-In at 100C baseplate temperature • Final visual inspection per MIL-STD-883, Method 2009 • Full component traceability www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 1 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Block Diagram REGULATION STAGE 1 7 ISOLATION STAGE POSITIVE OUTPUT POSITIVE INPUT 2 8 INPUT RETURN ISOLATION BARRIER N/C OUTPUT RETURN 3 9 -SENSE 4 10 ON/OFF 5 MAGNETIC +SENSE FEEDBACK TRIM SYNC OUT 6 SYNC IN N/C 11 12 Typical Connection Diagram 1 2 28Vdc + - 3 4 OPEN MEANS ON 5 6 +VIN N/C IN RTN N/C ON/OFF SYNC OUT MCOTS Demi DC-DC +SNS CONVERTER SYNC IN Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 TRIM www.synqor.com -SNS OUT RTN +VOUT 12 11 10 9 LOAD 8 + - 7 Doc.# 005-0006677 Rev. A 03/08/2016 Page 2 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Electrical Characteristics MCOTS-C-28-3R3S-DM ELECTRICAL CHARACTERISTICS Tb = 25 °C, Vin = 28 Vdc, full load, free running (see Note 5) unless otherwise noted; full operating temperature range is -55 °C to +100 °C baseplate temperature with appropriate power derating. Specifications subject to change without notice. Parameter ABSOLUTE MAXIMUM RATINGS Input Voltage Non-Operating Operating Operating Transient Protection Isolation Voltage Input to Output Input to Baseplate Output to Baseplate Operating Case Temperature Storage Case Temperature Voltage at ON/OFF INPUT CHARACTERISTICS Operating Input Voltage Range Input Under-Voltage Shutdown Turn-On Voltage Threshold Turn-Off Voltage Threshold Shutdown Voltage Hysteresis Input Over-Voltage Shutdown Turn-Off Voltage Threshold Turn-On Voltage Threshold Shutdown Voltage Hysteresis Input Filter Component Values (L\C) Maximum Input Current No Load Input Current Disabled Input Current Input Terminal Current Ripple (pk-pk) OUTPUT CHARACTERISTICS Output Voltage Set Point Output Voltage Regulation Over Line Over Load Over Temperature Total Output Voltage Range Output Voltage Ripple and Noise Peak to Peak Operating Output Current Range Operating Output Power Range Output DC Current-Limit Inception Back-Drive Current Limit while Enabled Back-Drive Current Limit while Disabled Maximum Output Capacitance Output Voltage Deviation Load Transient For a Pos. Step Change in Load Current Settling Time Response to Input Transient Output Voltage Trim Range Output Over-Voltage Shutdown EFFICIENCY Iout = 15 A (28 Vin) Iout = 7.5 A (28 Vin) Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 Min. Typ. Max. -1 -55 -65 -1.2 Units 60 40 60 V V V 1000 1000 1000 100 135 50 V V V °C °C V 16 28 40 V 14.75 14.00 15.50 14.75 0.80 16.00 15.50 V V V Notes & Conditions Continuous Continuous See Note 1 Baseplate temperature See Note 3 See Note 3 52.0 50.5 3.27 -0.4 -0.4 -50 3.22 0 0 16 55.0 58.0 54.0 56.5 2.0 1.0\11.47 3.9 75 100 10 15 40 75 3.30 3.33 3.30 15 0.4 0.4 50 3.38 75 15 50 21 18 2.5 10 V V V µH\µF A mA mA mA 0 V mV % % mV V mV A W A A mA µF 10 4.7 mV µs mV % V Internal values; see Figure F Vin = 16V; Iout = 15A Bandwidth = 100kHz – 10MHz; see Figure 14 Vout at sense leads Over sample, line, load, temperature & life Bandwidth = 10MHz; CL=11µF See Note 4 See Note 6 -400 200 150 -10 3.7 4.3 87 87 www.synqor.com See Figure 12, see Note 7 See Figure E % % Doc.# 005-0006677 Rev. A 03/08/2016 Page 3 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Electrical Characteristics MCOTS-C-28-3R3S-DM ELECTRICAL CHARACTERISTICS (Continued) Tb = 25 °C, Vin = 28 Vdc, full load, free running (see Note 5) unless otherwise noted; full operating temperature range is -55 °C to +100 °C baseplate temperature with appropriate power derating. Specifications subject to change without notice. Parameter Min. Typ. Max. ISOLATION CHARACTERISTICS Isolation Voltage (dielectric strength) Isolation Resistance Isolation Capacitance (input to output) TEMPERATURE LIMITS FOR POWER DERATING CURVES Semiconductor Junction Temperature Board Temperature Transformer Temperature Maximum Baseplate Temperature, Tb FEATURE CHARACTERISTICS Switching Frequency (free running) Synchronization Input Frequency Range 500 Logic Level High 2.0 Logic Level Low -0.5 Duty Cycle 20 Synchronization Output Pull Down Current 20 Duty Cycle ON/OFF Control Off-State Voltage Module Off Pulldown Current On-State Voltage Module On Pin Leakage Current Pull-Up Voltage DYNAMIC CHARACTERISTICS Turn-On Transient Output Voltage Rise Time Output Voltage Overshoot Turn-On Delay, Rising Vin Turn-On Delay, Rising ON/OFF Restart Inhibit Time Short Circuit Start Time RELIABILITY CHARACTERISTICS Calculated MTBF per MIL-HDBK-217F Calculated MTBF per MIL-HDBK-217F Units Notes & Conditions See Absolute Maximum Ratings 100 22 MΩ nF 125 125 125 100 550 °C °C °C °C kHz 700 5.5 0.8 80 kHz V V % mA 40 Package rated to 150 °C UL rated max operating temp 130 °C 60 % 0.8 3.2 4 20 4.8 V µA V µA V 12 6 0 5.5 3 100 14 10 2 8.0 6 150 20 ms % ms ms ms ms 80 2 4.03 0.83 106 Hrs. 106 Hrs. VSYNC OUT = 0.8V Output connected to SYNC IN of other MCOTS DM unit Current drain required to ensure module is off Imax draw from pin allowed with module still on See Figure A Vout = 0.33V to 2.97V; Full Resistive Load Resistive load On/Off = 5V; see Notes 8 & 2 See Note 2 See Note 2 Ground Benign, 70ºC Tb Ground Mobile, 70ºC Tb Electrical Characteristics Notes 1. Converter will undergo input over-voltage shutdown. 2. After a disable or fault event, module is inhibited from restarting for 100ms. See Shut Down section of the Control Features description. 3. High or low state of input voltage must persist for about 200µs to be acted on by the shutdown circuitry. 4. Current limit inception is defined as the point where the output voltage has dropped to 90% of its nominal value. See Current Limit discussion in Features Description section. 5. Operating the converter at a synchronization frequency above the free running frequency will cause the converter’s efficiency to be slightly reduced and it may also cause a slight reduction in the maximum output current/power available. 6. Load current transition time ≥ 10µs. 7. Line voltage transition time ≥ 100µs. 8. Input voltage rise time ≤ 250µs. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 4 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Technical Charts 95 95 90 90 Efficiency (%) 100 Efficiency (%) 100 85 80 75 16 Vin 70 28 Vin 65 6 9 Load Current (A) 12 40 Vin 5 15 25 35 45 55 65 75 85 95 Case Temperature ( ˚C) Figure 2: Efficiency at nominal output voltage and 60% rated power vs. case temperature for minimum, nominal, and maximum input voltage. 8 10 Power Dissipation (W) Power dissipation (W) 28 Vin -55 -45 -35 -25 -15 -5 12 8 6 4 16 Vin 28 Vin 2 40 Vin 7 6 5 4 3 16 Vin 2 28 Vin 1 40 Vin 0 0 0 3 6 9 Load Current (A) 12 -55 -45 -35 -25 -15 15 Figure 3: Power dissipation at nominal output voltage vs. load current for minimum, nominal, and maximum input voltage at 25°C. -5 5 15 25 35 45 55 65 75 85 95 Case Temperature ( ˚C) Figure 4: Power dissipation at nominal output voltage and 60% rated power vs. case temperature for minimum, nominal, and maximum input voltage 16 120 Output Voltage (%) 14 12 10 Iout (A) 16 Vin 70 15 Figure 1: Efficiency at nominal output voltage vs. load current for minimum, nominal, and maximum input voltage at 25°C. 8 6 4 2 0 75 60 60 3 80 65 40 Vin 0 85 100 80 60 40 28vin 20 0 50 60 70 80 90 100 110 0 Baseplate Temperature (°C) Figure 5: Maximum output current vs. baseplate temperature (nominal input voltage.) Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 25 50 75 100 Load current (%) 125 150 Figure 6: Output voltage vs. load current showing typical current limit curves. See Current limit section in application notes. www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 5 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Technical Charts Figure 7: Turn-on transient at no load and zero output capacitance initiated by On/Off. Input voltage pre-applied. Ch 1: Vout (1V/div). Ch 2: On/Off (5V/div) Figure 8: Turn-on transient at full resistive load and zero output capacitance initiated by On/Off. Input voltage pre-applied. Ch 1: Vout (1V/div). Ch 2: On/Off (5V/div) Figure 9: Input terminal current ripple, at full rated output current and Figure 10: Output voltage ripple, Vout, at nominal input voltage and full rated load current (1mV/div.) Figure 11: Output voltage response to step-change in load current 50%-100%-50% of Iout (max).No external load capacitance. Ch 1: Vout (200mV/div.) Ch 2: Iout (5A/div.) Figure 12: Output voltage response to step-change in input voltage (16V - 50V - 16V) in 1.2mS. Ch 1: Vout (50mV/div). Ch 2: Vin (20V/ div). nominal input voltage with SynQor MCOTS filter module. Ch 1: Module Iin (10mA/div). See Figure 17. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 6 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Technical Charts 0 0.1 -10 Forward Transmission (dB) Output Impedance (ohms) -20 0.01 0.001 16V 28V 40V -30 -40 -50 -60 -70 -80 16V 28V -90 40V -100 0.0001 10 100 1,000 Hz 10,000 1,000 100,000 Figure 13:Magnitude of incremental output impedance (Zout = vout/iout) for minimum, nominal, and maximum input voltage at full rated power. 10,000 100,000 Hz Figure 14: Magnitude of incremental forward transmission (FT = vout/ vin) for minimum, nominal, and maximum input voltage at full rated power. 100 10 Input Impedance (ohms) Reverse Transmission (dB) 0 -10 -20 -30 16V -40 28V 10 1 16V 0.1 28V 40V 40V 0.01 -50 10 100 1,000 10,000 10 100,000 Hz Figure 15: Magnitude of incremental reverse transmission (RT = iin/iout) for minimum, nominal, and maximum input voltage at full rated power. Figure 17:Test set-up diagram showing measurement points for Input Terminal Ripple Current (Figure 9) and Output Voltage Ripple (Figure 10). Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 100 1,000 Hz 10,000 100,000 Figure 16: Magnitude of incremental input impedance (Zin = vin/iin) for minimum, nominal, and maximum input voltage at full rated power. Figure 18: A short circuit across the output terminals. Ch 1: Vout (100mV/div). Ch 3: Iout (1A/div). www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 7 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Technical Charts Figure 19:SYNC OUT vs. time, driving Sync IN of a second SynQor converter. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 8 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Application Section BASIC OPERATION AND FEATURES The MCOTS DC-DC converter uses a two-stage power conversion topology. The first, or regulation, stage is a buck-converter that keeps the output voltage constant over variations in line, load, and temperature. The second, or isolation, stage uses transformers to provide the functions of input/output isolation and voltage transformation to achieve the output voltage required. Both the regulation and the isolation stages switch at a fixed frequency for predictable EMI performance. The isolation stage switches at one half the frequency of the regulation stage, but due to the push-pull nature of this stage it creates a ripple at double its switching frequency. As a result, both the input and the output of the converter have a fundamental ripple frequency of about 550 kHz in the free-running mode. Rectification of the isolation stage’s output is accomplished with synchronous rectifiers. These devices, which are MOSFETs with a very low resistance, dissipate far less energy than would Schottky diodes. This is the primary reason why the MCOTS converters have such high efficiency, particularly at low output voltages. Besides improving efficiency, the synchronous rectifiers permit operation down to zero load current. There is no longer a need for a minimum load, as is typical for converters that use diodes for rectification. The synchronous rectifiers actually permit a negative load current to flow back into the converter’s output terminals if the load is a source of short or long term energy. The MCOTS converters employ a “back-drive current limit” to keep this negative output terminal current small. There is a control circuit in the MCOTS converter that determines the conduction state of the power switches. It communicates across the isolation barrier through a magnetically coupled device. No opto-isolators are used. An input under-voltage shutdown feature with hysteresis is provided, as well as an input over-voltage shutdown and an output overvoltage limit. There is also an output current limit that is nearly constant as the load impedance decreases (i.e., there is not foldback or fold-forward characteristic to the output current under this condition). When a load fault is removed, the output voltage rises exponentially to its nominal value without an overshoot. If a load fault pulls the output voltage below about 60% of nominal, the converter will shut down to attempt to clear the load fault. After a short delay it will try to auto‑restart. The MCOTS converter’s control circuit does not implement an overtemperature shutdown. The following sections describe the use and operation of additional control features provided by the MCOTS converter. CONTROL FEATURES Remote ON/OFF: The MCOTS converter has one on/off function pin, ON/OFF (pin 4), which is referenced with respect to the converter’s input return (pin 2). It must have a logic high level for the converter to be enabled; a logic low inhibits the converter. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 The ON/OFF pin is internally pulled high so that an open connection will enable the converter. Figure A shows the equivalent circuit looking into the ON/OFF pin. It is TTL compatible and has hysteresis. SHUT DOWN: The MCOTS converter will shut down in response to only five conditions: ON/OFF input low, VIN input below under-voltage shutdown threshold, VIN input above over-voltage 5V 82.5K PIN4 PIN2 ON/OFF 10K TO ENABLE CIRCUITRY IN RTN Figure A: Circuit diagram shown for reference only, actual circuit components may differ from values shown for equivalent circuit. shutdown threshold, output voltage below the output undervoltage threshold, and output voltage above the output overvoltage threshold. Following any shutdown event, there is a startup inhibit delay which will prevent the converter from restarting for approximately 100ms. After the 100ms delay elapses, if the ON/ OFF inputs are high and the input voltage is within the operating range, the converter will restart. If the VIN input is brought down to nearly 0V and back into the operating range, there is no startup inhibit, and the output voltage will rise according to the “Turn-On Delay, Rising Vin” specification. REMOTE SENSE: The purpose of the remote sense pins is to correct for the voltage drop along the conductors that connect the converter’s output to the load. To achieve this goal, a separate conductor should be used to connect the +SENSE pin (pin 10) directly to the positive terminal of the load, as shown in the connection diagram on Page 2. Similarly, the –SENSE pin (pin 9) should be connected through a separate conductor to the return terminal of the load. NOTE: Even if remote sensing of the load voltage is not desired, the +SENSE and the -SENSE pins must be connected to +Vout (pin 7) and OUTPUT RETURN (pin 8), respectively, to get proper regulation of the converter’s output. If they are left open, the converter will have an output voltage that is approximately 200mV higher than its specified value. Inside the converter, +SENSE is connected to +Vout with a 100Ω resistor and –SENSE is connected to OUTPUT RETURN with a 10Ω resistor. It is also important to note that when remote sense is used, the voltage across the converter’s output terminals (pins 7 and 8) will be higher than the converter’s nominal output voltage due to resistive drops along the connecting wires. This higher voltage at the terminals produces a greater voltage stress on the converter’s internal components and may cause the converter to fail to deliver www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 9 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Application Section the desired output voltage at the low end of the input voltage range at the higher end of the load current and temperature range. Please consult the factory for details. SYNCHRONIZATION: The MCOTS converter’s switching frequency can be synchronized to an external frequency source that is in the 500 kHz to 700 kHz range. A pulse train at the desired frequency should be applied to the SYNC IN pin (pin 6) with respect to the INPUT RETURN (pin 2). This pulse train should have a duty cycle in the 20% to 80% range. Its low value should be below 0.8V to be guaranteed to be interpreted as a logic low, and its high value should be above 2.0V to be guaranteed to be interpreted as a logic high. The transition time between the two states should be less than 300ns. If the MCOTS converter is not to be synchronized, the SYNC IN pin should be left open circuit. The converter will then operate in its free-running mode at a frequency of approximately 550 kHz. If, due to a fault, the SYNC IN pin is held in either a logic low or logic high state continuously, or the SYNC IN frequency is outside the 500-700 kHz range, the MCOTS converter will revert to its freerunning frequency. The MCOTS converter also has a SYNC OUT pin (pin 5). This output can be used to drive the SYNC IN pins of as many as ten (10) other MCOTS converters. The pulse train coming out of SYNC OUT has a duty cycle of 50% and a frequency that matches the switching frequency of the converter with which it is associated. This frequency is either the free‑running frequency if there is no valid synchronization signal at the SYNC IN pin, or the synchronization frequency if there is. Figure B shows the equivalent circuit looking into the SYNC IN pin and Figure C shows the equivalent circuit looking into the SYNC OUT pin. OUTPUT VOLTAGE TRIM: the TRIM pin (pin 11) can adjust the MCOTS converter’s output voltage ±10% around its nominal value. To trim the output voltage above its nominal value, connect an external resistor from the TRIM pin to the –SENSE pin as shown in Figure D. The value of this trim up resistor should be chosen according to the following equation or from Figure E: 5V 5K PIN 6 PIN 2 SYNC IN 5K IN RTN Figure B: Equivalent circuit looking into the SYNC IN pin with respect to the IN RTN (input return) pin. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 TO SYNC CIRCUITRY 5V 5K SYNC OUT FROM SYNC CIRCUITRY IN RTN OPEN COLLECTOR OUTPUT PIN 5 PIN 2 Figure C: Equivalent circuit looking into SYNC OUT pin with respect to the IN RTN (input return) pin. 6100Ω*Vnom Rtrim up(Ω) = - 30000Ω Vout - Vnom where: Vnom = the converter’s nominal output voltage, Vout = the desired output voltage (greater than Vnom), and Rtrim up is in Ohms. As the output voltage is trimmed up, it produces a greater voltage stress on the converter’s internal components and may cause the converter to fail to deliver the desired output voltage at the low end of the input voltage range at the higher end of the load current and temperature range. Please consult the factory for details. To trim the output voltage below its nominal value, connect an external resistor between the TRIM pin and the +SENSE pin. The value of this trim down resistor should be chosen according to the following equation or from Figure E: 15400Ω*Vout - 6100Ω*Vnom - 30000Ω Vnom - Vout Rtrim down(Ω) = where: Vnom = the converter’s nominal output voltage, Vout = the desired output voltage (less than Vnom), and Rtrim down is in Ohms. INPUT UNDER-VOLTAGE SHUTDOWN: The MCOTS converter has an under-voltage shutdown feature that ensures the converter will be off if the input voltage is too low. The input voltage turnon threshold is higher than the turn-off threshold. In addition, the MCOTS converter will not respond to a state of the input voltage unless it has remained in that state for more than about 200µs. This hysteresis and the delay ensure proper operation when the source impedance is high or in a noisy environment. INPUT OVER-VOLTAGE SHUTDOWN: The MCOTS converter also has an over-voltage feature that ensures the converter will be off if the input voltage is too high. It also has a hysteresis and time delay to ensure proper operation. OUTPUT OVER-VOLTAGE SHUTDOWN: The MCOTS converter will shut down if the voltage at its power output pins ever exceeds www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 10 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Application Section 1 +VIN 2 28Vdc N/C 4 OPEN MEANS ON MCOTS DEMI IN RTN 3 + N/C DC-DC ON/OFF 5 SYNC OUT 6 CONVERTER SYNC IN TRIM +SNS -SNS OUT RTN +VOUT 12 11 RTRIM DOWN RTRIM UP/ RTRIM SENSE 10 9 LOAD + 8 7 Figure D: Typical connection for output voltage trimming. about 130% of the nominal value. The shutdown threshold does not change with output trim or sense drops; excessive trim-up or output wiring drops may cause an output over-voltage shutdown event. After a startup inhibit delay, the converter will attempt to restart. OUTPUT UNDER-VOLTAGE SHUTDOWN: The MCOTS converter will also shut down if the voltage at its power output pins ever dips below 60% of the nominal value for more than a few milliseconds. Output voltage reduction due to output current overload (current limit) is the most common trigger for this shutdown. The shutdown threshold does not change with output trim but at only 10%, trimdown should not trigger this event. After a startup inhibit delay, the converter will attempt to restart. This shutdown is disabled during startup. BACK-DRIVE CURRENT LIMIT: Converters that use MOSFETs as synchronous rectifiers are capable of drawing a negative current from the load if the load is a source of short- or long-term energy. This negative current is referred to as a “back-drive current”. Conditions where back-drive current might occur include paralleled converters that do not employ current sharing. It can also occur External Trim Resistance (kOhms) 10000 Trim Up Trim Down To avoid any problems that might arise due to back-drive current, the MCOTS converters limit the negative current that the converter can draw from its output terminals. The threshold for this backdrive current limit is placed sufficiently below zero so that the converter may operate properly down to zero load, but its absolute value (see the Electrical Characteristics page) is small compared to the converter’s rated output current. CURRENT LIMIT: In the event of excess load, the MCOTS converter will quickly reduce its output voltage to keep the load current within safe limits (see Figure 6). If the overload persists for more than 14 milliseconds, the converter will shut off, wait a restart delay, and then automatically attempt to re-start. The timeout is internally implemented with an integrator: counting up whenever current limit is active, and counting down at 1/5th the rate whenever current limit becomes inactive. In this way a series of short-duration overloads will not cause the converter to shut down, while it will shut down in response to sustained overloads. INPUT SYSTEM INSTABILITY: This condition can occur because any dc-dc converter appears incrementally as a negative resistance load. A detailed application note titled “Input System Instability” is available on the SynQor website which provides an understanding of why this instability arises, and shows the preferred solution for correcting it. 1000 100 Thermal Considerations: The maximum operating baseplate temperature, TB, is 100ºC. Refer to the thermal derating curve, Figure 5, to see the available output current at baseplate temperatures below 100ºC. 10 -10% when converters having different output voltages are connected together through either explicit or parasitic diodes that, while normally off, become conductive during startup or shutdown. Finally, some loads, such as motors, can return energy to their power rail. Even a load capacitor is a source of back-drive energy for some period of time during a shutdown transient. -8% -6% -4% -2% 0% 2% 4% 6% 8% Output Voltage Adjustment 10% A power derating curve can be calculated for any heatsink that is attached to the base-plate of the converter. It is only necessary to Figure E: Trim up and Trim down as a function of external trim resistance. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 11 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Application Section determine the thermal resistance, RTHBA, of the chosen heatsink between the base-plate and the ambient air for a given airflow rate. This information is usually available from the heatsink vendor. The following formula can then be used to determine the maximum power the converter can dissipate for a given thermal condition: = P diss max provides a diagram showing the internal input filter components. This filter dramatically reduces input terminal ripple current, which otherwise could exceed the rating of the converter’s external electrolytic input capacitor. More detailed information is available in the application note titled “EMI Characteristics” on the SynQor website. TB - TA RTHBA This value of power dissipation can then be used in conjunction with the data shown in Figure 3 to determine the maximum load current (and power) that the converter can deliver in the given thermal condition. INPUT FILTERING AND EXTERNAL CAPACITANCE: Figure F L Vin(+) Vout(+) Internal Input Filter C Converter Vin(_) Vout(-) Figure F: Internal Input Filter Diagram. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 12 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Encased Mechanical Diagram OVERALL HEIGHT 0.500 0.025 [ 12.70 0.63] 1.520 [38.61] 1.120 [28.45] PIN EXTENSION 0.180 [4.57] THREADED INSERT SEE NOTE 1 (4 PLCS) 12 11 10 9 8 7 1 2 3 4 5 6 0.004 [0.10] TOP VIEW 1.250 [31.75] 1.550 1.150 [39.37] [29.21] 1 0.06 [1.5] 0.05 [1.3] 0.200 0.400 0.600 0.800 1.000 NOTES: 1: APPLIED TORQUE PER M3 SCREW 4in-lb RECOMMENDED (5in-lb LIMIT) SCREW SHOULD NOT EXCEED 0.100” (2.54mm) DEPTH BELOW THE SURFACE OF THE BASEPLATE. 2: BASEPLATE FLATNESS TOLERANCE IS 0.004” (.10mm) TIR FOR SURFACE. 3: PINS 1-12 ARE .040” (1.02mm) DIA, WITH 0.080” (2.03mm) DIA. STANDOFF 4: ALL PINS: MATERIAL: COPPER ALLOY FINISH: MATTE TIN OVER NICKEL PLATE 5: WEIGHT: 1.97 oz. (56g) 6: ALL DIMENSIONS IN INCHES(mm) TOLERANCES: X.XXIN +/-0.02 (X.Xmm +/-0.5mm) X.XXXIN +/-0.010 (X.XXmm +/-0.25mm) Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Pin # 1 2 3 4 5 6 7 8 9 10 11 12 [5.08] [10.16] [15.24] [20.32] [25.40] PIN DESIGNATIONS Function Positive input Input return No connection On/Off Sync output Sync input Positive output Output return - Sense + Sense Trim No connection Pin Designation Notes: 1: Pin out differs from other Mil-COTS products. Doc.# 005-0006677 Rev. A 03/08/2016 Page 13 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Flanged Encased Mechanical Diagram 2.000 [50.80] 1.800 [45.72] OVERALL HEIGHT 0.500 0.025 [ 12.70 0.63] 1.520 [38.61] TOP VIEW PIN EXTENSION 0.180 [4.57] 12 .130 [3.30] SEE NOTE 1 (4 PLCS) 0.010 [0.25] 1.550 1.030 0.650 [39.37] [26.16] [16.51] 11 10 9 8 7 3 4 5 6 BOTTOM VIEW 1.250 [31.75] 1 1 0.30 [7.6] 0.40 [10.2] NOTES: 1: APPLIED TORQUE PER M3 OR 4-40 SCREW 4in-lb RECOMMENDED (5in-lb LIMIT) 2: BASEPLATE FLATNESS TOLERANCE IS 0.010” (.25mm) TIR FOR SURFACE. 3: PINS 1-12 ARE .040” (1.02mm) DIA, WITH 0.080” (2.03mm) DIA. STANDOFF 4: ALL PINS: MATERIAL: COPPER ALLOY FINISH: MATTE TIN OVER NICKEL PLATE 5: WEIGHT: 2.08 oz. (59g) ALL DIMENSIONS IN INCHES(mm) 6: TOLERANCES: X.XXIN +/-0.02 (X.Xmm +/-0.5mm) X.XXXIN +/-0.010 (X.XXmm +/-0.25mm) FLANGE THICKNESS 0.125 [3.18] 0.200 0.400 0.600 0.800 1.000 2 [5.08] [10.16] [15.24] [20.32] [25.40] Pin # 1 2 3 4 5 6 7 8 9 10 11 12 PIN DESIGNATIONS Function Positive input Input return No connection On/Off Sync output Sync input Positive output Output return - Sense + Sense Trim No connection Pin Designation Notes: 1: Pin out differs from other Mil-COTS products. Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 14 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Qualifications & Screening Mil-COTS Qualification Life Testing Visual, mechanical and electrical testing before, during and after 1000 hour burn-in @ full load # Tested (# Failed) 15 (0) ShockVibration Visual, mechanical and electrical testing before, during and after shock and vibration tests 5 (0) Temperature Cycling +85˚C, 95% RH, 1000 hours, 2 minutes on / 6 hours off 500 cycles of -55˚C to +100˚C (30 minute dwell at each temperature) Solderability 15 pins DMT -65˚C to +110˚C across full line and load specifications in 5˚C steps Altitude 70,000 feet (21 km), see Note 8 (0) 10 (0) 15 (0) 7 (0) 2 (0) Test Name Details Humidity Consistent with MILSTD-883F Method Consistent with MIL-STD-883F Method 5005 Method 1005.8 MIL-STD-202, Methods 201A & 213B Method 1004.7 Method 1010.8 Condition A Method 2003 Note: A conductive cooling design is generally needed for high altitude applications because of naturally poor convective cooling at rare atmospheres. Mil-COTS DC-DC Converter and Filter Screening Screening Process Description Baseplate Operating Temperature Storage Temperature Pre-Cap Inspection S-Grade M-Grade -55˚C to +100˚C -55˚C to +100˚C -65˚C to +135˚C -65˚C to +135˚C ● ● IPC-A-610, Class III MIL-STD-883F, Method 1010, Condition B, 10 Cycles Temperature Cycling Burn-In 100˚C Baseplate 12 Hours 96 Hours 100% 25˚C -55˚C, +25˚C, +100˚C MIL-STD-883F, Method 2009 ● ● Final Electrical Test Final Visual Inspection ● Mil-COTS MIL-STD-810G Qualification Testing MIL-STD-810G Test Fungus Method 508.6 Description Table 508.6-I 500.5 - Procedure I Storage: 70,000 ft / 2 hr duration 500.5 - Procedure II Operating: 70,000 ft / 2 hr duration; Ambient Temperature Rapid Decompression 500.5 - Procedure III Storage: 8,000 ft to 40,000 ft Acceleration 513.6 - Procedure II Operating: 15 g Salt Fog 509.5 Storage 501.5 - Procedure I Storage: 135°C / 3 hrs 501.5 - Procedure II Operating: 100°C / 3 hrs 502.5 - Procedure I Storage: -65°C / 4 hrs 502.5 - Procedure II Operating: -55°C / 3 hrs Temperature Shock 503.5 - Procedure I - C Storage: -65°C to 135°C; 12 cycles Rain 506.5 - Procedure I Wind Blown Rain Immersion 512.5 - Procedure I Non-Operating Humidity 507.5 - Procedure II Aggravated cycle @ 95% RH (Figure 507.5-7 aggravated temp - humidity cycle, 15 cycles) Random Vibration 514.6 - Procedure I 10 - 2000 Hz, PSD level of 1.5 g2/Hz (54.6 grms), duration = 1 hr/axis 516.6 - Procedure I 20 g peak, 11 ms, Functional Shock (Operating no load) (saw tooth) 516.6 - Procedure VI 514.6 - Category 14 510.5 - Procedure I Bench Handling Shock Rotary wing aircraft - helicopter, 4 hrs/axis, 20 g (sine sweep from 10 - 500 Hz) Blowing Dust 510.5 - Procedure II Blowing Sand Altitude High Temperature Low Temperature Shock Sinusoidal vibration Sand and Dust Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 15 MCOTS-C-28-3R3S-DM Input:16-40V Output:3.3V Current:15A Ordering Information Part Numbering Scheme Family Product Input Voltage Package Size Heatsink Option Screening Level DM: Demi Mega N: Normal Threaded F: Flanged S: S-Grade M: M-Grade Output Voltage Options 3R3S: 3.3V Single 05S: 5.0V Single 12S: 12V Single MCOTS C: Converter 28: 16-40V 28E: 16-70V 15S: 15V Single 28S: 28V Single [ ]: Standard Feature 05D: 5.0V Dual 12D: 12V Dual 15D: 15V Dual Application Notes Ordering Information / Part Numbering Example: MCOTS-C-28-3R3S-DM-N-S Not all combinations make valid part numbers, please contact SynQor for availability. STANDARDS COMPLIANCE Parameter A variety of application notes and technical white papers can be downloaded in pdf format from our website. Notes & Conditions STANDARDS COMPLIANCE UL 60950-1:2007/A2:2014 Basic Insulation CAN/CSA C22.2 No. 60950-1:2007/A2:2014 EN 60950-1:2006/A2:2013 Note: An external input fuse must always be used to meet these safety requirements. Contact SynQor for official safety certificates on new releases or download from the SynQor website. PATENTS Contact SynQor for further information and to order: Phone: Toll Free: Fax: E-mail: Web: Address: 978-849-0600 888-567-9596 978-849-0602 [email protected] www.synqor.com 155 Swanson Road Boxborough, MA 01719 USA Product # MCOTS-C-28-3R3S-DM Phone 1-888-567-9596 SynQor holds numerous U.S. patents, one or more of which apply to most of its power converter products. Any that apply to the product(s) listed in this document are identified by markings on the product(s) or on internal components of the product(s) in accordance with U.S. patent laws. SynQor’s patents include the following: 5,999,417 6,222,742 6,545,890 6,594,159 6,731,520 6,894,468 6,896,526 6,927,987 7,050,309 7,072,190 7,085,146 7,119,524 7,269,034 7,272,021 7,272,023 7,558,083 7,564,702 7,765,687 7,787,261 8,023,290 8,149,597 8,493,751 8,644,027 9,143,042 WARRANTY SynQor offers a two (2) year limited warranty. Complete warranty information is listed on our website or is available upon request from SynQor. www.synqor.com Doc.# 005-0006677 Rev. A 03/08/2016 Page 16