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MQFL-28-28S Single Output
HIGH RELIABILITY DC/DC CONVERTER
Continuous Input Transient Input
16-40V
16-50V
Output
28.0V
Output
TO
4A
91% @ 2A / 88% @ 4A
Efficiency
F U L L P O W E R O P E R AT I O N : - 5 5 C T he Mi l Qo r (R) s e r i e s o f h i g h - r e l i a b i l i t y D C / D C c o n v e r t e r s b r i n g s Sy n Q or' s f ie l d pr ove n h ig h- e ff ic i e nc y sy nc h ro nou s r e ct if i er t e c h n ology to th e Mi lit ar y/Aeros pace i n du str y. SynQ or' s i n nova tive QorSeal p ac k a gi ng a p p ro a c h e n su re s su r v iv a b il it y i n t he m ost h ost ile envi ron men ts . Co mpati ble wit h t he i ndus try st an dard f ormat, t hese con ver ters o perat e at a f ix ed f requency, h ave n o opto- iso lat ors, and follow con servati ve com po nen t d e ra t in g gui d e li ne s . T he y a re de s ign e d an d ma nu fa ctu re d t o com ply wit h a wide rang e of mili tary stan dar ds .
Design Pr ocess
MQFL series converters are: * Designed for reliability per NAVSO-P3641-A guidelines * Designed with components derated per: -- MIL-HDBK-1547A -- NAVSO P-3641A * * * * * * * *
TM
+125C
DESIGNED & MANUFACTURED IN THE USA FEATURING QORSEALTM HI-REL ASSEMBLY
Features
Fixed switching frequency No opto-isolators Parallel operation with current share Remote sense Clock synchronization Primary and secondary referenced enable Continuous short circuit and overload protection Input under-voltage lockout/over-voltage shutdown
Qualification Pr ocess
MQFL series converters are qualified to: * MIL-STD-810F -- consistent with RTCA/D0-160E * SynQor's First Article Qualification -- consistent with MIL-STD-883F * SynQor's Long-Term Storage Survivability Qualification * SynQor's on-going life test
Specification Compliance In-Line Manufacturing Pr ocess
* * * * * * AS9100 and ISO 9001:2000 certified facility Full component traceability Temperature cycling Constant acceleration 24, 96, 160 hour burn-in Three level temperature screening
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MQFL series converters (with MQME filter) are designed to meet: * MIL-HDBK-704-8 (A through F) * RTCA/DO-160E Section 16 * MIL-STD-1275B * DEF-STAN 61-5 (part 6)/5 * MIL-STD-461 (C, D, E) * RTCA/DO-160E Section 22
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 1
Product # MQFL-28-28S
Technical Specification
BLOCK DIAGRAM
1 2
REGULATION STAGE CURRENT SENSE T1 T2 T1
MQFL-28-28S Output: 28.0 V Current: 4 A
ISOLATION STAGE
POSITIVE INPUT INPUT RETURN
T2
POSITIVE OUTPUT
7
OUTPUT RETURN ISOLATION BARRIER
8
CASE GATE DRIVERS UVLO OVSD
3
GATE DRIVERS
ENABLE 1 SYNC OUTPUT SYNC INPUT
4 5 6
CURRENT LIMIT PRIMARY CONTROL
ENABLE 2 SHARE + SENSE
12 11 10 9
MAGNETIC
SECONDARY CONTROL
DATA COUPLING
BIAS POWER
- SENSE
CONTROL POWER
TRANSFORMER
TYPICAL CONNECTION DIAGRAM
1 2 3 28Vdc + -
open means on
+VIN IN RTN CASE ENA 1 SYNC OUT SYNC IN
ENA 2 SHARE
12 11 10 9 8 7
open means on
4 5 6
MQFL
+ SNS - SNS OUT RTN +VOUT
+ Load -
Product # MQFL-28-28S
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Doc.# 005-2MQ280S Rev. B
2/27/08
Page 2
Technical Specification
MQFL-28-28S ELECTRICAL CHARACTERISTICS
Parameter
ABSOLUTE MAXIMUM RATINGS
Input Voltage Non-Operating Operating 1 Reverse Bias (TCASE = 125C) Reverse Bias (TCASE = -55C) Isolation Voltage (input/output to case, input to output) Continuous Transient (100 s) Operating Case Temperature 2 Storage Case Temperature Lead Temperature (20 sec) Voltage at ENA1, ENA2, SYNC IN 60 60 -0.8 -1.2 -500 -800 -55 -65 -1.2 16 16 14.75 13.80 0.50 54.0 50.0 2.0 28 28 15.50 14.40 1.10 56.8 51.4 5.3 110 2 25 40 27.72 27.60 -20 120 27.44 0 0 4.1 4.1 28.00 28.00 0 135 28.00 30 500 800 135 135 300 50 40 50 16.00 15.00 1.80 60.0 54.0 8.0 9.5 160 5 50 60 28.28 28.40 20 150 28.56 100 4 112 5.0 5.5 50 3,000 V V V V V V C C C V V V V V V V V V A mA mA mA mA V V mV mV V mV A W A A A mA F
MQFL-28-28S Output: 28.0 V Current: 4 A
Min.
Nom.
Max.
Units Notes & Conditions
Vin=28V DC 5%, Iout = 4A, CL = 0 F, free running10 unless otherwise specified
Group A Subgroup13
INPUT CHARACTERISTICS
Operating Input Voltage Range (continuous) Operating Input Voltage Range (transient, 1 sec) Input Under-Voltage Lockout 3 Turn-On Voltage Threshold Turn-Off Voltage Threshold Lockout Voltage Hysteresis Input Over-Voltage Shutdown 3 Turn-Off Voltage Threshold Turn-On Voltage Threshold Shutdown Voltage Hysteresis Maximum Input Current No Load Input Current (operating) Disabled Input Current (ENA1) Disabled Input Current (ENA2) Input Terminal Current Ripple (peak to peak) 1, 2, 3 4, 5, 6 1, 2, 3 1, 2, 3 1, 2, 3 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3 3 3 3 3 3 3 3
Vin = 16V; Iout = 4A Vin = 16V, 28V, 50V Vin = 16V, 28V, 50V Bandwidth = 100 kHz - 10 MHz; see Figure 14 Vout at sense leads " " ; Vin = 16V, 28V, 50V " ; Vout @ (Iout=0A) - Vout @ (Iout=4A) " Bandwidth = 10 MHz; CL=11F Vout 1.2V
OUTPUT CHARACTERISTICS
Output Voltage Set Point (TCASE = 25C) Output Voltage Set Point Over Temperature Output Voltage Line Regulation Output Voltage Load Regulation 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 4 Short Circuit Output Current Back-Drive Current Limit while Enabled Back-Drive Current Limit while Disabled Maximum Output Capacitance 1 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 See Note 5
4.6 4.8 1.2 10
DYNAMIC CHARACTERISTICS
Output Voltage Deviation Load Transient 6 For a Positive Step Change in Load Current For a Negative Step Change in Load Current Settling Time (either case) 7 Output Voltage Deviation Line Transient 8 For a Positive Step Change in Line Voltage For a Negative Step Change in Line Voltage Settling Time (either case) 7 Turn-On Transient Output Voltage Rise Time Output Voltage Overshoot Turn-On Delay, Rising Vin 9 Turn-On Delay, Rising ENA1 Turn-On Delay, Rising ENA2 -1200 -650 650 50 1200 200 800 800 500 10 2 8.0 6.0 3.0 mV mV s mV mV s ms % ms ms ms % % % % % % W W Total Iout step = 2A 4A, 0.4A 2A; CL=11F " Vin step = 16V 50V; CL=11F; Iout=3.5A " Vout = 2.8V 25.2V ENA1, ENA2 = 5V ENA2 = 5V ENA1 = 5V 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 See Note 5 4, 5, 6 See Note 5 4, 5, 6 4, 5, 6 4, 5, 6 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3 3 3 3 3 3 3 3
-800 -800 250 6 0 5.5 3.0 1.5 84 88 84 87 83 85 88 91 88 91 87 89 22 24
EFFICIENCY
Iout = 4A (16Vin) Iout = 2A (16Vin) Iout = 4A (28Vin) Iout = 2A (28Vin) Iout = 4A (40Vin) Iout = 2A (40Vin) Load Fault Power Dissipation Short Circuit Power Dissipation
32 33
Iout at current limit inception point Vout 1.2V
4
Product # MQFL-28-28S
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Doc.# 005-2MQ280S Rev. B
2/27/08
Page 3
Technical Specification
MQFL-28-28S ELECTRICAL CHARACTERISTICS (Continued)
Parameter
ISOLATION CHARACTERISTICS
Isolation Voltage (dielectric strength) Input RTN to Output RTN Any Input Pin to Case Any Output Pin to Case Isolation Resistance (input rtn to output rtn) Isolation Resistance (any pin to case) Isolation Capacitance (input rtn to output rtn) 500 500 500 100 100 44 500 500 2 -0.5 20 20 25 550 600 700 10 0.8 80 V V V M M nF kHz kHz V V % mA % V A V A V
MQFL-28-28S Output: 28.0 V Current: 4 A
Min.
Nom.
Max.
Units Notes & Conditions
Vin=28V DC 5%, Iout = 4A, CL = 0 F, free running10 unless otherwise specified
Group A Subgroup13
1 1 1 1 1 1 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 See Note 5 VSYNC OUT = 0.8V Output connected to SYNC IN of another MQFL converter See Note 5 See Note 5 1, 2, 3 See Note 5 1, 2, 3 See Note 5 1, 2, 3
FEATURE CHARACTERISTICS
Switching Frequency (free running) Synchronization Input Frequency Range Logic Level High Logic Level Low Duty Cycle Synchronization Output Pull Down Current Duty Cycle Enable Control (ENA1 and ENA2) Off-State Voltage Module Off Pulldown Current On-State Voltage Module On Pin Leakage Current Pull-Up Voltage
75 0.8
80 2 3.2 4.0 20 4.5
Current drain required to ensure module is off Maximum current draw from pin allowed with module still on See Figure A
RELIABILITY CHARACTERISTICS
Calculated MTBF (MIL-STD-217F2) GB @ Tcase=70C AIF @ Tcase=70C Demonstrated MTBF 2800 440 TBD 79 103 Hrs. 103 Hrs. 103 Hrs. g
WEIGHT CHARACTERISTICS
Device Weight
Electrical Characteristics Notes 1. Converter will undergo input over-voltage shutdown. 2. Derate output power to 50% of rated power at Tcase = 135 C. 3. High or low state of input voltage must persist for about 200s to be acted on by the lockout or shutdown circuitry. 4. Current limit inception is defined as the point where the output voltage has dropped to 90% of its nominal value. 5. Parameter not tested but guaranteed to the limit specified. 6. Load current transition time 10s. 7. Settling time measured from start of transient to the point where the output voltage has returned to 1% of its final value. 9. Input voltage rise time 250s. 8. Line voltage transition time 100s.
10. 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. For more information consult the factory. 11. After a disable or fault event, module is inhibited from restarting for 300ms. See Shut Down section on Page 9. 12. SHARE pin outputs a power failure warning pulse during a fault condition. See Current Share section on Page 11. 13. Only the ES and HB grade products are tested at three temperatures. The B and C grade products are tested at one temperature. Please refer to the ESS table on Page 13 for details. 14. These derating curves apply for the ES- and HB- grade products. The C- grade product has a maximum case temperature of 100 C and a maximum junction temperature rise of 20 C above TCASE. The B- grade product has a maximum case temperature of 85 C and a maximum junction temperature rise of 20 C at full load.
Product # MQFL-28-28S Phone 1-888-567-9596 www.synqor.com Doc.# 005-2MQ280S Rev. B 2/27/08 Page 4
Technical Specification
100 95 90 100 95 90
MQFL-28-28S Output: 28.0 V Current: 4 A
Efficiency (%)
Efficiency (%)
85 80 75 70 65 60 0 1 2 3 4 16 Vin 28 Vin 40 Vin
85 80 75 70 65 60 -55C 25C 125C 16 Vin 28 Vin 40 Vin
Load Current (A)
Case Temperature (C)
Figure 1: Efficiency at nominal output voltage vs. load current for minimum, nominal, and maximum input voltage at TCASE =25C.
Figure 2: Efficiency at nominal output voltage and 60% rated power vs. case temperature for input voltage of 16V, 28V, and 40V.
20 18 16
20 18 16
Power Dissipation (W)
14 12 10 8 6 4 2 0 0 1 2 3 4 16 Vin 28 Vin 40 Vin
Power Dissipation (W)
14 12 10 8 6 4 2 0 -55C 25C 125C 16 Vin 28 Vin 40 Vin
Load Current (A)
Case Temperature (C)
Figure 3: Power dissipation at nominal output voltage vs. load current for minimum, nominal, and maximum input voltage at TCASE =25C.
Figure 4: Power dissipation at nominal output voltage and 60% rated power vs. case temperature for input voltage of 16V, 28V, and 40V.
6
168
32 28
5
140
24
4
112
Output Voltage (V)
3
84
Pout (W)
20 16 12 8
Iout (A)
2
56
1
Tjmax = 105C Tjmax = 125C Tjmax = 145C
25 45 65 85 105 125 135
28
4 28 Vin
0
0 145
0 0 1 2 3 4 5 6
Case Temperature (C)
Load Current (A)
Figure 5: Output Current / Output Power derating curve as a function of TCASE and the Maximum desired power MOSFET junction temperature at Vin = 28V (see Note 14).
Product # MQFL-28-28S Phone 1-888-567-9596
Figure 6: Output voltage vs. load current showing typical current limit curves.
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Doc.# 005-2MQ280S Rev. B
2/27/08
Page 5
Technical Specification
MQFL-28-28S Output: 28.0 V Current: 4 A
Figure 7: Turn-on transient at full resistive load and zero output capacitance initiated by ENA1. Input voltage pre-applied. Ch 1: Vout (5V/div). Ch 2: ENA1 (5V/div).
Figure 8: Turn-on transient at full resistive load and 3 mF output capacitance initiated by ENA1. Input voltage pre-applied. Ch 1: Vout (5V/div). Ch 2: ENA1 (5V/div).
Figure 9: Turn-on transient at full resistive load and zero output capacitance initiated by ENA2. Input voltage pre-applied. Ch 1: Vout (5V/div). Ch 2: ENA2 (5V/div).
Figure 10: Turn-on transient at full resistive load and zero output capacitance initiated by Vin. ENA1 and ENA2 both previously high. Ch 1: Vout (5V/div). Ch 2: Vin (10V/div).
Figure 11: Output voltage response to step-change in load current (50%100%-50% of Iout (max). Load cap: 1F ceramic cap and 10F, 100 m ESR tantalum cap. Ch 1: Vout (500mV/div). Ch 2: Iout (2A/div).
Product # MQFL-28-28S Phone 1-888-567-9596
Figure 12: Output voltage response to step-change in load current (0%-50%0% of Iout (max). Load cap: 1F ceramic cap and 10F, 100 m ESR tantalum cap. Ch 1: Vout (500mV/div). Ch 2: Iout (2A/div).
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 6
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Technical Specification
MQFL-28-28S Output: 28.0 V Current: 4 A
See Fig. 15
See Fig. 16
MQME Filter VSOURCE
iC
MQFL Converter 1 F
10 F,
VOUT
ceramic 100m ESR capacitor capacitor
Figure 13: Output voltage response to step-change in input voltage (16V 50V - 16V). Load cap: 10F, 100 m ESR tantalum cap and 1F ceramic cap. Ch 1: Vout (500mV/div). Ch 2: Vin (20V/div).
Figure 14: Test set-up diagram showing measurement points for Input Terminal Ripple Current (Figure 15) and Output Voltage Ripple (Figure 16).
Figure 15: Input terminal current ripple, ic, at full rated output current and nominal input voltage with SynQor MQ filter module (50 mA/div). Bandwidth: 20MHz. See Figure 14.
Figure 16: Output voltage ripple, Vout, at nominal input voltage and rated load current (20 mV/div). Load capacitance: 1F ceramic capacitor and 10F tantalum capacitor. Bandwidth: 10 MHz. See Figure 14.
Figure 17: Rise of output voltage after the removal of a short circuit across the output terminals. Ch 1: Vout (5V/div). Ch 2: Iout (2A/div).
Product # MQFL-28-28S Phone 1-888-567-9596
Figure 18: SYNC OUT vs. time, driving SYNC IN of a second SynQor MQFL converter. Ch1: SYNC OUT: (1V/div).
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 7
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Technical Specification
1 0 -10
MQFL-28-28S Output: 28.0 V Current: 4 A
Forward Transmission (dB)
Output Impedance (ohms)
-20 -30 -40 -50 -60 -70 -80 -90 16Vin 28Vin 40Vin 10 100 1,000 10,000 100,000
0.1
16Vin 28Vin 40Vin
0.01 10 100 1,000 10,000 100,000
-100
Hz
Hz
Figure 19: Magnitude of incremental output impedance (Zout = vout/iout) for minimum, nominal, and maximum input voltage at full rated power.
20 10
Figure 20: Magnitude of incremental forward transmission (FT = vout/vin) for minimum, nominal, and maximum input voltage at full rated power.
100
Reverse Transmission (dB)
Input Impedance (ohms)
0 -10 -20 -30 -40 -50 10 100 1,000 10,000 100,000 16Vin 28Vin 40Vin
10
1
0.1
16Vin 28Vin 40Vin
0.01 10 100 1,000 10,000 100,000
Hz
Hz
Figure 21: Magnitude of incremental reverse transmission (RT = iin/iout) for minimum, nominal, and maximum input voltage at full rated power.
Figure 22: Magnitude of incremental input impedance (Zin = vin/iin) for minimum, nominal, and maximum input voltage at full rated power.
Figure 23: High frequency conducted emissions of standalone MQFL-2805S, 5Vout module at 120W output, as measured with Method CE102. Limit line shown is the 'Basic Curve' for all applications with a 28V source.
Product # MQFL-28-28S Phone 1-888-567-9596
Figure 24: High frequency conducted emissions of MQFL-28-05S, 5Vout module at 120W output with MQFL-28-P filter, as measured with Method CE102. Limit line shown is the 'Basic Curve' for all applications with a 28V source.
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 8
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Technical Specification
BASIC OPERATION AND FEATURES
The MQFL 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 MQFL 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 MQFL converters employ a "back-drive current limit" to keep this negative output terminal current small. There is a control circuit on both the input and output sides of the MQFL converter that determines the conduction state of the power switches. These circuits communicate with each other across the isolation barrier through a magnetically coupled device. No opto-isolators are used. A separate bias supply provides power to both the input and output control circuits. Among other things, this bias supply permits the converter to operate indefinitely into a short circuit and to avoid a hiccup mode, even under a tough start-up condition. An input under-voltage lockout feature with hysteresis is provided, as well as an input over-voltage shutdown. There is also an output current limit that is nearly constant as the load impedance decreases to a short circuit (i.e., there is not fold-back 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.
MQFL-28-28S Output: 28.0 V Current: 4 A
The MQFL converter's control circuit does not implement an output over-voltage limit or an over-temperature shutdown. The following sections describe the use and operation of additional control features provided by the MQFL converter.
CONTROL FEATURES
ENABLE: The MQFL converter has two enable pins. Both must have a logic high level for the converter to be enabled. A logic low on either pin will inhibit the converter. The ENA1 pin (pin 4) is referenced with respect to the converter's input return (pin 2). The ENA2 pin (pin 12) is referenced with respect to the converter's output return (pin 8). This permits the converter to be inhibited from either the input or the output side. Regardless of which pin is used to inhibit the converter, the regulation and the isolation stages are turned off. However, when the converter is inhibited through the ENA1 pin, the bias supply is also turned off, whereas this supply remains on when the converter is inhibited through the ENA2 pin. A higher input standby current therefore results in the latter case.
5.6V
1N4148 PIN 4 (or PIN 12) ENABLE
82K TO ENABLE CIRCUITRY 2N3904 125K
250K
PIN 2 (or PIN 8)
RTN
Figure A: Equivalent circuit looking into either the ENA1 or ENA2 pins with respect to its corresponding return pin.
Both enable pins are internally pulled high so that an open connection on both pins will enable the converter. Figure A shows the equivalent circuit looking into either enable pins. It is TTL compatible. SHUT DOWN: The MQFL converter will shut down in response to only four conditions: ENA1 input low, ENA2 input low, VIN input below under-voltage lockout threshold, or VIN input above over-voltage shutdown threshold. Following a shutdown event, there is a startup inhibit delay which will prevent the converter
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 9
Product # MQFL-28-28S
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Technical Specification
from restarting for approximately 300ms. After the 300ms delay elapses, if the enable 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. If only the +SENSE pin is left open, the output voltage will be approximately 25mV too high. Inside the converter, +SENSE is connected to +Vout with a 100 resistor and -SENSE is connected to OUTPUT RETURN with a 10 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 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 MQFL 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 MQFL 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.
Product # MQFL-28-28S Phone 1-888-567-9596
MQFL-28-28S Output: 28.0 V Current: 4 A
If, due to a fault, the SYNC IN pin is held in either a logic low or logic high state continuously, the MQFL converter will revert to its free-running frequency. The MQFL 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 MQFL 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 synchronization signal at the SYNC IN pin, or the synchronization frequency if there is. The SYNC OUT signal is available only when the DC input voltage is above approximately 12V and when the converter is not inhibited through the ENA1 pin. An inhibit through the ENA2 pin will not turn the SYNC OUT signal off. NOTE: An MQFL converter that has its SYNC IN pin driven by the SYNC OUT pin of a second MQFL converter will have its start of its switching cycle delayed approximately 180 degrees relative to that of the second converter. Figure B shows the equivalent circuit looking into the SYNC IN pin. Figure C shows the equivalent circuit looking into the SYNC OUT pin.
5V 5K PIN 6 SYNC IN PIN 2 IN RTN 5K TO SYNC CIRCUITRY
Figure B: Equivalent circuit looking into the SYNC IN pin with respect to the IN RTN (input return) pin.
5V 5K FROM SYNC CIRCUITRY SYNC OUT PIN 5
IN RTN
OPEN COLLECTOR OUTPUT
PIN 2
Figure C: Equivalent circuit looking into SYNC OUT pin with respect to the IN RTN (input return) pin.
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 10
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Technical Specification
CURRENT SHARE: When several MQFL converters are placed in parallel to achieve either a higher total load power or N+1 redundancy, their SHARE pins (pin 11) should be connected together. The voltage on this common SHARE node represents the average current delivered by all of the paralleled converters. Each converter monitors this average value and adjusts itself so that its output current closely matches that of the average. Since the SHARE pin is monitored with respect to the OUTPUT RETURN (pin 8) by each converter, it is important to connect all of the converters' OUTPUT RETURN pins together through a low DC and AC impedance. When this is done correctly, the converters will deliver their appropriate fraction of the total load current to within +/- 10% at full rated load. Whether or not converters are paralleled, the voltage at the SHARE pin could be used to monitor the approximate average current delivered by the converter(s). A nominal voltage of 1.0V represents zero current and a nominal voltage of 2.2V represents the maximum rated current, with a linear relationship in between. The internal source resistance of a converter's SHARE pin signal is 2.5 k. During an input voltage fault or primary disable event, the SHARE pin outputs a power failure warning pulse. The SHARE pin will go to 3V for approximately 14ms as the output voltage falls. NOTE: Converters operating from separate input filters with reverse polarity protection (such as the MQME-28-T filter) with their outputs connected in parallel may exhibit hiccup operation at light loads. Consult factory for details. OUTPUT VOLTAGE TRIM: If desired, it is possible to increase the MQFL converter's output voltage above its nominal value. To do this, use the +SENSE pin (pin 10) for this trim function instead of for its normal remote sense function, as shown in Figure D. In this case, a resistor connects the +SENSE pin to the -SENSE pin
100,000
MQFL-28-28S Output: 28.0 V Current: 4 A
Trim Resistance (ohms)
10,000
1,000
100 0 0.5 1 1.5 2 2.5 3
Increase in Vout (V)
Figure E: Output Voltage Trim Graph
(which should still be connected to the output return, either remotely or locally). The value of the trim resistor should be chosen according to the following equation or from Figure E: Rtrim = 100 x
[Vout
Vnom - Vnom - 0.025
]
where: Vnom = the converter's nominal output voltage, Vout = the desired output voltage (greater than Vnom), and Rtrim 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. Factory trimmed converters are available by request.
1 2 3 28Vdc + -
open means on
+VIN IN RTN CASE ENA 1 SYNC OUT SYNC IN
ENA 2 SHARE + SNS - SNS OUT RTN +VOUT
12 11 10 9 8 7 Load +
Rtrim
4 5 6
-
Figure D: Typical connection for output voltage trimming.
Product # MQFL-28-28S Phone 1-888-567-9596 www.synqor.com Doc.# 005-2MQ280S Rev. B 2/27/08 Page 11
Technical Specification
INPUT UNDER-VOLTAGE LOCKOUT: The MQFL converter has an under-voltage lockout feature that ensures the converter will be off if the input voltage is too low. The threshold of input voltage at which the converter will turn on is higher that the threshold at which it will turn off. In addition, the MQFL converter will not respond to a state of the input voltage unless it has remained in that state for more than about 200s. This hysteresis and the delay ensure proper operation when the source impedance is high or in a noisy environment. INPUT OVER-VOLTAGE SHUTDOWN: The MQFL 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. 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, or where the current share feature does not adequately ensure sharing during the startup or shutdown transitions. It can also occur 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. To avoid any problems that might arise due to back-drive current, the MQFL 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. THERMAL CONSIDERATIONS: Figure 5 shows the suggested Power Derating Curves for this converter as a function of the case temperature and the maximum desired power MOSFET junction temperature. All other components within the converter are cooler than its hottest MOSFET, which at full power is no more than 20C higher than the case temperature directly below this MOSFET.
MQFL-28-28S Output: 28.0 V Current: 4 A
The Mil-HDBK-1547A component derating guideline calls for a maximum component temperature of 105C. Figure 5 therefore has one power derating curve that ensures this limit is maintained. It has been SynQor's extensive experience that reliable long-term converter operation can be achieved with a maximum component temperature of 125C. In extreme cases, a maximum temperature of 145C is permissible, but not recommended for long-term operation where high reliability is required. Derating curves for these higher temperature limits are also included in Figure 5. The maximum case temperature at which the converter should be operated is 135C. When the converter is mounted on a metal plate, the plate will help to make the converter's case bottom a uniform temperature. How well it does so depends on the thickness of the plate and on the thermal conductance of the interface layer (e.g. thermal grease, thermal pad, etc.) between the case and the plate. Unless this is done very well, it is important not to mistake the plate's temperature for the maximum case temperature. It is easy for them to be as much as 5-10C different at full power and at high temperatures. It is suggested that a thermocouple be attached directly to the converter's case through a small hole in the plate when investigating how hot the converter is getting. Care must also be made to ensure that there is not a large thermal resistance between the thermocouple and the case due to whatever adhesive might be used to hold the thermocouple in place. 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.
Product # MQFL-28-28S
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-2MQ280S Rev. B
2/27/08
Page 12
Technical Specification
CONSTRUCTION AND ENVIRONMENTAL STRESS SCREENING OPTIONS
Consistent with MIL-STD-883F B-Grade
(-40oC to +85oC)
MQFL-28-28S Output: 28.0 V Current: 4 A
C-Grade
(-40oC to +100oC)
ES-Grade
(-55oC to +125oC)
(Element Evaluation)
HB-Grade
(-55oC to +125oC)
(Element Evaluation)
Screening
Internal Visual Temperature Cycle Constant Acceleration
*
Method 1010 Method 2001 (Y1 Direction) Method 1015 Load Cycled
Yes No
Yes No
Yes Condition B (-55oC to +125oC) 500g
Yes Condition C (-65oC to +150oC) Condition A (5000g)
No
No
Burn-in
*10s period *2s @ 100% Load *8s @ 0% Load
12 Hrs @ +100oC
24 Hrs @ +125oC
96 Hrs @ +125oC
160 Hrs @ +125oC
Final Electrical Test Mechanical Seal, Thermal, and Coating Process External Visual Construction Process
Method 5005 (Group A)
+25oC
+25oC
-45, +25, +100oC
-55, +25, +125oC
Anodized Package
Full QorSeal
Full QorSeal
Full QorSeal
2009
*
Ruggedized
*
QorSeal
Yes QorSeal
Yes QorSeal
* Per IPC-A-610 (Rev. D) Class 3
MilQor converters and filters are offered in four variations of construction technique and environmental stress screening options. The three highest grades, C, ES, and HB, all use SynQor's proprietary QorSealTM Hi-Rel assembly process that includes a Parylene-C coating of the circuit, a high performance thermal compound filler, and a nickel barrier gold plated aluminum case. The B-grade version uses a ruggedized assembly process that includes a medium performance thermal compound filler and a black anodized aluminum case. Each successively higher grade has more stringent mechanical and electrical testing, as well as a longer burn-in cycle. The ESand HB-Grades are also constructed of components that have been procured through an element evaluation process that pre-qualifies each new batch of devices.
Note: Since the surface of the black anodized case is not guaranteed to be electrically conductive, a star washer or similar device should be used to cut through the surface oxide if electrical connection to the case is desired.
Product # MQFL-28-28S Phone 1-888-567-9596 www.synqor.com Doc.# 005-2MQ280S Rev. B 2/27/08 Page 13
Technical Specification
MQFL-28-28S Output: 28.0 V Current: 4 A
DC/DC CONVERTER 28Vin 28.0Vout @ 4A
MQFL-28-28S-X-HB
PACKAGE PINOUTS
Pin #
1 2 3 4 5 6 7 8 9 10 11 12
Function
POSITIVE INPUT INPUT RETURN CASE ENABLE 1 SYNC OUTPUT SYNC INPUT POSITIVE OUTPUT OUTPUT RETURN - SENSE + SENSE SHARE ENABLE 2
DC/DC CONVERTER 28Vin 28.0Vout @ 4A
MQFL-28-28S-Y-HB
NOTES
1) Case: Aluminum with gold over nickel plate finish for the C-, ES-, and HBGrade products. Aluminum with black anodized finish for the B-Grade products. 2) Pins: Diameter: 0.040" (1.02mm) Material: Copper Finish: Gold over Nickel plate 3) All dimensions as inches (mm) 4) Tolerances: a) x.xx +0.02" (x.x +0.5mm) b) x.xxx +0.010" (x.xx +0.25mm) 5) Weight: 2.8 oz. (79 g) typical 6) Workmanship: Meets or exceeds IPCA-610C Class III
Product # MQFL-28-28S Phone 1-888-567-9596 www.synqor.com Doc.# 005-2MQ280S Rev. B 2/27/08 Page 14
Technical Specification
MilQor MQFL FAMILY MATRIX
MQFL-28-28S Output: 28.0 V Current: 4 A
The tables below show the array of MQFL converters available. When ordering SynQor converters, please ensure that you use the complete part number according to the table in the last page. Contact the factory for other requirements. Single Output Converters
1.5V
(1R5S)
1.8V
(1R8S)
2.5V
(2R5S)
3.3V
(3R3S)
5V
(05S)
6V
(06S)
7.5V
(7R5S)
9V
(09S)
12V 15V
(12S) (15S)
28V
(28S)
MQFL-28 MQFL16-40Vin Cont. 1616-50Vin 1s Trans.* 16Absolute Max Vin = 60V
40A
40A
40A
30A
24A 20A
16A
13A 10A
8A
4A
MQFL-28E MQFL16-70Vin Cont. 1616-80Vin 1s Trans.* 16Absolute Max Vin =100V
40A
40A
40A
30A
24A 20A
16A
13A 10A
8A
4A
MQFL-28V MQFL16-40Vin Cont. 165.5-50Vin 1s Trans.* 5.5Absolute Max Vin = 60V
40A
40A
40A
30A
20A 17A
13A
11A
8A
6.5
3.3A
MQFL-28VE MQFL16-70Vin Cont. 165.5-80Vin 1s Trans.* 5.5Absolute Max Vin = 100V
40A
40A
40A
30A
20A 17A
13A
11A
8A
6.5
3.3A
MQFL-270 MQFL155-400Vin Cont. 155155-475Vin 0.1s Trans.* 155Absolute Max Vin = 550V
40A
40A
40A
30A
24A 20A
16A
13A 10A
8A
4A
MQFL-270E MQFL130-475Vin Cont. 130130-520Vin 0.1s Trans.* 130Absolute Max Vin = 600V
40A
40A
40A
30A
20A 17A
13A
11A
8A
6.5
3.3A
MQFL-270L MQFL65-350Vin Cont. 6565-475Vin 0.1s Trans.* 65Absolute Max Vin = 550V
40A
40A
30A
22A
15A 12A
10A
8A
6A
5A
2.7A
Dual Output Converters
5V
(05D)
Triple Output Converters
3.3V/12V
(3R312T)
12V
(12D)
15V
(15D)
3.3V/15V
(3R315T)
5V/12V
(0512T)
5V/15V 30V/15V
(0515T) (3015T)
MQFL-28 MQFL16-40Vin Cont. 1616-50Vin 1s Trans.* 16Absolute Max Vin = 60V
20A 10A 8A Total Total Total 20A 10A 8A Total Total Total 20A 8A 6.5A Total Total Total 20A 8A 6.5A Total Total Total 20A 10A 8A Total Total Total 20A 8A 6.5A Total Total Total 15A 6A 5A Total Total Total
MQFL-28 MQFL16-40Vin Cont. 1616-50Vin 1s Trans.* 16Absolute Max Vin = 60V
22A/ 1A 22A/ 1A 22A/ 1A 22A/ 1A 22A/ 1A 22A/ 1A 22A/ 1A
22A/ 0.8A 22A/ 0.8A 22A/ 0.8A 22A/ 0.8A 22A/ 0.8A 22A/ 0.8A 22A/ 0.8A
15A/ 1A 15A/ 1A 15A/ 1A 15A/ 1A 15A/ 1A 15A/ 1A 15A/ 1A
15A/ 0.8A 15A/ 0.8A 15A/ 0.8A 15A/ 0.8A 15A/ 0.8A 15A/ 0.8A 15A/ 0.8A
2.5A/ 0.8A 2.5A/ 0.8A 2.5A/ 0.8A 2.5A/ 0.8A 2.5A/ 0.8A 2.5A/ 0.8A 2.5A/ 0.8A
MQFL-28E MQFL16-70Vin Cont. 1616-80Vin 1s Trans.* 16Absolute Max Vin =100V
MQFL-28E MQFL16-70Vin Cont. 1616-80Vin 1s Trans.* 16Absolute Max Vin =100V
MQFL-28V MQFL16-40Vin Cont. 165.5-50Vin 1s Trans.* 5.5Absolute Max Vin = 60V
MQFL-28V MQFL16-40Vin Cont. 165.5-50Vin 1s Trans.* 5.5Absolute Max Vin = 60V
MQFL-28VE MQFL16-70Vin Cont. 165.5-80Vin 1s Trans.* 5.5Absolute Max Vin = 100V
MQFL-28VE MQFL16-70Vin Cont. 165.5-80Vin 1s Trans.* 5.5Absolute Max Vin = 100V
MQFL-270 MQFL155-400Vin Cont. 155155-475Vin 0.1s Trans.* 155Absolute Max Vin = 550V
MQFL-270 MQFL155-400Vin Cont. 155155-475Vin 0.1s Trans.* 155Absolute Max Vin = 550V
MQFL-270E MQFL130-475Vin Cont. 130130-520Vin 0.1s Trans.* 130Absolute Max Vin = 600V
MQFL-270E MQFL130-475Vin Cont. 130130-520Vin 0.1s Trans.* 130Absolute Max Vin = 600V
MQFL-270L MQFL65-350Vin Cont. 6565-475Vin 0.1s Trans.* 65Absolute Max Vin = 550V
MQFL-270L MQFL65-350Vin Cont. 6565-475Vin 0.1s Trans.* 65Absolute Max Vin = 550V
(75Wmax Total Output Power)
*Converters may be operated continuously at the highest transient input voltage, but some component electrical and thermal stresses would be beyond MIL-HDBK-1547A guidelines. Product # MQFL-28-28S Phone 1-888-567-9596 www.synqor.com
80% of total output current available on any one output. 2/27/08 Page 15
Doc.# 005-2MQ280S Rev. B
Technical Specification
PART NUMBERING SYSTEM
MQFL-28-28S Output: 28.0 V Current: 4 A
The part numbering system for SynQor's MilQor DC/DC converters follows the format shown in the table below.
Model Name
Input Voltage Range
28 28E 28V 28VE 270 270E 270L
Output Voltage(s)
Single Output Dual Output Triple Output
Package Outline/ Pin Configuration
Screening Grade
MQFL
1R5S 1R8S 2R5S 3R3S 05S 06S 7R5S 09S 12S 15S 28S
05D 12D 15D
3R312T 3R315T 0512T 0515T 3015T
X Y W Z
B C ES HB
Example:
MQFL - 28VE - 28S - Y - ES
APPLICATION NOTES
A variety of application notes and technical white papers can be downloaded in pdf format from the SynQor website.
PATENTS (additional patent applications may be filed)
SynQor holds the following patents, one or more of which might apply to this product: 5,999,417 6,594,159 6,927,987 6,222,742 6,731,520 7,050,309 6,545,890 6,894,468 7,072,190 6,577,109 6,896,526 7,085,146
Contact SynQor for further information:
Phone: Toll Free: Fax: E-mail: Web: Address:
978-849-0600 888-567-9596 978-849-0602 power@synqor.com www.synqor.com 155 Swanson Road Boxborough, MA 01719 USA
Phone 1-888-567-9596
Warranty SynQor offers a two (2) year limited warranty. Complete warranty information is listed on our website or is available upon request from SynQor.
Information furnished by SynQor is believed to be accurate and reliable. However, no responsibility is assumed by SynQor for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of SynQor.
Doc.# 005-2MQ280S Rev. B 2/27/08 Page 16
Product # MQFL-28-28S
www.synqor.com

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