MILITARY COTS DC‑DC CONVERTER

MCOTS-C-28-12S-DM
Single Output
Demi-brick
16-40V
Military COTS DC‑DC Converter
Continuous Input
16-50V
12V
4A
87% @ 2A / 85% @ 4A
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.
M-N-S
-28-12S-D
R
E
MCOTS-C
T
ONVER
DC-DC C2Vout @ 4A
1
28Vin
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 x 12.7 mm)
Total weight: 1.97 oz. (56 g)
Flanged baseplate version available
High efficiency, 85% 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-28-12S-DM
Phone 1-888-567-9596
•
•
•
•
AS9100 & ISO 9001 certified facility
Qualification consistent with 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-2008
• Full component traceability
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Doc.# 005-0006648 Rev. B
07/10/2015
Page 1
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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
Product # MCOTS-C-28-12S-DM
5
6
+VIN
N/C
IN RTN
N/C
ON/OFF
SYNC OUT
MCOTS
Demi
DC-DC
+SNS
CONVERTER
SYNC IN
Phone 1-888-567-9596
TRIM
www.synqor.com
-SNS
OUT RTN
+VOUT
12
11
10
9
LOAD
8
+
-
7
Doc.# 005-0006648 Rev. B
07/10/2015
Page 2
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Electrical Characteristics
MCOTS-C-28-12S-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
Min. Typ. Max.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Non-Operating
Operating
Operating Transient Protection
Isolation Voltage
Input to Output
Input to Base-Plate
Output to Base-Plate
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 = 4 A (28 Vin)
Iout = 2 A (28 Vin)
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
-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
11.88
-0.4
-0.4
-100
11.76
0
0
4.4
55.0
58.0
53.5
56.5
2.0
1.0\11.47
3.9
75
125
10
15
40
75
12.00
12.12
12.00
30
0.4
0.4
100
12.24
75
4
48
6.5
5.5
1
10
V
V
V
µH\µF
A
mA
mA
mA
1500
V
mV
%
%
mV
V
mV
A
W
A
A
mA
µF
10
18.8
mV
µs
mV
%
V
Internal values; see Figure F
Vin = 16V; Iout = 4A
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
200
-10
14.9
16.3
85
87
www.synqor.com
See Figure 12, see Note 7
See Figure E
%
%
Doc.# 005-0006648 Rev. B
07/10/2015
Page 3
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Electrical Characteristics
MCOTS-C-28-12S-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
Notes & Conditions
See Absolute Maximum Ratings
100
22
MΩ
nF
125
125
125
100
550
°C
°C
°C
°C
Package rated to 150 °C
UL rated max operating temp 130 °C
kHz
700
5.5
0.8
80
kHz
V
V
%
mA
40
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
60
%
0.8
3.2
4.0
20
4.8
V
µA
V
µA
V
12
6
0
5.5
3.0
100
14
10
2
8.0
6.0
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 = 1.2V to 10.8V; Full Resistive Load
Resistive load
On/Off = 5V; see Notes 8 & 2
See Note 2, see Note 9
See Note 2, see Note 9
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.
9. Time measured at 10% of the rising output voltage.
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
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Doc.# 005-0006648 Rev. B
07/10/2015
Page 4
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Technical Charts
95
95
90
90
Efficiency (%)
100
Efficiency (%)
100
85
80
75
16 Vin
70
28 Vin
65
2
Load Current (A)
3
Power Dissipation (W)
Power dissipation (W)
8
7
6
5
4
16 Vin
1
40 Vin
5
15 25 35 45 55 65 75 85 95
Figure 2: Efficiency at nominal output voltage and 60% rated power vs.
case temperature for minimum, nominal, and maximum input voltage.
8
28 Vin
40 Vin
Case Temperature ( ˚C)
9
2
28 Vin
-55 -45 -35 -25 -15 -5
9
3
16 Vin
70
4
Figure 1: Efficiency at nominal output voltage vs. load current for
minimum, nominal, and maximum input voltage at 25°C.
7
6
5
4
3
16 Vin
2
28 Vin
1
40 Vin
0
0
0
1
2
Load Current (A)
3
-55 -45 -35 -25 -15 -5
4
Figure 3: Power dissipation at nominal output voltage vs. load current
for minimum, nominal, and maximum input voltage at 25°C.
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
4.5
120
4.0
Output Voltage (%)
3.5
3.0
Iout (A)
75
60
60
1
80
65
40 Vin
0
85
2.5
2.0
1.5
1.0
100
80
60
40
28vin
20
0.5
0.0
0
50
60
70
80
90
100
110
0
Base Plate Temperature (°C)
Figure 5: Maximum output current vs. base plate temperature (nominal
input voltage.)
Product # MCOTS-C-28-12S-DM
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25
50
75
100
Load current (%)
125
150
175
Figure 6: Output voltage vs. load current showing typical current limit
curves. See Current limit section in application notes.
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 5
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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 (5V/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
(5V/div). Ch 2: On/Off (5V/div).
Figure 9: Input terminal current ripple, at full rated output current and
nominal input voltage with SynQor MCOTS filter module(20mA/div.)
See Figure 17.
Figure 10: Output voltage ripple, Vout, at nominal input voltage and
full rated load current (20mV/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 (1A/div.)
Figure 12: Output voltage response to step-change in input voltage
(16V - 50V - 16V) in 150μS. Ch 1: Vout (50mV/div). Ch 2: Vin (20V/
div).
Product # MCOTS-C-28-12S-DM
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Doc.# 005-0006648 Rev. B
07/10/2015
Page 6
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Technical Charts
0.1
0
-10
Forward Transmission (dB)
Output Impedance (ohms)
-20
0.01
0.001
16Vin
28Vin
40Vin
0.0001
-30
-40
-50
-60
-70
-80
-100
10
100
1,000
Hz
10,000
100,000
Figure 13:Magnitude of incremental output impedance (Zout = vout/iout)
for minimum, nominal, and maximum input voltage at full rated power.
16Vin
28Vin
-90
40Vin
100
1,000
Hz
10,000
100,000
Figure 14: Magnitude of incremental forward transmission (FT = vout/
vin) for minimum, nominal, and maximum input voltage at full rated
power.
100
10
10
Input Impedance (ohms)
Reverse Transmission (dB)
0
-10
-20
-30
16Vin
-40
28Vin
1
16Vin
0.1
28Vin
40Vin
40Vin
-50
10
100
1,000
10,000
100,000
0.01
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-28-12S-DM
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10
100
1,000
10,000
100,000
Hz
Hz
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
(50mV/div). Ch 2: Iout (500mA/div).
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 7
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Technical Charts
Figure 19:SYNC OUT vs. time, driving Sync IN of a second SynQor
converter.
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
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Doc.# 005-0006648 Rev. B
07/10/2015
Page 8
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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-28-12S-DM
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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
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 9
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Application Section
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 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
5V
5K
PIN 6
PIN 2
SYNC IN
5K
IN RTN
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.
in Figure D. The value of this trim up resistor should be chosen
according to the following equation or from Figure E:
7900Ω*Vnom
Rtrim up(Ω) =
- 39600Ω
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 (Rtrim down) between the TRIM pin and the
+SENSE pin, and another resistor (Rtrim sense) connected between
the TRIM pin and the –SENSE pin as shown in Figure D. The value of
this trim down resistor should be chosen according to the following
equation or from Figure E:
38100Ω*Vout - 20900Ω*Vnom
Rtrim down(Ω) =
- 104500Ω
Vnom - Vout
Rtrim sense(Ω) =
0.61*Rtrim down(Ω)
where:
Vnom = the converter’s nominal output voltage,
Vout = the desired output voltage (less than Vnom),
and
Rtrim down and Rtrim sense are 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.
Figure B: Equivalent circuit looking into the SYNC IN pin with
respect to the IN RTN (input return) pin.
Product # MCOTS-C-28-12S-DM
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Doc.# 005-0006648 Rev. B
07/10/2015
Page 10
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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.
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.
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”.
OUTPUT OVER-VOLTAGE SHUTDOWN: The MCOTS converter
will shut down if the voltage at its power output pins ever exceeds
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.
Conditions where back-drive current might occur include paralleled
converters that do not employ current sharing. 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.
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.
External Trim Resistance (kOhms)
10000
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.
Trim Up
Trim Down
Trim Sense
1000
100
10
-10%
-8%
-6%
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.
-4%
-2%
0%
2%
4%
6%
8%
10%
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.
Output Voltage Adjustment
Figure E: Trim up and Trim down as a function of external trim resistance.
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 11
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Application Section
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.
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.
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
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:
INPUT FILTERING AND EXTERNAL CAPACITANCE: Figure F
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
Pmax
diss RTHBA
L
Vin(+)
Vout(+)
Internal
Input
Filter
C
Converter
Vin(_)
Vout(-)
Figure F: Internal Input Filter Diagram.
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 12
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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-28-12S-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.# 005-0006648 Rev. B
07/10/2015
Page 13
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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-28-12S-DM
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 14
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
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
S-Grade
M-Grade
-55˚C to +100˚C
-55˚C to +100˚C
-65˚C to +135˚C
-65˚C to +135˚C
●
●
100˚C Baseplate
12 Hours
96 Hours
100%
25˚C
-55˚C, +25˚C, +100˚C
MIL-STD-2008
●
●
Baseplate Operating Temperature
Storage Temperature
Pre-Cap Inspection
IPC-610, Class III
Temperature Cycling
Method 1010, Condition B, 10 Cycles
Burn-In
Final Electrical Test
Final Visual Inspection
MIL-STD-810G Test
Fungus
Altitude
Method
508.6
●
Mil-COTS MIL-STD-810G Qualification Testing
Description
Table 508.6-I
500.5 - Procedure I
Storage: 70,000ft. / 2 Hr. duration
500.5 - Procedure II
Operating; 70,000ft. / 2 Hr. duration; Ambient Temperature
Rapid Decompression
500.5 - Procedure III
Storage: 8,000ft. to 40,000ft.
Acceleration
513.6 - Procedure II
Operating - 15g’s
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: -65C / 4 hrs
502.5 - Procedure II
Operating: -55C / 3 hrs
Temperature Shock
503.5 - Procedure I - C
Storage: -65C to 135C; 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(54.6grms), duration = 1 hr/axis
516.6 - Procedure I
20g’s peak, 11ms, 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, 4hrs/axis, 20g’s (sine sweep from 10 - 500HZ)
Blowing Dust
510.5 - Procedure II
Blowing Sand
High Temperature
Low Temperature
Shock
Sinusoidal vibration
Sand and Dust
Product # MCOTS-C-28-12S-DM
Phone 1-888-567-9596
www.synqor.com
Doc.# 005-0006648 Rev. B
07/10/2015
Page 15
MCOTS-C-28-12S-DM
Input:16-40V
Output:12V
Current:4A
Ordering Information
Part Numbering Scheme
Family
Product
Input
Voltage
Output Voltage
Heatsink Option
Screening
Level
N: Normal Threaded
F: Flanged
S: S-Grade
M: M-Grade
Package Size
Options
3R3S: 3.3V Single
05S: 5.0V Single
12S: 12V Single
MCOTS
C: Converter
28: 16-40V
15S: 15V Single
DM: Demi Mega
28S: 28V Single
[ ]: Standard Feature
05D: 5.0V Dual
12D: 12V Dual
15D: 15V Dual
Application Notes
Ordering Information / Part Numbering
Example: MCOTS-C-28-12S-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/R:2011-12
Basic Insulation
CAN/CSA-C22.2 No. 60950-1/A1:2011
EN 60950-1/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-28-12S-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
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.# 005-0006648 Rev. B
07/10/2015
Page 16