MCOTS-C-270-28-FT
Single Output
Full-brick
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 1
MCOTS-C-270-28-FT-N-M-F
DC/DC CONVERTER
270 (155-425V)
IN
28V
OUT
@ 21.4A
155-425V 155-475V 28V 21.4A 92% @ 10.7A /91% @ 21.4A
Continuous Input Transient Input Output Output Efciency
Operation: -55°C to +100°C
Mil-COTS
MILITARY COTS DC/DC CONVERTER
Designed and Manufactured in the USA
The
MilQor series of Mil-COTS DC-DC converters brings
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. Compatible with
the industry standard format, 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.
Protection Features
•Input under-voltage lockout/over-voltage shutdown
•Output current limit and short circuit protection
•Input over-voltage protection
•Output over-voltage protection
•Thermal shutdown
Screening/Qualification
• AS9100 and ISO 9001:2008 certied facility
• Qualication consistent with MIL-STD-883
•Available with S-Grade or M-Grade screening
•Pre-cap inspection per IPC-610, Class III
• 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
Operational Features
Mechanical Features
Control Features
Safety Features
• High efciency, 91% at full rated load current
•Operating input voltage range: 155-425 V
•Fixed frequency switching provides predictable EMI
•Fully Isolated On/Off control
•Remote sense for the output voltage
• Output voltage trim range of +10%, -20%
•Active current sharing (full feature option)
•Clock synchronization (full feature option)
•Start synchronization (full feature option)
• 4250V dc, 100 MΩ input-to-output isolation
• (see Standards and Qualications page)
• Industry standard full-brick pin-out conguration
•Size: 4.686” x 2.476” x .512”
119.0 x 62.9 x 13.0 mm
•Total weight: 9.9oz (280g)
•Flanged baseplate version available
Specification Compliance
MCOTS series converters (with an MCOTS lter) are designed to meet:
•MIL-HDBK-704 (A-F)
•RTCA/DO-160E Section 16
•MIL-STD-1275 (B,D)
•DEF-STAN 61-5 (Part 6)/(5 or 6)
•MIL-STD-461 (C, D, E)
•RTCA/DO-160E Section 22
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 2
BLOCK DIAGRAM
TYPICAL CONNECTION DIAGRAM
Vin
External
Input
Filter
Trim
Vin(+)
Iload
Cload
Vout(+)
Rtrim-up
or
Rtrim-down
Vsense(+)
ON/OFF
Vin(_)Vout(_)
Vsense(_)
Electrolytic
Capacitor
−
SENSE
REGULATION STAGE
UVLO
OVSD
SEC OND ARY
CONTROL
GATE CONTROL
PRIMARY
CONTROL
POSITIVE
INPUT
NEGATIVE
INPUT
ON/OFF+
10
11
5
6
3
POSITIVE
OUTPUT
NEGATIVE
OUTPUT
TRIM
+ SENSE
GATE DR IVERS
ISOLATION BARRIER
T1
T1
T2
T2
CURR ENT
LIMIT
CURR ENT
SENSE
OPTO-ISOLATION
DATA COUPLING
ISOLATION STAGE
4
1
2
ON /OFF -
SyncIn (Full Feature Option)
SyncOut (Full Feature Option)
16-18
13-15
12
7
VAUX
8
Start Sync
(Full Feature Option)
I Share
(Full Feature Option)
9
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 3
MCOTS-C-270-28-FT ELECTRICAL CHARACTERISTICS
Tb = 25 °C, Vin = 270dc unless otherwise noted; full operating temperature range is -55 °C to +100 °C baseplate temperature with appropriate power
derating. Specications subject to change without notice.
Parameter Min. Typ. Max. Units Notes & Conditions
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Non-Operating -0.5 600 V Continuous
Operating 425 V Continuous
Operating Transient Protection 475 V 1 s transient, square wave
Isolation Voltage
Input to Output 4250 V dc
Input to Base-Plate 2300 V dc
Output to Base-Plate 2300 V dc
Operating Temperature -55 +100 °C Baseplate temperature
Storage Temperature -65 +135 °C
Voltage at ON/OFF input pin -2 18 V
INPUT CHARACTERISTICS
Operating Input Voltage Range 155 270 425 V 475V transient for 1 s
Input Under-Voltage Turn-On Threshold 146 150 154 V
Input Under-Voltage Turn-Off Threshold 135 140 145 V
Input Over-Voltage Turn-Off Threshold 496 500 503 V
Input Over-Voltage Turn-On Threshold 446 453 460 V
Recommended External Input Capacitance 7 µF typical ESR 1Ω see Note 2
Input Filter Component Values (L\C) .272/5.5/1.2 µF\µH\µF Internal values; see Figure E
Maximum Input Current 5.6 A Vin min; trim up; in current limit
No-Load Input Current 35 70 mA
Disabled Input Current 10 20 mA
Response to Input Transient 1 V See Figure 12
Input Terminal Ripple Current 450 mA RMS , Full load
Recommended Input Fuse 10 A Fast acting external fuse recommended
OUTPUT CHARACTERISTICS
Output Voltage Set Point 27.72 28.00 28.28 V
Output Voltage Regulation
Over Line ±0.1 ±0.3 %
Over Load ±0.1 ±0.3 %
Over Temperature -220 220 mV
Total Output Voltage Range 27.3 28.7 V Over sample, line, load, temperature & life
Output Voltage Ripple and Noise 20 MHz bandwidth; see Note 1
Peak-to-Peak 220 440 mV Full load
RMS 157 320 mV Full load
Operating Output Current Range 0 21.4 A Subject to thermal derating
Operating Output Current Range (Start Up) 0.22 21.4 A See Application Notes
Output DC Current-Limit Inception 22.6 25.7 28.8 A Output voltage 10% Low
Output DC Current-Limit Shutdown Voltage 14 V
Back-Drive Current Limit while Enabled 400 mA Negative current drawn from output
Back-Drive Current Limit while Disabled 4 mA Negative current drawn from output
Maximum Output Capacitance 3,000 µF Vout nominal at full load (resistive load)
Output Voltage during Load Current Transient
Step Change in Output Current (0.1 A/µs) 500 mV 50% to 75% to 50% Iout max
Settling Time 900 µs To within 1% Vout nom
Output Voltage Trim Range -20 10 % Across Pins 13&18; Figure C; see Note 3
Output Voltage Remote Sense Range 10 % Across Pins 13&18
Output Over-Voltage Protection 31.5 35 38.5 V Over full temp range
Auxiliary power 7 8 10 V Maximum current of 50mA, Referenced to Vout(–)
Note 1: Output is terminated with 1 µF ceramic and 15 µF low-ESR tantalum capacitors. For applications requiring reduced output voltage ripple and
noise, consult SynQor applications support (e-mail: mqnbofae@synqor.com)
Note 2: An input capacitor with series resistance is necessary to provide system stability.
Note 3: Trim-up range is limited below 10% at low line and full load.Applying more than 6.2V between trim pin and Vout(-) may damage the unit.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 4
MCOTS-C-270-28-FT ELECTRICAL CHARACTERISTICS
Tb = 25 °C, Vin = 270dc unless otherwise noted; full operating temperature range is -55 °C to +100 °C baseplate temperature with appropriate power
derating. Specications subject to change without notice.
Parameter Min. Typ. Max. Units Notes & Conditions
DYNAMIC CHARACTERISTICS
Turn-On Transient
Turn-On Time 90 ms Full load, Vout=90% nom.
Start-Up Inhibit Time 360 400 440 ms See Figure F
Output Voltage Overshoot 0 % Maximum Output Capacitance
ISOLATION CHARACTERISTICS
Isolation Voltage (dielectric strength) 4250 V dc See Absolute Maximum Ratings
Isolation Resistance 100 MΩ
Isolation Capacitance (input to output) N/A pF See Note 5
TEMPERATURE LIMITS FOR POWER DERATING CURVES
Semiconductor Junction Temperature 125 °C Package rated to 150 °C
Board Temperature 125 °C UL rated max operating temp 130 °C
Transformer Temperature 125 °C
Maximum Baseplate Temperature, Tb 100 °C
FEATURE CHARACTERISTICS
Switching Frequency 350 375 400 kHz
ON/OFF Control
Off-State Voltage 2.4 18 V
On-State Voltage -1 0.8
ON/OFF Control Application notes Figures A & B
Input Resistance 3 kΩ
Over-Temperature Shutdown OTP Trip Point 125 °C Average PCB Temperature
Over-Temperature Shutdown Restart Hysteresis 10 °C
EFFICIENCY
100% Load 91 %
50% Load 92 %
FULL FEATURE OPTION
Clock Sync 350 375 400 kHz See Note 6
Current Share 2.2 V Full load
RELIABILITY CHARACTERISTICS
Calculated MTBF per MIL-HDBK-217F 1.2 106 Hrs. Ground Benign, 70°C Tb
Calculated MTBF per MIL-HDBK-217F 0.120 106 Hrs. Ground Mobile, 70°C Tb
Note 5: Input to output isolation capacitance external to the module is recommended.
Note 6: Do not apply a clock signal lower than specied frequency.
STANDARDS COMPLIANCE
Parameter Notes & Conditions
STANDARDS COMPLIANCE
UL 60950-1/R2011-12 Reinforced Insulation
CAN/CSA C22.2 No. 60950-1/A1:2011
EN 60950-1/A12:2011
CE Marked 2006/95/EC Low Voltage Directive
IEC 61000-4-2 ESD test, 8 kV - NP, 15 kV air - NP (Normal Performance)
Note: An external input fuse must always be used to meet these safety requirements. Contact SynQor for ofcial safety certicates on new
releases or download from the SynQor website.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 5
80
82
84
86
88
90
92
94
0 5 10 15 20
Efficiency (%)
Load Current (A)
425 Vin
270 Vin
155 Vin
Figure 1: Efficiency at nominal output voltage vs. load current for
minimum, nominal, and maximum input voltage at 25
°
C.
Figure 2: Efficiency at nominal output voltage and 60% rated power vs.
case temperature for minimum, nominal, and maximum input voltage.
Figure 3: Power dissipation at nominal output voltage vs. load current for
minimum, nominal, and maximum input voltage at T
CASE
=25
°
C.
Figure 4: Power dissipation at nominal output voltage and 60% rated
power vs. case temperature for minimum, nominal, and maximum input
voltage.
Figure 6: Output voltage vs. load current showing typical current limit
curves. See Current Limit section in the Application Notes.
80
82
84
86
88
90
92
94
25ºC
100ºC
Efficiency (%)
Case Temperature (ºC)
155 Vin
270 Vin
425 Vin
0
10
20
30
40
50
-55ºC
25ºC
100ºC
Power Dissipation (W)
Case Temperature (ºC)
155 Vin
270 Vin
425 Vin
0
10
20
30
40
50
60
0 5 10 15 20
Power Dissipation (W)
Load Current (A)
425 Vin
270 Vin
155 Vin
0.0
5.0
10.0
15.0
20.0
25.0
30.0
0 5 10 15 20 25 30
Output Voltage (V)
Load Current (A)
155 Vin
270Vin
425 Vin
Figure 5: Maximum output current vs. base plate temperature (nominal input
voltage).
0
5
10
15
20
25
50 60 70 80 90 100 110 120
Iout (A)
Base Plate Temperature (°C)
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 6
Figure 9: Input terminal current ripple, iC, at full rated output current and
nominal input voltage (500 mA/div). Bandwidth: 25MHz. See Figure 17.
Figure 10: Output voltage ripple, Vout, at nominal input voltage and rated load
current (200 mV/div). Load capacitance: 1µF ceramic capacitor and 10µF
tantalum capacitor. Bandwidth: 25 MHz. See Figure 17.
Figure 12: Output voltage response to step-change in input voltage (1000V/ms).
Load cap: 100 µF electrolytic output capacitance. Ch 1: Vin (200V/div), Ch 2:
Vout (1V/div).
Figure 11: Output voltage response to step-change in load current (50%-75%-
50% of Iout(max); dI/dt = 0.1 A/µs). Load cap: 1 µF ceramic and 15 µF tantalum
capacitors. Ch 3: Vout (500mV/div), Ch 2: Iout (10A/div).
Figure 8: Turn-on transient at full resistive load and zero output capacitance
initiated by Vin. ON/OFF Pin previously low. Ch 1: Vin (100V/div). Ch 2: Vout
(10V/div).
Figure 7: Start waveform with 1% load. Input voltage pre-applied, ON/OFF Pin
on Ch 1.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 7
Figure 13: Magnitude of incremental output impedance (Z
out
= v
out
/i
out
) for
minimum, nominal, and maximum input voltage at full rated power.
Figure 14: Magnitude of incremental forward transmission (FT = v
out
/v
in
)
for minimum, nominal, and maximum input voltage at full rated power.
Figure 15: Magnitude of incremental reverse transmission (RT = i
in
/i
out
) for
minimum, nominal, and maximum input voltage at full rated power.
Figure 16: Magnitude of incremental input impedance (Z
in
= v
in
/i
in
) 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).
DC/DC
Converter
V
SOURCE
i
C
V
OUT
0.001
0.01
0.1
1
10 100 1,000 10,000 100,000
Output Impedance (ohms)
Hz
270Vin
425Vin
155Vin
1
10
100
1000
10 100 1,000 10,000 100,000
Input Impedance (Ohms)
Hz
270Vin
425Vin
155Vin
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1,000 10,000 100,000
Forward Transmission (dB)
Hz
270Vin
425Vin
155Vin
-55
-45
-35
-25
-15
-5
10 100 1,000 10,000 100,000
Reverse Transmission (dB)
Hz
270Vin
425Vin
155Vin
4.5 µH
source impedance
7 µF,ceramic capacitor
in sereis with 1Ω Resistor
10 µF,
100mΩ ESR
tantalum capacitor
1 µF
ceramic capacitor
Figure 18: Load current (10A/div) as a function of time (5ms/div and 100ms/div)
when the converter attempts to turn on into a 10 mΩ short circuit.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 8
BASIC OPERATION AND FEATURES
This Mil-COTS converter series uses a two-stage power
conversion topology. The rst stage is a buck-converter
that keeps the output voltage constant over variations
in line, load, and temperature. The second stage uses
a transformer to provide the functions of input/output
isolation and voltage step-up or step-down to achieve the
output voltage required.
Both the rst stage and the second stage switch at a xed
frequency for predictable EMI performance.The switching
frequency of second stage is half of the swithcing frequency
of rst stage and locked in phase. Rectication of the
transformer’s output is accomplished with synchronous
rectiers. These devices, which are MOSFETs with a very low
on-state resistance, dissipate far less energy than Schottky
diodes. This is the primary reason that the converter has
such high efciency, even at very low output voltages and
very high output currents.
These converters are offered totally encased to withstand
harsh environments and thermally demanding applications.
Dissipation throughout the converter is so low that it does
not require a heatsink for operation in many applications;
however, adding a heatsink provides improved thermal
derating performance in extreme situations.
This series of converters uses the industry standard footprint
and pin-out conguration.
Figure A: Example of two congurations for the enable signal
VIN
IN
(+)
+ON/OFF
-ON/OFF
5V
5V
V (-)
VOUT (+)
SENSE (+)
SENSE (-)
VOUT (-)
VIN
IN
(+)
+ON/OFF
-ON/OFF
V (-)
VOUT (+)
SENSE (+)
SENSE (-)
VOUT (-)
On when switch is open
On when switch is closed
CONTROL FEATURES
ON/OFF(+) and ON/OFF(-) (Pin 3 and 4) - Remote
ON/OFF: The ON/OFF inputs, Pins 3 and 4, permit the
user to turn the converter on or off. These two inputs are
fully isolated from both the input and the output side of the
power converter, allowing the user the option to manage
the converter from the input or the output end. The user’s
on/off control signal is applied between the ON/OFF(+)
pin and the ON/OFF(-) pins. Figure A details two possible
circuits for driving the ON/OFF pin. Figure B is a detailed
look of the internal ON/OFF circuitry.
REMOTE SENSE(+) and SENSE(-) (Pins 11 and 12):
The SENSE inputs correct for voltage drops along the
conductors that connect the converter’s output pins to the
load.Pin 11 should be connected to Vout(+) and Pin 12
should be connected to Vout(-) at the point on the board
where regulation is desired. A remote connection at the
load can adjust for a voltage drop only as large as that
specied in this datasheet, that is
[Vout(+) - Vout(-)] – [Vsense(+) - Vsense(-)] ≤
Sense Range % x Vout
Pins 11 and 12 must be connected for proper regulation
of the output voltage. If these connections are not made,
the converter will deliver an output voltage that is slightly
higher than its set value.
The voltage at the output terminals of the module will be
trimmed up by the control circuit to compensate for voltage
drops between the output pins of the module and the
remote sense point. Note that the over-voltage protection
(OVP) circuit senses the voltage at the output pins of the
module. It is possible to inadvertently trip the OVP protection
circuit if the voltage drop between the output pins and the
sense point becomes too large. Hence, the remote sensing
feature should be used only to compensate for small values
of voltage drops to avoid triggering OVP due to a line or
load transient.
Figure B: Internal ON/OFF pin circuitry
C1
100p
D1
R1
3.01k
Pin 3
Pin 4
Opto
U1
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 9
Rtrim-down = (90.9 )- 0.909 (kΩ)
Δ%
where
To increase the output voltage, the user should connect a
resistor between Pin 10 (TRIM) and Pin 11 [SENSE(+)]. For
a desired increase of the nominal output voltage, the value
of the resistor should be:
Rtrim-up = (1.0VOUT x (100+Δ%) -90.9 - 0.909 )(kΩ)
1.225Δ% Δ%
It is not necessary for the user to add capacitance at the
Trim pin. The node is internally bypassed to eliminate noise.
Total DC Variation of VOUT: For the converter to meet its
full specications, the maximum variation of the dc value of
VOUT, due to both trimming and remote load voltage drops,
should not be greater than that specied for the output
voltage trim range.Note if the unit is started at no load the
output voltage may, under some conditions, regulate above
its rated value. This condition will be corrected once the
load is increased above 1%, and it will stay corrected even
if the load is lowered to zero.
The trim graphs show the relationship between the trim
resistor value and the percentage decrease or increase of
the output voltage relative to thenominal output voltage
set point. The graphs also show the total range the output
voltage can be trimmed up or down.
Note: the TRIM feature does not affect the voltage at
which the output over-voltage protection circuit is triggered.
Trimming the output voltage too high may cause the over-
voltage protection circuit to engage, particularly during
transients.
Δ% = |Vnominal – Vdesired | x 100%
Vnominal
where
Vout = Nominal Output Voltage
1
10
100
1,000
10,000
100,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Trim Resistance (kΩ)
% Increase in Vout % Decrease in Vout
Figure C: Trim graph for trim-up, trim down.
OUTPUT VOLTAGE TRIM (Pin 10): The TRIM input
permits the user to adjust the output voltage across
the sense leads up or down according to the trim range
specications.
To decrease the output voltage, the user should connect a
resistor between Pin 10 (TRIM) and Pin 12 [SENSE(-)]. For
a desired decrease of the nominal output voltage, the value
of the resistor should be:
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 10
Protection Features
Input Under-Voltage Lockout: The converter is designed
to turn off when the input voltage is too low, helping avoid
an input system instability problem, described in more detail
in the application note titled “Input System Instability”
available on www.SynQor.com . The lockout circuitry is a
comparator with DC hysteresis. When the input voltage is
rising, it must exceed the typical Turn-On Voltage Threshold
value (listed on the specication page) before the converter
will turn on. Once the converter is on, the input voltage
must fall below the typical Turn-Off Voltage Threshold value
before the converter will turn off.
Output Over-Voltage Limit: If the voltage across the
output pins exceeds the Output Over-Voltage Protection
threshold, the converter will immediately stop switching.
This prevents damage to the load circuit due to 1) excessive
series resistance in output current path from converter
output pins to sense point, 2) a release of a short-circuit
condition, or 3) a release of a current limit condition. Load
capacitance determines exactly how high the output voltage
will rise in response to these conditions. After 400 ms the
converter will automatically restart.
Over-Temperature Shutdown: A temperature sensor
on the converter senses the average temperature of the
module. The thermal shutdown circuit is designed to turn
the converter off when the temperature at the sensed
location reaches the Over-Temperature Shutdown value.
It will allow the converter to turn on again when the
temperature of the sensed location falls by the amount of
the Over-Temperature Shutdown Restart Hysteresis value.
Output Current Limit: The output current remains
constant as the output voltage drops. However, once the
impedance of the load across the output is small enough to
make the output voltage drop below the specied Output
DC Current-Limit Shutdown Voltage, the converter turns off.
The converter then enters a “auto-restart” mode where it
repeatedly turns on and off at a 2.5 Hz (nominal) frequency
until the overload condition is removed. This prevents
excessive heating of the converter or the load board.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 11
APPLICATION CONSIDERATIONS
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.
Application Circuits: Figure D provides a typical circuit diagram which details the input ltering and voltage trimming.
Figure D: Typical application circuit (negative logic unit, permanently enabled).
Input Filtering and External Capacitance: Figure E provides a diagram showing the internal input lter components.
This lter dramatically reduces input terminal ripple current, which otherwise could exceed the rating of the converter's
external electrolytic input capacitor. The recommended external input capacitance is specied in the Input Characteristics
section on the Electrical Characteristics page. More detailed information is available in the application note titled “EMI
Characteristics” on the SynQor website.
Figure E: Internal Input Filter Diagram (Component values listed on page 3)
Vin
External
Input
Filter
Trim
Vin(+)
Iload
Cload
Vout(+)
Rtrim-up
or
Rtrim-down
Vsense(+)
ON/OFF (
-
)
ON/OFF (+)
Vin(_)Vout(_)
Vsense(_)
Electrolytic
Capacitor
C2
C1
L
Vin(+)
Vin(_)
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 12
Under-Voltage
Lockout Turn-On
Threshold
ON/OFF
(Negative
logic)
Vout
Vin
(typical start-up
inhibit period
after shutdown)
(typical start-up)
t0t1t2t
(typical turn on time)
ON ON ON
OFF OFF
140ms 400ms 400ms
90ms
Figure F: Startup Inhibit Period (turn-on time not to scale)
Startup Inhibit Period: The Startup Inhibit Period
ensures that the converter will remain off for approximately
400 ms when it is shut down for any reason. For example,
when an output short is present the module will shutdown,
remain off for the startup inhibit period, and then attempt
to restart. This results in a 2.5Hz auto restart mode of
operation which prevents the converter from overheating.
In all, there are seven ways that the converter can be shut
down, initiating a Startup Inhibit Period:
• Input Under-Voltage Lockout
• Input Over-Voltage Lockout
• Output Over-Voltage Protection
• Over Temperature Shutdown
• Current Limit
• Short Circuit Protection
• Turned off by the ON/OFF input
Figure F shows three turn-on scenarios, where a Startup
Inhibit Period is initiated at t0, t1, and t2:
Before time t0, when the input voltage is below the UVL
threshold, the unit is disabled by the Input Under-Voltage
Lockout feature. When the input voltage rises above the
UVL threshold, the Input Under-Voltage lockout is released,
and a Startup Inhibit Period is initiated. At the end of this
delay, the ON/OFF pin is evaluated, and since it is active,
the unit turns on.
At time t1, the unit is disabled by the ON/OFF pin, and it
cannot be enabled again until the Startup Inhibit Period has
elapsed.
When the ON/OFF pin goes high after t2, the Startup Inhibit
Period has elapsed, and the output turns on within the
typical Turn-On Time.
Thermal Considerations: The maximum operating base-
plate temperature, TB, is 100 ºC. Refer to the thermal
derating curve gure to see the available output current at
baseplate temperatures below 100 ºC.
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 airow 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:
Pmax =TB - TA
diss 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.
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 13
.250 .020 [ 6.35 0.5]
.493 .020 [ 12.52 0.5 ]
.243 .020
[ 6.17 0.5 ]
2.00 [ 50.8 ]
2.486 .020 [ 63.14 0.5 ]
4.686 .020
[ 119.02 0.5 ]
.150 [ 3.81 ]
.300 [ 7.62 ]
.450 [ 11.43 ]
.850 [ 21.59 ]
1.250 [ 31.75 ]
.050 [ 1.27 ]
.300 [ 7.62 ]
.550 [ 13.97 ]
1.450 [ 36.83 ]
1.200 [ 30.48 ]
.950 [ 24.13 ]
1.800 [ 45.72 ]
4.200
[ 106.68 ]
3.150
[ 80.01 ]
3.300
[ 83.82 ]
3.450
[ 87.63 ]
3.600
[ 91.44 ]
3.750
[ 95.25 ]
3.900
[ 99.06 ]
OVERALL HEIGHT
+.002
0.512 -.005
+0.05
13.00
[-0.12 ]
.151 ±.010
[ 3.97 ]
SEE NOTE 5
BOTTOMSIDE CLEARANCE
+0.007
0.017 -0.010
+0.17
0.43
[-0.25 ]
4.20
[ 106.7 ]
11
2
3
4
5
6
17
16
15
14
13
12
18
11
10
9
8
7
M3 STANDOFF
x4
SEE NOTE 9
NOTES
1) Pins 1-4, 7-12 are 0.040” (1.02mm) diameter, with 0.080” (2.03mm)
diameter standoff shoulders.
2) Pins 5-6, 13-18 are 0.080” (2.03 mm) diameter with 0.125”
(3.18mm) diameter standoff shoulders.
3) All Pins: Material - Copper Alloy; Finish - Matte Tin over Nickel plate
4) Undimensioned components are shown for visual reference only.
5) Applied torque per screw should not exceed 6in-lb (0.7Nm).
6) Baseplate atness tolerance is 0.004" (.10mm) TIR for surface.
7) Weight: 9.9oz (280g) typical
8) Workmanship: Meets or exceeds IPC-A-610 Class II
9) Threaded or non-threaded options available.
10) All dimensions in inches (mm)
Tolerances: x.xx +/-0.02 in. (x.x +/-0.5mm)
x.xxx +/-0.010 in. (x.xx +/-0.25mm)
PIN DESIGNATIONS
Pin Name Function
1SyncIn Synchronization Input (full feature only)
2 SyncOut Synchronization Output (full feature only)
3 ON/OFF(+) Turn converter on and off, referenced to – ON/OFF
4 ON/OFF(–) Fully isolated ground
5 Vin(+) Positive input voltage
6 Vin(–) Negative input voltage
7 Vaux Auxiliary power, referenced to Vout(–)
8 Start Sync Startup synchronization (full feature only)
9I Share Single wire parallel signal (full feature only)
10 TRIM Output voltage trim (see note 1)
11 SENSE(+) Positive remote sense (see note 2)
12 SENSE(–) Negative remote sense (see note 3)
13 Vout(–) Negative output voltage
14 Vout(–) Negative output voltage
15 Vout(–) Negative output voltage
16 Vout(+) Positive output voltage
17 Vout(+) Positive output voltage
18 Vout(+) Positive output voltage
Pin Designations Notes:
1 Leave TRIM pin open for nominal output voltage.
2 SENSE(+) should be connected to Vout(+) remotely or at converter.
3 SENSE(–) should be connected to Vout(–) remotely or at converter.
4 Pins 1, 2, 8, and 9 are populated on full feature versions only.
Mechanical Diagram
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 14
1
2
3
4
5
6
17
16
15
14
13 18
12
11
10
9
8
7
1
0.050[1,270]
0.300[7,620]
0.550[13,970]
0.950[24,130]
1.200[30,480]
1.450[36,830]
4.200
[106,680]
0.150[3,810]
0.300[7,620]
0.450[11,430]
0.850[21,590]
1.250[31,750]
2.486±0.020 63,144±0,508[ ]
3.150±0.020 80,010±0,508[ ]
2.950±0.020 74,930±0,508[ ]
OVERALL HEIGHT
0.495±0.015
12,57±0,38[ ]
0.168
[4,27]
USE 4-40 OR
M3 SCREW (6x)
RECOM TORQUE
3in-lb
.13[3.3] 0.020
± 0,50 ]
0.125
[3,18]
0.493±0.020 12,52±0,50[ ]
0.725±0.020 18,42±0,50[ ]
0.825±0.020 20,96±0,50[ ]
0.600±0.020
15,24±0,50[ ]
0.017±0.020
0,43±0,50[ ]
0.243±0.020
6,17±0,50[ ]
1.50
[38,1]
3.00
[76,2]
4.17
[105,8]
4.686±
119,02[
3.150
[80,010]
3.300
[83,820]
3.450
[87,630]
3.600
[91,440]
3.750
[95,250]
3.900
[99,060]
NOTES
1) Applied torque per screw should not exceed 5in-lb (0.7Nm), 3in-lb
(0.4Nm) recommended.
2) Pins 1-4, 7-12 are 0.040” (1.02mm) diameter, with 0.080” (2.03mm)
diameter standoff shoulders.
3) Pins 5-6, 13-18 are 0.080” (2.03 mm) diameter with 0.125” (3.18mm)
4) All Pins: Material - Copper Alloy; Finish - Matte Tin over Nickel plate
5) Undimensioned components are shown for visual reference only.
6) Baseplate atness tolerance is 0.010" (.25mm) TIR for surface.
7) Weight: 10.1oz (285g) typical
8) Workmanship: Meets or exceeds IPC-A-610 Class II
9) All dimensions in inches (mm)
Tolerances: x.xx +/-0.02 in. (x.x +/-0.5mm)
x.xxx +/-0.010 in. (x.xx +/-0.25mm)
PIN DESIGNATIONS
Pin Name Function
1SyncIn Synchronization Input (full feature only)
2 SyncOut Synchronization Output (full feature only)
3 ON/OFF(+) Turn converter on and off, referenced to – ON/OFF
4 ON/OFF(–) Fully isolated ground
5 Vin(+) Positive input voltage
6 Vin(–) Negative input voltage
7 Vaux Auxiliary power, referenced to Vout(–)
8 Start Sync Startup synchronization (full feature only)
9I Share Single wire parallel signal (full feature only)
10 TRIM Output voltage trim (see note 1)
11 SENSE(+) Positive remote sense (see note 2)
12 SENSE(–) Negative remote sense (see note 3)
13 Vout(–) Negative output voltage
14 Vout(–) Negative output voltage
15 Vout(–) Negative output voltage
16 Vout(+) Positive output voltage
17 Vout(+) Positive output voltage
18 Vout(+) Positive output voltage
Pin Designations Notes:
1 Leave TRIM pin open for nominal output voltage.
2 SENSE(+) should be connected to Vout(+) remotely or at converter.
3 SENSE(–) should be connected to Vout(–) remotely or at converter.
4 Pins 1, 2, 8, and 9 are populated on full feature versions only.
Flanged Mechanical Diagram
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 15
Mil-COTS DC-DC Converter and Filter Screening
Screening Process Description S-Grade M-Grade
Baseplate Operating Temperature -55˚C to +100˚C -55˚C to +100˚C
Storage Temperature -65˚C to +135˚C -65˚C to +135˚C
Pre-Cap Inspection IPC-610, Class III ● ●
Temperature Cycling Method 1010, Condition B, 10 Cycles ●
Burn-In 100˚C Baseplate 12 Hours 96 Hours
Final Electrical Test 100% 25˚C -55˚C, +25˚C, +100˚C
Final Visual Inspection MIL-STD-2008 ● ●
Mil-COTS Qualication
Test Name Details # Tested
(# Failed)
Consistent with MIL-
STD-883F Method
Consistent with MIL-
STD-883F Method 5005
Life Testing Visual, mechanical and electrical testing before, during and
after 1000 hour burn-in @ full load
15
(0) Method 1005.8
Shock-Vibration Visual, mechanical and electrical testing before, during and
after shock and vibration tests
5
(0)
MIL-STD-202,
Methods 201A & 213B
Humidity +85˚C, 95% RH, 1000 hours, 2 minutes on / 6 hours off 8
(0) Method 1004.7
Temperature
Cycling
500 cycles of -55˚C to +100˚C
(30 minute dwell at each temperature)
10
(0) Method 1010.8 Condition A
Solderability 15 pins 15
(0) Method 2003
DMT -65˚C to +110˚C across full line and load specications in
5˚C steps
7
(0)
Altitude 70,000 feet (21 km), see Note 2
(0)
Note: A conductive cooling design is generally needed for high altitude applications because of naturally poor convective cooling at rare atmospheres.
MILCOTS MIL-STD-810G Qualication Testing
MIL-STD-810G Test Method Description
Fungus 508.6 Table 508.6-I
Altitude 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
High Temperature 501.5 - Procedure I Storage: 135°C / 3 hrs
501.5 - Procedure II Operating: 100°C / 3 hrs
Low Temperature 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
Shock 516.6 - Procedure I 20g's peak, 11ms, Functional Shock (Operating no load) (saw tooth)
516.6 - Procedure VI Bench Handling Shock
Sinusoidal vibration 514.6 - Category 14 Rotary wing aircraft - helicopter, 4hrs/axis, 20g's (sine sweep from 10 - 500HZ)
Sand and Dust 510.5 - Procedure I Blowing Dust
510.5 - Procedure II Blowing Sand
Technical Specification
MCOTS-C-270-28-FT
Output:
28V
Current:
21.4A
Product # MCOTS-C-270-28-FT Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005931 Rev. F 10/16/2013
Page 16
Warranty
SynQor offers a two (2) year limited warranty. Complete warranty infor-
mation 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.
Contact SynQor for further information and to order:
Phone: 978-849-0600
Toll Free: 888-567-9596
Fax: 978-849-0602
E-mail: mqnbofae@synqor.com
Web:
www.synqor.com
Address: 155 Swanson Road
Boxborough, MA 01719
USA
Example MCOTS-C-270-28-FT-N-S
Not all combinations make valid part numbers, please contact SynQor for availability. See
product summary page
for details.
APPLICATION NOTES
A variety of application notes and technical white papers can be downloaded
in pdf format from our website.
Ordering Information/ Part Numbering
PATENTS
SynQor holds the following U.S. patents, one or more of which apply to
each product listed in this document. Additional patent applications may
be pending or led in the future.
5,999,417 6,222,742 6,545,890 6,577,109 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
Family Product Input Voltage Output
Voltage Package Heatsink
Option
Screening
Level Options
MCOTS C: Converter 270: 155-425V
05:
12:
15:
24:
28:
48:
5V
12V
15V
24V
28V
48V
FT:Full Brick Tera
N:
F:
D:
Normal
Threaded
Flanged
Normal
Non-
Threaded
S: S-Grade
M: M-Grade
[ ]:
F:
Standard
Feature
Full Feature