Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 1
MQHL-28-15S
Single Output
MQHL-28-15S-Y-ES
28Vin 15Vout@3.3A
+VIN
IN RTN
CASE
ENA 1
SYNC OUT
SYNC IN +VOUT
OUT RTN
-SNS
+SNS
TRIM
N/C
HigH Reliability DC-DC ConveRteR
Full PoweR oPeRation: -55ºC to +125ºC
Features
MQHL series converters (with MQHE filter) are designed to meet:
Specification Compliance
MQHL series converters are:
Design Process
MQHL series converters are qualified to:
Qualification Process
In-Line Manufacturing Process
DesigneD & ManufactureD in the usa
featuring Qorseal
™
hi-rel asseMbly
• Designed for reliability per NAVSO-P3641-A guidelines
• Designed with components derated per:
— MIL-HDBK-1547A
— NAVSO P-3641A
• MIL-STD-810F
— consistent with RTCA/D0-160E
• SynQor’s First Article Qualication
— consistent with MIL-STD-883F
• SynQor’s Long-Term Storage Survivability Qualication
• SynQor’s on-going life test
• AS9100 and ISO 9001:2008 certied facility
• Full component traceability
• Temperature cycling
• Constant acceleration
• 24, 96, 160 hour burn-in
• Three level temperature screening
• MIL-HDBK-704-8 (A through F)
• RTCA/DO-160 Section 16
• MIL-STD-1275 for VIN > 16V
• DEF-STAN 61-5 (part 6)/5 for VIN > 16V
• MIL-STD-461 (C, D, E)
• RTCA/DO-160 Section 22
• Fixed switching frequency
• No opto-isolators
• Output over-voltage shutdown
• Remote sense
• Clock synchronization
• Primary referenced enable
• Continuous short circuit and overload protection
• Input under-voltage and over-voltage shutdown
The MilQor@ series of high-reliability DC-DC converters
brings SynQor’s eld proven high-efciency synchronous
rectier technology to the Military/Aerospace industry.
SynQor’s innovative QorSealTM packaging approach ensures
survivability in the most hostile environments. Compatible
with the industry standard format, these converters operate
at a xed frequency, have no opto-isolators, and follow
conservative component derating guidelines. They are
designed and manufactured to comply with a wide range of
military standards.
16-40V 16-50V 15V 3.3A 86% @ 1.65A / 86% @ 3.3A
Continuous Input Transient Input Output Output Efciency
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 2
Output:
Current:
15V
3.3A
MQHL-28-15S
Technical Specification
BLOCK DIAGRAM
TYPICAL CONNECTION DIAGRAM
− SENSE
ISOLATION STAGE
REGULATION STAGE 7
8
UVLO
OVSD
SECONDARY
CONTROL
GATE CONTROL
PRIMARY
CONTROL
POSITIVE
INPUT
INPUT
RETURN
CASE
ENABLE 1
SYNC OUT
SYNC IN
12
11
10
9
1
2
3
4
5
6
POSITIVE
OUTPUT
OUTPUT
RETURN
TRIM
NO CONNECT
+ SENSE
GATE DRIVERS
MAGNETIC
FEEDBACK
CONTROL POWER
OVP
T1 T1T2 T2
CURRENT
LIMIT
CURRENT
SENSE
MQHL
+VIN
IN RTN
CASE
ENA 1
SYNC OUT
SYNC IN
N/C
TRIM
+SNS
-SNS
OUT RTN
+VOUT
1
2
3
4
5
6
12
11
10
9
8
7
Load
+
+
28 Vdc
open
means
on
_
_
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 3
Output:
Current:
15V
3.3A
MQHL-28-15S
Technical Specification
MQHL-28-15S ELECTRICAL CHARACTERISTICS
Parameter Min. Typ. Max. Units Notes & Conditions Group A
Vin=28V dc ±5%, Iout=3.3A, CL=0µF, free running
(see Note 9) unless otherwise specied Subgroup
(see Note 11)
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Non-Operating 60 V
Operating 60 V See Note 1
Reverse Bias (Tcase = 125ºC) -0.8 V
Reverse Bias (Tcase = -55ºC) -1.2 V
Isolation Voltage (I/O to case, I to O)
Continuous -500 500 V
Transient (≤100µs) -800 800 V
Operating Case Temperature -55 125 °C See Note 2
Storage Case Temperature -65 135 °C
Lead Temperature (20s) 300 °C
Voltage at ENA1 -1.2 50 V
INPUT CHARACTERISTICS
Operating Input Voltage Range 16 28 40 V Continuous 1, 2, 3
“ 16 28 50 V Transient, 1s 4, 5, 6
Input Under-Voltage Shutdown See Note 3
Turn-On Voltage Threshold 14.75 15.50 16.00 V 1, 2, 3
Turn-Off Voltage Threshold 14.00 14.75 15.50 V 1, 2, 3
Shutdown Voltage Hysteresis 0.65 0.85 1.05 V 1, 2, 3
Input Over-Voltage Shutdown See Note 3
Turn-Off Voltage Threshold 52.0 55.0 58.0 V 1, 2, 3
Turn-On Voltage Threshold 50.5 54.0 56.5 V 1, 2, 3
Shutdown Voltage Hysteresis 1.0 2.0 3.0 V 1, 2, 3
Maximum Input Current 3.9 A Vin = 16V; Iout = 3.3A 1, 2, 3
No Load Input Current (operating) 75 100 mA 1, 2, 3
Disabled Input Current (ENA) 10 15 mA Vin = 16V, 28V, 50V 1, 2, 3
Input Terminal Current Ripple (pk-pk) 40 75 mA Bandwidth = 100kHz – 10MHz; see Figure 14 1, 2, 3
OUTPUT CHARACTERISTICS
Output Voltage Set Point (Tcase = 25ºC) 14.85 15.00 15.15 V Vout at sense leads 1
Output Voltage Set Point Over Temperature 14.78 15.00 15.22 V “ 2, 3
Output Voltage Line Regulation -50 0 50 mV “ ; Vin = 16V, 28V, 40V; Iout=3.3A 1, 2, 3
Output Voltage Load Regulation -70 0 70 mV “ ; Vout @ (Iout=0A) - Vout @ (Iout=3.3A) 1, 2, 3
Total Output Voltage Range 14.70 15.00 15.30 V “ 1, 2, 3
Output Over-Voltage Shutdown 16.8 18.4 21.3 V See Note 5
Output Voltage Ripple and Noise Peak to Peak 15 75 mV Bandwidth = 10MHz; CL=11µF 1, 2, 3
Operating Output Current Range 0 3.3 A 1, 2, 3
Operating Output Power Range 0 49.5 W 1, 2, 3
Output DC Current-Limit Inception 3.5 4.1 5 A See Note 4 1, 2, 3
Back-Drive Current Limit while Enabled 0.9 A 1, 2, 3
Back-Drive Current Limit while Disabled 10 50 mA 1, 2, 3
Maximum Output Capacitance 1,500 µF See Note 5
DYNAMIC CHARACTERISTICS
Output Voltage Deviation Load Transient See Note 6
For a Pos. Step Change in Load Current -650 -300 mV Total Iout step = 1.65A to 3.3A, 0.33A to 1.65A; CL=11µF 4, 5, 6
For a Neg. Step Change in Load Current 300 650 mV “ 4, 5, 6
Output Voltage Deviation Line Transient Vin step = 16V to 50V; CL=11µF; see Note 7
For a Pos. Step Change in Line Voltage -300 300 mV 4, 5, 6
For a Neg. Step Change in Line Voltage -300 300 mV 4, 5, 6
Turn-On Transient
Output Voltage Rise Time 6 10 ms Vout = 1.5V to 13.5V; Full Resistive Load 4, 5, 6
Output Voltage Overshoot 0 2 % Resistive load See Note 5
Turn-On Delay, Rising Vin 5.5 8.0 ms ENA = 5V; see Notes 8 & 10 4, 5, 6
Turn-On Delay, Rising ENA 3.0 6.0 ms See Note 10 4, 5, 6
Restart Inhibit Time 100 150 ms See Note 10 4, 5, 6
Short Circuit Start Time 12 14 20 ms 4
EFFICIENCY
Iout = 3.3 A (16 Vin) 83 87 % 1, 2, 3
Iout = 1.65 A (16 Vin) 86 88 % 1, 2, 3
Iout = 3.3 A (28 Vin) 83 86 % 1, 2, 3
Iout = 1.65 A (28 Vin) 84 86 % 1, 2, 3
Iout = 3.3 A (40 Vin) 81 85 % 1, 2, 3
Iout = 1.65 A (40 Vin) 81 84 % 1, 2, 3
Iout = 3.3 A (50 Vin) 80 83 % 1, 2, 3
Load Fault Power Dissipation 2.5 W Sustained short circuit on output
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 4
Output:
Current:
15V
3.3A
MQHL-28-15S
Technical Specification
MQHL-28-15S ELECTRICAL CHARACTERISTICS (Continued)
Parameter Min. Typ. Max. Units Notes & Conditions Group A
Vin=28V dc ±5%, Iout=3.3A, CL=0µF, free running
(see Note 9) unless otherwise specied Subgroup
(see Note 11)
ISOLATION CHARACTERISTICS
Isolation Voltage Dielectric strength
Input RTN to Output RTN 500 V 1
Any Input Pin to Case 500 V 1
Any Output Pin to Case 500 V 1
Isolation Resistance (in rtn to out rtn) 100 MΩ 1
Isolation Resistance (any pin to case) 100 MΩ 1
Isolation Capacitance (in rtn to out rtn) 22 nF 1
FEATURE CHARACTERISTICS
Switching Frequency (free running) 500 550 600 kHz 1, 2, 3
Synchronization Input
Frequency Range 500 700 kHz 1, 2, 3
Logic Level High 2.0 5.5 V 1, 2, 3
Logic Level Low -0.5 0.8 V 1, 2, 3
Duty Cycle 20 80 % See Note 5
Synchronization Output
Pull Down Current 20 mA VSYNC OUT = 0.8V See Note 5
Duty Cycle 40 60 % Output connected to SYNC IN of other MQHL unit See Note 5
Enable Control (ENA)
Off-State Voltage 0.8 V 1, 2, 3
Module Off Pulldown Current 80 µA Current drain required to ensure module is off See Note 5
On-State Voltage 2 V 1, 2, 3
Module On Pin Leakage Current 20 µA Imax draw from pin allowed with module still on See Note 5
Pull-Up Voltage 3.2 4.0 4.8 V See Figure A 1, 2, 3
Output Voltage Trim Range -10 10 % See Figure E 1, 2, 3
RELIABILITY CHARACTERISTICS
Calculated MTBF (MIL-STD-217F2)
GB @ Tcase = 70ºC 4030 103 Hrs.
AIF @ Tcase = 70ºC 338 103 Hrs.
WEIGHT CHARACTERISTICS
Device Weight 45 g
Electrical Characteristics Notes
1. Converter will undergo input over-voltage shutdown.
2. Derate output power for continuous operation per Figure 5.
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 dened as the point where the output voltage has dropped to 90% of its nominal value. See Current Limit discussion in
Features Description section.
5. Parameter not tested but guaranteed to the limit specied.
6. Load current transition time ≥ 10µs.
7. Line voltage transition time ≥ 100µs.
8. Input voltage rise time ≤ 250µs.
9. Operating the converter at a synchronization frequency above the free running frequency will cause the converter’s efciency to be slightly reduced
and it may also cause a slight reduction in the maximum output current/power available. For more i
10. After a disable or fault event, module is inhibited from restarting for 100ms. See Shut Down section of the Control Features description.
11. Only the ES and HB grade products are tested at three temperatures. The C grade products are tested at one temperature. Please refer to the
Construction and Environmental Stress Screening Options table for details.
12. These derating curves apply for the ES- and HB- grade products. The C- grade product has a maximum case temperature of 100ºC.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 5
Output:
Current:
15V
3.3A
MQHL-28-15S
Figures
60
65
70
75
80
85
90
95
100
0.00 0.66 1.32 1.98 2.64 3.30
Efficiency (%)
Load Current (A)
16 Vin
28 Vin
40 Vin
60
65
70
75
80
85
90
95
100
-55ºC
25ºC
125ºC
Efficiency (%)
Case Temperature (ºC)
16 Vin
28 Vin
40 Vin
0
2
4
6
8
10
12
0.00 0.66 1.32 1.98 2.64 3.30
Power Dissipation (W)
Load Current (A)
16 Vin
28 Vin
40 Vin
0
2
4
6
8
10
12
-55ºC 25ºC 125ºC
Power Dissipation (W)
Case Temperature (ºC)
16 Vin
28 Vin
40 Vin
0.0
0.7
1.3
2.0
2.6
3.3
4.0
25 45 65 85 105 125 145
Case Temperature (ºC)
Iout (A)
0
10
20
30
40
50
59
Tjmax = 105º C
Tjmax = 125º C
Tjmax = 145º C
Pout (W)
0
2
4
6
8
10
12
14
16
18
012345
Load Current (A)
Output Voltage (V)
Figure 1: Efciency at nominal output voltage vs. load current for
minimum, nominal, and maximum input voltage at Tcase=25°C.
Figure 2: Efciency at nominal output voltage and 60% rated power
vs. case temperature for input voltage of 16V, 28V, and 40V.
Figure 3: Power dissipation at nominal output voltage vs. load
current for minimum, nominal, and maximum input voltage at
Tcase=25°C.
Figure 4: Power dissipation at nominal output voltage and 60%
rated power vs. case temperature for input voltage of 16V, 28V, and
40V.
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 12).
Figure 6: Output voltage vs. load current showing typical current
limit curves at Vin = 28V.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 6
Output:
Current:
15V
3.3A
MQHL-28-15S
Figures
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 3: ENA1 (5V/div).
Figure 8: Turn-on transient at full resistive load and 1.5mF output
capacitance initiated by ENA1. Input voltage pre-applied. Ch 1:
Vout (5V/div). Ch 3: ENA1 (5V/div).
Figure 9: Turn-on transient at full resistive load and zero output
capacitance initiated by Vin. ENA1 previously high. Ch 1: Vout (5V/
div). Ch 3: Vin (10V/div).
Figure 10: Output voltage response to step-change in load current
50%-100%-50% of Iout (max). Load cap: 1µF ceramic cap and
10µF, 100mΩ ESR tantalum cap. Ch 1: Vout (200mV/div). Ch 2:
Iout (2A/div).
Figure 11: Output voltage response to step-change in load current
0%-50%-0% of Iout (max). Load cap: 1µF ceramic cap and 10µF,
100mΩ ESR tantalum cap. Ch 1: Vout (200mV/div). Ch 2: Iout (2A/
div).
Figure 12: Output voltage response to step-change in input voltage
(16V - 50V - 16V) in 150μS. Ch 1: Vout (100mV/div). Ch 3: Vin
(20V/div).
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 7
Output:
Current:
15V
3.3A
MQHL-28-15S
Figures
Data Pending
Figure 13: Test set-up diagram showing measurement points for
Input Terminal Ripple Current (Figure 14) and Output Voltage
Ripple (Figure 15).
Figure 14: Input terminal current ripple, ic, at full rated output
current and nominal input voltage with SynQor MQ lter module
(50mA/div). Bandwidth: 20MHz. See Figure 13.
Figure 15: Output voltage ripple, Vout, at nominal input voltage
and rated load current (10mV/div). Load capacitance: 1μF ceramic
capacitor and 10μF tantalum capacitor. Bandwidth: 10MHz. See
Figure 13.
Figure 16: Rise of output voltage after the removal of a short circuit
across the output terminals. Ch 1: Vout (5V/div). Ch 2: Iout (5A/
div).
Figure 17: SYNC OUT vs. time, driving SYNC IN of a second
SynQor MQHL converter. Ch1: SYNC OUT: (1V/div).
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 8
Output:
Current:
15V
3.3A
MQHL-28-15S
Figures
0.001
0.01
0.1
1
10 100 1,000 10,000 100,000
Output Impedance (ohms)
Hz
16V
28V
40V
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1,000 10,000 100,000
Forward Transmission (dB)
Hz
16V
28V
40V
-50
-40
-30
-20
-10
0
10
10 100 1,000 10,000 100,000
Reverse Transmission (dB)
Hz
16V
28V
40V
0.01
0.1
1
10
100
10 100 1,000 10,000 100,000
Input Impedance (ohms)
Hz
16V
28V
40V
Figure 18: Magnitude of incremental output impedance (Zout =
vout/iout) for minimum, nominal, and maximum input voltage at full
rated power.
Figure 19: Magnitude of incremental forward transmission (FT =
vout/vin) for minimum, nominal, and maximum input voltage at full
rated power.
Figure 20: Magnitude of incremental reverse transmission (RT = iin/
iout) for minimum, nominal, and maximum input voltage at full rated
power.
Figure 21: Magnitude of incremental input impedance (Zin = vin/
iin) for minimum, nominal, and maximum input voltage at full rated
power.
Figure 22: High frequency conducted emissions of standalone
MQHL-28-05S, 5Vout module at 50W output, as measured with
Method CE102. Limit line shown is the ‘Basic Curve’ for all
applications with a 28V source.
Figure 23: High frequency conducted emissions of MQHL-28-05S,
5Vout module at 50W output with MQHE-28-P lter, as measured
with Method CE102. Limit line shown is the ‘Basic Curve’ for all
applications with a 28V source.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 9
Output:
Current:
15V
3.3A
MQHL-28-15S
Application Section
BASIC OPERATION AND FEATURES
The
MQHL
DC/DC converter uses a two-stage power
conversion topology. The rst, 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 xed
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.
Rectication of the isolation stage’s output is accomplished
with synchronous rectiers. 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
MQHL
converters have such high efciency, particularly at
low output voltages.
Besides improving efciency, the synchronous rectiers
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 rectication. The synchronous rectiers
actually permit a negative load current to ow back into the
converter’s output terminals if the load is a source of short
or long term energy. The
MQHL
converters employ a “back-
drive current limit” to keep this negative output terminal
current small.
There is a control circuit in the
MQHL
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 over-voltage limit. There is also an output current
limit that is nearly constant as the load impedance decreases
(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. 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
MQHL
converter’s control circuit does not implement an
over-temperature shutdown.
The following sections describe the use and operation of
additional control features provided by the
MQHL
converter.
CONTROL FEATURES
ENABLE: The
MQHL
converter has one enable pin, ENA1
(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.
The enable pin is internally pulled high so that an open
connection will enable the converter. Figure A shows the
equivalent circuit looking into the enable pin. It is TTL
compatible and has hysteresis.
SHUT DOWN: The
MQHL
converter will shut down in
response to only ve conditions: ENA input low, VIN input
below under-voltage shutdown threshold, VIN input above
over-voltage shutdown threshold, output voltage below the
output under-voltage threshold, and output voltage above
the output over-voltage 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 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” specication.
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 specied value.
ENA1
82.5K
10K
TO ENABLE
CIRCUITRY
PIN4
PIN2 IN RTN
Figure A: Circuit diagram shown for reference only, actual circuit
components may differ from values shown for equivalent circuit.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 10
Output:
Current:
15V
3.3A
MQHL-28-15S
Application Section
Inside the converter, +SENSE is connected to +Vout with a
100Ω resistor and –SENSE is connected to OUTPUT RETURN
with a 10Ω resistor.
It is also important to note that when remote sense is used,
the voltage across the converter’s output terminals (pins 7
and 8) will be higher than the converter’s nominal output
voltage due to resistive drops along the connecting wires.
This higher voltage at the terminals produces a greater
voltage stress on the converter’s internal components and
may cause the converter to fail to deliver 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
MQHL
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
MQHL
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
MQHL
converter will
revert to its free-running frequency.
The
MQHL
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
MQHL
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.
The synchronization feature is entirely compatible with that
of SynQor’s MQFL family of converters.
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
MQHL
converter’s output voltage ±10% around its
nominal value.
To trim the output voltage above its nominal value, connect
an external resistor from the TRIM pin to the –SENSE pin
as shown in Figure D. The value of this trim up resistor
should be chosen according to the following equation or
from Figure E:
PIN 2
PIN 6
5K
5V
SYNC IN
IN RTN
TO SYNC
CIRCUITRY
5K
Figure B: Equivalent circuit looking into the SYNC IN pin with
respect to the IN RTN (input return) pin.
FROM SYNC
CIRCUITRY
5K
5V
SYNC OUT
IN RTN
PIN 2
PIN 5
OPEN COLLECTOR
OUTPUT
Figure C: Equivalent circuit looking into SYNC OUT pin with
respect to the IN RTN (input return) pin.
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 values of these trim down resistors
should be chosen according to the following equation or
from Figure E:
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.
Factory trimmed converters are available by request.
Rtrim up(Ω) = 8300Ω*Vnom - 41700Ω
Vout - Vnom
Rtrim down(Ω) = 50100Ω*Vout - 27500Ω*Vnom - 137500Ω
Vnom - Vout
Rtrim sense(Ω) = 0.43 * Rtrim down(Ω)
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 11
Output:
Current:
15V
3.3A
MQHL-28-15S
Application Section
INPUT UNDER-VOLTAGE SHUTDOWN: The
MQHL
converter has an under-voltage shutdown feature that
ensures the converter will be off if the input voltage is too
low. The input voltage turn-on threshold is higher than
the turn-off threshold. In addition, the
MQHL
converter will
not respond to a state of the input voltage unless it has
remained in that state for more than about 200µs. This
hysteresis and the delay ensure proper operation when the
source impedance is high or in a noisy environment.
INPUT OVER-VOLTAGE SHUTDOWN: The
MQHL
converter also has an over-voltage feature that ensures the
converter will be off if the input voltage is too high. It also
has a hysteresis and time delay to ensure proper operation.
OUTPUT OVER-VOLTAGE SHUTDOWN: The
MQHL
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.
OUTPUT UNDER-VOLTAGE SHUTDOWN: The
MQHL
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%, trim-
down should not trigger this event. After a startup inhibit
delay, the converter will attempt to restart. This shutdown
is disabled during startup.
BACK-DRIVE CURRENT LIMIT: Converters that use
MOSFETs as synchronous rectiers are capable of drawing
a negative current from the load if the load is a source of
short- or long-term energy. This negative current is referred
to as a “back-drive current”.
Conditions where back-drive current might occur include
paralleled converters that do not employ current sharing.
It can also occur 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
MQHL
converters limit the negative current
that the converter can draw from its output terminals. The
threshold for this back-drive current limit is placed sufciently
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.
10
100
1000
10000
-10% -8% -6% -4% -2% 0% 2% 4% 6% 8% 10%
Output Voltage Adjustment
External Trim Resistance (kOhms)
Trim Up
Trim Down
Trim Sense
Figure E: Trim up and Trim down as a function of external trim resistance.
Load
+
+
28 Vdc
open
means
on
R
TRIM DOWN
R
TRIM UP
/ R
TRIM SENSE
MQHL
+VIN
IN RTN
CASE
ENA 1
SYNC OUT
SYNC IN
N/C
TRIM
+SNS
-SNS
OUT RTN
+VOUT
1
2
3
4
5
6
12
11
10
9
8
7
__
__
Figure D: Typical connection for output voltage trimming.
MQHL
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 12
Output:
Current:
15V
3.3A
MQHL-28-15S
Application Section
CURRENT LIMIT: In the event of excess load, the
MQHL
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.
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 5-10ºC 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.
THERMAL CONSIDERTAIONS: 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 20ºC
higher than the case temperature directly below this MOSFET.
The Mil-HDBK-1547A component derating guideline calls
for a maximum component temperature of 105ºC. 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 125ºC. In extreme
cases, a maximum temperature of 145ºC 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 135ºC.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 13
Output:
Current:
15V
3.3A
MQHL-28-15S
Stress Screening
CONSTRUCTION AND ENVIRONMENTAL STRESS SCREENING OPTIONS
MilQor converters and filters are offered in three variations of environmental stress screening options. All MilQor converters use
SynQor’s proprietary QorSeal™ 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. Each successively higher grade has more stringent mechanical
and electrical testing, as well as a longer burn-in cycle. The ES- and HB-Grades are also constructed of components that have been
procured through an element evaluation process that pre-qualifies each new batch of devices.
Screening Consistent with
MIL-STD-883F
C-Grade
(-40 ºC to +100 ºC)
ES-Grade
(-55 ºC to +125 ºC)
(Element Evaluation)
HB-Grade
(-55 ºC to +125 ºC)
(Element Evaluation)
Internal Visual *Yes Yes Yes
Temperature Cycle Method 1010 No Condition B
(-55 ºC to +125 ºC)
Condition C
(-65 ºC to +150 ºC)
Constant
Acceleration
Method 2001
(Y1 Direction) No 500g Condition A
(5000g)
Burn-in
Method 1015
Load Cycled
• 10s period
• 2s @ 100% Load
• 8s @ 0% Load
24 Hrs @ +125 ºC 96 Hrs @ +125 ºC 160 Hrs @ +125 ºC
Final Electrical Test Method 5005
(Group A) +25 ºC -45, +25, +100 ºC -55, +25, +125 ºC
Mechanical Seal,
Thermal, and Coating
Process
Full QorSeal Full QorSeal Full QorSeal
External Visual 2009 *Yes Yes
Construction Process QorSeal QorSeal QorSeal
* Per IPC-A-610 Class 3
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 14
Output:
Current:
15V
3.3A
MQHL-28-15S
Mechanical Diagrams
Case U
Case W
PIN DESIGNATIONS
Pin # Function
1 Positive input
2 Input return
3 Case
4 Enable 1
5 Sync output
6 Sync input
7 Positive output
8 Output return
9 - Sense
10 + Sense
11 Trim
12 No connection
NOTES
1) Case: Aluminum with gold over
nickel plate nish for the C-,
ES-, and HB-Grade products.
2) Pins: Diameter: 0.040’’ (1.02mm)
Material: Copper
Finish: Copper alloy with Gold
over Nickel plating, followed
by Sn/Pb solder dip
3) All dimensions in inches (mm)
4) Tolerances: a) x.xx +/-0.02 in.
(x.x +/-0.5mm)
b) x.xxx +/-0.010 in.
(x.xx +/-0.25mm)
5) Weight: 1.6 oz (45.4 g) typical
6) Workmanship: Meets or exceeds
IPC-A-610 Class III
7) Pin 1 identication hole, not intended
for mounting
MQHL-28-15S-U-ES
DC-DC CONVERTER
28Vin 15Vout @ 3.3A
MQHL-28-15S-W-ES
DC-DC CONVERTER
28Vin 15Vout @ 3.3A
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 15
Output:
Current:
15V
3.3A
MQHL-28-15S
Mechanical Diagrams
Case X
Case Y
PIN DESIGNATIONS
Pin # Function
1 Positive input
2 Input return
3 Case
4 Enable 1
5 Sync output
6 Sync input
7 Positive output
8 Output return
9 - Sense
10 + Sense
11 Trim
12 No connection
NOTES
1) Case: Aluminum with gold over
nickel plate nish for the C-,
ES-, and HB-Grade products.
2) Pins: Diameter: 0.040’’ (1.02mm)
Material: Copper
Finish: Copper alloy with Gold
over Nickel plating, followed
by Sn/Pb solder dip
3) All dimensions in inches (mm)
4) Tolerances: a) x.xx +/-0.02 in.
(x.x +/-0.5mm)
b) x.xxx +/-0.010 in.
(x.xx +/-0.25mm)
5) Weight: 1.6 oz (45.4 g) typical
6) Workmanship: Meets or exceeds
IPC-A-610 Class III
7) Pin 1 identication hole, not intended
for mounting
MQHL-28-15S-X-ES
DC-DC CONVERTER
28Vin 15Vout @ 3.3A
MQHL-28-15S-Y-ES
DC-DC CONVERTER
28Vin 15Vout @ 3.3A
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 16
Output:
Current:
15V
3.3A
MQHL-28-15S
Mechanical Diagrams
Case Z
PIN DESIGNATIONS
Pin # Function
1 Positive input
2 Input return
3 Case
4 Enable 1
5 Sync output
6 Sync input
7 Positive output
8 Output return
9 - Sense
10 + Sense
11 Trim
12 No connection
NOTES
1) Case: Aluminum with gold over
nickel plate nish for the C-,
ES-, and HB-Grade products.
2) Pins: Diameter: 0.040’’ (1.02mm)
Material: Copper
Finish: Copper alloy with Gold
over Nickel plating, followed
by Sn/Pb solder dip
3) All dimensions in inches (mm)
4) Tolerances: a) x.xx +/-0.02 in.
(x.x +/-0.5mm)
b) x.xxx +/-0.010 in.
(x.xx +/-0.25mm)
5) Weight: 1.6 oz (45.4 g) typical
6) Workmanship: Meets or exceeds
IPC-A-610 Class III
7) Pin 1 identication hole, not intended
for mounting
MQHL-28-15S-Z-ES
DC-DC CONVERTER
28Vin 15Vout @ 3.3A
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 17
Output:
Current:
15V
3.3A
MQHL-28-15S
Ordering Information
MilQor Converter FAMILY MATRIX
The tables below show the array of MilQor 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 Dual Output †
Full Size 1.5V 1.8V 2.5V 3.3V 5V 6V 7.5V 9V 12V 15V 28V 5V 12V 15V
(1R5S) (1R8S) (2R5S) (3R3S) (05S) (06S) (7R5S) (09S) (12S) (15S) (28S) (05D) (12D) (15D)
MQFL-28
40A 40A 40A 30A 24A 20A 16A 13A 10A 8A 4A 24A
Total
10A
Total
8A
Total
16-40Vin Cont.
16-50Vin 1s Trans.*
Absolute Max Vin = 60V
MQFL-28E
40A 40A 40A 30A 24A 20A 16A 13A 10A 8A 4A 24A
Total
10A
Total
8A
Total
16-70Vin Cont.
16-80Vin 1s Trans.*
Absolute Max Vin =100V
MQFL-28V
40A 40A 40A 30A 20A 17A 13A 11A 8A 6.5A 3.3A 20A
Total
8A
Total
6.5A
Total
16-40Vin Cont.
5.5-50Vin 1s Trans.*
Absolute Max Vin = 60V
MQFL-28VE
40A 40A 40A 30A 20A 17A 13A 11A 8A 6.5A 3.3A 20A
Total
8A
Total
6.5A
Total
16-70Vin Cont.
5.5-80Vin 1s Trans.*
Absolute Max Vin = 100V
MQFL-270
40A 40A 40A 30A 24A 20A 16A 13A 10A 8A 4A 24A
Total
10A
Total
8A
Total
155-400Vin Cont.
155-475Vin 1s Trans.*
Absolute Max Vin = 550V
Single Output Dual Output †
Half Size 1.5V 1.8V 2.5V 3.3V 5V 6V 7.5V 9V 12V 15V 28V 5V 12V 15V
(1R5S) (1R8S) (2R5S) (3R3S) (05S) (06S) (7R5S) (09S) (12S) (15S) (28S) (05D) (12D) (15D)
MQHL-28
20A 20A 20A 15A 10A 8A 6.6A 5.5A 4A 3.3A 1.8A 10A
Total
4A
Total
3.3A
Total
16-40Vin Cont.
16-50Vin 1s Trans.*
Absolute Max Vin = 60V
MQHL-28E
20A 20A 20A 15A 10A 8A 6.6A 5.5A 4A 3.3A 1.8A 10A
Total
4A
Total
3.3A
Total
16-70Vin Cont.
16-80Vin 1s Trans.*
Absolute Max Vin =100V
MQHR-28
10A 10A 10A 7.5A 5A 4A 3.3A 2.75A 2A 1.65A 0.9A 5A
Total
2A
Total
1.65A
Total
16-40Vin Cont.
16-50Vin 1s Trans.*
Absolute Max Vin = 60V
MQHR-28E
10A 10A 10A 7.5A 5A 4A 3.3A 2.75A 2A 1.65A 0.9A 5A
Total
2A
Total
1.65A
Total
16-70Vin Cont.
16-80Vin 1s Trans.*
Absolute Max Vin = 100V
Check with factory for availability.
†80% of total output current available on any one output.
*Converters may be operated at the highest transient input voltage, but some component electrical and thermal stresses would be beyond MIL-
HDBK-1547A guidelines.
Product # MQHL-28-15S Phone 1-888-567-9596 www.synqor.com Doc.# 005-0005372 Rev. A 04/09/12 Page 18
Output:
Current:
15V
3.3A
MQHL-28-15S
Ordering Information
Model
Name
Input
Voltage
Range
Output Voltage(s) Package Outline/
Pin Conguration
Screening
Grade
Single
Output
Dual
Output
MQFL
MQHL
MQHR
28
28E
28V
28VE
270
1R5S
1R8S
2R5S
3R3S
05S
06S
7R5S
09S
12S
15S
28S
05D
12D
15D
U
X
Y
W
Z
C
ES
HB
Warranty
SynQor offers a two (2) year limited warranty. Complete warranty informa-
tion 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:
Phone: 978-849-0600
Toll Free: 1-888-567-9596
Fax: 978-849-0602
E-mail: mqnbofae@synqor.com
Web:
www.synqor.com
Address: 155 Swanson Road
Boxborough, MA 01719
USA
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
APPLICATION NOTES
A variety of application notes and technical white papers can be downloaded in pdf format from the SynQor website.
PART NUMBERING SYSTEM
The part numbering system for SynQor’s MilQor DC-DC converters follows the format shown in the table below.
Not all combinations make valid part numbers, please contact SynQor for availability. See the Product Summary web page for more options.
Example: MQHL-28-15S-Y-ES