DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
Output (V)
11.4
Current (A)
53
Nominal Input (V)
50
PRODUCT OVERVIEW
Typical unit
FEATURES
Designed for Regulated Intermediate
Bus Architectures (RIBA).
Industry standard 5pin eighth brick
package.
95.5% high efficiency at full load On/Off
control.
36-60Vdc input voltage range (50V
nominal).
Monotonic startup into pre-biased
output conditions.
Stable No Load operation.
Output Over-current & Overtemperature protection.
Input Under Voltage Lock Out.
Negative Logic Standard configuration
(Positive logic optional).
2250Vdc Input to output isolation,
functional insulation.
RoHS compliant.
Certification to UL/EN/IEC 60950
Designed & tested to meet the
requirements of IPC9592, Rev B.
The DRE-11.4/53-L48NB-C regulated DC-DC converter module is designed to perform as an
Intermediate Bus Converter delivering 11.4Vdc @ 53A (600W) in an standard 5pin DOSA compliant
eighth brick package.
The DRE module operates over a Vin range of 36-60Vdc delivering full power @ 55°C with 300LFM
air flow.
Applications include (but are not limited to) Telecommunications infrastructure equipment, Network
security, Wireless base stations, routers, computing equipment and other applications requiring a
highly efficient, 600W intermediate bus converter that will support a Vin range of 36-60Vdc.
Designed & tested to meet the rigorous requirements of the IPC9592, Rev B standard.
Features include input Under Voltage Lock Out (UVLO), Over Temperature Protection shutdown
(OTP), Over Current/Current Limit Protection (OCP), Output Over Voltage Protection (OVP), Galvanic
(2250Vdc) Input to Output Isolation and functional insulation, along with UL 60950 safety certification
and CB report (available upon request).
General PCB Layout
For full details go to
www.murata-ps.com/rohs
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 1 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE
Output
Model Family
DREDRE- 11.4/5311.4/53- L48
VOUT [1]
(V)
IOUT
(A)
Power [2]
(W)
11.4
53
604
Ripple & Noise
(mVp(mVp- p)
Typ.
Max.
100
150
Input
Regulation
IIN,
IIN,
(max.) VIN Nom. Range no load full load
(V)
(V)
(mA)
(A)
Line
±0.4%
50
36-60 150
12.2
Efficiency
Min.
94.5%
Typ.
95.5%
Dimensions
See Mechanical
Specifications
Notes:
[1] Output voltage @ 0% load.
[2] Output power @ 100% load.
[3] Please refer to the model number structure for additional ordering part numbers and options.
[4] All specifications are typical unless noted. General conditions for Specifications are +25°C, Vin=nominal, Vout = nominal (no trim installed), full rated load. Adequate airflow must be
supplied for extended testing under power.
All models are tested and specified with an external 1μF, and 10 μF paralleled output capacitors and a 220µF external input capacitor. All capacitors are low ESR types. Caps are layout
dependent. These capacitors are necessary to accommodate our test equipment and may not be required in your applications. All models are stable and regulate within spec under no-load
conditions.
PART NUMBER STRUCTURE
Notes:
[1] Special quantity order is required; samples available with standard pin length only.
[2] Some model number combinations may not be available. See website or contact your local Murata sales representative.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 2 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
FUNCTIONAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Conditions [1]
Minimum
Typical/Nominal Maximum
Units
Input Voltage, Continuous
36
50
60
Vdc
Isolation Voltage
Input to Output
2250
Vdc
On/Off Remote Control
Power on, referred to -Vin
0
20
Vdc
Output Power
0
604
605
W
Output Current
Current-limited, no damage, short-circuit protected
0
53
53
A
Storage Temperature Range
Vin=Zero (no power)
-40
125
°C
Absolute maximums are stress ratings. Exposure of devices to greater than any of these conditions may adversely affect long-term reliability. Proper operation
under conditions other than those listed in the Performance/Functional Specifications Table is not implied or recommended.
INPUT
Conditions [1]
Recommended External Fuse
Fast blow
25
A
Internal Filter Type
Pi
Input Voltage
Operating Voltage Range
36
50
60
Vdc
StartRising input voltage
34
35
36
Vdc
Start- up Threshold
Undervoltage Shutdown
Falling input voltage
32
33
34
Vdc
Overvoltage Shutdown
64
66
68
Vdc
Hysteresis
1
Vdc
Input Current
Full Load Conditions
Vin=Nominal
12.2
13.2
A
Low Line
Vin=Min.
17
18
A
No Load Current
Iout=Min., unit=ON
150
250
mA
Shut20
50
mA
Shut- Down Mode Input Current
Measured at input with specified filter [2]
400
mApp
Reflected (back) Ripple Current
Measured at input without filter
1000
mApp
GENERAL and SAFETY
Efficiency
Vin=Nominal, full load
94.5
95.5
%
Vin=Max., full load
93.4
94.8
%
Isolation
Input To Output
2250
Vdc
Insulation Safety Rating
Functional
Safety
Certified to UL-60950-1, CSA-C22.2 No. 60950Yes
1, IEC/EN60950-1, 2nd edition.
Calculated MTBF
Telcordia SR-332, issue 3, method 1, case1,
6000
khrs
ground fixed, Tambient = +25°C
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency
220
kHz
Startup Time
Power on to Vout regulated
20
25
30
ms
Remote ON to Vout regulated
2.5
5
ms
Dynamic Load Response
50-75-50% load step, settling time to within
500
µsec
1% of Vout
Dynamic Load Peak Deviation
with 2000µF output capacitance, 50% ceramic,
±350
mV
50% OSCON or POSCAP
FEATURES and OPTIONS
Remote On/Off Control [3]
“N” suffix:
Negative Logic, ON/OFF State
ON=Ground pin or external voltage
-0.1
0.8
Vdc
OFF=Pin open or external voltage
2.5
20
Vdc
Control Current
Open collector/drain
0.1
0.2
mA/mA
“P” suffix:
Positive Logic, ON/OFF State
ON=Pin open or external voltage
3.5
20
OFF=Ground pin or external voltage
0
1
Control Current
Open collector/drain
None
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 3 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
FUNCTIONAL SPECIFICATIONS (CONT.)
OUTPUT
Total Output Power
Output Voltage
Nominal Output Voltage(at
Voltage(at 50% Load)
Output Voltage @ 0% to 10 0% Load
OverMagnetic feedback
Over -Voltage Protection
Output Voltage (S optionoption-with Droop mode current sharing)
Nominal Output Voltage
Output Voltage @ 0% Load
Output Voltage @ 50% Load
Output Voltage @ 100% Load
OverMagnetic feedback
Over -Voltage Protection
Output Current
Output Current Range
Current Limit Inception
90% of Vout, after warm up
Short Circuit
Short Circuit Duration
Output shorted to ground, no damage
Short Circuit protection method
Current limiting, hiccup mode
Regulation
Line Regulation
Vin = Min. to Max., Vout = Nom;
Iout = Nom.
Ripple and Noise
With 600µF output capacitance, 50%
ceramic,
50% OSCON or POSCAP, 20MHz BW
Maximum Capacitive Loading
Typically 50% ceramic, 50% Oscon or
POSCAP
MECHANICAL
Outline Dimensions (Please refer to outline drawing)
With Baseplate
Minimum
0
Typical/Nominal
604
Maximum
605
Units
W
11.38
12.54
11.40
11.40
14.25
11.42
15.96
Vdc
Vdc
Vdc
10.73
11.15
10.94
10.73
12.31
11.19
11.40
11.19
10.98
13.99
11.65
11.65
11.44
11.23
15.66
Vdc
Vdc
Vdc
Vdc
Vdc
0
58.30
53
66.25
53
74.20
A
A
±0.4
% of Vout
150
mVpp
3125
μF
Continuous
100
2.3 x 0.9 x 0.57
58.4 x 22.9 x
14.48
1.41
40
0.04 & 0.06
1.016 x 1.524
Copper alloy
50
5
LxWxH
Weight
Through Hole Pin Diameter
Through Hole Pin Material
TH Pin Plating Metal and Thickness
ENVIRONMENTAL
Operating Ambient Temperature
Range
Storage Temperature
Thermal Protection/Shutdown
Nickel subplate
Gold overplate
With Derating
Vin=Zero (no power)
Measured in the center
-40
-40
120
Inches
mm
Ounces
Grams
Inches
mm
µ-inches
µ-inches
85
°C
125
°C
°C
Notes:
[1] Unless otherwise noted, all specifications are at nominal input voltage, nominal output voltage and full load.
General conditions are +25 Degree Celsius ambient temperature, near sea level altitude, natural convection airflow. All models are tested and specified with external parallel 1μF and 10 μF multilayer ceramic output capacitors.
A 220µF external input capacitor is used. All capacitors are low-ESR types wired close to the converter. These capacitors are necessary for our test equipment and may not be needed in the user’s
application.
[2] Measured at the input pin+ of module with a simulated source impedance of 10µH, 220µF, 100V, across source, 500µF, 100V external capacitors across input pins.
[3] The Remote On/Off Control is referred to -Vin. For external transistor control, use open collector logic or equivalent
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 4 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
PERFORMANCE DATA
Efficiency vs. Line Voltage and Load Current @ 25°C
Transient Response @25ºC
(Vin=50V, Vout=nom., Iout=50-75% of full load, Cout=2000μF, ScopeBW=20MHz, 10ms/div)
Ripple and Noise @25ºC
(Vin = 50V, Vout = nom., Iout= 0A, Cout = 400μF, ScopeBW = 20MHz, 2μs/div )
Ripple and Noise @25ºC
(Vin = 50V, Vout = nom., Iout = 50A, Cout = 400μF, ScopeBW = 20MHz, 2μs/div )
Turn-on transient at full load current
(5ms/div, Top Trace: Vout, 5V/div; Bottom Trace: ON/OFF, 2V/div)
Turn-on transient at full load current
(5ms/div, Top Trace: Vout, 5V/div; Bottom Trace: Vin, 20V/div)
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 5 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
Thermal Derating (DRE-11.4/53-L48, Unit mounted on a 10 X 10 inch PCB)
TRANSVERSE (AIRFLOW FROM VinVin- TO Vin+)
LONGITUDINAL (AIRFLOW FROM Vin TO Vout)
TRAN
TRANSVERSE
AN SVERSE AIRFLOW; (Baseplate Variant)
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 6 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
LONGITUDINAL AIRFLOW; (Baseplate Variant)
TRAN
TRANSVERSE
AN SVERSE AIRFLOW; (Heatsink Variant)
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 7 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
LONGITUDINAL AIRFLOW; (Baseplate Variant)
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 8 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
MECHANICAL SPECIFICATIONS
Dimensions are in inches (mm shown for ref. only)
Third Angle Projection
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25) Angles ± 2˚
INPUT/OUTPUT CONNECTIONS
Pin
Function
1
Vin(+)
2
On/Off
3
Vin(-)
4
Vout(-)
8
Vout(+)
Notes:
UNLESS OTHERWISE SPECIFIED:
[1] M3 SCREW USED TO BOLT UNIT'S BASEPLATE TO
OTHER SURFACES (SUCH AS HEATSINK) MUST NOT
EXCEED 0.110''(2.5mm) DEPTH BELOW THE
SURFACE OF BASEPLATE
[2] APPLIED TORQUE PER SCREW SHOULD NOT
EXCEED 5.3In-lb(0.6Nm); [3] ALL DIMENSION ARE IN
INCHES[MILLIMETER];
[4] ALL TOLERANCES:
×.××in ,±0.02in(×.×mm,±0.5mm)
×.×××in ,±0.01in(×.××mm,±0.25mm)
[5] COMPONENT WILL VARY BETWEEN MODELS [6]
STANDARD PIN LENGTH: 0.180 Inch
FOR L1 PIN LENGTH OPTION IN MODEL NAME, THE
L LENGTH SHOULD BE 0.110 INCH
FOR L2 PIN LENGTH OPTION IN MODEL NAME,
USE STANDARD L2 PIN WITH PIN LENGTH TO 0.145
Inch
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 9 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
RECOMMENDED PCB FOOTPRINT
Dimensions are in inches (mm shown for ref. only)
Third Angle Projection
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25) Angles ± 2˚
Components are shown for reference only
and may vary between units.
RECOMMENDED PCB FOOTPRINT
.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 10 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
SHIPPIMG TRAYS AND BOXES
SHIPPING TRAY
Notes:
[1] DRE modules are supplied in a 21-piece (3-by-7) shipping tray.
[2] The tray is an anti-static closed-cell polyethylene foam. Dimensions are shown above.
[3] Dimensions in inches (mm)
TECHNICAL NOTES
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 11 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
THROUGHTHROUGH -HOLE SOLDERING GUIDELINES
Murata Power Solutions recommends the specifications below when installing these converters. These specifications vary depending on the solder type.
Exceeding these specifications may cause damage to the product. Your production environment may differ; therefore please thoroughly review these guidelines with
your process engineers.
Wave Solder Operations for throughthrough-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
For Sn/Pb based solders:
Maximum Preheat Temperature 115ºC.
Maximum Preheat Temperature 105ºC.
Maximum Pot Temperature
270ºC.
Maximum Pot Temperature 250ºC.
Maximum Solder Dwell Time
7 seconds
Maximum Solder Dwell Time 6 seconds
Input Fusing
Certain applications and/or safety agencies may require fuses at the inputs of power conversion components. Fuses should also be used when there is the possibility of
sustained input voltage reversal which is not current limited. For greatest safety, we recommend a fast blow fuse installed in the ungrounded input supply line with a
value which is approximately twice the maximum line current, calculated at the lowest input voltage.
The installer must observe all relevant safety standards and regulations. For safety agency approvals, install the converter in compliance with the end-user safety
standard.
Input UnderUnder- Voltage Shutdown and StartStart-Up Threshold
Under normal start-up conditions, converters will not begin to regulate properly until the rising input voltage exceeds and remains at the Start-Up Threshold Voltage (see
Specifications). Once operating, converters will not turn off until the input voltage drops below the Under-Voltage Shutdown Limit. Subsequent restart will not occur until
the input voltage rises again above the Start-Up Threshold. This built-in hysteresis prevents any unstable on/off operation at a single input voltage.
Users should be aware however of input sources near the Under-Voltage Shutdown whose voltage decays as input current is consumed (such as capacitor inputs), the
converter shuts off and then restarts as the external capacitor recharges. Such situations could oscillate. To prevent this, make sure the operating input voltage is well
above the UV Shutdown voltage AT ALL TIMES.
StartStart-Up Delay
Assuming that the output current is set at the rated maximum, the Vin to Vout Start-Up Time (see Specifications) is the time interval between the point when the rising
input voltage crosses the Start-Up Threshold and the fully loaded regulated output voltage enters and remains within its specified regulation band. Actual measured
times will vary with input source impedance, external input capacitance, input voltage slew rate and final value of the input voltage as it appears at the converter.
These converters include a soft start circuit to moderate the duty cycle of the PWM controller at power up, thereby limiting the input inrush current. The On/Off Remote
Control interval from inception to Vout regulated assumes that the converter already has its input voltage stabilized above the Start-Up Threshold before the On
command. The interval is measured from the On command until the output enters and remains within its specified regulation band. The specification assumes that the
output is fully loaded at maximum rated current.
Input Source Impedance
These converters will operate to specifications without external components, assuming that the source voltage has very low impedance and reasonable input voltage
regulation. Since real-world voltage sources have finite impedance, performance is improved by adding external filter components. Some- times only a small ceramic
capacitor is sufficient. Since it is difficult to totally characterize all applications, some experimentation may be needed. Note that external input capacitors must accept
high speed switching currents.
I/O Filtering, Input Ripple Current and Output Noise
All models in this converter series are tested and specified for input reflected ripple current and output noise using designated external input/output components,
circuits and layout as shown in the figures below. External input capacitors (Cin in the figure) serve primarily as energy storage elements, minimizing line voltage
variations caused by transient IR drops in the input conductors. Users should select input capacitors for bulk capacitance (at appropriate frequencies), low ESR and high
RMS ripple current ratings. In the figure below, the Cbus and Lbus components simulate a typical DC voltage bus. Your specific system configuration may require
additional considerations. Please note that the values of Cin, Lbus and Cbus will vary according to the specific converter model.
In critical applications, output ripple and noise (also referred to as periodic and
random deviations (PARD) may be reduced by adding filter elements such as
multiple external capacitors. Be sure to calculate component temperature rise from
reflected AC current dissipated inside the capacitor ESR.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 12 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
Minimum Output Loading Requirements
All models regulate within specification and are stable under no load to full load conditions. Operation under no load might however slightly increase output ripple and noise.
Thermal Shutdown
To protect against thermal overstress, these converters include thermal shutdown circuitry.
If environmental conditions cause the temperature of the DC/DC’s to rise above their
operating temperature range (up to the shutdown temperature) an on-board electronic
temperature sensor will power down the unit. When the temperature decreases below the
turn-on threshold, the converter will automatically restart. There is a small amount of
hysteresis to prevent rapid on/off cycling.
The temperature sensor is typically located adjacent to the switching controller, approximately
in the center of the unit. See the Performance and Functional Specifications.
CAUTION:
CAUTION If you operate too close to the thermal limits, the converter may shut down
suddenly without warning. Be sure to thoroughly test your application to the fan flowrate
specifications.
Temperature Derating Curves
The graphs in this data sheet illustrate typical operation under a variety of conditions. The Derating curves show the maximum continuous ambient air temperature and decreasing
maximum output current, which is acceptable under increasing forced (airflow measured in Linear Feet per Minute “LFM”). Note that these are AVERAGE measurements. The converter
will accept brief increases in current or reduced airflow as long as the average is not exceeded.
Note that the temperatures are of the ambient airflow, not the converter itself which is obviously running at higher temperature than the outside air. Also note that very low flow rates
(below about 25 LFM) are similar to “natural convection,” that is, not using fan-forced airflow.
Murata Power Solutions performs characterization measurements in a closed cycle wind tunnel with calibrated airflow. Both thermocouples and an infrared camera system are used to
observe thermal performance. As a practical matter, it is quite difficult to insert an anemometer to precisely measure airflow in most applications. Sometimes it is possible to estimate the
effective airflow if you thoroughly understand the enclosure geometry, entry/exit orifice areas and the fan flowrate specifications.
CAUTION: If you exceed these Derating guidelines, the converter may have an unplanned Over Temperature shut down. Also, these graphs are all collected near Sea Level altitude. Be
sure to reduce the derating for higher altitude.
Output Fusing
The converter is extensively protected against current, voltage and temperature extremes. However your application circuit may need additional protection. In the extremely unlikely event
of output circuit failure, excessive voltage could be applied to your circuit. Consider using appropriate external protection.
Output Current Limiting
As soon as the output current increases to approximately 125% to 150% of its maximum rated value, the DC/DC converter shall enter current limiting mode. The output voltage shall
decrease proportionally with increase in output current, thereby maintaining a somewhat constant power output. This is also commonly referred to as power limiting.
Current limiting inception is defined as the point at which full power falls below the rated tolerance. See the Performance/Functional Specifications. Note particularly that the output current
may briefly rise above its rated value in normal operation as long as the average power is not exceeded. This enhances reliability and continued operation of your application. If the output
current is too high the converter shall enter short circuit protection.
Output Short Circuit Protection
When a converter is in current-limit mode, the output voltage will drop as the output current demand increases. If the output voltage drops too low (approximately 98% of nominal output
voltage for most models), the magnetically coupled voltage used to develop the PWM bias voltage will also drop, thereby shutting down the PWM controller.
Following a time-out period, the PWM will restart, causing the output voltage to begin rising to its appropriate value. If the short-circuit condition persists, another shutdown cycle will
initiate. This rapid on/off cycling is called “hiccup mode.” The hiccup cycling reduces the average output current, thereby preventing excessive internal temperatures and/or component
damage.
The “hiccup” system differs from older latching short circuit systems because you do not have to power down the converter to make it restart. The system will automatically restore
operation as soon as the short circuit condition is removed.
Remote On/Off Control
On the input side, a remote On/Off Control can be specified with either positive or negative logic.
Positive: Models equipped with positive logic are enabled when the On/Off pin is left open or is pulled high to +Vin with respect to –Vin. An internal bias current causes the open pin to
rise to approximately +15V. Some models will also turn on at lower intermediate voltages (see Specifications). Positive-logic devices are disabled when the On/Off is grounded or brought
to within a low voltage (see Specifications) with respect to –Vin.
Negative: Models with negative logic are on (enabled) when the On/Off is grounded or brought to within a low voltage (see Specifications) with respect to –Vin. The device is off (disabled)
when the On/Off is left open or is pulled high to approximately +15V with respect to –Vin.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 13 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
Dynamic control of the On/Off function should be able to sink the specified signal current when brought low and withstand appropriate voltage when brought high. Be aware to that there
is a finite time in milliseconds (see Specifications) between the time of On/Off Control activation and a stable, regulated output. This time will vary slightly with output load type and current
and input conditions.
Output Capacitive
Capaci tive Load
These converters do not require external capacitance added to achieve rated specifications. Users should only consider adding capacitance to reduce switching noise and/or to handle
spike current step loads. Install only enough capacitance to achieve noise objectives. Excess external capacitance may cause regulation problems, slower transient response and possible
instability. Proper wiring of the Sense inputs will improve these factors under capacitive load.
The maximum rated output capacitance and ESR specification is given for a capacitor installed immediately adjacent to the converter. Any extended output wiring or smaller wire gauge or
less ground plane may tolerate somewhat higher capacitance. Also, capacitors with higher ESR may use a larger capacitance.
Load Sharing
Load sharing occurs when two or more DREs are connected in parallel, at both the input and output terminals, to supply greater output current than one unit alone or to offer system
redundancy for moderate loads. If one converter fails, the other converter(s) will carry the load until the system is repaired.
The DRE’s design allows load sharing using the “droop” method, also called the “direct connect” technique. Simply put, at light loads, the converter shall exhibit slightly higher output
voltage and shall carry more of the output current. Since the DRE’s synchronous rectifier design will not accept appreciable reverse output current, starting at zero load, the DRE with the
higher output voltage will carry more of the full load until the voltage at the output drops to that of the lower DRE’s.
Load Sharing Guidelines
If you wish to operate two or more DRE’s in load sharing, use the following guidelines:
[1] Operate both converters connected in parallel from the same 48V input power source. This simplifies the design and makes for more balanced power sharing. Using two different
48V input supplies must be carefully analyzed to avoid overloading one of the converters and is not recommended.
Make sure the single 48V input source can supply the total current needed by all the parallel-connected DRE’s. (Actually, it is possible to rate the full system at more than the current
capacity of a single DRE. However, you now lose the redundancy protection feature.)
[2] Use conservative loading. Do not assume for example that two parallel DRE’s can always supply “times two” amounts of output current. Allow for limits in input voltage and other
factors.
If one DRE overloads while in load share, it will protect itself by entering overcurrent mode. If the whole system is running close to maximum output current, the remaining good DRE will
soon also enter overcurrent mode. These two events probably will not happen together, possibly leaving the system operating in degraded mode for a while. The solution here is
conservative design to avoid getting close to the load limits.
[3] Make the input wiring lengths and wire gauges identical on both inputs and outputs. If in doubt, make some precision measurements under full load. But if you attempt to measure the
current in one of the converters using a series shunt, remember that the current meter, itself, may introduce enough finite resistance to affect the readings.
(Hint: Use a non-contacting “clamp-on” Hall effect DC current meter with zero IR loss.)
[4] If you add the optional input filters, use identical components with the same layout.
[5] Operate both converters in the same temperature and airflow environment. Under load
sharing, small differences in cooling can amplify into load imbalances.
[6] Avoid operation near the low input voltage limit of the converter. Another subtle factor
here is the external source impedance of the input supply. A source with higher impedance at
full load may make the net input voltage seen by the converter close to its minimum input
voltage. Be sure to account for the decrease in effective input voltage under load.
For battery sources, this means that the batteries should be freshly charged and that the AC
trickle charger is in good working order. Note that older batteries increase their internal cell
impedance even if their no-load output voltage appears acceptable. Remember that what
counts here is the voltage seen at the DRE input connections with full current.
[7] As with any system design, thoroughly test the DRE’s connected in load sharing before
committing the design to a real application.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 14 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
CAUTION – This converter is not internally fused. To avoid danger to persons or equipment and to retain safety certification, the user must connect an external fast-blow input fuse as
listed in the specifications.
Be sure that the PC board pad area and etch size are adequate to provide enough current so that the fuse will blow with an overload.
Vertical Wind Tunnel
IR transparent
optical window
IR Video
Camera
Unit Under
Test (UUT)
Variant
Speed Fan
Heating
Element
Precision low-rate
anemometer 3”
below UUT
Ambient
temperature sensor
Murata Power Solutions employs a computer controlled custom designed closed
loop vertical wind tunnel, infrared video camera system, and test instrumentation
for accurate airflow and heat dissipation analysis of power products.
The system includes a precision low flow-rate anemometer, variable speed fan,
power supply input and load controls, temperature gauges, and adjustable
heating element.
The IR camera monitors the thermal performance of the Unit Under Test (UUT)
under static steady-state conditions. A special optical port is used which is
transparent to infrared wavelengths.
Both through-hole and surface mount converters are soldered down to a 10" x
10" host carrier board, for realistic heat absorption and spreading. Both
longitudinal and transverse airflow studies are possible by rotation of this carrier
board since there are often significant differences in the heat dissipation in the
two airflow directions.
The combination of adjustable airflow, adjustable ambient heat, and adjustable
Input/Output currents and voltages mean that a very wide range of measurement
conditions can be studied.
The collimator reduces the amount of turbulence adjacent to the UUT. Such
turbulence influences the effective heat transfer characteristics and gives false
readings. Excess turbulence removes more heat from some surfaces and less
heat from others, possibly causing uneven overheating.
Both sides of the UUT are studied since there are different thermal gradients on
each side. The adjustable heating element and fan, built-in temperature gauges,
and no-contact IR camera mean that power supplies are tested in real-world
conditions.
Airflow collimator
Fig 6. Vertical Wind Tunnel
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 15 of 16
DRE-11.4/53-L48
Regulated Eighth-Brick, 600W Isolated DC-DC Converter
Emissions Performance
Murata Power Solutions measures its products for conducted emissions against the EN 55022 and CISPR 22 standards. Passive resistance loads are employed and the output is set to
the maximum voltage. If you set up your own emissions testing, make sure the output load is rated at continuous power while doing the tests.
The recommended external input and output capacitors (if required) are included. Please refer to the fundamental switching frequency. All of this information is listed in the Product
Specifications. An external discrete filter is installed and the circuit diagram is shown below.
[1] Conducted Emissions Parts List
Reference
Part Number
C1, C2, C3, C4, C5
GRM32ER72A105KA01L
C6
GRM319R72A104KA01D
L1, L2
PG0060T
C8, C9, C10, C11
GRM55DR72J224KW01L
C7
UHE2A221MHD
C12
N/A
Description
SMD CERAMIC-100V-1000nFX7R-1210
SMD CERAMIC100V-100nF±10%-X7R-1206
COMMON MODE-473uH±25%-14A
SMD CERAMIC 630V-0.22uF±10%-X7R-2220
Aluminum100V-220Uf-±10%long lead
---
Vendor
Murata
Murata
Pulse
Murata
Nichicon
[2] Conducted Emissions Test Equipment Used
Hewlett Packard HP8594L Spectrum Analyzer – S/N 3827A00153
2Line V-networks LS1-15V 50Ω/50Uh Line Impedance Stabilization Network
[3]Conducted Emissions Test Results – Positive Line
[3]Conducted Emissions Test Results – Negative Line
Graph
2.
Graph 1. Conducted emissions performance, Positive Line
CISPR 22, Class B, full load
Conducted emissions performance, Negative Line
CISPR 22, Class B, full load
[4]Layout Recommendations
Most applications can use the filtering which is already installed inside the converter or with the addition of the recommended external capacitors. For greater emissions
suppression, consider additional filter components and/or shielding. Emissions performance will depend on the user’s PC board layout, the chassis shielding
environment and choice of external components.
Since many factors affect both the amplitude and spectra of emissions, we recommend using an engineer who is experienced at emissions suppression.
Murata Power Solutions, Inc.
129 Flanders Rd, Westborough, MA 01581 USA
ISO 9001 and 14001 REGISTERED
This product is subject to the following operating requirements and the Life and Safety Critical
Application Sales Policy:
Refer to: http://www.muratahttp://www.murata- ps.com/requirements/
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe
upon existing or future patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications
are subject to change without notice.
© 2019 Murata Power Solutions, Inc.
https://www.murata-ps.com/support
SDC_DRE-11.4/53-L48.A02 Page 16 of 16
