For full details go to
www.murata-ps.com/rohs
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www.murata-ps.com UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 1 of 13
SIMPLIFIED SCHEMATIC
Featuring a full 50-60 Watt output in 2.9 square inches of board area,
the UEI series isolated DC/DC converter family offers efficient
regulated DC power for printed circuit board mounting.
GATE
DRIVE
OPTO
ISOLATION
Control
Reference, trim &
Error Amplifier
+V
IN
+V
OUT
–V
OUT
–V
IN
On/Off
Control
TRIM
–SENSE
+SENSE
ISOLATION
BARRIER
Typical topology is shown.
Typical unit
Wide range 4:1 inputs on the 1.50" x 1.90" x
0.38" converter are either 9 to 36 Volts DC (Q12
models) or 18 to 75 Volts DC (Q48 models), ideal
for battery-powered and telecom equipment.
Fixed output voltages from 3.3 VDC to 15 VDC are
regulated to within ±0.05% and may be trimmed
within ±10% of nominal output. Applications
include small instruments, computer-based
systems, data communications equipment, remote
sensor systems, vehicle and portable electronics.
The UEI 50-60W Series includes full magnetic
and optical isolation up to 2250 Volts DC (basic
insulation). For connection to digital systems, the
outputs offer fast settling to current step loads
and tolerance of higher capacitive loads. Excellent
ripple and noise specifi cations assure compatibil-
ity to circuits using CPU’s, ASIC’s, programmable
logic and FPGA’s. No minimum load is required.
For systems requiring controlled startup/shut-
down, an external switch, transistor or digital logic
may be used to activate the remote On/Off control.
Remote Sense inputs compensate for resistive line
drops at high currents.
A wealth of self-protection features avoid both
converter and external circuit problems. These
include input undervoltage lockout, input overvolt-
age and overtemperature shutdown. The outputs
current limit using the “hiccup” autorestart
technique and the outputs may be short-circuited
indefi nitely. Additional features include output
overvoltage and reverse conduction elimination.
The synchronous rectifi er forward topology offers
high effi ciency for minimal heat buildup and “no
fan” operation.
PRODUCT OVERVIEW
FEATURES
Small footprint DC/DC converter, ideal for high
current applications
Industry standard 1.50˝ x 1.90˝ x 0.38˝ open
frame package and pinout
Wide range input voltages 9-36 and 18-75Vdc
Assembly and attachment for RoHS standards
Isolation up to 2250 VDC (basic)
Up to 50-60W total output power with
overtemperature shutdown
High effi ciency synchronous rectifi er forward
topology
Stable no-load operation with no required
external components
–40 to +85°C temperature range with derating
Certifi ed to UL60950-1, CSA-C22.2 No. 234,
EN60950-1, 2nd Edition safety approvals
Extensive self-protection shut down features
RoHS-6 compliant
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PART NUMBER STRUCTURE
UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 2 of 13
c These are partial model numbers. Please refer to the full model number structure for complete
ordering part numbers.
d Sense input is not included for 12 VOUT and higher models. Sense is optional for 5 VOUT and lower.
e All specifi cations are typical at nominal line voltage and full load, +25 deg.C. unless otherwise
noted. See detailed specifi cations.
f Output capacitors are 1 μF ceramic || 10 μF electrolytic. Input cap is 22 μF, low ESR.
g I/O caps are necessary for our test equipment and may not be needed for your application.
Maximum Rated Output
Current in Amps
Nominal Output Voltage
UEI -/Q12-3.3 15
Input Voltage Range:
Q12 = 9-36V
Q48 = 18-75V
C
RoHS-6 Hazardous Substance Compliance
(does not claim EU RoHS exemption 7b–lead in solder)
-P R
Note:
Not all model number combinations are
available. Contact Murata Power Solutions.
Sense Inputs (5 VOUT and lower):
R = Sense included as standard (for 5 VOUT
and lower models only. 12 VOUT and higher
models do not offer the sense option.)
Blank = Sense not installed for 5 VOUT and
lower models. Pins 5 and 8 omitted.
PERFORMANCE SPECIFICATIONS AND ORDERING GUIDE
Root Modelc
Output Input
Effi ciency
Sense
Input
Package
VOUT
(V)
IOUT
(A)
Power R/N (mVp-p) Regulation (Max.) VIN
Nom.
(V)
Range
(V)
IIN,
no load
(mA)
IIN, full
load (A)
(W) Typ. Max. Line Load Min. Typ. Case Pinout
UEI-3.3/15-Q12PR-C 3.3 15.0 49.5 15 30 ±0.05% ±0.06% 24 9-36 130 2.33 86.8% 88.5% yes C74 P52
UEI-3.3/18-Q48NR-C 3.3 18.0 59.4 60 125 ±0.075% ±0.2% 48 18-75 130 1.38 87% 89.5% yes C74 P52
UEI-5/10-Q12PR-C 5 10.0 50.0 35 50 ±0.1% ±0.1% 24 9-36 130 2.31 89% 90% yes C74 P52
UEI-5/12-Q48NR-C 5 12.0 60.0 70 100 ±0.1% ±0.15% 48 18-75 130 1.37 89.5% 91% yes C74 P52
UEI-12/4.2-Q12P-C 12 4.2 50.4 50 120 ±0.05% ±0.05% 24 9-36 130 2.35 87.8% 89.5% no C74 P51
UEI-12/5-Q48N-C 12 5.0 60.0 40 70 ±0.2% ±0.2% 48 18-75 130 1.42 87% 89.8% no C74 P51
UEI-15/3.3-Q12P-C 15 3.3 49.5 30 100 ±0.075% ±0.05% 24 9-36 130 2.29 88.3% 90% no C74 P51
UEI-15/4-Q48N-C 15 4.0 60.0 35 60 ±0.075% ±0.05% 48 18-75 50 1.40 87.5% 89.3% no C74 P51
Soldering Guidelines
Murata Power Solutions recommends the specifi cations below when installing these converters. These specifi cations vary depending on the solder type. Exceeding these specifi ca-
tions 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 through-hole mounted products (THMT)
For Sn/Ag/Cu based solders: For Sn/Pb based solders:
Maximum Preheat Temperature 115° C. Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 270° C. Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 7 seconds Maximum Solder Dwell Time 6 seconds
On/Off Control Polarity:
P = Positive
N = Negative
Positive “P” polarity is standard for Q12 models and optional special
order for Q48 models. Negative “N” polarity is standard for Q48
models and optional special order for Q12 models.
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 3 of 13
MECHANICAL SPECIFICATIONS
PHYSICAL CHARACTERISTICS
Outline dimensions See mechanical specs
Pin material Copper alloy with gold plate over
nickel underplate
Pin diameter 0.04" (1mm)
Pin Finish Gold plate
Weight 1 oz (28.5g)
Electromagnetic interference Meets class B, EN55022/CISPR22
(requires external fi lter)
Flammability Rating UL 94V-0
Safety Certifi ed to IEC/EN/UL/cUL 60950-1,
CSA-C22.2 No. 60950-1, 2nd Edition
Pins 5 and 8 are omitted for models without sense inputs.
INPUT/OUTPUT CONNECTIONS, WITHOUT SENSE
Pin Function P51 Pin Function P51
5 No pin
1 Positive Input 6 Positive Output
2 Negative Input No pin
3 No pin 7 Negative Output
4 On/Off Control In 8 No pin
9 Trim
Third Angle Projection
Dimensions are in inches (mm shown for ref. only).
Components are shown for reference only.
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
INPUT/OUTPUT CONNECTIONS, WITH SENSE
Pin Function P52 Pin Function P52
5 +Sense In
1 Positive Input 6 Positive Output
2 Negative Input No pin
3 No pin 7 Negative Output
4 On/Off Control In 8 –Sense In
9 Trim
Important: If sense inputs are not connected to a remote load, connect them
to their respective VOUT pins at the converter.
UEI50 Open Frame
50-60W
Case C74
.200
.600
15.24
2.54
.100
2.54
.500
.100
12.70
5.08
.400
.200
10.16
5.08
10.16
.400
.900
22.86
MIN0.25
.010 MIN
CLEARANCE
0.25
6.35 0.38 (9.7)
1.90
(48.3)
1.50 (38.1)
1
2
4
5
6
7
8
9
C
L
C
L
C
L
C
L
BOTTOM VIEW
1.800 0.05 (1.3)
45.72
SIDE VIEW
.040±.002 PINS
1.02±0.05
TOP VIEW
9
8
7
6
5
4
2
1
0.05 (1.3)
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 4 of 13
INPUT CHARACTERISTICS
Model Family VIN Start-up
threshold
Under-
voltage
Shut-
down
Refl ected
(back)
Ripple
Current
2
Input Current Recom-
mended
Fuse
Internal
Input
Filter
Type
Reverse
Polarity
Protection
Remote On/Off Control
Inrush
Tran-
sient
Output
Short
Circuit
Low
Line
Standby
Mode
On/Off
Current Positive Logic Negative Logic
VV V mA pk-pk A2sec mA A mA A mA “P” model suffi x “N” model suffi x
UEI-3.3/15-Q12 24 9.5 8.5
30
0.05 50
6.25
1
12
L-C
None
- see
notes
1
OFF=Gnd pin or
–0.7 to +1.2V
max. ON=open
pin or +10 to
+15V max.
OFF=open pin
or +10 to +15V
max. ON=Gnd
pin or –0.7 to
+1.2V max.
UEI-3.3/18-Q48 48 17.3 16.0 3.71 6
UEI-5/10-Q12 24 9.5 8.5 6.21 12
UEI-5/12-Q48 48 17.3 16.0* 3.70 6
UEI-12/4.2-Q12 24 9.5 8.5 6.31 10
UEI-12/5-Q48 48 17.5 16.7 3.88 6
UEI-15/3.3-Q12 24 9.5 8.5 45 6.15 9
UEI-15/4-Q48 48 17.2 16.3 30 3.77 6
OUTPUT CHARACTERISTICS
Model Family
IOUT
Max.
VOUT
Accuracy Adjustment
Range
Temperature
Coeffi cient
Remote Sense
Compensation
Capacitive Loading Max. Overvoltage
protection
Minimum
loading
OV
protection
method
Ripple/Noise
(20 MHz
bandwidth)8
Line/Load
Regulation
Effi ciency
50% Load Low ESR <0.02Ω Max,
resistive load
Hiccup auto-start
after fault removal
A % of VNOM % of VNOM % of VOUT /ºC % of VOUT max. µF V
UEI-3.3/15-Q12 15 ±2
±10 ±0.02
+5
2,000
3.9
No
mini-
mum
load
Magnetic
feedback See ordering guide
UEI-3.3/18-Q48 18
±1
+5 3.9
UEI-5/10-Q12 10 +5 5.9
UEI-5/12-Q48 12 +5 6.4
UEI-12/4.2-Q12 4.2
Not Available
16.5
UEI-12/5-Q48 5 16
UEI-15/3.3-Q12 3.3 24
UEI-15/4-Q48 4 21.5
*At 50% load
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Q12 models Volts, max. continuous 0-36 VDC to rated specifi cations
Volts, transient, 100 mSec 50 VDC, no damage
Q48 models Volts, max. continuous 0-75 VDC to rated specifi cations
Volts, transient, 100 mSec 100 VDC, no damage
On/Off control, referred to –Vin -0.7 V. min to +15V max.
Input Reverse Polarity Protection See fuse section
Output Overvoltage VOUT nom. +20% max.
Output Current
Current-limited. Devices can
withstand sustained short circuit
without damage. The outputs are
not intended to accept appreci-
able reverse current.
Overtemperature Protection
Device includes electronic over-
temperature shutdown protection
under normal operation.
Storage Temperature -55 to +125° C.
Lead Temperature See soldering specifi cations
Absolute Maximum Ratings
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 Specifi cations Table is not implied nor
recommended.
Maximum Ratings Notes
The UEI-50/60W series does not include electronic Input Overvoltage
Protection. Therefore it is possible for the input to exceed the con-
tinuous ratings listed above and still operate. However, units are not
routinely Production-tested above the continuous ratings. Therefore,
the rated specifi cations do not apply at excessive input voltage and
performance is undetermined.
The transient specifi cations indicate that sample lots were suc-
cessfully tested for 100 mS at the transient stress voltage and were
not damaged. As a practical matter in your application, it is often
diffi cult to determine how long an input overvoltage was applied.
Therefore, do not exceed the continuous voltage rating.
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 5 of 13
MISCELLANEOUS CHARACTERISTICS
Model Family
Output Current
Limit Inception Output
Short
Circuit
Protection
Method
Output
Short
Circuit
Current
Output
Short Circuit
Duration
(output shorted
to ground)
Pre-biased
setup
Calculated
MTBF Operating Temperature
Range
Storage
temperature
range
Thermal
protection/
shutdown
Relative
Humidity,
non-
condensing
98% of VOUT,
after warmup
A A Hours ºC ºC ºC
UEI-3.3/15-Q12 20
Current
limiting,
hiccup
auto
restart
0.5 Continuous
Monotonic
(external
VOUT < VSET)
2,000,000
–40 to +85ºC;
with Derating
(see Notes)
–55 to 125ºC 115 To +85ºC/
85%
UEI-3.3/18-Q48 23
UEI-5/10-Q12 13
UEI-5/12-Q48 15.5
UEI-12/4.2-Q12 6
UEI-12/5-Q48 6.1
UEI-15/3.3-Q12 5.3
UEI-15/4-Q48 5.8
DYNAMIC CHARACTERISTICS
Model Family
Dynamic Load
Response
(50-75-50%
load step)
Start-up Time
Switching
Frequency
VIN to VOUT
regulated
(Max.)
Remote On/Off
to VOUT
regulated (Max.)
sec mSec mSec KHz
UEI-3.3/15-Q12 100 to 2% VOUT
50 50
275
UEI-3.3/18-Q48 180 to 2% VOUT 280
UEI-5/10-Q12 200 to 2% VOUT
275UEI-5/12-Q48 100 to 2% VOUT
UEI-12/4.2-Q12 200 to 1% VOUT
UEI-12/5-Q48 400 to 1% VOUT 250
UEI-15/3.3-Q12 150 to 1% VOUT 265
UEI-15/4-Q48 150 to 1% VOUT 255
ISOLATION CHARACTERISTICS
Model Family
Input to
Output.
Isolation
Resistance Isolation
Capacitance Isolation Safety
Rating
Min Min
VDC MΩ pF
UEI-3.3/15-Q12 2000 10
1000 Basic
insulation
UEI-3.3/18-Q48 2250 10
UEI-5/10-Q12 2000 10
UEI-5/12-Q48 2250 10
UEI-12/4.2-Q12 2000 10
UEI-12/5-Q48 2250 10
UEI-15/3.3-Q12 2000 10
UEI-15/4-Q48 2250 10
Specifi cation Notes:
(1) All models are tested and specifi ed with external 1||10 μF output capacitors and a 22 μF external
input capacitor. All capacitors are low ESR types. These capacitors are necessary to accommodate
our test equipment and may not be required to achieve specifi ed performance in your applications. All
models are stable and regulate within spec under no-load conditions.
All specifi cations are typical unless noted. General conditions for Specifi cations are +25 deg.C,
Vin=nominal, Vout=nominal, full load. Adequate airfl ow must be supplied for extended testing under
power.
(2) Input Back Ripple Current is tested and specifi ed over a 5 Hz to 20 MHz bandwidth. Input fi ltering
is Cin=33 μF, 100V, Cbus=220 μF, 100V, Lbus=12 μH.
(3) Note that Maximum Power Derating curves indicate an average current at nominal input voltage.
At higher temperatures and/or lower airfl ow, the DC/DC converter will tolerate brief full current
outputs if the total RMS current over time does not exceed the Derating curve. All Derating curves
are presented at sea level altitude. Be aware of reduced power dissipation with increasing density
altitude.
(4) Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3,
ground fi xed conditions, Tpcboard=+25 deg.C, full load, natural air convection.
(5) The On/Off Control is normally selected by a switch or an open collector or open drain transistor.
But it may also be driven with external logic or by applying appropriate external voltages which are
referenced to Input Common and do not exceed the On/Off voltage specifi cations.
(6) Output current limiting begins when the output voltage degrades approximately 2% from the
selected setting.
(7) The outputs are not intended to sink appreciable reverse current.
(8) Output noise may be further reduced by adding an external fi lter. Low voltage logic circuits may
have a small voltage margin between logic ZERO and logic ONE, requiring noise suppression. Use only
as much output fi ltering as needed to achieve your noise requirements. Excessive output capacitance
can retard transient response or possibly cause instability. Low ESR ceramic capacitors may degrade
dynamic performance. Be sure to thoroughly test your system under full load with all components
installed.
(9) All models are fully operational and meet published specifi cations, including “cold start” at –40°C.
(10) Regulation specifi cations describe the deviation as the line input voltage or output load current is
varied from a nominal midpoint value to either extreme.
(11) The output overvoltage protection is automatic recovery. The overvoltage may occur either from
internal failure or from an external forcing voltage as in a shared power system.
(12) Output current limit and short circuit protection is non-latching. When the overcurrent fault is
removed, the converter will immediately recover. After an output overcurrent or short circuit, “hiccup”
operation repeatedly attempts to restart the converter with a brief, full-current output. If the overcur-
rent condition still exists, the restart current will be removed and then tried again. This short current
pulse prevents overheating and damaging the converter. Once the fault is removed, the converter
immediately resumes normal operation.
(13) Do not exceed maximum power specifi cations when adjusting the output trim.
(14) At zero output current, the output may contain low frequency components which exceed the
ripple specifi cation. The output may be operated indefi nitely with no load.
(15) If reverse polarity is accidentally applied to the input, to ensure reverse input protection with full
output load, always connect an external input fuse in series with the +Vin input. Use approximately
twice the full input current rating with nominal input voltage.
CAUTION: This product is not internally fused. To comply with safety agency certifi cations and to
avoid injury to personnel or equipment, the user must connect an external fast-blow fuse to the input
terminals. See fuse information.
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 6 of 13
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. We
recommend a time delay fuse installed in the ungrounded input supply line
with a value which is approximately twice the maximum line current, calcu-
lated 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 Reverse-Polarity Protection
If the input voltage polarity is reversed, an internal diode will become forward
biased and likely draw excessive current from the power source. If this source
is not current-limited or the circuit appropriately fused, it could cause perma-
nent damage to the converter.
Input Under-Voltage Shutdown and Start-Up Threshold
Under normal start-up conditions, converters will not begin to regulate properly
until the ramping-up input voltage exceeds and remains at the Start-Up
Threshold Voltage (see Specifi cations). 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 opera-
tion 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 capaci-
tor inputs), the converter shuts off and then restarts as the external capacitor
recharges. Such situations could oscillate. To prevent this, make sure the operat-
ing input voltage is well above the UV Shutdown voltage AT ALL TIMES.
Start-Up Time
Assuming that the output current is set at the rated maximum, the Vin to Vout Start-
Up Time (see Specifi cations) is the time interval between the point when the ramping
input voltage crosses the Start-Up Threshold and the fully loaded regulated output
voltage enters and remains within its specifi ed accuracy band. Actual measured
APPLICATION NOTES
C
IN
V
IN
C
BUS
L
BUS
C
IN
= 33μF, ESR < 700mΩ @ 100kHz
C
BUS
= 220μF, ESR < 100mΩ @ 100kHz
L
BUS
= 12μH
1
2
+INPUT
−INPUT
CURRENT
PROBE
TO
OSCILLOSCOPE
+
–
+
–
times will vary with input source impedance, external input capacitance, input volt-
age slew rate and fi nal value of the input voltage as it appears at the converter.
These converters include a soft start circuit to moderate the duty cycle of its
PWM controller at power up, thereby limiting the input inrush current.
The On/Off Remote Control interval from On command 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 specifi ed accuracy
band. The specifi cation assumes that the output is fully loaded at maximum
rated current. Similar conditions apply to the On to VOUT regulated specifi cation
such as external load capacitance and soft start circuitry.
Input Source Impedance
These converters will operate to specifi cations without external components,
assuming that the source voltage has very low impedance and reasonable
input voltage regulation. Since real-world voltage sources have fi nite imped-
ance, performance is improved by adding external fi lter components. Some-
times only a small ceramic capacitor is suffi cient. Since it is diffi cult to totally
characterize all applications, some experimentation may be needed. Note that
external input capacitors must accept high speed switching currents.
Because of the switching nature of DC/DC converters, the input of these
converters must be driven from a source with both low AC impedance and
adequate DC input regulation. Performance will degrade with increasing input
inductance. Excessive input inductance may inhibit operation. The DC input
regulation specifi es that the input voltage, once operating, must never degrade
below the Shut-Down Threshold under all load conditions. Be sure to use
adequate trace sizes and mount components close to the converter.
I/O Filtering, Input Ripple Current and Output Noise
All models in this converter series are tested and specifi ed for input refl ected
ripple current and output noise using designated external input/output compo-
nents, circuits and layout as shown in the fi gures below. External input capaci-
tors (CIN in the fi gure) 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 fi gure below,
Figure 2. Measuring Input Ripple Current
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 7 of 13
Floating Outputs
Since these are isolated DC/DC converters, their outputs are “fl oating” with
respect to their input. The essential feature of such isolation is ideal ZERO
CURRENT FLOW between input and output. Real-world converters however do
exhibit tiny leakage currents between input and output (see Specifi cations).
These leakages consist of both an AC stray capacitance coupling component
and a DC leakage resistance. When using the isolation feature, do not allow
the isolation voltage to exceed specifi cations. Otherwise the converter may
be damaged. Designers will normally use the negative output (-Output) as
the ground return of the load circuit. You can however use the positive output
(+Output) as the ground return to effectively reverse the output polarity.
Minimum Output Loading Requirements
These converters employ a synchronous rectifi er design topology. All models
regulate within specifi cation 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 prevent many over temperature problems and damage, these converters
include thermal shutdown circuitry. If environmental conditions cause the
temperature of the DC/DC’s to rise above the 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.
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
avoid unplanned thermal shutdown.
Temperature Derating Curves
The graphs in the next section illustrate typical operation under a variety of condi-
tions. The Derating curves show the maximum continuous ambient air temperature
and decreasing maximum output current which is acceptable under increasing
forced airfl ow measured in Linear Feet per Minute (“LFM”). Note that these are
AVERAGE measurements. The converter will accept brief increases in temperature
and/or current or reduced airfl ow as long as the average is not exceeded.
Note that the temperatures are of the ambient airfl ow, not the converter
itself which is obviously running at higher temperature than the outside air.
Also note that “natural convection” is defi ned as very fl ow rates which are not
using fan-forced airfl ow. Depending on the application, “natural convection” is
usually about 30-65 LFM but is not equal to still air (0 LFM).
MPS makes Characterization measurements in a closed cycle wind
tunnel with calibrated airfl ow. We use both thermocouples and an infrared
camera system to observe thermal performance. As a practical matter, it is
quite diffi cult to insert an anemometer to precisely measure airfl ow in most
applications. Sometimes it is possible to estimate the effective airfl ow if you
thoroughly understand the enclosure geometry, entry/exit orifi ce areas and the
fan fl owrate specifi cations. If in doubt, contact MPS to discuss placement and
measurement techniques of suggested temperature sensors.
CAUTION: If you routinely or accidentally exceed these Derating guidelines,
the converter may have an unplanned Over Temperature shut down. Also, these
graphs are all collected at slightly above Sea Level altitude. Be sure to reduce
the derating for higher density altitude.
Output Overvoltage Protection
This converter monitors its output voltage for an over-voltage condition using
an on-board electronic comparator. The signal is optically coupled to the pri-
mary side PWM controller. If the output exceeds OVP limits, the sensing circuit
will power down the unit, and the output voltage will decrease. After a time-out
period, the PWM will automatically attempt to restart, causing the output volt-
age to ramp up to its rated value. It is not necessary to power down and reset
the converter for the this automatic OVP-recovery restart.
If the fault condition persists and the output voltage climbs to excessive
levels, the OVP circuitry will initiate another shutdown cycle. This on/off cycling
is referred to as “hiccup” mode. It safely tests full current rated output voltage
without damaging the converter.
Output Fusing
The converter is extensively protected against current, voltage and temperature
extremes. However your output 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 an appropriate fuse in series with the output.
Output Current Limiting
As soon as the output current increases to approximately 125% to 150% of
its maximum rated value, the DC/DC converter will enter a current-limiting
mode. The output voltage will decrease proportionally with increases in output
Figure 3 – Measuring Output Ripple and Noise (PARD)
C1
C1 = 0.1μF CERAMIC
C2 = 10μF LOW ES
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2 R
LOAD
5
6
COPPER STRIP
COPPER STRIP
SCOPE
+OUTPUT
+SENSE
7
8
−SENSE
−OUTPUT
the CBUS and LBUS components simulate a typical DC voltage bus. Your specifi c
system confi guration may require additional considerations. Please note that the
values of CIN, LBUS and CBUS will vary according to the specifi c converter model.
In critical applications, output ripple and noise (also referred to as periodic
and random deviations or PARD) may be reduced by adding fi lter elements
such as multiple external capacitors. Be sure to calculate component tem-
perature rise from refl ected AC current dissipated inside capacitor ESR. Our
Application Engineers can recommend potential solutions.
In the fi gure, the two copper strips simulate real-world printed circuit
impedances between the power supply and its load. In order to minimize circuit
errors and standardize tests between units, scope measurements should be
made using BNC connectors or the probe ground should not exceed one half
inch and soldered directly to the fi xture.
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 8 of 13
current, thereby maintaining a somewhat constant power output. This is com-
monly referred to as power limiting.
Current limiting inception is defi ned as the point at which full power falls
below the rated tolerance. See the Performance/Functional Specifi cations. Note
particularly that the output current may briefl y rise above its rated value. This
enhances reliability and continued operation of your application. If the output
current is too high, the converter will enter the short circuit condition.
Output Short Circuit Condition
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, the mag-
netically coupled voltage used to develop primary side voltages will also drop,
thereby shutting down the PWM controller. Following a time-out period, the
PWM will restart, causing the output voltage to begin ramping up to its appro-
priate value. If the short-circuit condition persists, another shutdown cycle will
initiate. This on/off cycling is called “hiccup mode”. The hiccup cycling reduces
the average output current, thereby preventing excessive internal tempera-
tures. A short circuit can be tolerated indefi nitely.
Remote Sense Input
Sense inputs compensate for output voltage inaccuracy delivered at the load.
This is done by correcting voltage drops along the output wiring such as mod-
erate IR drops and the current carrying capacity of PC board etch. Sense inputs
also improve the stability of the converter and load system by optimizing the
control loop phase margin.
Note: The Sense input and power Vout lines are internally connected through
low value resistors to their respective polarities so that the converter can
operate without external connection to the Sense. Nevertheless, if the Sense
function is not used for remote regulation, the user should connect +Sense to
+VOUT and –Sense to –VOUT at the converter pins.
Output overvoltage protection is monitored at the output voltage pin, not the
Sense pin. Therefore excessive voltage differences between Vout and Sense
together with trim adjustment of the output can cause the overvoltage protec-
tion circuit to activate and shut down the output.
Power derating of the converter is based on the combination of maximum
output current and the highest output voltage. Therefore the designer must insure:
(VOUT at pins) x (IOUT) ≤ (Max. rated output power)
Trimming the Output Voltage
The Trim input to the converter allows the user to adjust the output voltage over
the rated trim range (please refer to the Specifi cations). In the trim equations and
circuit diagrams that follow, trim adjustments use either a trimpot or a single
fi xed resistor connected between the Trim input and either the +Sense or –Sense
terminals. (On some converters, an external user-supplied precision DC voltage
may also be used for trimming). Trimming resistors should have a low tempera-
ture coeffi cient (±100 ppm/deg.C or less) and be mounted close to the converter.
Keep leads short. If the trim function is not used, leave the trim unconnected.
With no trim, the converter will exhibit its specifi ed output voltage accuracy.
There are two CAUTION’s to be aware for the Trim input:
CAUTION: To avoid unplanned power down cycles, do not exceed EITHER the
maximum output voltage OR the maximum output power when setting the trim.
Be particularly careful with a trimpot. If the output voltage is excessive, the
The remote Sense lines carry very little current. They are also capacitively
coupled to the output lines and therefore are in the feedback control loop to
regulate and stabilize the output. As such, they are not low impedance inputs
and must be treated with care in PC board layouts. Sense lines on the PCB
should run adjacent to DC signals, preferably Ground. In cables and discrete
wiring, use twisted pair, shielded tubing or similar techniques.
Please observe Sense inputs tolerance to avoid improper operation:
[VOUT(+) –VOUT(-)] – [ Sense(+) – Sense(-)] ≤ 10% of VOUT
Figure 4 – Remote Sense Circuit Confi guration
LOAD
6
8
9
5
7
Contact and PCB resistance
losses due to IR drops
Contact and PCB resistance
losses due to IR drops
+OUTPUT
+SENSE
TRIM
−
SENSE
-OUTPUT
−
INPUT
ON/OFF
CONTROL
+INPUT
2
4
1
Sense Current
IOUT
Sense Return
IOUT Return
Figure 5 – Trim adjustments using a trimpot
LOAD
6
8
7
5
95-22
TURNS
2
4
17
+OUTPUT
+SENSE
TRIM
−
SENSE
−
OUTPUT
−
INPUT
ON/OFF
CONTROL
+INPUT
Figure 6 – Trim adjustments to decrease Output Voltage using a Fixed Resistor
LOAD
6
8
9
5
RTRIM DOWN
2
4
17
+OUTPUT
+SENSE
TRIM
−
SENSE
−
OUTPUT
−
INPUT
ON/OFF
CONTROL
+INPUT
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 9 of 13
Figure 7 – Trim adjustments to increase Output Voltage using a Fixed Resistor
2
4
1
6
8
9
5
7
+OUTPUT
+SENSE
TRIM
−
SENSE
−
OUTPUT
−
INPUT
ON/OFF
CONTROL
+INPUT
LOAD
R TRIM UP
UP VO– 5
RT (:) = – 2050
12775
5– VO
RT (:) = – 2050
5110 (Vo - 2.5)
DOWN
UP VO– 12
RT (:) = – 5110
25000
12 – VO
RT (:) = –5110
10000 (Vo-2.5)
DOWN
UP DOWN
UEI-5/10-Q12, -5/12-Q48
UEI-12/4.2-Q12, -12/5-Q48
UP VO– 3.3
RT (:) = – 2050
12775
3.3 – VO
RT (:) = – 2050
5110 (Vo - 2.5)
DOWN
UEI-3.3/15-Q12, -3.3/18-Q48
VO– 15
RT (:) = – 5110
25000
15 – VO
RT (:) = –5110
10000 (Vo-2.5)
UEI-15/3.3-Q12, UEI-15/4-Q48
Trim Equations
Trim Up Trim Down
<Connect trim resistor
between Trim and –Sense>
<Connect trim resistor
between Trim and +Sense>
Positive: Standard models are enabled when the On/Off pin is left open or
is pulled high to +15V with respect to –VIN. An internal bias current causes the
open pin to rise to +15V. Some models will also turn on at lower intermediate
voltages (see Specifi cations). Positive-polarity devices are disabled when the
On/Off is grounded or brought to within a low voltage (see Specifi cations) with
respect to –VIN.
Negative: Optional negative-polarity devices are on (enabled) when the On/
Off is grounded or brought to within a low voltage (see Specifi cations) with
respect to –VIN. The device is off (disabled) when the On/Off is left open or is
pulled high to +15VDC Max. with respect to –VIN.
Dynamic control of the On/Off function should be able to sink appropriate
signal current when brought low and withstand appropriate voltage when
brought high. Be aware too that there is a fi nite time in milliseconds (see
Specifi cations) between the time of On/Off Control activation and stable,
regulated output. This time will vary slightly with output load type and current
and input conditions.
OVP circuit may inadvertantly shut down the converter. If the maximum power
is exceeded, the converter may enter current limiting. If the power is exceeded
for an extended period, the converter may overheat and encounter overtem-
perature shut down.
CAUTION: Be careful of external electrical noise. The Trim input is a senstive
input to the converter’s feedback control loop. Excessive electrical noise may
cause instability or oscillation. Keep external connections short to the Trim
input. Use shielding if needed.
Where Vo = Desired output voltage. Adjustment accuracy is subject to resis-
tor tolerances and factory-adjusted output accuracy. Mount trim resistor close
to converter. Use short leads.
Remote On/Off Control
On the input side, a remote On/Off Control can be ordered with either polarity.
There are two CAUTIONs for the On/Off Control:
CAUTION: While it is possible to control the On/Off with external logic if you
carefully observe the voltage levels, the preferred circuit is either an open
drain/open collector transistor or a relay (which can thereupon be controlled by
logic).
CAUTION: Do not apply voltages to the On/Off pin when there is no input
power voltage. Otherwise the converter may be permanently damaged.
Figure 8 – Driving the On/Off Control Pin (suggested circuit)
1
3
ON/OFF
CONTROL
-INPUT
+ Vcc
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 10 of 13
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
100 LFM
Natural Convection
200 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-3.3/15-Q12N Maximum Current Temperature Derating at Sea Level
(VIN = 24V, air flow is from pin 2 to pin 1)
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
Output Current (Amps)
Ambient Temperature (°C)
300 LFM
100 LFM
Natural Convection
400 LFM
UEI-3.3/18-Q48N Maximum Current Temperature Derating at Sea Level
(VIN = 48V air flow direction is transverse)
200 LFM
Efficiency (%)
UEI-3.3/18-Q48
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
70
72
74
76
78
80
82
84
86
88
90
123456789101112131415161718
V
IN
= 75V
V
IN
= 60V
V
IN
= 48V
V
IN
= 36V
V
IN
=
18V
V
IN
=
24V
1 2 3 4 5 6 7 8 9 101112131415
60
65
70
75
80
85
90
V
IN
= 36V
V
IN
= 24V
V
IN
=
10V
V
IN
=
12V
Efficiency (%)
UEI-3.3/15-Q12
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
30
40
50
60
70
80
90
100
12345678910
V
IN
= 36V
V
IN
= 24V
V
IN
= 10V
Efficiency (%)
UEI-5-10-Q12
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
Output Current (Amps)
Ambient Temperature (°C)
Natural Convection
UEI-5/10-Q12N Maximum Current Temperature Derating at Sea Level
(VIN = 24V, airflow is from pin 2 to pin 1)
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
40 45 50 55 60 65 70 75 80 85
Typical Performance Curves
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UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 11 of 13
123456789101112
72
74
76
78
80
82
84
86
88
90
92
V
IN
= 36V
V
IN
=
18V
V
IN
=
24V
V
IN
= 60V
V
IN
= 75V
V
IN
=
48V
Efficiency (%)
UEI-5/12-Q48
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
8.5
9
9.5
10
10.5
11
11.5
12
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
100 LFM
Natural Convection
200 LFM
300 LFM
400 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-5/12-Q48N Maximum Current Temperature Derating at Sea Level
(VIN = 48V, air flow is from pin 1 to pin 2)
60.0
62.5
65.0
67.5
70.0
72.5
75.0
77.5
80.0
82.5
85.0
87.5
90.0
92.5
0.31 0.69 1.13 1.48 1.87 2.25 2.64 3.01 3.42 3.81 4.20
V
IN
= 36V
V
IN
=
9V
V
IN
=
24V
Efficiency (%)
UEI-12/4.2-Q12
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
3.80
3.85
3.90
3.95
4.00
4.05
4.10
4.15
4.20
4.25
40 45 50 55 60 65 70 75 80 85 90
100 LFM
Natural Convection
200 LFM
300 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-12/4.2-Q12 Maximum Current Temperature Derating at Sea Level
(VIN = 24V, airflow is from pin 1 to pin 2)
Typical Performance Curves
66
68
70
72
74
76
78
80
82
84
86
88
90
92
0.5 1 1.75 2.5 3 3.5 4 4.5 5
V
IN
= 36V
V
IN
= 18V
V
IN
= 24V
V
IN
= 75V
V
IN
= 48V
Efficiency (%)
UEI-12/5-Q48
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
2.95
3.2
3.45
3.7
3.95
4.2
4.45
4.7
4.95
5.2
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
100 LFM
Natural Convection
200 LFM
300 LFM
400 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-12/5-Q48 Maximum Current Temperature Derating at Sea Level
(VIN = 48V, air flow is from pin 2 to pin 1)
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UEI Series
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MDC_UEI Series 50-60W.C01 Page 12 of 13
0.82 1.06 1.32 1.57 1.82 2.07 2.32 2.57 2.82 3.07 3.3
2
77.0
79.5
82.0
84.5
87.0
89.5
92.0
V
IN
= 12V
V
IN
=
9V
V
IN
= 36V
V
IN
=
24V
Efficiency (%)
UEI-15/3.3-Q12
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
70 75 80 85
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
100 LFM
Natural Convection
200 LFM
300 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-15/3.3-Q12 Maximum Current Temperature Derating at Sea Level
(VIN = 12V, open frame, air flow is from pin 1 to pin 2)
70 75 80 85
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
100 LFM
Natural Convection
200 LFM
300 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-15/3.3-Q12 Maximum Current Temperature Derating at Sea Level
(VIN = 24V, open frame, air flow is from pin 1 to pin 2)
Typical Performance Curves
1.5 1.7 2.0 2.2 2.5 2.7 3.0 3.2 3.5 3.7 4.0
76
78
80
82
84
86
88
90
92
77
79
81
83
85
87
89
91
V
IN
= 18V
V
IN
= 24V
V
IN
= 75V
V
IN
= 48V
Efficiency (%)
UEI-15/4-Q48N-C
Efficiency vs. Line Voltage and Load Current @ 25ºC
Load Current (Amps)
25 30 35 40 45 50 55 60 65 70 75 80 85
2.0
2.5
3.0
3.5
4.0
100 LFM
Natural Convection
200 LFM
300 LFM
400 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-15/4-Q48 Maximum Current Temperature Derating at Sea Level
(VIN = 24V, transverse airflow)
25 30 35 40 45 50 55 60 65 70 75 80 85
2.0
2.5
3.0
3.5
4.0
100 LFM
Natural Convection
200 LFM
300 LFM
400 LFM
Output Current (Amps)
Ambient Temperature (°C)
UEI-15/4-Q48 Maximum Current Temperature Derating at Sea Level
(VIN = 48V, transverse airflow)
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. Specifi cations are subject to change without
notice. © 2011 Murata Power Solutions, Inc.
www.murata-ps.com/support
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
UEI Series
50-60W Isolated Wide-Range DC/DC Converters
MDC_UEI Series 50-60W.C01 Page 13 of 13
