UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 1 of 24
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For full details go to
www.murata-ps.com/rohs
F1
External
DC
Power
Source
Reference and
Error Amplifier
t4XJUDIJOH
t'JMUFST
t$VSSFOU4FOTF
-Vout (5)
+Vout (3)
Trim (4)
On/Off
Control
(6)
-Vin (2)
Open = On
$MPTFE0GG
+Vin (1)
1PTJUJWF
MPHJD
Controller
and Power
5SBOTGFS
*TPMBUJPO
Barrier
Typical topology is shown. Murata Power Solutions
recommends an external fuse.
Typical unit
PRODUCT OVERVIEW
Featuring a full 25 Watt output in one square inch
of board area, the UEI25 series isolated DC/DC
converter family offers effi cient regulated DC power
for printed circuit board mounting. The 0.96" x 1.1"
x 0.32" (24.4 x 27.9 x 8.1 mm) converter accepts a
2:1 input voltage range of 36 to 75 Volts DC, ideal
for telecom equipment. The industry-standard pin-
out fi ts larger 1" x 2" converters. The fi xed output
voltage is tightly regulated. Applications include
small instruments, area-limited microcontrollers,
data communications equipment, remote sensor
systems, telephone equipment, vehicle and portable
electronics.
The UEI25 series includes full magnetic and
optical isolation with Basic protection up to 2250
Volts DC. For powering digital systems, the outputs
offer fast settling to step transients and will accept
higher capacitive loads. Excellent ripple and noise
specifi cations assure compatibility to noise-sus-
ceptible circuits. For systems requiring controlled
startup/shutdown, an external remote On/Off control
may use a switch, transistor or digital logic.
A wealth of self-protection features avoid both
converter and external circuit faults. These include
input undervoltage lockout and overtemperature
shutdown. The outputs current limit using the
“hiccup” autorestart technique and the outputs are
short-circuit protected. Additional features include
output overvoltage and reverse conduction elimina-
tion. The high effi ciency offers minimal heat buildup
and “no fan” operation.
Figure 1. Connection Diagram
FEATURES
Cost effective small footprint DC/DC converter,
ideal for high current applications
Industry standard 0.96" x 1.1" x 0.32" open
frame package and pinout
Input voltage range of 36-75 Vdc
3.3V, 5V, or 12Vdc fi xed output voltages
Isolation up to 2250 VDC (basic)
Up to 25 Watts total output power with exten-
sive self-protection shutdown features
High effi ciency synchronous rectifi er forward
topology up to 91%
Stable operation with no required external
components
Usable -40 to 85°C temperature range (with
derating)
Certifi ed to UL 60950-1, CAN/CSA-C22.2 No.
60950-1, IEC60950-1, EN60950-1 safety
approvals, 2nd edition
Output (V) Current (A) Nominal Input (V)
3.3 7.5 48
5548
12 2.1 48
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 2 of 24
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PART NUMBER STRUCTURE
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE ➀ ➂
Root Models ➀
Output Input
Effi ciency Package, C75
VOUT
(V)
IOUT
(A,
max)
Total
Power
(W)
R/N (mVp-p) Regulation (Max.)
VIN
Nom.
(V)
Range
(V)
IIN,
min.
load
(mA)
IIN,
full
load
(A)Typ. ➁Max. Line Load Min. Typ. Case (inches) Case (mm) Pinout
UEI25-033-D48 ➃3.3 7.5 25 50 80 ±0.1% ±0.2% 48 36-75 75 0.58 87.0% 89.5% 0.96x1.1x0.32 24.4x27.9x8.1 P85
UEI25-050-D48 5 5 25 50 80 ±0.1% ±0.2% 48 36-75 30 0.57 89.0% 91% 0.96x1.1x0.32 24.4x27.9x8.1 P85
UEI25-120-D48 12 2.1 25.2 95 120 ±0.1% ±0.1% 48 36-75 20 0.6 86.0% 87.5% 0.96x1.1x0.32 24.4x27.9x8.1 P85
Nominal Output Voltage
in Tenths of a Volt
Unipolar Output Isolated
25-Watt Series
UEI25 -D48-033 -C
RoHS-6 Hazardous Substance Compliance
(Does not claim EU RoHS exemption 7b, lead in solder)
Input Voltage Range
D48 = 36-75 Vdc
MP
On/Off Control Logic:
P = Positive
N = Negative
Notes:
➀Please refer to the part number structure for additional options and complete order-
ing part numbers.
➁Ripple and Noise is shown at 20 MHz bandwidth.
➂All specifi cations are at nominal line voltage and full load, +25 °C. unless otherwise
noted. See detailed specifi cations for full conditions.
Output capacitors are 1 µF ceramic in parallel with 10 µF electrolytic. The input cap
is 4.7 µF ceramic, low ESR.
I/O caps are necessary for our test equipment and may not be needed for your ap-
plication.
➃Minimum load is 10% for rated specifi cations.
Lx
Pin Length Option (through-hole only)
Blank = Std. pin length 0.25˝ (6.3mm)
L1 = 0.110˝ (2.79mm) ➀
L2 = 0.145˝ (3.68mm) ➀
Surface Mount Option
Blank = Through-hole mount
M = Surface mount (MSL rating 2) ➁
➀Special quantity order is required; samples available with standard pin length only.
➁SMT (M) versions not available in sample quantities.
➂Some model number combinations may not be available. See website or contact your local Murata sales representative.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 3 of 24
www.murata-ps.com/support
FUNCTIONAL SPECIFICATIONS – MODEL UEI25-033-D48
ABSOLUTE MAXIMUM RATINGS Conditions ➀Minimum Typical/Nominal Maximum Units
Input Voltage, Continuous Full power operation 0 80 Vdc
Input Voltage, Transient Operating or non-operating, 100 mS max.
duration 0 100 Vdc
Isolation Voltage Input to output 2250 Vdc
Input Reverse Polarity None, install external fuse None Vdc
On/Off Remote Control Power on or off, referred to -Vin 0 15 Vdc
Output Power 0 25.25 W
Output Current Current-limited, no damage, short-circuit protected 0 7.5 A
Storage Temperature Range Vin = Zero (no power) -55 125 ˚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 Specifi cations Table is not implied or recommended.
INPUT
Operating voltage range 36 48 75 Vdc
Recommended External Fuse Fast blow 1.5 A
Start-up threshold Rising input voltage 34 35.2 36 Vdc
Undervoltage shutdown Falling input voltage 32 34.0 35.2 Vdc
Overvoltage shutdown None Vdc
Reverse Polarity Protection None, install external fuse None Vdc
Internal Filter Type LC
Input current
Full Load Conditions Vin = nominal 0.58 0.60 A
Low Line Vin = minimum 0.79 0.81 A
Inrush Transient 0.05 A2-Sec.
Output in Short Circuit 50 100 mA
No Load Iout = minimum, unit=ON 75 100 mA
Standby Mode (Off, UV, OT) 12mA
Refl ected (back) ripple current ➁Measured at input with specifi ed fi lter 30 mA, RMS
Pre-biased startup External output voltage < Vset Monotonic
GENERAL and SAFETY
Effi ciency Vin=48V, full load 87 89.5 %
Vin=36V, full load 86.5 87.5 %
Isolation
Isolation Voltage Input to output, continuous 2250 Vdc
Insulation Safety Rating basic
Isolation Resistance 10 Mohm
Isolation Capacitance 1000 pF
Safety Certifi ed to UL-60950-1, CSA-C22.2 No.60950-1,
IEC/EN60950-1, 2nd edition Yes
Calculated MTBF Per MIL-HDBK-217F, ground benign,
Tambient=+30˚C TBD Hours x 106
Calculated MTBF Per Telcordia SR332, issue 1, class 3, ground
fi xed, Tambient=+40°C 2 Hours x 106
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency 300 330 360 KHz
Startup Time Power On to Vout regulated 50 mS
Startup Time Remote ON to Vout regulated 50 mS
Dynamic Load Response 50-75-50% load step, settling time to within
±2% of Vout 180 250 µSec
Dynamic load di/dt 2 A/µSec
Dynamic Load Peak Deviation same as above ±30 ±100 mV
FEATURES and OPTIONS
Remote On/Off Control ➃
"N" suffi x
Negative Logic, ON state ON = Ground pin or external voltage -0.7 1.2 V
Negative Logic, OFF state OFF = Pin open or external voltage 10 15 V
Control Current 1mA
"P" suffi x
Positive Logic, ON state ON = Pin open or external voltage 10 15 V
Positive Logic, OFF state OFF = Ground pin or external voltage -0.7 1.2 V
Control Current 1mA
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 4 of 24
www.murata-ps.com/support
OUTPUT Conditions ➀ ➂ Minimum Typical/Nominal Maximum Units
Total Output Power See Derating 0.0 25.0 25.25 W
Voltage
Nominal Output Voltage No trim 3.267 3.30 3.333 Vdc
Setting Accuracy At 50% load -1 +1 % of Vset.
Output Voltage Range User-adjustable -10 +10 % of Vnom.
Overvoltage Protection Via magnetic feedback 4.2 5 5.7 Vdc
Current
Output Current Range 0.7575 7.575 7.575 A
Minimum Load ➂10% minimum load % of Iout
Current Limit Inception 98% of Vnom., after warmup 8.5 10 11 A
Short Circuit
Short Circuit Current Hiccup technique, autorecovery 0.3 A
Short Circuit Duration (remove short for
recovery) Output shorted to ground, no damage Continuous
Short circuit protection method Current limiting
Regulation ➄
Line Regulation Vin=min. to max., Vout=nom., 50% load ±0.1 % of Vout
Load Regulation Iout=min. to max., Vin=48V ±0.2 % of Vout
Ripple and Noise 5 Hz- 20 MHz BW 50 80 mV pk-pk
Temperature Coeffi cient At all outputs 0.02 % of Vnom./°C
Maximum Capacitive Loading (10% ceramic,
90% Oscon) Cap. ESR=<0.02, full resistive load 0 2000 F
MECHANICAL (Through Hole Models) Conditions ➀Minimum Typical/Nominal Maximum Units
Outline Dimensions (no baseplate) C75 case 0.9x1.1x0.32 Inches
(Please refer to outline drawing) WxLxH 22.86x27.9x8.1 mm
Weight 0.32 Ounces
9.07 Grams
Through Hole Pin Diameter 0.04 Inches
1.016 mm
Through Hole Pin Material Copper alloy
TH Pin Plating Metal and Thickness Nickel subplate 50 µ-inches
Gold overplate 5 µ-inches
ENVIRONMENTAL
Operating Ambient Temperature Range With derating, 200 LFM -40 85 °C
No derating, 200 LFM -40 70 °C
Storage Temperature Vin = Zero (no power) -55 125 °C
Thermal Protection/Shutdown Measured in center 110 115 120 °C
Electromagnetic Interference External fi lter is required
Conducted, EN55022/CISPR22 B Class
Radiated, EN55022/CISPR22 B Class
Relative humidity, non-condensing To +85°C 10 90 %RH
Altitude must derate -1%/1000 feet -500 10,000 feet
-152 3048 meters
RoHS rating RoHS-6
FUNCTIONAL SPECIFICATIONS (CONT.) – MODEL UEI25-033-D48
Notes
➀Unless otherwise noted, all specifi cations are at nominal input voltage, nominal out-
put voltage and full load. General conditions are +25˚ Celsius ambient temperature,
near sea level altitude, natural convection airfl ow. All models are tested and specifi ed
with external parallel 1 µF and 10 µF multi-layer ceramic output capacitors. The ex-
ternal input capacitor is 4.7 µF ceramic. 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.
➁Input (back) ripple current is tested and specifi ed over 5 Hz to 20 MHz bandwidth.
Input fi ltering is Cbus=220 µF, Cin=33 µF and Lbus=12 µH.
➂All models are stable and regulate to specifi cation under minimum (10%) load.
Operation under no load will not damage the converter but may increase regulation,
output ripple, and noise.
➃The Remote On/Off Control is referred to -Vin.
➄Regulation specifi cations describe the output voltage changes as the line voltage or
load current is varied from its nominal or midpoint value to either extreme.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 5 of 24
www.murata-ps.com/support
FUNCTIONAL SPECIFICATIONS – MODEL UEI25-050-D48
ABSOLUTE MAXIMUM RATINGS Conditions ➀Minimum Typical/Nominal Maximum Units
Input Voltage, Continuous Full power operation 0 80 Vdc
Input Voltage, Transient Operating or non-operating, 100 mS max.
duration 0 100 Vdc
Isolation Voltage Input to output 2250 Vdc
Input Reverse Polarity None, install external fuse None Vdc
On/Off Remote Control Power on or off, referred to -Vin 0 15 Vdc
Output Power 0 25.25 W
Output Current Current-limited, no damage, short-circuit protected 0 5 A
Storage Temperature Range Vin = Zero (no power) -55 125 ˚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 Specifi cations Table is not implied or recommended.
INPUT
Operating voltage range 36 48 75 Vdc
Recommended External Fuse Fast blow 1.5 A
Start-up threshold Rising input voltage 34 35 36 Vdc
Undervoltage shutdown Falling input voltage 32 33.5 34.5 Vdc
Overvoltage shutdown None Vdc
Reverse Polarity Protection None, install external fuse None Vdc
Internal Filter Type LC
Input current
Full Load Conditions Vin = nominal 0.57 0.59 A
Low Line Vin = minimum 0.76 0.79 A
Inrush Transient 0.05 A2-Sec.
Output in Short Circuit 50 100 mA
No Load Iout = minimum, unit=ON 30 50 mA
Standby Mode (Off, UV, OT) 13mA
Refl ected (back) ripple current ➁Measured at input with specifi ed fi lter 30 mA, RMS
Pre-biased startup External output voltage < Vset Monotonic
GENERAL and SAFETY
Effi ciency Vin=48V, full load 89 91 %
Vin=36V, full load 89 91 %
Isolation
Isolation Voltage Input to output, continuous 2250 Vdc
Insulation Safety Rating basic
Isolation Resistance 10 Mohm
Isolation Capacitance 2000 pF
Safety Certifi ed to UL-60950-1, CSA-C22.2 No.60950-1,
IEC/EN60950-1, 2nd edition Yes
Calculated MTBF Per MIL-HDBK-217F, ground benign,
Tambient=+30˚C TBD Hours x 106
Calculated MTBF Per Telcordia SR332, issue 1, class 3, ground
fi xed, Tambient=+40°C 2 Hours x 106
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency 300 330 360 KHz
Startup Time Power On to Vout regulated 50 mS
Startup Time Remote ON to Vout regulated 50 mS
Dynamic Load Response 50-75-50% load step, settling time to within
±2% of Vout 200 µSec
Dynamic load di/dt 2 A/µSec
Dynamic Load Peak Deviation same as above ±150 mV
FEATURES and OPTIONS
Remote On/Off Control ➃
"N" suffi x
Negative Logic, ON state ON = Ground pin or external voltage -0.7 0.7 V
Negative Logic, OFF state OFF = Pin open or external voltage 10 15 V
Control Current 1mA
"P" suffi x
Positive Logic, ON state ON = Pin open or external voltage 10 15 V
Positive Logic, OFF state OFF = Ground pin or external voltage -0.7 0.8 V
Control Current 1mA
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 6 of 24
www.murata-ps.com/support
OUTPUT Conditions ➀ ➂ Minimum Typical/Nominal Maximum Units
Total Output Power See Derating 0.0 25.0 25.25 W
Voltage
Nominal Output Voltage No trim 4.95 5.00 5.05 Vdc
Setting Accuracy At 50% load -1 +1 % of Vset.
Output Voltage Range User-adjustable -10 +10 % of Vnom.
Overvoltage Protection Via magnetic feedback 6 6.5 7.5 Vdc
Current
Output Current Range 0 5.0 5.0 A
Minimum Load ➂No minimum load % of Iout
Current Limit Inception 98% of Vnom., after warmup 5.3 6.8 7.3 A
Short Circuit
Short Circuit Current Hiccup technique, autorecovery 0.3 A
Short Circuit Duration (remove short for
recovery) Output shorted to ground, no damage Continuous
Short circuit protection method Current limiting
Regulation ➄
Line Regulation Vin=min. to max., Vout=nom., 50% load ±0.1 % of Vout
Load Regulation Iout=min. to max., Vin=48V ±0.2 % of Vout
Ripple and Noise 5 Hz- 20 MHz BW 50 80 mV pk-pk
Temperature Coeffi cient At all outputs 0.02 % of Vnom./°C
Maximum Capacitive Loading (10% ceramic,
90% Oscon) Cap. ESR=<0.02, full resistive load 0 2000 F
MECHANICAL (Through Hole Models) Conditions ➀Minimum Typical/Nominal Maximum Units
Outline Dimensions (no baseplate) C75 case 0.96x1.1x0.32 Inches
(Please refer to outline drawing) WxLxH 24.4x27.9x8.1 mm
Weight 0.32 Ounces
9.07 Grams
Through Hole Pin Diameter 0.04 Inches
1.016 mm
Through Hole Pin Material Copper alloy
TH Pin Plating Metal and Thickness Nickel subplate 50 µ-inches
Gold overplate 5 µ-inches
ENVIRONMENTAL
Operating Ambient Temperature Range With derating, 200 LFM -40 85 °C
No derating, 200 LFM, full power -40 82 °C
Operating Case Temperature Range No derating -40 105 °C
Storage Temperature Vin = Zero (no power) -55 125 °C
Thermal Protection/Shutdown Measured in center 110 115 120 °C
Electromagnetic Interference External fi lter is required
Conducted, EN55022/CISPR22 B Class
Radiated, EN55022/CISPR22 B Class
Relative humidity, non-condensing To +85°C 10 90 %RH
Altitude must derate -1%/1000 feet -500 10,000 feet
-152 3048 meters
RoHS rating RoHS-6
FUNCTIONAL SPECIFICATIONS (CONT.) – MODEL UEI25-050-D48
Notes
➀Unless otherwise noted, all specifi cations are at nominal input voltage, nominal out-
put voltage and full load. General conditions are +25˚ Celsius ambient temperature,
near sea level altitude, natural convection airfl ow. All models are tested and specifi ed
with external parallel 1 µF and 10 µF multi-layer ceramic output capacitors. The ex-
ternal input capacitor is 4.7 µF ceramic. 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.
➁Input (back) ripple current is tested and specifi ed over 5 Hz to 20 MHz bandwidth.
Input fi ltering is Cbus=220 µF, Cin=33 µF and Lbus=12 µH.
➂All models are stable and regulate to specifi cation under no load.
➃The Remote On/Off Control is referred to -Vin.
➄Regulation specifi cations describe the output voltage changes as the line voltage or
load current is varied from its nominal or midpoint value to either extreme.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 7 of 24
www.murata-ps.com/support
FUNCTIONAL SPECIFICATIONS – MODEL UEI25-120-D48
ABSOLUTE MAXIMUM RATINGS Conditions ➀Minimum Typical/Nominal Maximum Units
Input Voltage, Continuous Full power operation 0 80 Vdc
Input Voltage, Transient Operating or non-operating, 100 mS max.
duration 0 100 Vdc
Isolation Voltage Input to output 2250 Vdc
Input Reverse Polarity None, install external fuse None Vdc
On/Off Remote Control Power on or off, referred to -Vin 0 15 Vdc
Output Power 025W
Output Current Current-limited, no damage, short-circuit protected 0 2.1 A
Storage Temperature Range Vin = Zero (no power) -55 125 ˚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 Specifi cations Table is not implied or recommended.
INPUT
Operating voltage range 36 48 75 Vdc
Recommended External Fuse Fast blow 1.5 A
Start-up threshold Rising input voltage 34 35.2 36 Vdc
Undervoltage shutdown Falling input voltage 32 34.0 35.2 Vdc
Overvoltage shutdown None Vdc
Reverse Polarity Protection None, install external fuse None Vdc
Internal Filter Type capacitive
Input current
Full Load Conditions Vin = nominal 0.600 0.617 A
Low Line Vin = minimum 0.809 0.842 A
Inrush Transient 0.05 A2-Sec.
Output in Short Circuit 50 100 mA
No Load Iout = minimum, unit=ON 20 35 mA
Standby Mode (Off, UV, OT) 12mA
Refl ected (back) ripple current ➁Measured at input with specifi ed fi lter 30 mA, RMS
Pre-biased startup External output voltage < Vset Monotonic
GENERAL and SAFETY
Effi ciency Vin=48V, full load 86.0 87.5 %
Isolation
Isolation Voltage Input to output, continuous 2250 Vdc
Insulation Safety Rating basic
Isolation Resistance 10 Mohm
Isolation Capacitance 1700 pF
Safety Certifi ed to UL-60950-1, CSA-C22.2 No.60950-
1, IEC/EN60950-1 Yes
Calculated MTBF Per MIL-HDBK-217F, ground benign,
Tambient=+30˚C TBD Hours x 106
Calculated MTBF Per Telcordia SR332, issue 1, class 3, ground
fi xed, Tambient=+40°C 2 Hours x 106
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency 295 325 355 KHz
Startup Time Power On to Vout regulated 10 50 mS
Startup Time Remote ON to Vout regulated 10 50 mS
Dynamic Load Response 50-75-50% load step, settling time to within
±1% of Vout 100 200 µSec
Dynamic load di/dt 1 A/µSec
Dynamic Load Peak Deviation same as above ±250 ±350 mV
FEATURES and OPTIONS
Remote On/Off Control ➃
"N" suffi x
Negative Logic, ON state ON = Ground pin or external voltage -0.7 0.7 V
Negative Logic, OFF state OFF = Pin open or external voltage 10 15 V
Control Current 1mA
"P" suffi x
Positive Logic, ON state ON = Pin open or external voltage 10 15 V
Positive Logic, OFF state OFF = Ground pin or external voltage -0.7 0.8 V
Control Current 1mA
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 8 of 24
www.murata-ps.com/support
OUTPUT Conditions ➀ ➂ Minimum Typical/Nominal Maximum Units
Total Output Power See Derating 0.0 25.2 25.45 W
Voltage
Nominal Output Voltage No trim 11.88 12.00 12.12 Vdc
Setting Accuracy At 50% load -1 +1 % of Vset.
Output Voltage Range User-adjustable -10 +10 % of Vnom.
Overvoltage Protection Via magnetic feedback 14 19 22 Vdc
Current
Output Current Range 0.0 2.1 2.1 A
Minimum Load ➂No minimum load
Current Limit Inception 97% of Vnom., after warmup 2.3 3 3.4 A
Short Circuit
Short Circuit Current Hiccup technique, autorecovery within ±1.25%
of Vout 0.1 A
Short Circuit Duration (remove short for
recovery) Output shorted to ground, no damage Continuous
Short circuit protection method Current limiting
Regulation ➄
Line Regulation Vin=min. to max., Vout=nom., 50% load ±0.075 % of Vout
Load Regulation Iout=min. to max., Vin=48V ±0.05 % of Vout
Ripple and Noise 5 Hz- 20 MHz BW 95 120 mV pk-pk
Temperature Coeffi cient At all outputs 0.02 % of Vnom./°C
Maximum Capacitive Loading (10% ceramic,
90% Oscon) Cap. ESR=<0.02, full resistive load 0 470 F
MECHANICAL (Through Hole Models) Conditions ➀Minimum Typical/Nominal Maximum Units
Outline Dimensions (no baseplate) C75 case 0.96x1.1x0.32 Inches
(Please refer to outline drawing) WxLxH 24.38x27.94x8.13 mm
Weight 0.32 Ounces
9.07 Grams
Through Hole Pin Diameter 0.04 Inches
1.016 mm
Through Hole Pin Material Copper alloy
TH Pin Plating Metal and Thickness Nickel subplate 50 µ-inches
Gold overplate 5 µ-inches
ENVIRONMENTAL
Operating Ambient Temperature Range With derating, 200 LFM -40 85 °C
Storage Temperature Vin = Zero (no power) -55 125 °C
Thermal Protection/Shutdown Measured at hotspot 130 135 150 °C
Electromagnetic Interference External fi lter is required
Conducted, EN55022/CISPR22 B Class
Radiated, EN55022/CISPR22 B Class
Relative humidity, non-condensing To +85°C 10 90 %RH
Altitude must derate -1%/1000 feet -500 10,000 feet
-152 3048 meters
RoHS rating RoHS-6
FUNCTIONAL SPECIFICATIONS (CONT.) – MODEL UEI25-120-D48
Notes
➀Unless otherwise noted, all specifi cations are at nominal input voltage, nominal out-
put voltage and full load. General conditions are +25˚ Celsius ambient temperature,
near sea level altitude, natural convection airfl ow. All models are tested and specifi ed
with external parallel 1 µF and 10 µF multi-layer ceramic output capacitors. The ex-
ternal input capacitor is 4.7 µF ceramic. 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.
➁Input (back) ripple current is tested and specifi ed over 5 Hz to 20 MHz bandwidth.
Input fi ltering is Cbus=220 µF, Cin=33 µF and Lbus=12 µH.
➂All models are stable and regulate to specifi cation under no load.
➃The Remote On/Off Control is referred to -Vin.
➄Regulation specifi cations describe the output voltage changes as the line voltage or
load current is varied from its nominal or midpoint value to either extreme.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 9 of 24
www.murata-ps.com/support
UEI25-033-D48 PERFORMANCE DATA
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=7.5A, Cload=0uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=.7575mA, Cload=0uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
Maximum Current Temperature Derating @sea level
(airfl ow is from input to output)
Thermal image with "hot spot" at full load current with 63°C ambient, air fl owing at
minimal rate of 65 LFM. Air is fl owing across the converter from +Vo to -Vo at 48V input.
Identifi able and recommended maximum value to be verifi ed in application.
5
6
7
8
30
35
40
45
55
60
65
70
7
5
80
85
A
m
A
A
b
i
e
n
t
T
e
m
p
e
r
a
t
u
r
e
(°C
)
0.33 m/s (65
L
F
M)
0.5 m/s (100
0.
L
F
M)
(200 to 400
1.0 to 2.0 m/s
(
2
00 to 40
0
L
F
M)
=
75
V
Vi
n
=
O
u
t
p
u
t
C
urrent
(
A
(
(
mps
)
0.33 to 2.0 m
/
s
(
65 to 400
L
F
M)
V
in = 36V
,
48V
,
and 60
V
Effi ciency vs. Line Voltage and Load Current @ 25°C
7
12
17
22
27
32
37
42
47
52
57
62
67
72
77
82
87
92
0.2 0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7 6.2 6.7 7.2 7.7
Vin = 36V
Vin = 48V
Vin = 60V
Vin = 75V
Load Current (Amps)
Efficiency (%)
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 10 of 24
www.murata-ps.com/support
UEI25-033-D48 PERFORMANCE DATA, CONTINUED
Output Ripple and Noise (Vin=48V, Vout=nom., Iout=.7575mA, Cload= 1 uFb ceramic ||
10uF tantalum, Ta=+25°C., ScopeBW=20Mhz)
Output Ripple and Noise (Vin=48V, Vout=nom., Iout=7.5A, Cload= 1 uFb ceramic || 10uF
tantalum, Ta=+25°C., ScopeBW=20Mhz)
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=7.5A, Cload=2000uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
Step Load Transient Response (Vin=48V, Vout=nom., Iout=50-75-50% of full load, Cload=
1 uFb ceramic || 10uF tantalum, Ta=+25°C., ScopeBW=20Mhz)
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 11 of 24
www.murata-ps.com/support
UEI25-050-D48 PERFORMANCE DATA
Maximum Current Temperature Derating @sea level
(VIN = 36V, 48V, 60V, and 75V, airfl ow is from pin 1 to pin 3)
Power Dissipation vs. Load Current @ 25°C
4
.5
4
.
6
4
.7
4
.
8
4
.
9
5
.
0
5
.
1
30
35
40
45
50
55
60
65
70
75
80
85
A
m
A
A
b
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
(
°C
)
0.33 to 2.0 m/s
(
65 to 400
L
F
M)
O
u
t
p
u
t
Cu
rr
e
nt
(
A
(
(
m
ps
)
1
.
0
1
.
4
1
.
8
2
.
2
2
.
6
3
.
0
3
.
4
3
.
8
4
.
2
4
.
6
5
.
0
0
.
50
1
.
00
1
.
50
2.
00
2
.5
0
3
.
00
3
.
50
V
in = 36V
Vi
n = 48
V
Vi
n = 60
V
V
in = 7
5
V
L
o
a
d
C
urrent
(
A
(
(
m
ps
)
L
o
ss
(
Watts)
(
(
Effi ciency vs. Line Voltage and Load Current @ 25°C
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
1.0 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0
Vin = 36V
Vin = 48V
Vin = 60V
Vin = 75V
Load Current (Amps)
Efficiency (%)
Thermal image with "hot spot" at full load current with 80°C ambient, air fl owing at
minimal rate of 65 LFM. Air is fl owing across the converter from +Vo to -Vo at 48V input.
Identifi able and recommended maximum value to be verifi ed in application.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 12 of 24
www.murata-ps.com/support
UEI25-050-D48 PERFORMANCE DATA, CONTINUED
On/Off Enable Delay (Vin=48V, Vout=nom., Iout=no load, Cload=0 µF, Ta=+25°C.,
ScopeBW=20MHz) Trace 1=Enable, Trace 4=Vout
On/Off Enable Delay (Vin=48V, Vout=nom., Iout=5A, Cload=2000 µF, Ta=+25°C.,
ScopeBW=20MHz) Trace 1=Enable, Trace 4=Vout
Output Ripple and Noise (Vin=48V, Vout=nom., Iout=no load, Cload=1 µF ceramic || 10µF
tantalum, Ta=+25°C., ScopeBW=20MHz)
On/Off Enable Delay (Vin=48V, Vout=nom., Iout=5A, Cload=0 µF, Ta=+25°C.,
ScopeBW=20MHz) Trace 1=Enable, Trace 4=Vout
Step Load Transient Response (Vin=48V, Vout=nom., Iout=50-75-50% of full load, Cload=1
µF ceramic || 10µF tantalum, Ta=+25°C., ScopeBW=20MHz)
Output Ripple and Noise (Vin=48V, Vout=nom., Iout=5A, Cload=1 µF ceramic || 10µF
tantalum, Ta=+25°C., ScopeBW=20MHz)
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 13 of 24
www.murata-ps.com/support
UEI25-120-D48 PERFORMANCE DATA
Maximum Current Temperature Derating @sea level
(VIN = 48V, airfl ow is from pin 1 to pin 3)
Maximum Current Temperature Derating @sea level
(VIN = 36V, airfl ow is from pin 1 to pin 3)
Power Dissipation vs. Load Current @ 25°C
65
70
75
80
85
2
2.
0
2
5
2
.
05
2
.
0
75
2
.1
2.12
5
2
.
1
5
2.17
5
2
.2
A
m
A
A
b
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
(
°C
)
O
u
t
p
u
t
Cu
rr
e
nt
(
A
(
(
m
ps
)
0.33 m/s
(
65
L
F
M)
0
.5 m
/
s
(
100
L
F
M)
1
.0 m/s
(
200
L
F
M)
65
70
7
5
80
85
2
2
.
02
5
2
.
05
2.
0
7
5
2
.
1
2
.
12
5
2
.1
5
2.17
5
2
.
2
A
m
A
A
b
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
(
°
C)
O
u
t
p
u
t
C
urrent
(
A
(
(
m
ps
)
0.33 m/s (65
L
F
M)
0.5 m
/
s
(
100
L
F
M)
1.0 m
/
s
(
200
L
F
M)
65
70
75
80
85
1.9
1.
95
2.
05
2
.
0
2
.1
2.1
5
2
.2
2.2
5
A
m
A
A
b
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
(
°
C)
O
u
t
p
u
t
C
urrent
(
A
(
(
mps
)
0.33 m
/
s
(
65
L
F
M)
0.5 m/s
(
100
L
F
M)
1
.0 m/s
(
200
L
F
M)
(
1.5 m/s (300
L
F
)
M)
0
.
4
0
.
6
0
.
8
0
.
9
1
.
1
1
.
3
1
.
4
1
.
6
1
.
8
1
.
9
2
.
1
0
.
46
0
.
96
1
.
46
1
.
96
2
.
46
2
.
96
3
.
46
3
.
96
4
.
46
V
in =
36
V
V
in = 4
8
V
V
in =
60
V
Vi
n = 75
V
L
o
a
d Current
(
A
(
(
m
ps)
L
o
ss
(
Watts)
(
(
Effi ciency vs. Line Voltage and Load Current @ 25°C
0.4 0.6 0.8 0.9 1.1 1.3 1.4 1.6 1.8 1.9 2.1
78
79
80
81
82
83
84
85
86
87
88
89
Vin = 36V
Vin = 48V
Vin = 60V
Vin = 75V
Load Current (Amps)
Efficiency (%)
Maximum Current Temperature Derating @sea level
(VIN = 60V, airfl ow is from pin 1 to pin 3)
Thermal image with "hot spot" at full load current with 65°C ambient, air fl owing at
minimal rate of 65 LFM. Air is fl owing across the converter from +Vo to -Vo at 48V input.
Identifi able and recommended maximum value to be verifi ed in application.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 14 of 24
www.murata-ps.com/support
UEI25-120-D48 PERFORMANCE DATA, CONTINUED
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=0A, Cload=0uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=2.1A, Cload=2000uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
Output Ripple and Noise (Vin=48V, Iout = 2.1A, Cout = 1&10F, Ta = +25°C,
Scope BW = 20MHz)
On/Off ENABLE DELAY (Vin=48, Vout=nom, Iout=2.1A, Cload=0uF, Ta=+25°C.,
ScopeBW=20Mhz) Trace 1= Enable. Trace 4=Vout
Stepload Transient Response (Vin = 48V, Iout = 25-75-25% of Imax, Cout = 1&10F,
Ta = +25°C, Scope BW = 20MHz)
Maximum Current Temperature Derating @sea level
(VIN = 75V, airfl ow is from pin 1 to pin 3)
65
70
7
5
80
85
1
.
9
1
.
95
2
.
05
2
.
1
2
.
15
2.
2
A
m
A
A
b
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
(°C
)
0.33 m
/
s (65
L
F
M)
0.5 m
/
s (100
L
F
M)
1.0 m/s (200
L
F
M
)
(
1.5 m/s (300
L
F
)
M
)
O
u
t
p
u
t
Cu
rr
e
nt
(
A
(
(
mps
)
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 15 of 24
www.murata-ps.com/support
MECHANICAL SPECIFICATIONS, OPEN FRAME THROUGH-HOLE MOUNT
0.32 MAX
8.1
0.41
[10.4]
0.30
[7.62]
0.400
10.16
TYP0.15
[3.8]
0.58
[14.7]
SIDE VIEW
MOUNTING
PLANE
.040±.002 PIN DIAMETER
.071 .002 SHOULDER DIAMETER
6X AT PINS 1-6
BOTTOM VIEW
#5
#4
#3
C
L
C
L
C
L
#6
#2
#1
RECOMMENDED
PRI-SEC BARRIER
0.400
10.16
0.400
10.16
0.100
2.54
0.200
5.08
0.800
20.32
TOP VIEW
PIN #1
1.10
27.9
0.96
24.4
END VIEW
0.475
[12.07]
REF
0.25
6.3
INPUT/OUTPUT CONNECTIONS
Pin Function P85
1 +Vin
2 -Vin
3 +Vout
4 Output Trim
5 -Vout
6 On/Off Control*
*The Remote On/Off can be provided
with either positive (P suffi x) or nega-
tive (N suffi x) logic
Case 75 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 ± 1˚
These converters are plug-compatible to
competitive units. In case of pinout numbering
inconsistency, follow the pin FUNCTION, not
the pin number when laying out your PC board.
Standard pin length is shown. Please refer to
the Ordering Guide for alternate pin lengths.
SECTION A-A
Depth
Pocket
9.5 [.38 in]
19.1 [.75 in]
Notes:
Material: Dow 220 antistat ethafoam1.
(Density: 34-35 kg/m3)
Dimensions: 252 x 252 x 19.1 mm2.
6 x 5 array (30 per tray)
3. All dimensions in millimeters [inches]
4. Tolerances unless otherwise specified: +1/-0
Typ
Typ
R
28.4
177.8
[9.92]
252.0
Typ
6.4
Typ
6.4
6.4
Typ 18.0
5x
Ref
38.1
22.9
190.5
Ref
252.0
[9.92]
25.4
4x 44.5
AA
19.1
Ref
252.0
Ref 252.0
Ref
9.5 deep
Ref
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 16 of 24
www.murata-ps.com/support
SHIPPING TRAYS AND BOXES, THROUGH-HOLE MOUNT
SHIPPING TRAY DIMENSIONS
Anti-static foam
Label
Label
Each tray is 6 x 5 units
(30 units per tray)
UEI modules are supplied in a 30-piece (6 x 5) shipping tray. The tray is an anti-static closed-cell polyethylene foam. Dimensions are shown below.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 17 of 24
www.murata-ps.com/support
MECHANICAL SPECIFICATIONS, SURFACE MOUNT (MSL RATING 2)
TOP VIEW
1.10
27.9
0.96
24.4
PIN #1
SIDE VIEW
MOUNTING
PLANE
0.093 [2.4] TYP
0.41
[10.4]
0.30
[7.62]
0.400
10.16
TYP0.15
[3.8]
0.58
[14.7]
BOTTOM VIEW
#5
#4
#3
C
L
C
L
C
L
#6
#2
#1
RECOMMENDED
PRI-SEC BARRIER
0.400
10.16
0.400
10.16
0.100
2.54
0.200
5.08
0.800
20.32
END VIEW
0.13 [3.3]
REF
0.34
[8.64]
MAX
0.093
[2.4]
Case 75 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 ± 1˚
These converters are plug-compatible to
competitive units. In case of pinout numbering
inconsistency, follow the pin FUNCTION, not
the pin number when laying out your PC board.
INPUT/OUTPUT CONNECTIONS
Pin Function P85
1 +Vin
2 -Vin
3 +Vout
4 Output Trim
5 -Vout
6 On/Off Control*
*The Remote On/Off can be provided
with either positive (P suffi x) or nega-
tive (N suffi x) logic
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 18 of 24
www.murata-ps.com/support
RECOMMENDED SMT PAD LAYOUT
SURFACE MOUNT TAPE AND REEL INFORMATION (MSL RATING 2)
NOTE: The SMT package has an MSL 2 rating.
0.909
23.10
32.00
1.260
Pitch
2.00
0.079
0.118
3.00
13.0
R.256
Feed (unwind) direction
5.0mm Nozzle Pick &
Place Location
PACKAGING CONFORMS TO EIA-481
CONVERTERS SHIPPING IN QUANTITIES
OF 100 PER REEL
2.20
56.0
Cover Tape
0.365
9.27
Dimensions in inches [mm]
[10.16]
0.400
0.400
[10.16]
[2.54]
0.100
[2.54]
[20.32]
0.800
±.010.102
±0.25][2.60
6X
0.100
1.00
[25.4]
1
2
6
4
5
3
1.14
[29.0]
C
L
C
L
INPUT/OUTPUT CONNECTIONS
Pin Function P85
1 +Vin
2 -Vin
3 +Vout
4 Output Trim
5 -Vout
6 On/Off Control*
*The Remote On/Off can be provided
with either positive (P suffi x) or nega-
tive (N suffi x) logic
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 19 of 24
www.murata-ps.com/support
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.
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 rising 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 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 re-
charges. Such situations could oscillate. To prevent this, make sure the operating
input voltage is well above the UV Shutdown voltage AT ALL TIMES.
Start-Up Delay
Assuming that the output current is set at the rated maximum, the Vin to Vout Start-
Up Delay (see Specifi
cations) 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 specifi ed regulation band. Actual measured
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 the
PWM controller at power up, thereby limiting the input inrush current.
The On/Off Remote Control interval from inception to VOUT regulated as-
sumes 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 regulation
band. The specifi cation assumes that the output is fully loaded at maximum
rated current.
Input Source Impedance
These converters will operate to specifi cations without external components,
assuming that the source voltage has very low impedance and reasonable in-
put voltage regulation. Since real-world voltage sources have fi nite impedance,
performance is improved by adding external fi lter components. Sometimes only
a small ceramic capacitor is suffi cient. Since it is diffi cult to totally characterize
TECHNICAL NOTES 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,
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 may 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 tempera-
ture rise from refl ected AC current dissipated inside capacitor ESR.
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.
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
+VIN
−VIN
CURRENT
PROBE
TO
OSCILLOSCOPE
+
–
+
–
Figure 2. Measuring Input Ripple Current
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 20 of 24
www.murata-ps.com/support
Minimum Output Loading Requirements
These converters employ a synchronous rectifi er design topology. All models
regulate within specifi cation and are stable from 0% load to full load conditions,
unless otherwise specifi ed. Operation under no load will not damage the con-
verter but might, however, slightly increase regulation, output ripple, and noise.
Thermal Shutdown
To protect against thermal over-stress, these converters include thermal shut-
down circuitry. If environmental conditions cause the temperature of the DC/
DC’s to rise above the Operating Temperature Range up to the shutdown tem-
perature, 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 performance data section 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 airfl ow measured in Linear Feet per Minute (“LFM”). Note that
these are AVERAGE measurements. The converter will accept brief increases in tem-
perature 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 it-
self which is obviously running at higher temperature than the outside air. Also
note that “natural convection” is defi ned as very low 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).
Murata Power Solutions 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.
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 Overvoltage Protection (OVP)
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 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.
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 an appropriate external protection.
Output Current Limiting
As soon as the output current increases to approximately its overcurrent limit,
the DC/DC converter will enter a current-limiting mode. The output voltage will
decrease proportionally with increases in output current, thereby maintaining a
somewhat constant power output. This is commonly 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
magnetically coupled voltage used to develop 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 initi-
ate. This on/off cycling is called “hiccup mode.” The hiccup cycling reduces the
average output current, thereby preventing excessive internal temperatures.
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 a single fi xed resistor
connected between the Trim input and either Vout pin. Trimming resistors should
have a low temperature coeffi cient (±100 ppm/°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.
Figure 3. Measuring Output Ripple and Noise (PARD)
C1
C1 = 1µF
C2 = 10µF
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2 R
LOAD
SCOPE
+VOUT
−VOUT
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 21 of 24
www.murata-ps.com/support
There are two CAUTIONs to observe 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.
If the output voltage is excessive, the 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 overtemperature 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.
Trim Equations
Trim Up Trim Down
<Connect trim resistor
between Trim and –Vout>
<Connect trim resistor
between Trim and +Vout>
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 specifi ed with either positive
or negative logic as follows:
Positive: Models equipped with Positive Logic are enabled when the On/Off
pin is left open or is pulled high to +15VDC with respect to –VIN. An internal bias
current causes the open pin to rise to +VIN. Positive-logic devices are disabled
when the On/Off is grounded or brought to within a low voltage (see Specifi ca-
tions) 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 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 the specifi ed
signal current when brought low and withstand specifi ed 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.
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). The On/Off prefers to be set at approx. +15V (open pin) for the ON state,
assuming positive 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 4. Trim adjustments to decrease Output Voltage using a Fixed Resistor
LOAD
RTRIM DOWN
+VOUT
TRIM
ON/OFF
CONTROL
−VIN −VOUT
+VIN
– 2050
VO – 3.3
12775
–2050
3.3 – VO
5110 x (Vo –2.5)
UEI25-033-D48
RTUP (Ω) = RTDOWN (Ω) =
– 2050
VO – 5
12775
–2050
5 – VO
5110 x (Vo –2.5)
UEI25-050-D48
RTUP (Ω) = RTDOWN (Ω) =
– 5110
VO – 12
25000
–5110
12 – VO
10000 (Vo-2.5)
UEI25-120-D48
RTUP (Ω) = RTDOWN (Ω) =
Figure 5. Trim adjustments to increase Output Voltage using a Fixed Resistor
+VOUT
TRIM
ON/OFF
CONTROL
−VIN
LOAD
RTRIM UP
−VOUT
+VIN
Figure 6. Driving the On/Off Control Pin (suggested circuit)
ON/OFF
CONTROL
-VIN
+VCC
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 22 of 24
www.murata-ps.com/support
Emissions Performance
Murata Power Solutions measures its products for radio frequency 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 Specifi cations. An external discrete fi lter is
installed and the circuit diagram is shown below.
[1] Conducted Emissions Parts List
[2] Conducted Emissions Test Equipment Used
Rohde & Schwarz EMI Test Receiver (9KHz – 1000MHz) ESPC
Rohde & Schwarz Software ESPC-1 Ver. 2.20
OHMITE 25W – 1 Ohm resistor combinations
DC Source Programmable DC Power Supply Model 62012P-100-50
[3] Conducted Emissions Test Results
[4] Layout Recommendations
Most applications can use the fi ltering which is already installed inside the
converter or with the addition of the recommended external capacitors. For
greater emissions suppression, consider additional fi lter 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.
Reference Part Number Description Vendor
L1 PE-62913 1mH, 6A Pulse
L2 NC 4.7uH, 3.6A Murata
C1, C2 VZ Series Electrolytic Capacitor 22ufd, 100V Panasonic
C3 VZ Series Qty 2 - Electrolytic Capacitor 22ufd, 100V Panasonic
C4, C5 Unknown 3.3nF, 1500V Unknown
C6 VZ Series Electrolytic Capacitor 22ufd, 100V Panasonic
DC Source
Test Card
UUT
V+
V- Vin- Vout-
Vin+
Resistive Load
inside a metal
container
Vout+
Black C1
L1
C2
L2
C3 C6
C4
C5
Resistive Load
Figure 7. Conducted Emissions Test Circuit
Graph 1. Conducted emissions performance with fi lter, Negative Line, CISPR 22, Class B,
full load, for UEI25-033-D48PM-C
dBµV
100
0
10
20
30
40
50
60
70
80
90
MHz
30.00.15 1.0 10.0
QP AV
Graph 3. Conducted emissions performance without fi lter, Negative Line, CISPR 22, Class
B, full load, for UEI25-050-D48NM-C
dBµV
100
0
10
20
30
40
50
60
70
80
90
MHz
30.00.15 1.0 10.0
QP Average
Graph 2. Conducted emissions performance with fi lter, Negative Line, CISPR 22, Class B,
full load, for UEI25-050-D48NM-C
dBµV
100
0
10
20
30
40
50
60
70
80
90
MHz
30.00.15 1.0 10.0
QP AV
Graph 4. Conducted emissions performance with fi lter, Negative Line, CISPR 22, Class B,
full load, for UEI25-120-D48P-C
dBµV
100
0
10
20
30
40
50
60
70
80
90
MHz
30.00.15 1.0 10.0
QP AV
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 23 of 24
www.murata-ps.com/support
Figure 8. Vertical Wind Tunnel
IR Video
Camera
IR Transparent
optical window Variable
speed fan
Heating
element
Ambient
temperature
sensor
Airflow
collimator
Precision
low-rate
anemometer
3” below UUT
Unit under
test (UUT)
Vertical Wind Tunnel
Murata Power Solutions employs a computer controlled
custom-designed closed loop vertical wind tunnel, infrared
video camera system, and test instrumentation for accurate
airfl ow and heat dissipation analysis of power products.
The system includes a precision low fl ow-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 host carrier board for realistic heat
absorption and spreading. Both longitudinal and transverse
airfl ow studies are possible by rotation of this carrier board
since there are often signifi cant differences in the heat
dissipation in the two airfl ow directions. The combination of
adjustable airfl ow, 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 by minimizing airfl ow turbulence. Such turbu-
lence infl uences 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.
UEI25 Series
Single Output Isolated 25-Watt DC/DC Converters
MDC_UEI25W.B10 Page 24 of 24
www.murata-ps.com/support
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. © 2018 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
129 Flanders Road, Westborough, MA 01581 U.S.A.
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.murata-ps.com/requirements/
Through-hole Soldering Guidelines
Murata Power Solutions recommends the TH soldering specifi cations below when install-
ing these converters. These specifi cations vary depending on the solder type. Exceeding
these specifi cations 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:
Maximum Preheat Temperature 115° C.
Maximum Pot Temperature 270° C.
Maximum Solder Dwell Time 7 seconds
For Sn/Pb based solders:
Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 6 seconds
SMT Refl ow Soldering Guidelines
The surface-mount refl ow solder profi le shown below is suitable for SAC305 type lead-
free solders. This graph should be used only as a guideline. Many other factors infl uence
the success of SMT refl ow soldering. Since your production environment may differ,
please thoroughly review these guidelines with your process engineers.
Mouser Electronics
Authorized Distributor
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D48N-C UEI25-033-D48NM-C UEI25-033-D48PM-C UEI25-050-D48NM-C UEI25-050-D48PM-C UEI25-120-D48NM-
C UEI25-120-D48PM-C