Isolated 1W Regulated Single Output DC/DC Converters
SELECTION GUIDE
Input Current
(Typ.)
Ripple &
Noise (Max.)
Isolation
Capacitance
pF
40
30
40
50
40
60
35
45
40
30
40
50
40
60
35
45
Ripple &
Noise (Typ.)
Efficiency
(Min.)
Efficiency
(Typ.)
Nominal
Input
Voltage
Output
Voltage
Output
Current
Order Code
V
MEF1S0303SPC
MEF1S0305SPC
MEF1S0503SPC
MEF1S0505SPC
MEF1S1203SPC
MEF1S1205SPC
MEF1S2403SPC
MEF1S2405SPC
MEF1S0303SP3C
MEF1S0305SP3C
MEF1S0503SP3C
MEF1S0505SP3C
MEF1S1203SP3C
MEF1S1205SP3C
MEF1S2403SP3C
MEF1S2405SP3C
3.3
3.3
5
5
12
12
24
24
3.3
3.3
5
5
12
12
24
24
V
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
3.3
5
mA
mVp-p
mA
%
63
68
65
69
65
69
64
68
63
68
65
69
65
69
64
68
%
66
71
68.5
73
69
73.5
69
73
66
71
68.5
73
69
73.5
69
73
kHrs
495
867
665
1051
511
1044
580
834
495
867
665
1051
511
1044
580
834
FEATURES
UL60950 recognised
Short circuit protection
Operation to zero load
Output regulation <1%
Single isolated output
1kVDC or 3.5kVDC isolation options ‘Hi Pot
Test’
3.3V, 5V, 12V & 24V input
3.3V & 5V output
SMD construction
Fully encapsulated with toroidal magnetics
303
11
35
460
200
9
35
430
303
8
30
290
200
10
40
275
303
11
35
120
200
10
35
115
303
13
40
60
200
13
40
55
3.5kVDC Isolation Part Numbers
303
11
35
460
200
9
35
430
303
8
30
290
200
10
40
275
303
11
35
120
200
10
35
115
303
13
40
60
200
13
40
55
INPUT CHARACTERISTICS
Parameter
Voltage range
Conditions
Continuous operation, 3.3V input types
Continuous operation, 5V input types
Continuous operation, 12V input types
Continuous operation, 24V input types
Min.
3.135
4.75
11.4
22.8
Typ.
3.3
5
12
24
5
Max.
3.465
5.25
12.6
25.2
20
Units
V
DESCRIPTION
The MEF1 series of DC/DC converters is used
where a tightly regulated supply is required. They
are ideal for situations where the input voltage
is not tightly controlled. The single rail regulated
output makes the ideal choice to power sensors,
such as pressure transducers, hall effect sensors
and mass airflow sensors.
Reflected ripple current
mA p-p
OUTPUT CHARACTERISTICS
Parameter
Voltage set point accuracy
Rated power
Line regulation
Load regulation
Conditions
3.3V Output
5V Output
T
A
= -40
°C
to 85
°C
High V
IN
to low V
IN
10% load to rated load
Min.
Typ.
Max.
± 2.5
±2
1
0.25
1
Units
%
W
%/%
%
0.3
ABSOLUTE MAXIMUM RATINGS
Short-circuit protection
Lead temperature 1.5mm from case for 10 seconds
Input voltage V
IN,
MEF1S03 types
Input voltage V
IN
, MEF1S05 types
Input voltage V
IN
, MEF1S12 types
Input voltage V
IN
, MEF1S24 types
Continuous
260°C
4V
7V
18V
28V
1. Calculated using MIL-HDBK-217F with nominal input voltage at full load.
For full details go to
www.murata-ps.com/rohs
All specifications typical at T
A
=25°C, nominal input voltage and rated output current unless otherwise specified.
www.murata-ps.com/support
KDC_MEF1.C03
Page 1 of 7
MTTF
1
MEF1 Series
Isolated 1W Regulated Single Output DC/DC Converters
ISOLATION CHARACTERISTICS
Parameter
Isolation test voltage
Resistance
Conditions
SPC Versions Flash tested for 1 second
SP3C Versions Flash tested for 1 minute
Viso= 1kVDC
Min.
1000
3500
10
Typ.
Max.
Units
VDC
GΩ
GENERAL CHARACTERISTICS
Parameter
Switching frequency
Conditions
0303
5V input types
12V input types & 0305
24V input types
Min.
Typ.
45
50
60
75
Max.
Units
kHz
TEMPERATURE CHARACTERISTICS
Parameter
Specification
Case temperature above ambient
Storage
Cooling
Conditions
All output types
Min.
-40
-50
Typ.
Max.
85
40
125
Units
°C
Free air convection
TEMPERATURE DERATING GRAPH
1.5
1.0
0.5
0
-40
85°C
RoHS COMPLIANCE INFORMATION
Safe Operating Area
This series is compatible with RoHS soldering
systems with a peak wave solder temperature of
260ºC for 10 seconds. The pin termination finish
on the SIP package type is Tin Plate, Hot Dipped
over Matte Tin over Nickel Preplate. This series
is backward compatible with Sn/Pb soldering
systems.
Output Power (W)
100
50
0
Ambient Temperature (°C)
150
For further information, please visit www.murata-ps.com/rohs
www.murata-ps.com/support
KDC_MEF1.C03
Page 2 of 7
MEF1 Series
Isolated 1W Regulated Single Output DC/DC Converters
EFFICIENCY VS LOAD
3.3V Input
90
80
70
60
Efficiency (%)
50
40
30
20
10
0
0
10
20
30
40
50
Load (%)
60
70
80
90
100
MEF1S0303SPC
MEF1S0305SPC
20
10
0
0
10
20
30
40
50
Load (%)
60
70
80
90
100
90
80
70
60
50
40
30
MEF1S0503SPC
MEF1S0505SPC
5V Input
12V Input
90
80
70
60
Efficiency (%)
Efficiency (%)
50
40
30
20
10
0
0
10
20
30
40
50
Load (%)
60
70
80
90
100
90
80
70
60
50
40
30
Efficiency (%)
24V Input
MEF1S1205SPC
MEF1S1203SPC
MEF1S2405SPC
20
10
0
0
10
20
30
40
50
Load (%)
60
70
80
90
100
MEF1S2403SPC
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KDC_MEF1.C03
Page 3 of 7
MEF1 Series
Isolated 1W Regulated Single Output DC/DC Converters
APPLICATION NOTES
Capacitive loading and start up
Typical start up times for this series, with a typical input voltage rise time of 2.2μs and output capacitance of 10μF, are shown in the table below. The product
series will start into a capacitance of 47μF with an increased start time, however, the maximum recommended output capacitance is 10μF.
Start-up time
MEF1S0303SPC
MEF1S0305SPC
MEF1S0503SPC
MEF1S0505SPC
MEF1S1203SPC
MEF1S1205SPC
MEF1S2403SPC
MEF1S2405SPC
MEF1S0303SP3C
MEF1S0305SP3C
MEF1S0503SP3C
MEF1S0505SP3C
MEF1S1203SP3C
MEF1S1205SP3C
MEF1S2403SP3C
MEF1S2405SP3C
μs
310
550
225
460
185
390
160
430
310
550
225
460
185
390
160
430
MEF1S0305SP3C
Ripple & Noise Characterisation Method
Ripple and noise measurements are performed with the following test configuration.
C1
1μF X7R multilayer ceramic capacitor, voltage rating to be a minimum of 3 times the output voltage of the DC/DC converter
10μF tantalum capacitor, voltage rating to be a minimum of 1.5 times the output voltage of the DC/DC converter with an ESR of less
C2
than 100mΩ at 100 kHz
C3
100nF multilayer ceramic capacitor, general purpose
R1
450Ω resistor, carbon film, ±1% tolerance
R2
50Ω BNC termination
T1
3T of the coax cable through a ferrite toroid
RLOAD
Resistive load to the maximum power rating of the DC/DC converter. Connections should be made via twisted wires
Measured values are multiplied by 10 to obtain the specified values.
Differential Mode Noise Test Schematic
DC/DC Converter
OSCILLOSCOPE
C1 C2 C3
+
SUPPLY
Input
R1
T1
R2
Y INPUT
+
Output
-
-
R LOAD
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KDC_MEF1.C03
Page 4 of 7
MEF1 Series
Isolated 1W Regulated Single Output DC/DC Converters
TECHNICAL NOTES
ISOLATION VOLTAGE
‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Voltage’, ‘Proof Voltage’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’ are all terms that relate to the same thing, a test voltage,
applied for a specified time, across a component designed to provide electrical isolation, to verify the integrity of that isolation.
Murata Power Solutions MEF1 series of DC/DC converters are all 100% production tested at their stated isolation voltage. This is 1kVDC for 1 second for SPC versions and 3.5kVDC
for 1 minute for SP3C versions.
A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?”
The MEF1 has been recognised by Underwriters Laboratory for functional insulation, both input and output should normally be maintained within SELV limits i.e. less than 42.4V
peak, or 60VDC. The isolation test voltage represents a measure of immunity to transient voltages and the part should never be used as an element of a safety isolation system.
The part could be expected to function correctly with several hundred volts offset applied continuously across the isolation barrier; but then the circuitry on both sides of the barrier
must be regarded as operating at an unsafe voltage and further isolation/insulation systems must form a barrier between these circuits and any user-accessible circuitry according
to safety standard requirements.
REPEATED HIGH-VOLTAGE ISOLATION TESTING
It is well known that repeated high-voltage isolation testing of a barrier component can actually degrade isolation capability, to a lesser or greater degree depending on materials,
construction and environment. The MEF1 series has toroidal isolation transformers, with no additional insulation between primary and secondary windings of enameled wire. While
parts can be expected to withstand several times the stated test voltage, the isolation capability does depend on the wire insulation. Any material, including this enamel (typically
polyurethane) is susceptible to eventual chemical degradation when subject to very high applied voltages thus implying that the number of tests should be strictly limited. We
therefore strongly advise against repeated high voltage isolation testing, but if it is absolutely required, that the voltage be reduced by 20% from specified test voltage.
This consideration equally applies to agency recognised parts rated for better than functional isolation where the wire enamel insulation is always supplemented by a further
insulation system of physical spacing or barriers.
SAFETY APPROVAL
The MEF1 series has been recognised by Underwriters Laboratory (UL) to UL 60950 for functional insulation, file number E151252 applies. The MEF1 Series of converters are not
internally fused so to meet the requirements of UL 60950 an anti-surge input line fuse should always be used with ratings as defined below.
MEF1S03xxxC: 600mA
MEF1S05xxxC: 400mA
MEF1S12xxxC: 160mA
MEF1S24xxxC: 100mA
All fuses should be UL approved and rated to at least the maximum allowable DC input voltage.
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