Isolated 1W Regulated Single Output DC/DC Converters
INPUT CHARACTERISTICS
Parameter
Voltage range
Conditions
Continuous operation, 5V input types
Continuous operation, 12V input types
Continuous operation, 24V input types
Continuous operation, 48V input types
Min.
4.75
11.4
22.8
45.6
Typ.
5
12
24
48
Max.
5.25
12.6
25.2
50.4
Units
V
OUTPUT CHARACTERISTICS
Parameter
Voltage set point accuracy
Rated power
1
Line regulation
Load regulation
Ripple & noise
Conditions
100% load
T
A
= 0
°C
to 70
°C
High V
IN
to low V
IN
10% load to rated load
BW=DC to 20MHz, all output types
Min.
Typ.
Max.
5
1
0.25
1.5
60
Units
%
W
%/%
%
mV p-p
0.9
ISOLATION CHARACTERISTICS
Parameter
Isolation test voltage
Resistance
Conditions
Flash tested for 1 second
Viso= 500VDC
Min.
1000
0.1
Typ.
Max.
Units
VDC
GΩ
GENERAL CHARACTERISTICS
Parameter
Switching frequency
Conditions
All input types
Min.
Typ.
90
Max.
Units
kHz
TEMPERATURE CHARACTERISTICS
Parameter
Specification
Case temperature above ambient
Storage
Cooling
Conditions
All output types
Min.
0
Typ.
38
Max.
70
Units
°C
-55
Free air convection
150
TEMPERATURE DERATING GRAPH
RoHS COMPLIANCE INFORMATION
This series is compatible with RoHS soldering
systems with a peak wave solder temperature of
300ºC for 10 seconds. The pin termination finish
on the SIP package type is Tin Plate, Hot Dipped
over Matte Tin over Nickel Preplate. The DIP
types are Matte Tin over Nickel Preplate. Both
types in this series are backward compatible
with Sn/Pb soldering systems.
For further information, please visit www.murata-ps.com/rohs
Output Power (W)
100%
70°C
50% Safe Operating Area
125ºC
0
0
50
100
Ambient Temperature (ºC)
150
OUTPUT VOLTAGE ADJUSTMENT (for 5V output variants)
The trimming (adjust) input on the device allows output voltage adjustment from 1.2V to 3.3VDC by using a resistor as shown here. The table below provides R
TRIM
values for the
most commonly required output voltages. For applications not requiring the TRIM function, this pin must be left unconnected for normal regulated output.
Isolated 1W Regulated Single Output DC/DC Converters
TYPICAL APPLICATIONS
Pressure sensor, or strain gauge equivalent circuit
Scmitt Trigger
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 NMF series of DC/DC converters are all 100% production tested at their stated isolation voltage. This is 1kVDC for 1 second.
A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?”
For a part holding no specific agency approvals, such as the NMF series, 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 NMF 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 recognized 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.
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