Isolated 250mW Single Output DC/DC Converters
All output types
Free air convection
Min. Typ. Max. Units
TEMPERATURE DERATING GRAPH
50 100 150
Ambient Temperature (°C)
Typical Load Line
10 25 50 75 100
Output Load Current (%)
The voltage tolerance envelope shows typical load regulation characteristics for this product series. The toler-
ance envelope is the maximum output voltage variation due to changes in output loading.
‘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 LME 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 LME 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 LME 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.
RoHS COMPLIANT INFORMATION
This series is compatible with RoHS soldering systems with a peak wave solder temperature of
300°C for 10 seconds. The pin termination ﬁnish on the SIP package type is Tin Plate, Hot Dipped
over Matte Tin with 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
The minimum load to meet datasheet speciﬁcation is 10% of the full rated load across the speciﬁed input voltage range. Lower than 10% minimum loading will result in an
increase in output voltage, which may rise to typically double the speciﬁed output voltage if the output load falls to less than 5%.
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