NMXU Series
Isolated 5W Single & Dual Output DC/DC Converters
KDC_NMXU.D01 Page 2 of 3
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ISOLATION CHARACTERISTICS
Parameter Conditions Min. Typ. Max. Units
Isolation test voltage Flash tested for 1 second 1000 VDC
Resistance Viso= 1000VDC 1 GΩ
GENERAL CHARACTERISTICS
Parameter Conditions Min. Typ. Max. Units
Switching frequency All input types 70 kHz
TEMPERATURE CHARACTERISTICS
Parameter Conditions Min. Typ. Max. Units
Specification All output types 0 70
°C
Storage -55 100
Case temperature rise above
ambient
5V output types 30
All other output types
20
Cooling Free air convection
TOLERANCE ENVELOPE
+10%
Output Load Current (%)
Output Voltage
+5%
-7.5%
-2.5%
+2.5%
Typical Load Line
V
NOM
100
75
50
25
10
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 NMXU 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 NMXU 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 materi-
als, construction and environment. The NMXU 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 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 this product series is Matte Tin over Nickel
Preplate. The series is backward compatible with
Sn/Pb soldering systems.
For further information, please visit www.murata-ps.com/rohs
