NML Series

Isolated 2W Single Output DC/DC Converters

KDC_NML.E02 Page 2 of 5

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GENERAL CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Switching frequency

5V input types

90

kHz

12V input types

90

TEMPERATURE CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Specification

All output types

-40

85

°C

Storage

-50

130

Case Temperature above ambient

5V output types

45

All other output types

36

Cooling

Free air convection

TEMPERATURE DERATING GRAPH

TOLERANCE ENVELOPE

+10%

Output Load Current (%)

+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 NML 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 NML 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 NML 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.

150

100

50

0

-40

0

1

2

3

Safe Operating Area

85°C

Ambient Temperature (°C)

The voltage tolerance envelope shows typical load regulation characteristics for this

product series. The tolerance envelope is the maximum output voltage variation due to

changes in output loading.