KDC_NDTD_E03 Page 2 of 7

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NDTD Series

Isolated 3W Wide Input Dual Output DC/DC Converters

OUTPUT CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Voltage set point accuracy

With external input/output capacitors

3.3V & 5V outputs

±2

±5

%

12V & 15V outputs

±1

±3

Line regulation

Low line to high line with external input/output capacitors

0.15

0.5

%

Load regulation

25% load to 100% load with external input/output

capacitors with balanced load

3.3V & 5V outputs

0.5

1.0

%

12V & 15V outputs

0.2

0.5

%

Ripple

BW = 20Hz to 300kHz with external input/output capacitors

15

40

mV rms

Ripple & noise

BW = DC to 20MHz with external input/output capacitors

90

150

mV p-p

Cross regulation

% voltage change on negative output when

positive load varies from 12% to 50% of 3W rating,

with negative load fixed at 50%

NDTD05XXC, NDTD1203C,

NDTD1205C, NDTD2403C,

NDTD2405C, NDTD4803C,

NDTD4805C

5.0

%

NDTD1212C, NDTD1215C,

NDTD2412C, NDTD2415C,

NDTD4812C, NDTD4815C

2.1

3.0

Short circuit protection

Continuous

GENERAL CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Switching frequency

100% to 25% load, VIN min to max

60

620

kHz

TEMPERATURE CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Operation

-40

85

ºC

Storage

-50

130

Case temperature rise above

ambient in still air

NDTD0503

54

NDTD1203C, NDTD2403C, NDTD4803C

40

NDTD0505C, NDTD0512C, NDTD1205C, NDTD2405C, NDTD4805C

35

NDTD0515C, NDTD1212C, NDTD1215C, NDTD2412C, NDTD4812C, NDTD2415C,

NDTD4815C

28

ISOLATION CHARACTERISTICS

Parameter

Conditions

Min.

Typ.

Max.

Units

Isolation voltage

Flash tested for 1 second

1000

VDC

Resistance

Viso=1KVDC

1

GΩ

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 NDTD 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 NDTD 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 NDTD series has an EI ferrite core, 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.