ISOLATION CHARACTERISTICS
Parameter
Conditions
Isolation test voltage
Flash tested for 1 minute
Resistance
Viso= 1000VDC
GENERAL CHARACTERISTICS
Parameter
Conditions
Switching frequency
5V input types
12V input types
TEMPERATURE CHARACTERISTICS
Parameter
Conditions
Specification
All output types
Storage
5V output types
Case temperature above ambient
All other output types
Cooling
Free air convection
TEMPERATURE DERATING GRAPH
1.5
1.0
85°C
0.5 Safe Operating Area
0
-40 0 50 100 150
Ambient Temperature (°C)
NTV Series
3kVDC Isolated 1W Dual Output SM DC/DC Converters
Min.
Typ.
Max.
Units
3000
VDC
10
GΩ
Min.
Typ.
Max.
Units
115
kHz
120
Min.
Typ.
Max.
Units
-40
85
-55
125
°C
33
25
TOLERANCE ENVELOPE
+10%
+5%
V
NOM
Typical Load Line
+2.5%
-2.5%
-7.5%
10 25
50
75 100
Output Load Current (%)
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 NTV series of DC/DC converters are all 100% production tested at their stated isolation voltage. This is 3kVDC for 1 minute.
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 NTV 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 NTV 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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