NKA Series
Isolated Sub-Miniature 1W Dual Output DC/DC Converters
OUTPUT CHARACTERISTICS
Parameter
Rated Power
Voltage Set Point Accuracy
Line regulation
1
Conditions
T
A
=-40
°C
to 120
°C
See tolerance envelope
High V
IN
to low V
IN
10% load to rated load, 0312 & 0315
10% load to rated load, 3.3V output types
10% load to rated load, 5V output types
10% load to rated load, 9V output types
10% load to rated load, 12V output types
10% load to rated load, 15V output types
BW=DC to 20MHz, 0312 & 0315
BW=DC to 20MHz, 3.3V output types
BW=DC to 20MHz, 5V output types
BW=DC to 20MHz, 9V output types
BW=DC to 20MHz, 12V output types
BW=DC to 20MHz, 15V output types
Min.
Typ.
Max.
1
Units
W
%/%
Load Regulation
2
Ripple and Noise
1.0
8
10
10
6.5
6
6
25
40
50
40
40
40
1.2
14
15
12
8
8.5
7
60
80
75
65
60
60
%
mV p-p
ISOLATION CHARACTERISTICS
Parameter
Isolation test voltage
Resistance
Conditions
Flash tested for 1 second
Viso= 1000VDC
Min.
3000
Typ.
10
Max.
Units
VDC
GΩ
GENERAL CHARACTERISTICS
Parameter
Switching frequency
Conditions
0303, 0305, 0312, 0315, 0503 and 0505XE
All other types
Min.
Typ.
95
120
Max.
Units
kHz
TEMPERATURE CHARACTERISTICS
Parameter
Specification
Storage
Case temperature rise above
ambient
Cooling
Conditions
All output types
5V output types
All other output types
Free air convection
Min.
-40
-50
Typ.
Max.
85
130
Units
°C
30
21
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 NKA 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 NKA 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 NKA 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.
1. See Derating Graphs.
2. 12V input types have typically 3% less load regulation.
www.murata-ps.com
Technical enquiries
-
email:
mk@murata-ps.com,
tel:
+44 (0)1908 615232
KDC_NKAC.I02
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