Isolated Sub-Miniature 1W Single Output DC/DC Converters
SELECTION GUIDE
Input
Current at Rated Load
Isolation Capacitance
Output Current
Nominal Input
Voltage
Efficiency
Output
Voltage
MTTF
1
Order Code
FEATURES
RoHS Compliant
Sub-Miniature SIP & DIP Styles
3kVDC Isolation ‘Hi Pot Test’
UL60950 Recognised
Wide Temperature performance at full
1 Watt load, –40°C to 85°C
UL 94V-0 Package Material
Footprint at 0.69cm
2
Industry Standard Pinout
3.3V, 5V & 12V Input
3.3V, 5V, 9V, 12V and 15V Output
Internal SMD Construction
Fully Encapsulated with Toroidal
Magnetics
MTTF up to 2.4 Million hours
Custom Solutions Available
No Electrolytic or Tantalum Capacitors
NKE0303DC
NKE0305DC
NKE0309DC
NKE0303SC
NKE0305SC
NKE0309SC
NKE0503DC
NKE0505DC
NKE0505DEC
NKE0509DC
NKE0512DC
NKE0515DC
NKE0503SC
NKE0505SC
NKE0505SEC
NKE0509SC
NKE0512SC
NKE0515SC
NKE1205DC
NKE1209DC
NKE1212DC
NKE1215DC
NKE1205SC
NKE1209SC
NKE1212SC
NKE1215SC
V
3.3
3.3
3.3
3.3
3.3
3.3
5
5
5
5
5
5
5
5
5
5
5
5
12
12
12
12
12
12
12
12
V
3.3
5
9
3.3
5
9
3.3
5
5
9
12
15
3.3
5
5
9
12
15
5
9
12
15
5
9
12
15
mA
303
200
111
303
200
111
303
200
200
111
83
66
303
200
200
111
83
66
200
111
83
66
200
111
83
66
mA
400
400
403
400
400
403
270
289
250
266
260
256
270
289
250
266
260
256
117
107
105
103
117
107
105
103
%
Min.
68
72
71
68
72
71
70
66
73
72
73
74
70
66
73
72
73
74
68
72
73
76
68
72
73
76
Typ.
72
75
74
72
75
74
74
69
77
75
78
78
74
69
77
75
78
78
72
78
79
81
72
78
79
81
pF
30
35
30
30
35
30
40
28
34
29
30
32
40
28
34
29
30
32
35
50
57
60
35
50
57
60
PRODUCT OVERVIEW
The NKE sub-miniature series of DC/DC Converters
is particularly suited to isolating and/or converting
DC power rails. A smaller package size, improved
efficiency, lower output ripple and 3kVDC isolation
capability through state of the art packaging and
improved technology. The galvanic isolation allows
the device to be configured to provide an isolated
negative rail in systems where only positive rails
exist. The wide temperature range guarantees
startup from –40°C and full 1 watt output at 85°C.
MIL.
Tel.
kHrs
4337 46,969
4105 46,783
1904 28,918
4337 46,969
4105 46,783
1904 28,918
3710 36,234
4277 34,897
2686 35,919
3729 76,553
2910 73,523
2211 71,725
3710 36,234
4277 34,897
2686 35,919
3729 76,553
2910 73,523
2211 71,725
3981 58,202
3482 57,895
1982 77,806
2122 56,404
3981 58,202
3482 57,895
1982 77,806
2122 56,404
NKE0505SEC/NKE0505DEC offers higher efficiency than NKE0505SC/NKE0505DC but over a narrower operating temperature range.
See temperature characteristics graph.
INPUT CHARACTERISTICS
Parameter
Voltage range
Reflected ripple current
Conditions
Continuous operation, 3.3V input types
Continuous operation, 5V input types
Continuous operation, 12V input types
3.3V input types
Min.
2.97
4.5
10.8
Typ.
3.3
5.0
12.0
40
Max.
3.63
5.5
13.2
60
mA p-p
ABSOLUTE MAXIMUM RATINGS
Lead temperature 1.5mm from case for 10 seconds
Input voltage V
IN
, NKE03 types
Input voltage V
IN
, NKE05 types
Input voltage V
IN
, NKE12 types
260°C
5.5V
7V
15V
1. Calculated using MIL-HDBK-217 FN2 and Telcordia SR-332 calculation model with nominal input voltage at full load.
All specifications typical at T
A
=25°C, nominal input voltage and rated output current unless otherwise specified.
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KDC_NKE.K08
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Package
Style
DIP
SIP
DIP
SIP
DIP
SIP
Units
V
NKE Series
Isolated Sub-Miniature 1W Single Output DC/DC Converters
OUTPUT CHARACTERISTICS
Parameter
Rated Power
Voltage Set Point Accuracy
Line regulation
Conditions
T
A
=-40°C to 120°C, see derating graphs
See tolerance envelope
High V
IN
to low V
IN
10% load to rated load, 3.3V output types & 0309
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, 3.3V output types & 0305, 0505SEC, 0505DEC
BW=DC to 20MHz, other 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.
1.0
Units
W
%/%
Load Regulation
1
Ripple and Noise
1.0
10
12
7.5
6.5
6.0
40
77
43
35
32
1.2
15
15
10
9.5
8.5
80
100
90
65
55
%
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
All output types
Min.
Typ.
115
Max.
Units
kHz
TEMPERATURE CHARACTERISTICS
Parameter
Specification
Storage
Case temperature rise above
ambient
Cooling
Conditions
All output types
0505D/S, 1205D/S
All other output types
Free air convection
Min.
-40
-50
Typ.
Max.
85
130
41
32
Units
°C
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 NKE series of dc/dc converters are all 100% production tested at their stated isolation voltage. This is 3000V DC for 1 second.
A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?”
The NKE series has been recognized by Underwriters Laboratory for functional insulation. 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 sys-
tem. 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. While manufactured parts can 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.
SAFETY APPROVAL
The NKE series has been recognised by Underwriters Laboratory (UL) to UL 60950 for functional insulation in a maximum ambient temperature of 85ºC and/or case temperature
limit of 130ºC. Case temperature measured on the face opposite the pins. File number E151252 applies.
1. 12V input types have typically 3% less load regulation.
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NKE Series
Isolated Sub-Miniature 1W Single Output DC/DC Converters
TEMPERATURE DERATING GRAPHS
NKE 0303DC/SC, 0305DC/
SC, 0309DC/SC, 0503DC/SC,
0505DEC/SEC types only.
1.5
All other types.
85°C
1.5
Output Power (W)
Output Power (W)
1.0
0.5
0
-40
1.0
0.5
0
-40
85°C
Safe Operating Area
UL recognition to a
maximum ambient
temperature of 85ºC and/
or case temperature limit of
130ºC.
Safe Operating Area
120°C
100
50
0
Ambient Temperature (°C)
150
100
50
0
Ambient Temperature (°C)
150
TOLERANCE ENVELOPES
3.3V output types.
+9%
V
NOM
+1%
-7%
All other types.
+10%
+5%
V
NOM
Typical
L
Typical
L
oad Lin
e
+1%
-7%
-15%
oad Line
+2.5%
-2.5%
-7.5%
Output Voltage
Output Voltage
10
75
50
25
Output Load Current (%)
100
10
75
50
25
Output Load Current (%)
100
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.
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NKE Series
Isolated Sub-Miniature 1W Single Output DC/DC Converters
APPLICATION NOTES
Minimum load
The minimum load to meet datasheet specification is 10% of the full rated load across the specified input voltage range. Lower than 10% minimum loading will result in
an increase in output voltage, which may rise to typically double the specified output voltage if the output load falls to less than 5%.
Capacitive loading and start up
Typical start up times for this series, with a typical input voltage rise time of 2.2μs and output capacitance of 10μF, are shown in the table below. The product
series will start into a capacitance of 47μF with an increased start time, however, the maximum recommended output capacitance is 10μF.
Typical Start-Up Wave Form
Start-up time
μs
544
1306
5250
496
1075
894
3140
Start-up time
μs
5040
9940
1671
2835
5295
8475
NKE0303SC
NKE0305SC
NKE0309SC
NKE0503SC
NKE0505SC
NKE0505SEC
NKE0509SC
NKE0512SC
NKE0515SC
NKE1205SC
NKE1209SC
NKE1212SC
NKE1215SC
Ripple & Noise Characterisation Method
Ripple and noise measurements are performed with the following test configuration.
1μF X7R multilayer ceramic capacitor, voltage rating to be a minimum of 3 times the output voltage of the DC/DC converter
10μF tantalum capacitor, voltage rating to be a minimum of 1.5 times the output voltage of the DC/DC converter with an ESR of less
C2
than 100mΩ at 100 kHz
C3
100nF multilayer ceramic capacitor, general purpose
R1
450Ω resistor, carbon film, ±1% tolerance
R2
50Ω BNC termination
T1
3T of the coax cable through a ferrite toroid
RLOAD
Resistive load to the maximum power rating of the DC/DC converter. Connections should be made via twisted wires
Measured values are multiplied by 10 to obtain the specified values.
C1
Differential Mode Noise Test Schematic
DC/DC Converter
OSCILLOSCOPE
C1 C2 C3
+
SUPPLY
Input
R1
T1
R2
Y INPUT
+
Output
-
-
R LOAD
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NKE Series
Isolated Sub-Miniature 1W Single Output DC/DC Converters
APPLICATION NOTES (continued)
Output Ripple Reduction
By using the values of inductance and capacitance stated, the output ripple at the rated load is lowered to 5mV p-p max.
Component selection
Capacitor: It is required that the ESR (Equivalent Series Resistance) should be as low as possible, ceramic types are recommended.
The voltage rating should be at least twice (except for 15V output), the rated output voltage of the DC/DC converter.
Inductor: The rated current of the inductor should not be less than that of the output of the DC/DC converter. At the rated current, the DC resistance of the inductor
should be such that the voltage drop across the inductor is <2% of the rated voltage of the DC/DC converter. The SRF (Self Resonant Frequency) should be
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