NKE Series
Isolated Sub-Miniature 1W Single Output DC/DC Converters
KDC_NKE.K07 Page 4 of 7
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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.
Ripple & Noise Characterisation Method
Ripple and noise measurements are performed with the following test configuration.
C1 1µF X7R m ultilayer ceramic capacitor, voltage rating to be a minimum of 3 times the output voltage of the DC/DC converter
C2
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
than 100m at 100 kHz
C3 100nF multilayer ceramic capacitor, general purpose
R1 450 resistor, carbon film, ±1% tolerance
R2 50 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.
Differential Mode Noise Test Schematic
OSCILLOSCOPE
Y INPUT
SUPPLY
C1 C2 C3 R1 T1
R2
Input Output
DC/DC Converter
R LOAD
+
+
-
-
Typical Start-Up Wave Form
Start-up time Start-up time
µs
µs
NKE0303SC 544 NKE0512SC 5040
NKE0305SC 1306 NKE0515SC 9940
NKE0309SC 5250 NKE1205SC 1671
NKE0503SC 496 NKE1209SC 2835
NKE0505SC 1075 NKE1212SC 5295
NKE0505SEC 894 NKE1215SC 8475
NKE0509SC 3140
