NKA Series
Isolated Sub-Miniature 1W Dual Output DC/DC Converters
KDC_NKA.J02 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
ms ms
NKA0303SC 1.35 NKA0509SC 8.01
NKA0305SC 3.35 NKA0512SC 14.63
NKA0309SC 9.30 NKA0515SC 28.38
NKA0312SC 22.13 NKA1205SC 2.11
NKA0315SC 25.04 NKA1209SC 7.62
NKA0503SC 0.80 NKA1212SC 9.08
NKA0505SC 2.32 NKA1215SC 14.39
NKA0505SEC 2.03
