MEJ1 Series
5.2kVDC Isolated 1W DC/DC Converters
KDC_MEJ1_D03 Page 4 of 9
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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
Start-up time Start-up time
s s
MEJ1S0303SC 900 MEJ1D0503SC 700
MEJ1S0305SC 2000 MEJ1D0505SC 1600
MEJ1S0503SC 500 MEJ1D0509SC 3700
MEJ1S0505SC 2000 MEJ1D0512SC 4200
MEJ1S0509SC 3200 MEJ1D0515SC 7000
MEJ1S0512SC 7500 MEJ1D1203SC 600
MEJ1S0515SC 10500 MEJ1D1205SC 1200
MEJ1S1203SC 600 MEJ1D1209SC 3600
MEJ1S1205SC 1200 MEJ1D1212SC 3900
MEJ1S1209SC 2900 MEJ1D1215SC 6000
MEJ1S1212SC 2900 MEJ1D1505SC 1200
MEJ1S1215SC 3900 MEJ1D1509SC 3200
MEJ1S1505SC 1100 MEJ1D1512SC 3300
MEJ1S1509SC 2400 MEJ1D1515SC 4800
MEJ1S1512SC 2700 MEJ1D2405SC 1100
MEJ1S1515SC 3800 MEJ1D2409SC 2000
MEJ1S2405SC 1700 MEJ1D2412SC 3300
MEJ1S2409SC 2300 MEJ1D2415SC 6400
MEJ1S2412SC 2200
MEJ1S2415SC 3600
Typical Start-Up Wave Form
OSCILLOSCOPE
Y INPUT
SUPPLY
C1 C2 C3 R1 T1
R2
Input Output
DC/DC Converter
R LOAD
+
+
-
-
