NXJ1 Series
Isolated 1W Single Output SM DC/DC Converters
KDC_NXJ1.C02 Page 7 of 10
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APPLICATION NOTES
Short Circuit Performance
Advisory Notes Minimum Load
The NXJ1 series is not hermetically sealed, customers should ensure that parts
are fully dried before input power application.
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 & Start Up
Typical start up times for this series, with a typical input voltage rise time of 2.2s with resistive only load, and with added output capacitance of
47F, are shown in the table below.
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 >20MHz.
DC
DC
L
C
Load
Power
Source
Inductor Capacitor
L, µH SMD Through Hole C, µF
NXJ1S0303MC 4.7 82472C 11R472C 22
NXJ1S0305MC 10 82103C 11R103C 10
NXJ1S0505MC 10 82103C 11R103C 2.2
NXJ1S1205MC 10 82103C 11R103C 4.7
NXJ1S1212MC 22 82223C 11R223C 4.7
NXJ1S1215MC 22 82223C 11R223C 4.7
Resistive Load
Resistive Load and
47µF
Part Number Start-up time (µS)
NXJ1S0303MC 40 190
NXJ1S0305MC 95 1700
NXJ1S0505MC 50 1100
NXJ1S1205MC 35 600
NXJ1S1212MC 80 2650
NXJ1S1215MC 100 4000
Typical Start-Up Wave Form
NXJ1 short circuit protection is not continuous and varies with output voltage and temperature as shown in the following graph:
0.1
1
10
100
1000
25 35 45 55 65 75
Time (s)
Ta (°C)
NXJ1S0303MC
NXJ1S0305MC
NXJ1S0505MC
NXJ1S1205MC
NXJ1S1212MC
NXJ1S1215MC
