MTU1 Series
Isolated 1W Single & Dual Output SM DC/DC Converters
KDC_MTU.C02 Page 4 of 8
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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
MTU1S0305MC 1.7 MTU1D0305MC 3.1
MTU1S0505MC 0.9 MTU1D0505MC 1.8
MTU1S0509MC 2.7 MTU1D0509MC 5.7
MTU1S0512MC 4.3 MTU1D0512MC 10.1
MTU1S0515MC 7.5 MTU1D0515MC 19.1
MTU1S1205MC 0.9 MTU1D1205MC 1.5
MTU1S1209MC 1.9 MTU1D1209MC 4
MTU1S1212MC 3.3 MTU1D1212MC 7.5
MTU1S1215MC 4.7 MTU1D1215MC 12.5
