KDC_NDTD_E03 Page 3 of 7

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NDTD Series

Isolated 3W Wide Input Dual Output DC/DC Converters

TERMINOLOGY

LINE REGULATION

The percentage change in output voltage between low intput voltage and high intput voltage, measured with fixed output load i.e. a 5V part with an output voltage of 5.05V @ high

input voltage and 5.03V @ low input voltage would have a line regulation of 0.4%.

APPLICATION NOTES

Recommended Input & Output Capacitors

Although these converters will work without external capacitors, they are necessary in order to guarantee the full parametric performance over the full line and load range. All

parts have been tested and characterized using the following values and test circuit.

Input Voltage

Output Voltage

5V, 12V

100μF, 25V (0.25Ω at 100kHz)

3.3V, 5V

100μF, 25V (0.25Ω at 100kHz)

24V, 48V

10μF, 100V (1.5Ω at 100kHz)

12V, 15V

47μF, 25V (0.4Ω at 100kHz)

Test circuit

Reflected Ripple Current Measurement

Cross Regulation

Load regulation is at its best when the positive and negative loads are balanced. When the loads are asymmetric, the negative output is not as tightly regulated as the positive out-

put. To meet ripple specification a total minimum load of 25% full load is required, however, the NDTD can be used with much lighter loading at the expense of increased ripple. A

small load is required on the negative output of 150mW to ensure the maximum negative output voltage is not exceeded.

Line regulation =

x100%

NDTD

12μH

Current

Probe

Load

Load

OV

NDTD

OV