NKE Series

Isolated Sub-Miniature 1W Single Output DC/DC Converters

KDC_NKE.K03 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 multilayer 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 100mΩ at 100 kHz

C3

100nF multilayer ceramic capacitor, general purpose

R1

450Ω resistor, carbon film, ±1% tolerance

R2

50Ω 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

μs

μs

NKE0303SC

544

NKE0512SC

5040

NKE0305SC

1306

NKE0515SC

9940

NKE0309SC

5250

NKE1205SC

1671

NKE0503SC

496

NKE1209SC

2835

NKE0505SC

1075

NKE1212SC

5295

NKE0505SEC

894

NKE1215SC

8475

NKE0509SC

3140