NDX Series

Isolated 7.5W Wide Input Single & Dual Output DC/DC Converters

KDC_NDXC.G01 Page 5 of 6

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OSCILLOSCOPE

Y INPUT

SUPPLY

C1 C2 C3

R1

T1

R2

Input

Output

DC/DC Converter

R LOAD

+

+

-

-

CHARACTERISATION TEST METHODS

Ripple & Noise Characterisation Method

Ripple and noise measurements are performed with the following test configuration with the inclusion of recommended input and output capacitors.

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

Input Reflected Ripple Current Test Method

Input reflected ripple current measurements are performed with the following test configuration with the inclusion of recommended input and output capacitors.

C1

220uF with ESR of <0.1Ω at 100kHz, rated at supply voltage

L1

12uH rated at 150% minimum of the DC current taken by the converter.

C2

The recommended input capacitor for the DC/DC converter.

L

Load

DC/DC

Converter

+ Input

- Input

C1

C2

Supply +v

Supply

-v

Current Probe