NMK Series

3kVDC Isolated 2W Single & Dual Output DC/DC Converters

KDC_NMK.E03 Page 4 of 6

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APPLICATION NOTES (continued)

Ripple & Noise Characterisation Method

All measurement to be taken with the following components connected to the UUT as detailed below.

50 Ohm coax cable, solder connections one end, BNC plug at the other end.

C1

1μF X7R multilayer ceramic capacitor rated at minimum 3 x the output voltage of the UUT

C2

10μF tantalum capacitor rated at minimum 1.5 x the output voltage of the UUT with ESR of less than 100 milliohms at 100 kHz e.g. AVX TPS

C3

100nF multilayer ceramic capacitor, general purpose

R1

450 Ohm resistor, carbon film, ±1%

R2

50 Ohm BNC termination

T1

3T of the coax cable through a ferrite toroid eg Ferroxcube TN32/19/13-3E25

RLOAD

Resistive load at the UUT maximum rating. Connections via twisted wires.

Differential Mode Noise Test Schematic

OSCILLOSCOPE

Y INPUT

SUPPLY

C1 C2 C3

R1

T1

R2

Input

Output

DC/DC Converter

R LOAD

+

+

-

-

EFFICIENCY VS LOAD

NMK05XXSAC

NMK12XXSAC

0

10

20

30

40

50

60

70

80

90

0

10203040

5060708090

100

Load (%)

5V

9V

12V

15V

0

10

20

30

40

50

60

70

80

90

0

10203040

5060708090

100

Load (%)

5V

9V

12V

15V