Datasheet

NDTD Series
Isolated 3W Wide Input Dual Output DC/DC Converters
KDC_NDTD.E05 Page 3 of 7
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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%.
Where V
OUT (Nominal Input V) is 5V.
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 C
IN Output Voltage COUT
5V, 12V 100µF, 25V (0.25 at 100kHz) 3.3V, 5V 100µF, 25V (0.25 at 100kHz)
24V, 48V 10µF, 100V (1.5 at 100kHz) 12V, 15V 47µF, 25V (0.4 at 100kHz)
Test circuit
Reflected Ripple Current Measurement
C1 = 220µF, ESR < 0.1Ω at 100kHz
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%
V
OUT (Low Input V) - VOUT (High Input V)
V
OUT (Nominal Input V)
NDTD
Supply +VIN
Supply -VIN
12µH
Current
Probe
C1
CIN
+VIN
-VIN
Load
+VOUT
-VOUT
Load
C
OUT
COUT
OV
NDTD
COUT
CIN
- VIN
+ VIN
+ VOUT
Supply + VIN
Supply - VIN
- VOUT
OV
C
OUT