CUI Inc │ SERIES: VWRAT2 │ DESCRIPTION: DC-DC CONVERTER
date 11/01/2012 │ page 4 of 5
APPLICATION NOTES
1. Requirement on Output Load
In order to ensure the product operates efficiently and reliably, make sure the specified range of input voltage is not exceeded and
the minimum output load is not less than 10% load. If the actual load is less than the specifi ed minimum load, the output ripple may
increase sharply while its effi ciency and reliability will reduce greatly. If the actual output power is very small, please add an
appropriate resistor as extra loading.
2. Recommended Circuit
All VWRBT2 converters have been tested according to the following recommended testing circuit before leaving the factory. This
series should be tested under load, never under no load (Figure 1).
+Vo
Vin
Cout
Cout
Figure 1
Cin
0V
DC DC
GND
-Vo
However, the capacitance of the output filter capacitor must be proper. If the capacitance is too big, a startup problem might arise.
For every channel of output, provided the safe and reliable operation is ensured, the greatest capacitance of its filter capacitor sees
(Table 1).
General:
12 V
24, 48 V
100 μF
10 ~ 47 μF
Vout
(Vdc)
Cout
(μF)
Cin
Cout
10 μF / 100 mA
±5
±9
680
470
330
220
Table 1
±12
±15
3. Input Current
While using unstable power source, please ensure the output voltage and ripple voltage do not excced indexes of the converter. The
preceding power source must be able to provide for converter sufficient starting current Ip.
General: Ip ≤1.4*Iin-max
Ip
Input Voltage
Range
Input Voltage (V)
4. No parallel connection or plug and play
5. Solderability
reflow soldering, 240°C max.
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