CUI Inc │ SERIES: VWRBS2 │ DESCRIPTION: DC-DC CONVERTER
date 09/10/2012 │ page 4 of 5
APPLICATION NOTES
1. CTRL Terminal
When open or high impedance,the converter work well; When this pin is ‘high’; the converter shutdown; It should be note that the
input current (Ic) should between 5-10mA, exceeding the maximum 20mA will cause permanence damage to the converter. The value
of R Can be derived as follows :
VC-VD-1.0
R=
IC
2. Recommended Circuit
If you want to further decrease the input/output ripple, an “LC” filtering network may be connected to the input and output ends of
the DC/DC converter, see (Figure 1).
D1 Ic
R
Vc
3
Lin
2
1
6
8
Figure 1
Vi n
+Vo
0V
Cin
Co ut
Cs
GND
7
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).
Vin
(Vdc)
Cout
(μF)
5, 12 V
24, 48 V
100 μF
10 ~ 22 μF
Cin
3.3
5
2,200
1,000
820
Lin
Cout
Lout
Cs
--
--
--
--
4.7 ~ 120 μH
100 μF (typ)
2.2 ~ 10 μH
10 ~ 22 μF
Table 1
9
12
15
24
680
560
470
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 Ipy.
General: Ip ≤1.4*Iin-max
Ip
Input Voltage
Range
Input Voltage (V)
4. No parallel connection or plug and play
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