cui.com
CUI Inc │ SERIES: VASD2-SIP │ DESCRIPTION: DC-DC CONVERTER date 09/04/2012 │ page 4 of 5
1. Requirement on Output Load
In order to ensure the product operates effi ciently and reliably, make sure the specifi ed 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. Overload Protection
Under normal operating conditions, the output circuit of these products has no protection against over-current and short-circuits. The
simplest method is to connect a self-recovery fuse in series at the input end or add a circuit breaker to the circuit.
3. Filtering
In some circuits which are sensitive to noise and ripple, a fi ltering capacitor may be added to the DC/DC output end and input end to
reduce the noise and ripple. However, the capacitance of the output fi lter 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 fi lter capacitor sees the external capacitor table. To get an extremely low ripple, an “LC” fi ltering network may be
connected to the input and output ends of the DC/DC converter, which may produce a more signifi cant fi ltering effect. It should also
be noted that the inductance and the frequency of the “LC” fi ltering network should be staggered with the DC/DC frequency to avoid
mutual interference (Figure 1).
4. Output Voltage Regulation and Over-voltage Protection Circuit
The simplest device for output voltage regulation, over-voltage and over-current protection is a linear voltage regulator with overheat
protection that is connected to the input or output end in series (Figure 2).
5. External Capacitor Table
It is not recommended to connect any external capacitor in the application fi eld with less than 0.5 W output.
Vin
GN D
+Vo
0V
DC
Cin
DC
Co ut
Cout
-Vo
Vin
(Vdc)
Cout
(μF)
Vout
(Vdc)
Cout
(μF)
5 4.7 ±5 4.7
12 2.2 ±9 2.2
24 1 ±12 1
-- -- ±15 0.47
Table 1
Figure 1
APPLICATION NOTES
Figure 2
Vin
GND
0V
+Vo
DC DC
-Vo
REG
RE G
RE G
For more information, please visit the product page.
