VFSD1-S3.3-S3.3-SIP_12 Datasheet, PDF (4/5 Pages) CUI INC – DC-DC CONVERTER

CUI Inc │ SERIES: VFSD1-SIP Series │ DESCRIPTION: DC-DC CONVERTER
date 01/27/2012 │ page 4 of 5
APPLICATION NOTES
1. Requirement on output load
To ensure this module can operate efficiently and reliably, During operation, the minimum output load could not be less than 10% of
the full load. If the actual output power is very small, please connect a resistor with proper resistance at the output end in parallel to
increase the load, or use our company’s products with a lower rated output power (E_S-W25&F_S-W25).
2. Overload Protection
Under normal operating conditions, the output circuit of these products has no protection against overload. 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. Recommended testing and application 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). It should also be noted that the inductance and the frequency of the “LC” filtering network
should be staggered with the DC/DC frequency to avoid mutual interference. 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 recommended capacitance of its filter capacitor sees (Table 1).
Figure 1
External Capacitor Table (Table 1)
Vin
(Vdc)
3.3, 5
12
15
24
Cin
(μF)
4.7
2.2
2.2
1.0
Single Vout
(Vdc)
3.3, 5
9.0
12
15, 24
Cout
(μF)
10
4.7
2.2
1.0
Dual Vout
(Vdc)
±5
±9
±12
±15
Cout
(μF)
4.7
2.2
1.0
0.47
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).
Figure 2
5. No parallel connection or plug and play
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