3 Wiring to Input/Output
Pin Terminals
¡
Basically, SU/SUC series do not need any external capacitor.
However, you can create a
P
-shaped filter circuit by adding a
capacitor Ci near the input pin terminal and reduce reflected input
noise from a converter. Please connect the capacitor as needed.
¡
When you use a capacitor Ci, please use the one with high fre-
quency and good temperature characteristics.
¡
Connecting Ci to the input pin terminal is effective in reducing a
surge voltage when abnormal voltage such as a surge voltage is
generated on the input side. To have a better effect, connect Ci
near the input pin terminal.
¡
If an external filter containing L (inductance) is added to the input
line or a wire from the input source to the DC-DC converter is
long, not only the reflected input noise becomes large, but also
the input voltage a several times higher than the normal level may
be applied or the output of the converter may become unstable.
In such case, connecting Ci to the input pin terminal is recom-
mended.
¡
If you use an aluminum electrolytic capacitor, please pay attention
to its ripple current rating.
*
Please adjust the capacitance in accordance with a degree of the
effect you want to achieve.
¡
If a reverse polarity voltage is applied to the input pin terminal, the
power supply will fail.
If there is a possibility that a reverse polarity voltage is applied,
connect a protection circuit externally as described below.
(a)
(b)
¡
Basically, SU/SUC series do not need any external capacitor.
However, if you want to further reduce the output ripple noise,
connect an electrolytic capacitor or a ceramic capacitor Co to the
output pin terminal as shown below.
*
If you use a ceramic capacitor, keep the capacitance within the
rage between about 0.1 to 10 F.
*
Please adjust the capacitance in light of the effect you want to
achieve.
*
If you need to use an external capacitor whose capacitance ex-
ceeds the range provided in Table 3.2, please contact us.
¡
If the distance between the output and the load is long and there-
fore the noise is created on the load side, connect a capacitor
externally to the load as shown below.
On-board type
Instruction Manual
G-40
SU.SUC
On-board type
Instruction Manual
G-41
SU.SUC
Fig.3.1 Connecting an External Capacitor to the Input Side
Schottky barrier diode generates a power loss
of input current multiplied by forward voltage.
Model
Input Voltage(V)
SU/SUC1R5 SU/SUC3 SU/SUC6 SU/SUC10
5
10 - 100
10 - 220
10 - 470
10 - 470
12
10 - 47
10 - 100
10 - 220
10 - 220
24
10 - 33
10 - 47
10 - 100
10 - 100
48
4.7 - 10
10 - 22
10 - 47
10 - 47
Ci
L
-Vin
+Vin
Input
Table 3.1 Recommended Capacitance of an External Capacitor on the Input Side [ F]
Input
Schottky Barrier Diode
+Vin
-Vin
Fuse
Input
+Vin
-Vin
Schottky Barrier
Diode
Fig.3.2 Connecting a Reverse Voltage Protection Circuit
Co
Co
Co
COM
Load
Load
Load
SUW/SUCW
SUS/SUCS
+Vout
-Vout
-Vout
+Vout
Fig.3.3 Connecting Example of an External Capacitor to the Output Side
Model
Output Voltage(V)
SU/SUC1R5 SU/SUC3 SU/SUC6 SU/SUC10
3.3
1 - 100
1 - 220
1 - 220
1 - 220
5
1 - 100
1 - 220
1 - 220
1 - 220
12
1 - 100
1 - 100
1 - 100
1 - 100
15
1 - 100
1 - 100
1 - 100
1 - 100
Table 3.2 Recommended Capacitance of External Capacitor on the Output Side [ F]
Load
Input
+Vin
-Vin
+Vout
-Vout
