Information

CC-E
・All specifications are subject to change without notice.
24
2-1. Ripple noise measurement method
The measured value of the converter noise may differ de-
pending on the measurement method. Measurement should
be conducted in a position close to the output terminal.
When connecting a prove, do not allow a loop to be config-
ured in order not to pick up flux.
As well, note that the spike voltage greatly differs depend-
ing on the ripple voltmeter and frequency band of the oscil-
loscope.
Our noise measurement is conducted by the wiring shown
i
n the figure below and in the frequency band of 50MHz.
+Vin
Vin
Vout
Iin
+Vout
–Vin
–Vout
lout
1.5m
50Ω coaxial cable
50MHz
0.1µF
A
V
10mm 20mm
50MHz
V
A
Ripple
voltmeter
or
End-point: 50Ω+0.1µF
Oscilloscope
Load
2-2. Input ripple noise
This series is equipped with a built-in capacitor for input.
+Vin +Vout
–Vin –Vout
+Vin +Vout
–Vin –Vout
Load Load
When the distance to the input of the converter from the
input power supply is long, attach a capacitor as close as
possible to the input terminal.
+Vin +Vout
–Vin –Vout
Load
When the distance to the input of the converter from the
input power supply is long, the impedance of the input line
can become high, causing high spike noise.
In this case, it is recommended to connect a capacitor as
close as possible to the input of the DC-DC converter.
2-3. Output ripple & noise
To reduce Output ripple & noise, connect a capacitor to
the output of the converter. In addition, reduction can be
enhanced if a π type filter is incorporated as shown in the
figure below. In this case, use of a coil with around 100µH
is recommended.
+Vin +Vout
–Vin –Vout
+Vin +Vout
–Vin –Vout
Load
Load
When the distance to the load from the output of the con-
verter is long, connect the capacitor as close as possible
to the load.
To reduce output spike noise, connect a ceramic capacitor
with around 1µF to the output of the converter.
+Vin +Vout
–Vin –Vout
1
F
Load
2-4. Capacity of external capaci-
tor connected to output
Note that if a capacitor with capacity over the value shown
in the table below is connected to the output, or several
capacitors with low impedance are connected in parallel,
operation of the converter may become unstable.
Model name
Electrostatic capacitance (µF) max.
2. Noise reduction methods
However, by connecting a capacitor with around 10 µ F,
input ripple noise and input return noise can be reduced.