CC3-4805SR-E Datasheet, PDF (24/25 Pages) TDK Electronics – Insulation type DC-DC converter

CC-E
24
2. Noise reduction methods
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
in the figure below and in the frequency band of 50MHz.
10mm
20mm
Vin _V
Iin
A
+Vin
–Vin
+Vout
–Vout
Vout
V _0.1µF
A
lout
50Ω coaxial cable
1.5m
0TDJMMPTDPQF _PS
50MHz
&OEQPJOU
⒋Ÿ'
3JQQMF
WPMUNFUFS
50MHz
2-2. Input ripple noise
This series is equipped with a built-in capacitor for input.
Therefore, this series can operate without an external
capacitor connected to input. However, by connecting a
capacitor, input ripple noise and input return noise can be
reduced.
In addition, it is more effective if a π type filter is installed
as shown in the figure below.
+Vin
+Vout
+Vin
+Vout
–Vin
–Vout
–Vin
–Vout
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
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
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
–Vin
+Vout
1MF
–Vout
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.
–Vin
–Vout
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.
・All specifications are subject to change without notice.