Application Notes
Correspond to Analog Ciruits, Ultra Low Noise 8mVp-p
Small Size, Long-Life, Isolated Type DC-DC Converter
1.5 Watt VY-L Series
<EMI Evaluation Test>
VY-L series is most suitable for analog and digital circuit which has
achieved ultra low noise.
The test data below is an EMI test data which proves that it passed the
FCC Class B (3m) standards
<Method to decrease the noise level>
Usually for VY-L series, output capacitors are not required. However, in order to
obtain lower noise level by taking advantage of the performance of the converte
make sure to design the printed board with special attention to the following item
The input/ output noise can be lowered.
1. Use low impedance capacitor with good high frequency characteristic.
2. Shorten the lead of each capacitor as much as possible, and make it low lead
inductance.
3. Make the wiring loop space between the (+) and (-) of both input and output p
side as small as possible. The possibilities of leakage inductance can be
decreased.
4. Design the print pattern of the main circuit as thick and short as possible.
5. The pin side of VY-L series do not have a metallic shield, so if the pin side of
printed circuit board is ground plane, the radiation noise will be shut off and
noise can be lowered.
RADIATED EMISSION FCC Class B <3m>
Model Name
Serial No.
Power Supply
Load
DET. Mode
Limits
Band Number
Antenna Mode
Test Equip.
VY05-12W06L
ES1
+5V
±12V 65mA
Peak
30MHz - 1000KHz
3 Meas Mode : D
Horizontal
TR4172, TR14307
Figure 9
Lowering the noise level of VY-SL series
C1=33µF C2=4.7µF C3=0.47µF (Electrolytic or multilayer ceramic)
Figure 7
Model Name
Serial No.
Power Supply
Load
DET. Mode
Limits
Band Number
Antenna Mode
Test Equip.
VY05-12W06L
ES1
+5V
±12V 65mA
Peak
30MHz- 1000KHz
3 Meas Mode : D
Vertical
TR4172, TR14307
Figure 10
Lowering the noise level of VY-WL series
C1=33µF C2, C3=4.7µF C4, C5=0.47µF (Electrolytic or multilayer ceramic)
Figure 11
Output noise of VY-05-12W06L (measured by figure 11 circuit)
+12V65mA
3.8mVp-p
10mV/div
100%
Figure
* The above test has been performed at the following site.
Testing institution: Shindengen Electric Manufacturing Co., Ltd. EMI Laboratory
Field intensity measuring set: R-205
Power supply terminal interfering voltage measuring set: C-205
2µs/div
-12V65mA
4.2mVp-p
10mV/div
2µs/div
0%
10mV
2μs
Kaga Electronics/Volgen
DC-DC CONVERTERS
Figure 12
www.volgen.com
VOLGEN [ VOLGEN KAGA ELECTRONICS INC. ]
