■
The TUNS1200 doesn't have noise filter internally
Install an external noise filter and capacitor (CY) to reduce conducted noise and stabilize
the operation of the power supply.
■
Noise filters should be properly designed when the unit must conform to the EMI/EMS
standards or when surge voltage may be applied to the unit.
■
Install the primary Y capacitor (CY1) as close as possible to the input pins (within 50 mm
from the pins).
A capacitance of 470 pF or more is required.
■
When the total capacitance of CYs exceeds 8,800 pF, input-output withstanding voltage
may be dropped. In this case, either reduce the capacitance of Y capacitors or install a
grounding capacitor between output and FG.
■
Use capacitors that comply with safety standards as CY.
■
Install an external capacitor, Co, bVOUT and -VOUT pins for stable operation
of the power supply. Recommended capacitance of Co is shown in Table 2.3.
■
Use low impedance electrolytic capacitors with excellent temperature characteristics.
■
When Using at ambient temperatures below 0 ºC, the output ripple voltage increases due
to the characteristics of equivalent series resistor (ESR). In this case, connect three
capacitors, Co, of recommended capacitance in parallel connection.
■
Specifications, output ripple and ripple noise as evaluation data values are measured
according to Fig.2.3.
Table 2.3
Recommended
capacitance
Co
Fig.2.3
Measuring
environment
2.4 Y Capacitors and noise filters: CY, CX, L11, L12
2.5 Output capacitors: Co, C40
A-4
Output Voltage
12V
28V
48V
Tc = 0
～
100
℃
470u
Ｆ
×3parallel
2,200u
Ｆ
1,000u
Ｆ
470u
Ｆ
Tc = -40
～
100
℃
2,200u
Ｆ
×3parallel
1,000u
Ｆ
×3parallel
Applications Manual
TUNS1200
R=50Ω
C=0.01uF
Load
1.5m 50Ω
Coaxial Cable
C40:
12V 10μF
28V 4.7μF
48V 2.2μF
+VOUT
-VOUT
-S
+S
0
0
0
0
Co
+
C40
50mm
Oscilloscope
BW:100MHz
R
C
C40=1.0uF
