TDK-Lambda PH-A280 Series Instruction Manual - Tdk-Lambda
5
5
TDK-Lambda
PH-A280 Series
INSTRUCTION MANUAL
C2:
For stable operation of the power supply, add ceramic capacitor of 470 pF or more with high voltage rating
between -Vin terminal and baseplate as close as possible to the terminals. However, if the external FG
capacitor between Output terminal and Baseplate is not used, capacitance value should be less than 4200pF.
If external FG capacitor is used, select capacitance taking into consideration clause 6-21. Withstand Voltage
"Withstand Voltage including external components."
Moreover, take note that noise might become large or
stable operation might not be attained due to wiring method of printed circuit board, etc. In such case,
countermeasure is possible by increasing C2 capacitance value or adding common mode choke coil before
C1.
Addition of common mode choke coil is recommended to improve EMI.
When using multiple power
supplies, add choke to each power supply input.
Recommended Withstand Voltage : more than 2.5kVac
C3 :
Add ceramic capacitor as close as possible to the terminals of the power supply in order to reduce output
spike noise voltage. (Recommended
: 2.2
μF)
Take note that, PCB wiring design might influence output spike noise.
C4:
For stable operation, connect a electrolytic capacitor between +V and –V.
Take note that output ripple could be affected by electrolytic capacitor, equivalent impedance and
inductance characteristics of wiring.
For cases of abrupt changes in load current or input voltage, increasing capacitance value of the external
capacitors could reduce the voltage fluctuation.
Model and C4 recommended values of external output capacitor are below.
Table5-1 C4 : Recommended Values of External Output Capacitor
Note) 1. Use low impedance electrolytic capacitor with excellent temperature characteristics.
(Nippon Chemi-Con LXY Series or equivalent)
2. Use more than
three recommended capacitor above in parallel when ambient temperature becomes
lower than –20 ºC to reduce ESR.
3.
Take note of the allowable ripple current of the capacitor to be used.
Especially, for sudden load
current change, verify actual ripple current and make sure that allowable maximum ripple
current is not be exceeded.