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5.3
L1 (6.3mH); L2 (6.3mH) Common Mode Choke
Add recommend common mode chokes to reduce EMI noise. When using multiple PFH500 series modules in parallel, it is
important to provide EMI filtering (including X caps, Y caps, and common mode chokes) for each PFH500 module.
5.4
C2 (3300pF); C3 (3300pF) Ceramic Capacitor or Class Y Capacitor
Y-capacitors are used to protect against common mode noise. Be sure to consider leakage current requirement of your
equipment or instrument when selecting these capacitors.
5.5
R1 (470 k, 2W); R3 (470 k, 2W); R4 (470 k, 2W)
Connect bleeder resistor, R1, across the AC input terminals and connect R3 and R4 in series across C9 and C10 as shown
in Fig. 5-1.
5.6
C6 (470pF); C7 (470pF) Ceramic Capacitor or Class Y Capacitor
Add these Y capacitors as an EMI common-mode noise countermeasure. Be sure to consider leakage current of your
equipment when selecting these capacitors.
Connect C6 as close as possible to AC(L) terminal. Connect C7 as close as possible to AC(N) terminal.
5.7
Electrolytic Bulk Capacitors: C9 (470µF); C10 (470µF)
Recommended Voltage Rating: 450VDC (105 ºC rated capacitor)
Recommended Capacitance: 2 x 470µF
Notes:
1.
Connecting capacitors with a higher capacitance value than mentioned could result in the PFH Series power
module being damaged. Consult TDK-Lambda for higher bulk capacitance requirement.
2.
When using the PFH power modules below -20℃ ambient temperature, both AC ripple of VBUS and output ripple
voltage might be affected by ESR characteristics of the bulk capacitors. Therefore, be sure to verify characteristics by
actual evaluation.
3.
Bleeder resistors, R3 & R4 (470KΩ / 2W), are required to be connected across C9 or C10 to discharge the bulk
capacitor voltage to a safe level after power off. Refer to Figure 5-1.
4.
Do not connect any external load to the Bulk Capacitors or the module may be damaged.
REV 2.8 (March 30, 2020)
TDK-Lambda
PFH500-SERIES
INSTRUCTION MANUAL
11
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