Even when the wiring pattern length is short, a large electric current
flows in the oscillator circuit. Therefore, the oscillator circuit generates
high-level noise. The current flow can be suppressed mainly by installing
the BLM Series (Chip Ferrite Bead) on the oscillator circuit output.
When necessary, a capacitor type EMI filter, such as the NFM21C Series
(Chip Solid "EMIFIL®") is combined.
Current may sometimes be conducted through the GND pattern and flow into
other circuits. Therefore, the oscillator circuit is sometimes connected
to GND via a ferrite bead. In this case, great care must be paid to the
operation because oscillation may become unstable. |
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