MPC555 / MPC556
CLOCK AND BOARD GUIDELINES
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
E-6
Figure E-5 Bypass Capacitors Example (Alternative)
E.3.3 PLL External Components
VDDSYN and VSSSYN are the PLL dedicated power supplies. These supplies must
be used only for the PLL and isolated from all other noisy signals in the board.
VDDSYN could be isolated with RC filter (see
), or LC filter. The maximum
noise allowed on VDDSYN, and VSSSYN is 50 mV with typical cut-off frequency of
500 Hz.
Figure E-6 RC Filter Example
KAPWR
BOARD
MPC555
/
MPC556
VSSSYN
KAP 3 V
100 nF
1
µ
F
VDDSYN
BOARD
MPC555
/
MPC556
VSSSYN
Keyed
100 nF
10
Ω
Vcc 3 V
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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