Hitachi H8S/2646 Hardware Manual page 752

External circuitry such as that shown below is recommended around the PLL.
Note: * CB is laminated ceramic capacitors.
Figure 21-5 Points for Attention when Using PLL Oscillation Circuit
Place oscillation stabilization capacitor C1 and resistor R1 close to the PLLCAP pin, and ensure
that no other signal lines cross this line. Supply the C1 ground from PLLVSS.
Separate PLLVSS from the other VSS lines at the board power supply source, and be sure to insert
bypass capacitors CB close to the pins.
720
R1: 3 kΩ
PLLCAP
PLLV
SS
V
CC
CB: 0.1 µF *
V
SS
C1: 470 pF
(Values are preliminary recommended values.)