h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 606

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 20 Clock Pulse Generator
20.8.2
When designing the board, place the crystal resonator and its load capacitors as close as possible
to the XTAL and EXTAL pins. Other signal lines should be routed away from the oscillator
circuit, as shown in figure 20.9. This is to prevent induction from interfering with correct
oscillation.
Figure 20.10 shows external circuitry recommended to be provided around the PLL circuit. Place
oscillation settling capacitor C1 and resistor R1 close to the PLLCAP pin, and ensure that no other
signal lines cross this line. Separate PLLVss from the other Vcc and Vss lines at the board power
supply source, and be sure to insert bypass capacitors CB close to the pins.
Rev. 2.00 Dec. 05, 2005 Page 568 of 724
REJ09B0200-0200
Note on Board Design
Note: * CB is laminated ceramic.
Figure 20.10 External Circuitry Recommended for PLL Circuit
Figure 20.9 Note on Board Design of Oscillator Circuit
PLLCAP
Avoid
PLLV
V
V
V
CC
SS
CL
SS
C
C
L2
L1
R1 : 3 kΩ
CB : 0.1 µF*
Signal A Signal B
C1 : 470 pF
(Values are preliminary recommended values.)
CB : 0.1 µF
XTAL
EXTAL
This LSI