HD64F2636F20 Datasheet, PDF (957/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Section 22A Clock Pulse Generator
(H8S/2636 Group, H8S/2638 Group, H8S/2630 Group)
Crystal Resonator: Figure 22A-3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 22A-3. The crystal resonator frequency
should not exceed 20 MHz.
XTAL
C_L
L
R_s
EXTAL
C₀
AT-cut parallel-resonance type
Figure 22A-3 Crystal Resonator Equivalent Circuit
Table 22A-3 Crystal Resonator Parameters
Frequency (MHz)
RS max (Ω)
C0 max (pF)
4
8
12
16
20
120
80
60
50
40
7
7
7
7
7
Note on Board Design: When a crystal resonator is connected, the following points should be
noted:
Other signal lines should be routed away from the oscillator circuit to prevent induction from
interfering with correct oscillation. See figure 22A-4.
When designing the board, place the crystal resonator and its load capacitors as close as possible
to the XTAL and EXTAL pins.
Avoid
C_L2
Signal A Signal B
Chip
XTAL
EXTAL
C_L1
Figure 22A-4 Example of Incorrect Board Design
REJ09B0103-0800 Rev. 8.00
May 28, 2010
Page 907 of 1458