HD64F2638F20J Datasheet, PDF (969/1512 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 22B Clock Pulse Generator
(H8S/2639 Group, H8S/2635 Group)
Crystal Resonator: Figure 22B-3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 18-3. The crystal resonator frequency
should not exceed 5 MHz.
XTAL
C_L
L
R_s
EXTAL
C₀
AT-cut parallel-resonance type
Figure 22B-3 Crystal Resonator Equivalent Circuit
Table 22B-3 Crystal Resonator Parameters
Frequency (MHz)
4
5
RS max (Ω)
120
80
C0 max (pF)
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 22B-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 22B-4 Example of Incorrect Board Design
REJ09B0103-0800 Rev. 8.00
May 28, 2010
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