Renesas H8S/2318 series, Hardware Manual

Page: 803 / 1121

Rev. 5.00, 12/03, page 773 of 1088
XTAL
C
L
AT-cut parallel-resonance type
EXTAL
C
0
L R
s
Figure 18-3 Crystal Resonator Equivalent Circuit
Table 18-3 Crystal Resonator Characteristics
Frequency (MHz) 2 4 8 12 16 20 25
R
S
max (
Ω Ω Ω Ω
) 500 120 80 60 50 40 40
C
0
max (pF) 7 7 7 7 7 7 7
Notes 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 18-4.
When designing the board, place the crystal resonator and its load capacitors as close as possible
to the XTAL and EXTAL pins.
C
L2
Signal A Signal B
C
L1
Chip
XTAL
EXTAL
Avoid
Figure 18-4 Example of Incorrect Board Design