Connection Of Crystal Oscillator (Example); Crystal Oscillator Equivalent Circuit; External Crystal Parameters - Hitachi H8/500 Series Hardware Manual

(2) Crystal Oscillator: The external crystal should have the characteristics listed in table 8-1.
XTAL
Table 8-1 External Crystal Parameters
Frequency (MHz)
Rs max (Ω)
C (pF)
0
(3) Note on Board Design: When an external crystal is connected, other signal lines should be
kept away from the crystal circuit to prevent induction from interfering with correct
oscillation. See figure 8-4.
When the board is designed, the crystal and its load capacitors should be placed as close as
possible to the XTAL and EXTAL pins.
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EXTAL
XTAL
Figure 8-2 Connection of Crystal Oscillator (Example)
C
L
Figure 8-3 Crystal Oscillator Equivalent Circuit
2 4 8
500 120 60
7pF max
C
L1
C C =C
L2 L1 L2
L
R
S
C
0
AT-cut parallel resonating crystal
12 16
40 30
136
=10 to 22pF
EXTAL
20
20