HD6475348R Datasheet, PDF (154/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

EXTAL
XTAL
CL1
CL2
CL1 =CL2 =10 to 22pF
Figure 8-2 Connection of Crystal Oscillator (Example)
(2) Crystal Oscillator: The external crystal should have the characteristics listed in table 8-1.
XTAL
CL
L
RS
EXTAL
C0
AT-cut parallel resonating crystal
Figure 8-3 Crystal Oscillator Equivalent Circuit
Table 8-1 (1) External Crystal Parameters
(HD6475368R, HD6475348R, HD6435368R, HD6435348R)
Fig. 8-3
Frequency (MHz) 2
4
8
12
16
20
Rs max (Ω)
500 120 60
40
30
20
C0 (pF)
7pF max
Table 8-1 (2) External Crystal Parameters
(HD6475368S, HD6475348S, HD6435368S, HD6435348S)
Frequency (MHz) 4
8
12
16
20
24
Rs max (Ω)
120 80
60
50
40
40
C0 (pF)
7pF max
Note: Use a fundamental-mode crystal (not an overtone crystal).
(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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