4.2 System Clock Generator
Clock pulses can be supplied to the system clock divider either by connecting a crystal or ceramic
oscillator, or by providing external clock input.
1.
Connecting a crystal oscillator
Figure 4-2 shows a typical method of connecting a crystal oscillator.
Figure 4-2 Typical Connection to Crystal Oscillator
Figure 4-3 shows the equivalent circuit of a crystal oscillator. An oscillator having the
characteristics given in table 4-1 should be used.
Figure 4-3 Equivalent Circuit of Crystal Oscillator
Table 4-1 Crystal Oscillator Parameters
Frequency (MHz)
1
4.193
R
S
max (
Ω
)
40
100
C
0
(pF)
3.5 pF max
16 pF
C
S
C
0
R
S
OSC
1
OSC
2
L
S
1
2
C
1
C
2
OSC
OSC
R = 1 M
±
20%
f
Ω
R
f
Frequency
1.0 MHz
4.0 MHz
Crystal
oscillator
NDK
NDK
C
1
, C
2
Recommendation
value
27 pF
±
10%
12 pF
±
20%
Products Name
NR-18 (NDK45)
NR-18 (NDK03)
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