Datasheet

Section 23B Clock Pulse Generator
(H8S/2633R, H8S/2695)
Page 1010 of 1434 R01UH0166EJ0600 Rev. 6.00
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
Table 23B.2 Damping Resistance Value
Frequency (MHz) 2 4 8 12 16 20 25
R
d
(Ω) 1 k 500 200 0 0 0 0
Crystal Resonator: Figure 23B.3 shows the equivalent circuit of the crystal resonator. Use a
crystal resonator that has the characteristics shown in table 23B.3.
XTAL
C
L
AT-cut parallel-resonance type
EXTAL
C
0
LR
s
Figure 23B.3 Crystal Resonator Equivalent Circuit
Table 23B.3 Crystal Resonator Parameters
Frequency (MHz) 2 4 8 12 16 20 25
R
S
max (Ω) 500 120 80 60 50 40 40
C
0
max (pF) 7 7 7 7 7 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 23B.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
H8S/2633R Group
XTAL
EXTAL
Avoid
Figure 23B.4 Example of Incorrect Board Design