HD64F3048F16 Datasheet, PDF (660/903 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 19 Clock Pulse Generator
Crystal Resonator
Figure 19.3 shows an equivalent circuit of the crystal resonator. The crystal resonator should have
the characteristics listed in table 19.3.
XTAL
C_L
L
Rs
EXTAL
C₀
AT-cut parallel-resonance type
Figure 19.3 Crystal Resonator Equivalent Circuit
Table 19.3 Crystal Resonator Parameters
Frequency (MHz)
2
4
8
10
12
16
18
20
25
Rs max (Ω)
500 120 80
70
60
50
40
40
40
C max (pF)
7
0
Use a crystal resonator with a frequency equal to the system clock frequency (φ).
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 19.4.
When the board is designed, the crystal resonator and its load capacitors should be placed as close
as possible to the XTAL and EXTAL pins.
Rev. 3.00 Sep 27, 2006 page 632 of 872
REJ09B0325-0300