SH7050 Datasheet, PDF (77/841 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH RISC engine Family/

Section 4 Clock Pulse Generator (CPG)
Crystal Oscillator: Figure 4.3 shows an equivalent circuit of the crystal oscillator. Use a crystal
oscillator with the characteristics listed in table 4.4.
EXTAL
L
C_L
Rs
C₀
XTAL
Figure 4.3 Crystal Oscillator Equivalent Circuit
Table 4.4 Crystal Oscillator Parameters (Recommended Values)
Parameter
Rs max (Ω)
C0 max (pF)
Frequency (MHz)
4
8
10
120
80
60
7
7
7
4.3.2 External Clock Input Method
An example of external clock input connection is shown in figure 4.4. When the external clock is
stopped in standby mode, ensure that it goes high.
When the XTAL pin is placed in the open state, the parasitic capacitance should be 10 pF or less.
Even when an external clock is input, provide for a wait of at least the oscillation settling time
when powering on or exiting standby mode in order to secure the PLL settling time.
Open
XTAL
External clock input
EXTAL
Figure 4.4 External Clock Input Method (Example)
Rev. 5.00 Jan 06, 2006 page 57 of 818
REJ09B0273-0500