SH7047 Datasheet, PDF (95/764 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTMRISC engine Family/SH7000 Series

4.3 Usage Notes
4.3.1 Note on Crystal Resonator
A sufficient evaluation at the user’s site is necessary to use the LSI, by referring the resonator
connection examples shown in this section, because various characteristics related to the crystal
resonator are closely linked to the user’s board design. As the resonator circuit constants will
depend on the resonator and the floating capacitance of the mounting circuit, the component value
should be determined in consultation with the resonator manufacturer. Ensure that a voltage
exceeding the maximum rating is not applied to the oscillator pin.
4.3.2 Notes on Board Design
When using a crystal oscillator, place the crystal oscillator and its load capacitors as close as
possible to the XTAL and EXTAL pins. Do not route any signal lines near the oscillator circuitry
as shown in figure 4.5. Otherwise, correct oscillation can be interfered by induction.
Measures against radiation noise are taken in this LSI. If radiation noise needs to be further
reduced, usage of a multi-layer printed circuit board with ground planes is recommended.
Avoid
C_L2
Signal A Signal B
This LSI
XTAL
EXTAL
C_L1
Figure 4.5 Cautions for Oscillator Circuit System Board Design
Rev. 2.00, 09/04, page 55 of 720