HD64F7047 datasheet(95/764 Pages) RENESAS

95 / 764 page

Rev. 2.00, 09/04, page 55 of 720

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.

CL2

Signal A Signal B

This LSI

CL1

XTAL

EXTAL

Avoid

Figure 4.5 Cautions for Oscillator Circuit System Board Design

HD64F7047 Datasheet(PDF) 95 Page - Renesas Technology Corp