SH7101 datasheet(84/486 Pages) RENESAS

84 / 486 page

4. Clock Pulse Generator

Rev.2.00 Sep. 27, 2007 Page 50 of 448

REJ09B0394-0200

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 ratings will depend

on the resonator and the floating capacitance of the mounting circuit, the ratings 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

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.

When using a crystal resonator, place the crystal resonator 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.

CL2

Signal A Signal B

This LSI

CL1

XTAL

EXTAL

Avoid

Figure 4.5 Cautions for Oscillator Circuit System Board Design

A circuitry shown in figure 4.6 is recommended as an external circuitry around the PLL. Place

oscillation stabilization capacitor C1 close to the PLLCAP pin, and ensure that no other signal

lines cross this line. Separate PLLV

CL, PLLVSS, VCC, and VSS from the board power supply source,

and be sure to insert bypass capacitors CB close to the pins.

SH7101 Datasheet(PDF) 84 Page - Renesas Technology Corp