SH7046 Datasheet, PDF (94/611 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7046 Series

Section 4 Clock Pulse Generator
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
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 PLLVcL and PLLVss circuit against Vcc and Vss circuit from the
board power supply source, and be sure to insert bypass capacitors CB and CPB close to the pins.
R1: 3kΩ
PLLCAP
C1: 470 pF
PLLV_CL
PLLV_SS
CPB = 0.47 µF^*
V_CC
CB = 0.47 µF^*
V_SS
(Values are recommended values.)
Note: * CB and CPB are laminated ceramic type.
Figure 4.6 Recommended External Circuitry Around the PLL
Rev. 4.00 Dec 05, 2005 page 50 of 564
REJ09B0270-0400