SH7041A datasheet(123/923 Pages) RENESAS

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External circuitry such as that shown in figure 4.6 is recommended around the PLL.

PLLCAP

PLLVCC

PLLVSS

VCC

VSS

R1: 3 k

Ω

C1: 470 pF

Rp: 200

Ω

CPB: 0.1

µF*

CB: 0.1

µF*

Note: * CB and CPB are laminated ceramic capacitors

(Recommended values)

Figure 4.6 Cautions for Use of PLL Oscillator Circuit

Place oscillation stabilization capacitor C1 and resistor R1 near the PLLCAP pin, and ensure that

these lines do not cross any other signal lines. Supply the C1 ground from PLLV

SS.

Also, separate PLLV

CC and PLLVSS, and the other VCC and VSS pins, from the board power supply

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

If V

CC and PLLVCC are both 3.3 V ± 0.3 V, it is recommended that Rp be set to 0 Ω.

4.5.3

Spread Spectrum Clock Generator Usage Notes

The following points should be borne in mind when using a spread spectrum clock generator as an

external oscillator in order to reduce radiation noise.

• Set the center frequency and the spread amplitude such that the internal clock does not exceed

the maximum frequency during spread spectrum operation.

• Using a spread spectrum clock generator may trigger the oscillator halt function described in

section 4.4. If the system configuration is such that this function will cause problems, a spread

spectrum clock generator should not be used.

SH7041A Datasheet(PDF) 123 Page - Renesas Technology Corp