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XC25BS3

Series

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TYPICAL APPLICATION CIRCUITS

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NOTES ON USE

(1) Please insert a by-pass capacitor of 0.1μF.

(2) Rq0 and Rq1 are matching resistors. Their use is recommended in order to counter unwanted radiations.

(3) Please place a by-pass capacitor and matching resistors as close to the IC as possible. The output may not be

locked if the by-pass capacitor is not close enough to the IC. Further, there is a possibility of unwanted radiation

occurrence between the resistor and the IC pin if the matching resistors are not close enough to the IC.

(4)

When selecting GND for the Q1 pin, although the IC will be connected to GND internally, it is also recommended that

the PCB be connected to GND.

(5) When the CE pin is not controlled by external signals, it is recommended that a time constant circuit of R1=1kΩ×

C1=0.1μF be added for stability.

(6) With this IC, output is achieved by dividing and multiplying the reference oscillation by means of the PLL circuit. In

cases where this output is further used as a reference oscillation of another PLL circuit, the final output signal's jitter

may increase, so all necessary precautions should be taken to avoid this.

(7) It is recommended that a low noise power supply, such as a series regulator, be used for the supply voltage. Using

a power supply such as a switching regulator might lead to a larger jitter, which in turn may lead to an inability to lock

due to the ripple of the switching regulator.

(8) As for this IC, synchronization of input and output signal’s edge is not guaranteed though the input frequency

operates to the output frequency multiply.

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Circuit Example

①

Q1 Pin - reference oscillation, PLL output frequency/2, comparative frequency/2

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Q1 Pin - GND